Click on image for larger annotated version
Recently named after the 12th century Chinese artist, Xiao Zhao crater on the central left side of this image is small in comparison with many other craters on Mercury and even with many other craters in this scene. However, Xiao Zhao's long bright rays make it a readily visible feature. The fresh, bright rays, which were created by material ejected outward during the impact event that formed the crater, indicate that Xiao Zhao is a relatively young crater on Mercury's surface.
Date Acquired: January 14, 2008
Image Mission Elapsed Time (MET): 108828473
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 500 meter/pixel (0.3 miles/pixel)
Scale: Xiao Zhao crater is 23 kilometers (14 miles) in diameter
Spacecraft Altitude: 19,760 kilometers (12,280 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10668: Xiao Zhao's Rays Paint Mercury's Surface sur le site de la NASA.
This is the last image MDIS took of Mercury during MESSENGER’s first flyby of the planet before the spacecraft turned its antennas to begin transmitting the flyby data to Earth. Even at this great distance, the giant Caloris basin can be identified as a brighter circular region in the upper right of the planet. Two weeks from today, on October 6, 2008, MESSENGER will fly by Mercury again. The geometry of the second Mercury flyby is different from the first encounter, in that the point of closest approach will be nearly on the opposite side of the planet. As a result, MESSENGER will view about 30% of Mercury’s surface previously never before seen by spacecraft. This new territory is located just to the left of the day/night terminator in this image.
During the second encounter, 1287 MDIS images are planned. MESSENGER’s Magnetometer will also be making the first magnetic field measurements over the western hemisphere of the planet. The observations of Mercury’s tenuous atmosphere and neutral sodium tail will be more extensive than during the first flyby, and the angular resolution of the plasma spectrometer has been improved since the first flyby as a result of new software. The laser altimetry profile during the second flyby will be over areas that have been imaged by Mariner 10 or MESSENGER, which will permit the correlation of topographic characteristics and imaged features such as craters and faults to a degree never before possible.
Date Acquired: January 15, 2008
Image Mission Elapsed Time (MET): 108899804
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 22 kilometers/pixel (14 miles/pixel)
Scale: Mercury’s diameter is 4880 kilometers (3030 miles)
Spacecraft Altitude: 440,000 kilometers (270,000 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11220: MESSENGER and Mercury - Soon to Meet Again! sur le site de la NASA.
Click on image for
larger annotated version
MESSENGER snapped this image of Mercury’s horizon about 56 minutes before the spacecraft’s closest pass by the planet. The distinctive peak-ring basin Dürer (named from Mariner 10 photos for the German artist Albrecht Dürer) is visible. The smaller crater Mickiewicz (named for the Polish poet Adam Mickiewicz) can also be seen, with a smaller central peak-ring structure in the middle of its crater floor. Craters form ring structures during the impact process that creates the crater, and the number and characteristics of the rings depend on the crater’s size. Raditladi, imaged for the first time by MESSENGER and recently named, also shows a pronounced peak-ring structure.
Date Acquired: January 14, 2008
Image Mission Elapsed Time (MET): 108821505
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Scale: Dürer crater is about 190 kilometers (120 miles) in diameter
Spacecraft Altitude: 18,300 kilometers (11,400 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10936: Peak Rings on Mercury sur le site de la NASA.
This NAC image shows a bright crater with an extensive system of impact ejecta rays; the crater is also clearly visible on the southern portion of Mercury near the limb of the planet in the departure full-planet image (PIA11245). This impact crater and its associated system of rays were originally detected in 1969 as a “bright feature” in radar images at 12.5-centimeter wavelength obtained by the Goldstone Observatory in California. Subsequently, about a decade ago, radar images acquired by the Arecibo Observatory in Puerto Rico clearly revealed this feature to be a crater with a fresh system of rays of rough material radiating outward from it. This feature has been referred to simply as feature “A.” MESSENGER’s recent Mercury flyby provided the first spacecraft images of feature “A,” enabling this relatively young crater with its impressive set of rays to be seen here in close-up detail.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131773947
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 530 meters/pixel (0.33 miles/pixel)
Scale: The bright rayed crater is approximately 80 kilometers (50 miles) in diameter
Spacecraft Altitude: 20,600 kilometers (12,800 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11371: “A” Spectacular Rayed Crater sur le site de la NASA.
MESSENGER's Narrow Angle Camera (NAC) on the Mercury Dual Imaging System (MDIS) acquired this view of Mercury's surface illuminated obliquely from the right by the Sun. The unnamed crater (52 kilometers, or 31 miles, in diameter) in the center of the image displays a telephone-shaped collapse feature on its floor. Such a collapse feature could reflect past volcanic activity at and just below the surface of this particular crater. MESSENGER team members are examining closely the more than 1200 images returned from this flyby for other surface features that can provide clues to the geological history of the innermost planet.
The crater is located in the southern hemisphere of Mercury, on the side that was not viewed by Mariner 10 during any of its three flybys (1974-1975). This scene was imaged while MESSENGER was departing from Mercury from a distance of about 19,300 kilometers (12,000 miles), about 1 hour after the spacecraft's closest encounter with Mercury. The image is of a region approximately 236 kilometers (147 miles) across, and craters as small as 1.6 kilometers (1 mile) can be seen.
Mission Elapsed Time (MET) of image: 108828208
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10186: MESSENGER Views an Intriguing Crater sur le site de la NASA.
As MESSENGER approached Mercury, the NAC acquired images to create a mosaic of the entire planet. The mosaic shown here was created from about half of those images and is shown in an orthographic projection. This view is in contrast to the cylindrical equidistant map mosaic previously released. For this mosaic, an orthographic projection was used to create a view that has the perspective that one would see from deep space. Over three decades earlier, Mariner 10 viewed this portion of Mercury’s surface, and the craters that were named on the basis of those images are labeled on this mosaic. The MESSENGER images of this same territory are allowing scientists to study Mercury’s surface under different illumination conditions, and these complementary views provide new insight into the nature of the geologic features on Mercury.
Date Acquired: January 14, 2008
Instrument:Mosaic created with images taken by the Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 1.5 kilometers/pixel (0.93 miles/pixel)
Scale: This mosaic shows Mercury from the equator nearly to the northern pole, a distance of about one Mercury radius (2440 kilometers, 1516 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10938: Mercury’s Craters from a New Perspective sur le site de la NASA.
Click on the image for movie of
MESSENGER Departs Mercury
As MESSENGER completed its successful flyby of Mercury, the Narrow Angle Camera (NAC), part of the Mercury Dual Imaging System (MDIS), took images of the planet as the spacecraft departed. Beginning on January 14, 2008, about 100 minutes after MESSENGER's closest pass by the surface of Mercury, until January 15, 2008, about 19 hours later, the NAC acquired one image every four minutes. In total, 288 images were snapped during this time and were compiled sequentially to produce this movie. At the start of the movie, MESSENGER is about 34,000 kilometers (about 21,000 miles) from Mercury, and the first image has a field of view of about 950 kilometers (about 590 miles) in width. At the end of the movie, the MESSENGER spacecraft is a distance of about 440,000 kilometers (270,000 miles) from Mercury.
This movie shows the end of MESSENGER's first encounter with Mercury. MESSENGER will fly by Mercury two additional times during the mission, in October 2008 and September 2009. In March 2011, MESSENGER will enter into an orbit around Mercury and begin a year-long scientific investigation of the planet.
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10197: MESSENGER Departs Mercury sur le site de la NASA.
Numerous examples of craters that have been deformed and shortened by younger faults have been identified on images returned from MESSENGER’s first flyby of Mercury. In three cases shown here (arrows), portions of the floor and rim of a crater were buried when a large block of crust was thrust over the crater during the formation of a prominent fault scarp or cliff. By comparing the estimated size and shape of the original, undeformed crater with the crater’s current geometry, scientists can infer the amount of movement between the two crustal blocks on either side of the fault. This figure was recently published in Science magazine. For each of the three examples of deformed and shortened craters shown here, movement on the faults buried at least a kilometer of the original crater. A: 17-kilometer (11-mile) diameter crater (arrows) shortened by Beagle Rupes. B: 5-kilometer (3-mile) diameter crater deformed near the rim of an older, larger crater, shown enlarged in the box on the lower left. C: 11-kilometer (7-mile) diameter crater (arrows) shortened by a northwest-southeast-trending fault scarp.
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10984: Craters Deformed and Shortened sur le site de la NASA.
This pair of images illustrates the dramatic effect that illumination and viewing geometry (i.e., the angle at which Sunlight strikes the surface, and the angle from which the spacecraft views the surface) has on the appearance of terrain on Mercury. The image on the right is a frame captured by MESSENGER’s NAC as the spacecraft was departing the planet after its second Mercury flyby. On the left is a portion of a mosaic made from Mariner 10 clear-filter images, obtained by that mission in 1974. The yellow arrows point to the 90-kilometer- (56-mile-) diameter crater Asvaghosa (named for the first century AD Indian philosopher and poet), and the purple arrows indicate a smaller crater to the southwest. A bright ray, prominently visible in the high-Sun MESSENGER frame, crosses both craters. The stripe of high-reflectance material may have originated at Kuiper crater (to the southwest PIA11355) or may come from a newly imaged crater to the northeast (PIA11356) that has an extensive ray system. This ray and others seen in the NAC image were mostly invisible to Mariner 10, because low-Sun illumination emphasizes topography instead of differences in reflectance. As another example, the curving scarp (cliff) named Santa Maria Rupes (white arrows in the left image) is visible in the Mariner 10 image by the shadow it casts, but this rupes disappears in the MESSENGER image when the Sun is high overhead. Images collected under both high- and low-Sun conditions are needed for geologists to develop a complete understanding of the features on a planetary surface. For another example of the appearance of Mercury under contrasting lighting conditions, see the October 11 featured image (PIA11361).
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131774145
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 550 meters/pixel (0.34 miles/pixel)
Scale: Asvaghosa crater is 90 kilometers in diameter (56 miles)
Spacecraft Altitude: 21,000 kilometers (13,000 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11367: Changing Stripes sur le site de la NASA.
Click on image for larger annotated version
Earlier today, at 4:40 am EDT, MESSENGER passed a mere 200 kilometers (124 miles) above Mercury’s surface for its closest approach to the planet during the mission’s second Mercury flyby. Now, the spacecraft is speeding away from Mercury, acquiring science observations as it goes. The planned flyby science observations continue for about 20 hours following closest approach, and only after the completion of all science observations will the data be transmitted to Earth. For the moment, the MESSENGER team waits.
However, scientists on the team are already eagerly exploring the optical navigation images acquired just prior to the flyby. Shown here is a NAC image from the eighth and final optical navigation image set, taken about 14.5 hours before the flyby’s closest approach; Mercury appears as a thin sunlit crescent. Though much of Mercury is in darkness in this image, the visible portion had never been seen by spacecraft before. This portion of Mercury’s surface was not viewed during any of Mariner 10’s three flybys or during MESSENGER’s first flyby earlier this year. The newly imaged terrain shows a wide range of geologic features. Near the northern limb of the planet, extensive smooth plains, possibly volcanic in origin, are identified. A nearby crater is the brightest feature visible in the image, suggesting a relatively young age. This bright crater is consistent with a bright feature seen in Earth-based telescopic observations. In the southern region, a large basin is seen with a smooth floor, likely also a product of volcanism. A large scarp that appears to cut through this basin may have formed as Mercury cooled and contracted.
Many more features in this image have also captured the MESSENGER team’s interest. Hints of ridges and scarps are barely discernable near the terminator, and a crater near the limb suggests the presence of intriguing dark and light materials. With the comparatively low resolution of this image, any insight that can be gained into these areas is limited. But that limitation will not last long. After all, this is just an optical navigation image. Early this morning, MESSENGER acquired a NAC mosaic of this same area with a resolution ten times higher! As the first images from the flyby begin to arrive early Tuesday morning, the MESSENGER team will see these features in great detail as well as other large expanses of Mercury not yet viewed by spacecraft.
Date Acquired: October 5, 2008
Image Mission Elapsed Time (MET): 131717310
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 7 kilometers/pixel (4 miles/pixel)
Scale: Mercury’s diameter is 4880 kilometers (3030 miles)
Spacecraft Altitude: 270,000 kilometers (170,000 miles)
Sub-spacecraft Latitude and Longitude: 1.6°N, 129.8°E
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11244: Exploring Mercury’s Newly Seen Surface and Waiting for More sur le site de la NASA.
As the MESSENGER spacecraft approached Mercury on January 14, 2008, the Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS) snapped this image of the crater Matisse. Named for the French artist Henri Matisse, Matisse crater was imaged during the Mariner 10 mission and is about 210 kilometers (130 miles) in diameter. Matisse crater is in the southern hemisphere and can be seen near the terminator of the planet (the line between the sunlit, day side and the dark, night side) in both the color (see PIA10189) and single-filter, black-and-white single (see PIA10179) images released previously that show an overview of the entire incoming side of Mercury.
On Mercury, craters are named for people, now deceased, who have made contributions to the humanities, such as artists, musicians, painters, and authors. The International Astronomical Union (IAU) oversees the official process of naming new craters and other new features discovered on bodies throughout the solar system. Scientists studying and mapping unnamed features can suggest names for consideration by the IAU. The 1213 images taken by MESSENGER during its first flyby encounter with Mercury cover a large region of Mercury's surface previously unseen by spacecraft, revealing many new craters and other features that will need to be named.
Mission Elapsed Time (MET) of image: 108821375
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10190: MESSENGER Dances by Matisse sur le site de la NASA.
Click on image for larger annotated version
By examining the characteristics of craters and their relationships to each other, geologists are able to unravel the history of Mercury. This image shows a northern portion of Mercury’s surface, looking at the terminator (the transition from the sunlit dayside to the dark night side of the planet). The crater in the lower left, Vyasa, has a rough floor, with other craters superimposed onto it, indicating that this crater is relatively old. In contrast, the neighboring crater, Stravinsky, has a much smoother floor and appears to overlap the rim of Vyasa, suggesting that this crater is relatively younger. These craters appear to be aptly named to support this relative age relationship; Vyasa is named for the ancient Indian poet from about 1500 BC, while Igor Stravinsky was a 20th century Russian-born composer. The nearby crater Rubens, named for the 17th century Flemish painter, may indeed represent an event intermediate in time between Vyasa and Stravinsky.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131774338
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 580 meters/pixel (0.36 miles/pixel)
Scale: Stravinsky crater is 190 kilometers in diameter (120 miles)
Spacecraft Altitude: 23,000 kilometers (14,000 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11360: Mercury Through Time sur le site de la NASA.
The gallery of images acquired by the MESSENGER mission is filled with both Wide Angle Camera (WAC) and Narrow Angle Camera (NAC) images. The two MDIS cameras, though they cannot operate simultaneously, are used together in a complementary fashion. The NAC acquires images at a factor of seven higher spatial resolution than the WAC, while the WAC is equipped with 11 narrow-band color filters; thus, the NAC can see features in much more detail, but the WAC can see them in color. This NAC image was taken just 22 seconds prior to the beginning of a set of WAC images used to create full-planet color images of Mercury (PIA11364). The higher resolution of the NAC is evident by comparing these narrow and wide views of the same scene, taken back-to-back. In this NAC image, bright rays from nearby Kuiper crater (PIA11355) enter the frame from the bottom of the image.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131775206
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 700 meters/pixel (0.43 miles/pixel)
Scale: This image is about 710 kilometers wide (440 miles)
Spacecraft Altitude: 27,000 kilometers (17,000 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11369: Mercury as Seen in Both Narrow and Wide Views sur le site de la NASA.
MESSENGER's Wide Angle Camera (WAC), part of the Mercury Dual Imaging System (MDIS), is equipped with 11 narrow-band color filters. As the spacecraft receded from Mercury after making its closest approach on January 14, 2008, the WAC recorded a 3x3 mosaic covering part of the planet not previously seen by spacecraft. The color image shown here was generated by combining the mosaics taken through the WAC filters that transmit light at wavelengths of 1000 nanometers (infrared), 700 nanometers (far red), and 430 nanometers (violet). These three images were placed in the red, green, and blue channels, respectively, to create the visualization presented here. The human eye is sensitive only across the wavelength range from about 400 to 700 nanometers. Creating a false-color image in this way accentuates color differences on Mercury's surface that cannot be seen in black-and-white (single-color) images.
Color differences on Mercury are subtle, but they reveal important information about the nature of the planet's surface material. A number of bright spots with a bluish tinge are visible in this image. These are relatively recent impact craters. Some of the bright craters have bright streaks (called "rays" by planetary scientists) emanating from them. Bright features such as these are caused by the presence of freshly crushed rock material that was excavated and deposited during the highly energetic collision of a meteoroid with Mercury to form an impact crater. The large circular light-colored area in the upper right of the image is the interior of the Caloris basin. Mariner 10 viewed only the eastern (right) portion of this enormous impact basin, under lighting conditions that emphasized shadows and elevation differences rather than brightness and color differences. MESSENGER has revealed that Caloris is filled with smooth plains that are brighter than the surrounding terrain, hinting at a compositional contrast between these geologic units. The interior of Caloris also harbors several unusual dark-rimmed craters, which are visible in this image. The MESSENGER science team is working with the 11-color images in order to gain a better understanding of what minerals are present in these rocks of Mercury's crust.
The diameter of Mercury is about 4880 kilometers (3030 miles). The image spatial resolution is about 2.5 kilometers per pixel (1.6 miles/pixel). The WAC departure mosaic sequence was executed by the spacecraft from approximately 19:45 to 19:56 UTC on January 14, 2008, when the spacecraft was moving from a distance of roughly 12,800 to 16,700 km (7954 to 10377 miles) from the surface of Mercury.
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10398: Mercury Shows its True Colors sur le site de la NASA.
Just 21 minutes after MESSENGER's closest approach to Mercury, the Narrow Angle Camera (NAC) took this picture showing a variety of intriguing surface features, including craters as small as about 400 meters (about 400 yards) across. This is one of a set of 68 NAC images showing landscapes near Mercury's equator on the side of the planet never before imaged by spacecraft. From such highly detailed close-ups, planetary geologists can study the processes that have shaped Mercury's surface over the past 4 billion years. One of the highest and longest scarps (cliffs) yet seen on Mercury curves from the top center down across the left side of this image. (The Sun is shining low from the right, so the scarp casts a wide shadow.) Great forces in Mercury's crust have thrust the terrain occupying the right two-thirds of the picture up and over the terrain to the left. An impact crater has subsequently destroyed a small part of the scarp near the bottom of the image.
This image was taken from a distance of only 5,800 kilometers (3,600 miles) from surface of the planet and shows a region about 200 kilometers (about 125 miles) across.
Mission Elapsed Time (MET) of image: 108826105
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10174: Detailed Close-up of Mercury's Previously Unseen Surface sur le site de la NASA.
During Monday’s flyby of Mercury, MESSENGER’s NAC captured a new view of the bright, radial ejecta rays of Kuiper crater that were previously imaged by Mariner 10 at a lower Sun angle. Kuiper crater is named for Gerard Kuiper, a Dutch-American astronomer who was also a member of the Mariner 10 team. Bright ejecta rays such as these are produced as impacts excavate and eject relatively unweathered subsurface material. The ejecta rays of Kuiper and other large craters are observed to extend for hundreds of kilometers across the cratered terrain of Mercury, as seen on the full planet image from MESSENGER’s Wide Angle Camera (WAC) released previously (PIA11245).
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131774036
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 530 meters/pixel (0.33 miles/pixel)
Scale: Kuiper crater is 62 kilometers in diameter (39 miles)
Spacecraft Altitude: 21,000 kilometers (13,000 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11355: Bright Ejecta Rays of Kuiper sur le site de la NASA.
As MESSENGER flew by Mercury, the Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS) captured this view on January 14, 2008. Two of the larger craters in this image appear to have darkened crater rims and partial "halos" of dark material immediately surrounding the craters. Both craters appear to have nearly complete rims and interior terraced walls, suggesting that they formed more recently than the other nearby shallower craters of similar size. There are two possible explanations for their dark halos: (1) Darker subsurface material may have been excavated during the explosions from the asteroid or comet impacts that produced the craters. (2) Large cratering explosions may have melted a fraction of the rocky surface material involved in the explosions, splashing so-called "impact melts" across the surface; such melted rock is often darker (lower albedo) than the pre-impact target material. In either case, the association of the dark material with relatively recently formed craters suggests that the processes that gradually homogenize Mercury's surface materials have not yet had time to reduce the contrast of these dark halos. The crater with associated dark material in the lower-left part of this image is about 100 km (60 miles) in diameter, and the crater with patches of dark material in the upper right is about 70 km (40 miles) across. These dark-halo craters, located near Mercury's south pole, are also visible in the previously released false-color image created from three Wide Angle Camera (WAC) frames (see PIA10398).
Information from images taken in the 11 different color filters of the WAC will help MESSENGER scientists to understand the nature of the dark material associated with the craters shown in this image and will determine whether they reveal the presence of subsurface material of a different composition, are examples of impact melt, or perhaps have some other explanation.
Image Mission Elapsed Time (MET): 108828161
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10602: Craters with Dark Halos on Mercury sur le site de la NASA.
During its flyby of Mercury, the MESSENGER spacecraft acquired high-resolution images of the planet's surface. This image, taken by the Narrow Angle Camera (NAC) on the Mercury Dual Imaging System (MDIS), was obtained on January 14, 2008, about 37 minutes after MESSENGER's closest approach to the planet. The image reveals the surface of Mercury at a resolution of about 360 meters/pixel (about 1180 feet/pixel), and the width of the image is about 370 kilometers (about 230 miles). This image is the 98th in a set of 99 images that were taken in a pattern of 9 rows and 11 columns to enable the creation of a large, high-resolution mosaic of the northeast quarter of the region not seen by Mariner 10. During the encounter with Mercury, the MDIS instrument acquired image sets for seven large mosaics with the NAC.
This image shows a crater with distinctive bright rays of ejected material extending radially outward from the crater's center. A chain of craters nearby is also visible. Studying impact craters provides insight into the history and composition of Mercury as well as dynamical processes that occurred throughout our Solar System. The MESSENGER Science Team has begun analyzing these high-resolution images to unravel these fundamental questions.
Mission Elapsed Time (MET) of image: 108827082
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10173: Mercury's Cratered Surface sur le site de la NASA.
Click on image for the animation
The WAC snapped this image just 8 minutes and 47 seconds after the MESSENGER spacecraft passed 200 kilometers (124 miles) above Mercury’s surface, its closest distance to the planet during the mission’s second Mercury flyby. The closest approach occurred over the dark night side of Mercury, as can be seen in the animation, so the MDIS cameras had to wait until the sunlit surface was visible before beginning to image while departing from the planet. The crater in the upper right corner of this image is Boethius, which can also be seen in the WAC image released yesterday (see PIA11246). These images overlap and will be used to produce the highest-resolution color mosaic ever obtained of Mercury’s surface.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131770346
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC Filter: 1 (700 nanometers)
Resolution: 290 meters/pixel (0.18 miles/pixel)
Scale: This image is about 300 kilometers across (190 miles)
Spacecraft Altitude: 1,640 kilometers (1,020 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11352: The First Image After Closest Approach sur le site de la NASA.
As MESSENGER approached Mercury on January 14, 2008, the Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS) snapped images of the nearing planet in a sequence that covered the entire sunlit portion of the surface. This mosaic was made from these images, shown as thumbnails on the image context sheet released last week (PIA10604).
This mosaic is shown in a cylindrical equidistant (also known as equirectangular) projection, which simply is a map with longitude lines being vertical and equally spaced and latitude lines being horizontal and equally spaced. The mosaic covers the entire approach crescent view of Mercury (PIA10179), so the vertical extent of the mosaic is comparable to Mercury's diameter of 4880 kilometers (about 3030 miles). Surface features on the right side of the mosaic show long shadows that accentuate height differences because these images were taken near Mercury's terminator, the transition between the sunlit dayside of the planet and the dark night side; the previously released image of the crater Matisse (PIA10190) is an example of one of these near-terminator images used in the mosaic. Features near the left side of the mosaic are looking toward the limb of the planet, and this very low viewing geometry and higher Sun angle do not provide much detail about the surface structures; the previously released image looking at Mercury's horizon (PIA10176) is an example of such a view that was used to create this mosaic.
This low-resolution version of the mosaic is only 8% of the resolution of the full mosaic and contains only one pixel for approximately every 156 pixels in the original images.
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10605: Making a Mosaic—Part II sur le site de la NASA.
One week ago, on January 14, 2008, the MESSENGER spacecraft passed 200 kilometers (124 miles) above the surface of Mercury and snapped the first pictures of a side of Mercury not previously seen by spacecraft. This image shows that previously unseen side, with a view looking toward Mercury's south pole. The southern limb of the planet can be seen in the bottom right of the image. The bottom left of the image shows the transition from the sunlit, day side of Mercury to the dark, night side of the planet, a transition line known as the terminator. In the region near the terminator, the sun shines on the surface at a low angle, causing the rims of craters and other elevated surface features to cast long shadows, accentuating height differences in the image. A raised crater rim that is just catching the last glint of sunlight can be seen prominently in this terminator region.
This image is just one in a planned sequence of 42 images acquired by the Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS). From these 42 images, the MESSENGER team is creating a high-resolution mosaic image of this previously unseen portion of Mercury. In total during the flyby, MDIS took more than 1200 images, which are being combined to create multiple mosaics with different resolutions and of different portions of the planet. The creation of high-resolution mosaic images will enable a global view of Mercury's surface and will be used to understand the geologic processes that made Mercury the planet we see today.
This image was acquired about 98 minutes after MESSENGER's closest approach to Mercury, when the spacecraft was at a distance of about 33,000 kilometers (21,000 miles).
Mission Elapsed Time (MET) of image: 108830711
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10187: Looking Toward the South Pole of Mercury sur le site de la NASA.
Named for Júlíana Sveinsdóttir, an Icelandic painter and textile artist, Sveinsdóttir crater superimposed by Beagle Rupes is a distinctive feature on Mercury's landscape. Unusually elliptical in shape, the crater was produced by the impact of an object that hit Mercury’s surface obliquely. More than 600 kilometers (370 miles) long and one of the largest fault scarps on the planet, Beagle Rupes marks the surface expression of a large thrust fault believed to have formed as Mercury cooled and the entire planet shrank. Beagle Rupes crosscuts Sveinsdóttir crater and has uplifted the easternmost portion (right side portion) of the crater floor by almost a kilometer, indicating that most of the fault activity at Beagle Rupes occurred after the impact that created Sveinsdóttir. Crosscutting relationships such as this are used to understand the sequence in time of the different processes that have affected Mercury’s evolution.
Date Acquired: January 14, 2008
Image Mission Elapsed Time (MET):108830230
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 0.77 kilometers/pixel (0.48 miles/pixel)
Scale: This image is about 780 kilometers (490 miles) across; Sveinsdóttir crater is about 120 kilometers by 220 kilometers (75 miles by 140 miles)
Spacecraft Altitude: 30,300 kilometers (18,800 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10939: Beagle Rupes Gives Sveinsdóttir an Uplifting Experience sur le site de la NASA.
This dramatic NAC image was acquired about 56 minutes prior to MESSENGER’s closest approach during the mission’s recent Mercury flyby, as the spacecraft approached the planet's illuminated crescent (PIA11247). Prominent toward the horizon in this view of newly imaged terrain is a long cliff face. A small impact crater (about 30 kilometers, or 19 miles, in diameter) overlies this lengthy scarp. The scarp extends for over 400 kilometers (250 miles) and likely represents a sign of aging unique to Mercury among the planets in the Solar System. As time passes, the interior of a planet cools. However, the relative size of Mercury's central metallic core is larger than that of the other planets and hence has significantly affected the planet’s geologic evolution. The numerous long scarps on Mercury are believed to be the surface expression of faults formed in the rocks of Mercury's crust as the interior of the planet cooled and contracted. This contraction compressed the surface and thrust some sections of crust over others, creating long curving cliffs like the one shown here.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131766454
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 420 meters/pixel (0.26 miles/pixel) on the right side of the image
Scale: The small crater superimposed on the long cliff is about 30 kilometers (19 miles) in diameter
Spacecraft Altitude: 16,500 kilometers (10,300 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11370: Mercury Shows Signs of Aging sur le site de la NASA.
Click on image for
larger annotated version
As reported in the July 4, 2008 issue of Science magazine, volcanoes have been discovered on Mercury’s surface from images acquired during MESSENGER’s first Mercury flyby. This image shows the largest feature identified as a volcano in the upper center of the scene. The volcano has a central kidney-shaped depression, which is the vent, and a broad smooth dome surrounding the vent. The volcano is located just inside the rim of the Caloris impact basin. The rim of the basin is marked with hills and mountains, as visible in this image. The role of volcanism in Mercury’s history had been previously debated, but MESSENGER’s discovery of the first identified volcanoes on Mercury’s surface shows that volcanism was active in the distant past on the innermost planet.
Date Acquired: January 14, 2008
Image Mission Elapsed Time (MET:108826877
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 270 meters/pixel (0.17 miles/pixel)
Scale: This image is about 270 kilometers across (170 miles)
Spacecraft Altitude: 10,500 kilometers (6,500 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10942: MESSENGER Discovers Volcanoes on Mercury sur le site de la NASA.
One week ago, the MESSENGER spacecraft transmitted to Earth the first high-resolution image of Mercury by a spacecraft in over 30 years, since the three Mercury flybys of Mariner 10 in 1974 and 1975. MESSENGER's Wide Angle Camera (WAC), part of the Mercury Dual Imaging System (MDIS), is equipped with 11 narrow-band color filters, in contrast to the two visible-light filters and one ultraviolet filter that were on Mariner 10's vidicon camera. By combining images taken through different filters in the visible and infrared, the MESSENGER data allow Mercury to be seen in a variety of high-resolution color views not previously possible. MESSENGER's eyes can see far beyond the color range of the human eye, and the colors seen in the accompanying image are somewhat different from what a human would see.
The color image was generated by combining three separate images taken through WAC filters sensitive to light in different wavelengths; filters that transmit light with wavelengths of 1000, 700, and 430 nanometers (infrared, far red, and violet, respectively) were placed in the red, green, and blue channels, respectively, to create this image. The human eye is sensitive across only the wavelength range 400 to 700 nanometers. Creating a false-color image in this way accentuates color differences on Mercury's surface that cannot be seen in the single-filter, black-and-white image released last week (see PIA10179).
This visible-infrared image shows an incoming view of Mercury, about 80 minutes before MESSENGER's closest pass of the planet on January 14, 2008, from a distance of about 27,000 kilometers (17,000 miles).
Image sequences acquired through the 11 different MDIS filters are being used to distinguish subtle color variations indicative of different rock types. By analyzing color differences across all 11 filters, the MESSENGER team is investigating the variety of mineral and rock types present on Mercury's surface. Such information will be key to addressing fundamental questions about how Mercury formed and evolved.
Mercury has a diameter of about 4880 kilometers (3030 miles), and the smallest feature visible in this color image is about 10 kilometers (6 miles) in size.
Mission Elapsed Times (MET) of images: 108820022, 108820037, 108820057
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10189: Mercury—in Color! sur le site de la NASA.
About 91 minutes after MESSENGER’s closest pass by the planet, MDIS acquired this image of Mercury’s northern surface, which is one in a set of 48 that form a mosaic of the departing planet. In this image, the left portion of the surface fades into darkness at the terminator, the line between the sunlit dayside of the planet and the dark night side. The left-side portions of the surface that are just coming out of the darkness are being hit with the first rays of morning sunlight. Some of the surface to the right of this scene can be viewed in this previously released image looking toward Mercury’s north pole (PIA10193).
Date Acquired: January 14, 2008
Image Mission Elapsed Time (MET): 108830334
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 0.8 kilometers/pixel (0.5 miles/pixel)Scale: The width of this image is about 800 kilometers (500 miles)
Spacecraft Altitude: 30,700 kilometers (19,100 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10937: By Dawn's Early Light sur le site de la NASA.
Giant scarps (cliffs), called rupes (see PIA10609), are believed to have formed when Mercury’s interior cooled and the entire planet shrank slightly as a result. This figure, recently published in Science magazine, shows one of these scarps (white arrows) that is about 270 kilometers (170 miles) long. This portion of Mercury’s surface was seen during the Mariner 10 flybys, but this scarp, despite its large size, was not visible in the Mariner 10 photos because the Sun was nearly overhead at the time and, consequently, the scarp did not cast a discernable shadow. In contrast, MESSENGER acquired a mosaic of this area (see PIA10605) before the spacecraft’s closest approach to the planet, when this portion of the surface was near the terminator, the line between the sunlit dayside and the dark night side of the planet. Such lighting produced long shadows, enabling this rupes to be recognized for the first time.
Date Acquired: January 14, 2008
Image Mission Elapsed Time (MET): Mosaic of images from 108821370, 108821375, 108821397, and 108821402
Instrument: A: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11012: Rupes, Rupes, Every Where sur le site de la NASA.
This false-color image of Mercury, recently published in Science magazine, shows the great Caloris impact basin (see PIA10383), visible in this image as a large, circular, orange feature in the center of the picture. The contrast between the colors of the Caloris basin floor and those of the surrounding plains indicate that the composition of Mercury's surface is variable. Many additional geological features with intriguing color signatures can be identified in this image. For example, the bright orange spots just inside the rim of Caloris basin are thought to mark the location of volcanic features, such as the volcano shown in this previously released Narrow Angle Camera (NAC) image (see PIA10942). MESSENGER Science Team members are studying these regional color variations in detail, to determine the different mineral compositions of Mercury's surface and to understand the geologic processes that have acted on it. Images taken through the 11 different WAC color filters were used to create this false-color image. The 11 different color images were compared and contrasted using statistical methods to isolate and enhance subtle color differences on Mercury's surface.
Date Acquired: January 14, 2008
Image Mission Elapsed Times (MET): 108827278-108827328
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 2.3 kilometers/pixel (1.4 miles/pixel)
Scale: Caloris basin is about 1,550 kilometers in diameter (960 miles)
Spacecraft Altitude: 13,000 kilometers (8,000 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10359: Caloris Basin—in Color! sur le site de la NASA.
When Mariner 10 flew past Mercury three times in 1974 and 1975, the same hemisphere was in sunlight during each encounter. As a consequence, Mariner 10 was able to image less than half the planet. Planetary scientists have wondered for more than 30 years about what spacecraft images might reveal about the hemisphere of Mercury that Mariner 10 never viewed. (See Mariner 10 images.)
On January 14, 2008, the MESSENGER spacecraft observed about half of the hemisphere missed by Mariner 10. This image was snapped by the Wide Angle Camera, part of the Mercury Dual Imaging System (MDIS) instrument, about 80 minutes after MESSENGER's closest approach to Mercury (2:04 pm EST), when the spacecraft was at a distance of about 27,000 kilometers (about 17,000 miles). The image shows features as small as 10 kilometers (6 miles) in size. This image was taken through a filter sensitive to light near the red end of the visible spectrum (750 nm), one of a sequence of images taken through each of MDIS's 11 filters.
Like the previously mapped portion of Mercury, this hemisphere appears heavily cratered. It also reveals some unique and distinctive features. On the upper right is the giant Caloris basin, including its western portions never before seen by spacecraft. Formed by the impact of a large asteroid or comet, Caloris is one of the largest, and perhaps one of the youngest, basins in the Solar System. The new image shows the complete basin interior and reveals that it is brighter than the surrounding regions and may therefore have a different composition. Darker smooth plains completely surround Caloris, and many unusual dark-rimmed craters are observed inside the basin. Several other multi-ringed basins are seen in this image for the first time. Prominent fault scarps (large ridges) lace the newly viewed region.
Other images obtained during the flyby will reveal surface features in color and in much more detail. Collectively, these images and measurements made by other MESSENGER instruments will soon provide a detailed global view of the surface of Mercury, yielding key information for understanding the formation and geologic history of the innermost planet.
Mission Elapsed Time (MET) of image: 108829708
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10172: MESSENGER's First Look at Mercury's Previously Unseen Side sur le site de la NASA.
This image shows a portion of Mercury in previously unseen terrain, taken as MESSENGER approached the planet during its second flyby. This view is looking out toward the limb of the planet (north is to the image right). In the foreground is a region of rough, heavily cratered terrain; a large, ancient two-ring impact basin may be seen at the bottom center of the image. In the distance is a region of younger, tectonically modified smooth plains that have been pockmarked by small craters. The origin of smooth plains on Mercury remains a topic of active inquiry by the MESSENGER team.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131766496
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 420 meters/pixel (0.26 miles/pixel) at the bottom of the image
Scale: Foreground is about 430 kilometers across (270 miles)
Spacecraft Altitude: 16,300 kilometers (10,200 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11353: MESSENGER Looks out on a Limb sur le site de la NASA.
During MESSENGER's flyby of Mercury on January 14, 2008, the Mercury Dual Imaging System (MDIS) acquired images to create eight different mosaics. Shown here is an image context sheet with small thumbnail versions of the MDIS Narrow Angle Camera (NAC) images that were captured as the spacecraft approached the planet and used to create a high-resolution mosaic of Mercury. The MDIS instrument is mounted on a pivot, which enables the camera to point in different directions and see different portions of the surface. Both small motions of the spacecraft and movement of the pivot were used to take the images that compose this mosaic sequence. This mosaic has images in 5 columns by 11 rows, but images of just black space or of the unlit, dark planet are not shown on this context sheet.
MDIS started this mosaic 55 minutes before MESSENGER's closest pass by Mercury. The first image of the mosaic was taken in the lower left corner, and images were subsequently acquired by moving across a row and then up to start the next row. An image where Mercury's surface fills the image is about 500 kilometers (310 miles) across. Image names, which are abbreviated under each image in this context sheet, are derived from the mission elapsed time (MET) when the image was taken, which is approximately the time in seconds since launch. The mosaic was planned to have about 10% overlap between neighboring images, to ensure that a mosaic could be formed without any gaps. The resulting mosaic is ultimately created by using the time of each image and corresponding information about the spacecraft location and viewing geometry at that time to place all of the images onto a common map of Mercury.
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10604: Making a Mosaic sur le site de la NASA.
The Narrow Angle Camera of the Mercury Dual Imaging System (MDIS) on the MESSENGER spacecraft obtained high-resolution images of the floor of the Caloris basin on January 14, 2008. Near the center of the basin, an area unseen by Mariner 10, this remarkable feature—nicknamed "the spider" by the science team—was revealed. A set of troughs radiates outward in a geometry unlike anything seen by Mariner 10. The radial troughs are interpreted to be the result of extension (breaking apart) of the floor materials that filled the Caloris basin after its formation. Other troughs near the center form a polygonal pattern. This type of polygonal pattern of troughs is also seen along the interior margin of the Caloris basin. An impact crater about 40 km (~25 miles) in diameter appears to be centered on "the spider." The straight-line segments of the crater walls may have been influenced by preexisting extensional troughs, but some of the troughs may have formed at the time that the crater was excavated.
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10397: "The Spider"—Radial Troughs within Caloris sur le site de la NASA.
As MESSENGER approached Mercury on January 14, 2008, the spacecraft's Narrow-Angle Camera on the Mercury Dual Imaging System (MDIS) instrument captured this view of the planet's rugged, cratered landscape illuminated obliquely by the Sun. The large, shadow-filled, double ringed crater to the upper right was glimpsed by Mariner 10 more than three decades ago and named Vivaldi, after the Italian composer. Its outer ring has a diameter of about 200 kilometers (about 125 miles). MESSENGER's modern camera has revealed detail that was not well seen by Mariner 10, including the broad ancient depression overlapped by the lower-left part of the Vivaldi crater. The MESSENGER science team is in the process of evaluating later images snapped from even closer range showing features on the side of Mercury never seen by Mariner 10. It is already clear that MESSENGER's superior camera will tell us much that could not be resolved even on the side of Mercury viewed by Mariner's vidicon camera in the mid-1970s.
This MESSENGER image was taken from a distance of about18,000 kilometers (11,000 miles), about 56 minutes before the spacecraft's closest encounter with Mercury. It shows a region roughly 500 kilometers (300 miles) across, and craters as small as 1 kilometer (0.6 mile) can be seen in this image.
Mission Elapsed Time (MET) of image: 108821483
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10175: MESSENGER Reveals Mercury in New Detail sur le site de la NASA.
In the 1970s, the Mariner 10 spacecraft flew by Mercury three times, imaging nearly all of one hemisphere (45% of the planet). Due to the geometry of the flybys, a large swath of terrain in the northern portion of that hemisphere was never seen (left image), until October 6, 2008, when the MESSENGER spacecraft flew by the planet for the second time, revealing this ancient cratered terrain (right image). Filling in this gap allows scientists to use both Mariner 10 and MESSENGER data to better characterize the various processes that shaped the surface of Mercury over time. (View images taken by Mariner 10.)
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131771118 to 131772268
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Scale: Mercury’s diameter is 4880 kilometers (3030 miles)
Spacecraft Altitude: 5,000-11,000 kilometers (3,000-6,900 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11354: Filling the Gaps sur le site de la NASA.
As MESSENGER sped by Mercury on January 14, 2008, the Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS) captured this image, which includes the edge of the planet against the blackness of space. Much of the foreground shows a portion of Caloris basin, one of the largest impact basins in the solar system. The two large craters near the bottom of this image can be identified on the northwestern floor of the basin on the mosaicked image of Caloris (see PIA10383) released at MESSENGER's NASA press conference on January 30. The large crater in the bottom middle of this image has a diameter of about 70 kilometers (40 miles).
Caloris basin is an area of particular interest to the MESSENGER science team, since understanding its formation can lead to insights about the nature of large impacts in the early solar system and the results of these catastrophic events. In a false-color image of Mercury (see PIA10398), also released on January 30, Caloris basin is visible in the northern hemisphere of the planet as a large, light-colored, roughly circular feature; the floor of the basin may have some differences in its composition compared with the darker surrounding surfaces. The two large craters shown in today's released image are each surrounded by a "halo" of dark material, like the craters shown in our release of February 21 (see PIA10602). The smaller of the two craters has an unusual pattern of bright, highly reflective material on its floor. The fact that both of these craters, which show different material characteristics, are located within Caloris basin provides information about the variety and complexity of processes that have shaped Mercury's surface.
Image Mission Elapsed Time (MET): 108826622
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10603: Craters in Caloris sur le site de la NASA.
As MESSENGER sped by Mercury on January 14, 2008, the Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS) captured this image before its closest approach with the planet. The scene is near Mercury's terminator (the line between the sunlit day side and dark night side of the planet), where shadows are long and height differences accentuated, revealing rising crater walls that tower over the floors below. The large crater situated on the right side in the bottom half of the image is Sullivan crater, a structure about 135 kilometers (84 miles) in diameter also seen during the Mariner 10 mission. An influential American architect, Louis Sullivan and his work are often associated with the rise of modern skyscrapers, and this crater named in his honor finds a fitting home in Mercury's ancient geological architecture.
Mission Elapsed Time (MET) of image: 108821402
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10399: Mercury's Geological Architecture sur le site de la NASA.
Click on the image for movie of
MESSENGER Departs Mercury
On January 13, 2008, beginning 30 hours before MESSENGER's closest approach to Mercury, the Wide Angle Camera, part of the Mercury Dual Imaging System (MDIS), began snapping images as it approached the planet. Over this period, MESSENGER imaged the planet once every 20 minutes to produce this approach sequence, which has been compiled into a movie. At the start of the movie, the MESSENGER spacecraft is about 630,000 kilometers (about 390,000 miles) from Mercury. The movie ends when MESSENGER is about 34,000 kilometers (about 21,000 miles) from Mercury and about 100 minutes before its closest approach, when it passed a mere 200 kilometers (124 miles) above Mercury's surface.
In the approach movie, Mercury appears as a sunlit crescent. During the encounter, MESSENGER passed over the night side of the planet, experienced its closest approach with Mercury, and then emerged into daylight. This encounter was the first of three flybys of Mercury planned for the MESSENGER mission.
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10198: MESSENGER Approaches Mercury sur le site de la NASA.
Click on image for larger annotated version
This NAC image, taken about 85 minutes after MESSENGER’s closest approach during the mission’s second Mercury flyby, shows a view of Astrolabe Rupes, named for the ship of the French explorer Jules Dumont d’Urville. Rupes is the Latin word for cliff. Mercury’s day/night transition (the terminator) is located on the left side of the image, and the Sun is striking the cliff face of Astrolabe Rupes in the upper right of the image. Also visible in the image are additional unnamed rupes, whose cliff faces are casting dark shadows. One of these rupes intersects the crater Ghiberti, named for the Italian Renaissance sculptor. Rupes on Mercury are thought to have formed as the interior of Mercury cooled and the planet consequently contracted slightly. Determining the number and extent of rupes on Mercury can thus be used to understand the thermal history of the planet.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131774936
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 660 meters/pixel (0.41 miles/pixel)
Scale: Ghiberti crater is 123 kilometers in diameter (76 miles)
Spacecraft Altitude: 26,000 kilometers (16,000 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11368: Astrolabe Rupes and More sur le site de la NASA.
Yesterday, at 4:40 am EDT, MESSENGER successfully completed its second flyby of Mercury. Today, at about 1:50 am EDT, the images taken during the flyby encounter began to be received back on Earth. The spectacular image shown here is one of the first to be returned and shows a WAC image of the departing planet taken about 90 minutes after the spacecraft’s closest approach to Mercury. The bright crater just south of the center of the image is Kuiper, identified on images from the Mariner 10 mission in the 1970s. For most of the terrain east of Kuiper, toward the limb (edge) of the planet, the departing images are the first spacecraft views of that portion of Mercury’s surface. A striking characteristic of this newly imaged area is the large pattern of rays that extend from the northern region of Mercury to regions south of Kuiper. This extensive ray system appears to emanate from a relatively young crater newly imaged by MESSENGER, providing a view of the planet distinctly unique from that obtained during MESSENGER’s first flyby (see PIA10172). This young, extensively rayed crater, along with the prominent rayed crater to the southeast of Kuiper, near the limb of the planet, were both seen in Earth-based radar images of Mercury but not previously imaged by spacecraft. As the MESSENGER team is busy examining this newly obtained view that is only a few hours old, data from the flyby continue to stream down to Earth, including higher resolution close-up images of this previously unseen terrain.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131775256
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC Filter: 6 (430 nanometers)
Resolution: 5 kilometers/pixel (3 miles/pixel)
Scale: Mercury’s diameter is 4880 kilometers (3030 miles)
Spacecraft Altitude: 27,000 kilometers (17,000 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11245: Mercury as Never Seen Before sur le site de la NASA.
On January 14, 2008, MESSENGER flew by Mercury and snapped images of a large portion of the surface that had not been previously seen by spacecraft. Ever since the first images were received back on Earth one day later, January 15, MESSENGER team members have been closely examining and studying this "new" terrain with great interest and excitement.
One of many investigations underway includes identifying and measuring the impact craters on these previously unseen regions. The density of craters on the surface of a planet can be used to indicate the relative age of different places on the surface; the more craters the surface has accumulated, the older the surface. By counting craters on different areas of Mercury's surface, a relative geologic history of the planet can be constructed, indicating which surfaces formed first and which formed later. However, this process is also time consuming; Mercury has a lot of craters! This image shows just a portion (276 kilometers, or 172 miles, wide) of one frame taken with the Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS). In this image alone, 763 craters have been identified and measured (shown in green) along with 189 hills (shown in yellow). Altogether, 491 frames were taken by the NAC to create high-resolution mosaics of Mercury's surface.
Of course, simply counting the craters is not enough. Each crater has to be measured and classified to fully interpret the differences in crater density. Many small craters form as "secondaries," as clumps of material ejected from a "primary" crater re-impact the surface in the regions surrounding the primary. In order to learn about the history of asteroid and comet impacts on Mercury, scientists have to distinguish between the primary and secondary craters. Once many more craters are measured, MESSENGER researchers will have new insights into the geological history of Mercury.
Image Mission Elapsed Time (MET): 108826672
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10191: Counting Mercury's Craters sur le site de la NASA.
These two images show the same terrain on Mercury as imaged by Mariner 10 in the 1970s and by the MESSENGER spacecraft on October 6, 2008. The reason they look so different is that the angle that the Sun illuminates the surface is dramatically different between the two observations. When Mariner 10 acquired the image on the left, the Sun was high in the sky, which highlights the relative differences in brightness between geologic units on the surface. When the Sun is lower in the sky, as was the case during the second MESSENGER Mercury flyby (right image), shadows become more prominent and it is easier to see the rugged topography of the surface. Most noticeably, a peak-ring impact crater with a diameter of about 150 kilometers (93 miles) is clearly seen in new MESSENGER data, whereas it was nearly invisible in Mariner 10 data. (View images taken by Mariner 10.)
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131774839
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 430 meters/pixel (0.27 miles/pixel)
Scale: A scale bar is given on the images
Spacecraft Altitude: 25,000 kilometers (16,000 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11361: A New Look at Old Terrain sur le site de la NASA.
After MESSENGER completed its successful flyby of Mercury, the Narrow Angle Camera (NAC), part of the Mercury Dual Imaging System (MDIS), took images of the receding planet. Beginning on January 14, 2008, about 100 minutes after MESSENGER's closest pass by the surface of Mercury, until January 15, 2008, about 19 hours later, the NAC acquired one image every four minutes. In all, 288 images were snapped during this sequence; shown here are just 12 of those departing shots. The top left image was taken when MESSENGER was about 34,000 kilometers (21,000 miles) from Mercury, and the bottom right image was snapped from a distance of about 400,000 kilometers (250,000 miles).
This large set of departing NAC images has been assembled into a movie, which will be shown tomorrow during a NASA press conference at 1 pm EST. Tune in tomorrow, via the web or NASA TV, to watch the NASA press conference, see this movie, and hear about the major discoveries made by MESSENGER from its historic flyby of Mercury!
Mission Elapsed Times (MET) of images: 108830924, 108836684, 108842444, 108848204, 108853964, 108859724, 108865484, 108871244, 108877004, 108882764, 108888524, 108894284.
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10196: MESSENGER's Departing Shots sur le site de la NASA.
In both the optical navigation images (PIA11244) and the full-planet Wide Angle Camera (WAC) approach frame (PIA11247), a bright feature is clearly visible in the northern portion of the crescent-shaped Mercury. This NAC image resolves details of this bright feature, showing that it surrounds a small crater about 30 kilometers (19 miles) in diameter, seen nearly edge-on. Presumably, the bright material was ejected from this small crater, which apparently formed relatively recently in Mercury’s past, because Mercury’s surface materials tend to darken with time. The brilliant ejecta are so bright compared with the neighboring surface that Earth-based telescopic observations also detected this feature, despite its being associated with such a small crater.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131766564
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 410 meters/pixel (0.25 miles/pixel) in the lower right corner of the image
Scale: The bright crater is about 30 kilometers in diameter (19 miles)
Spacecraft Altitude: 16,000 kilometers (9,900 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11366: A Small Crater Makes a Bright Impact sur le site de la NASA.
A crater discovered in the newly imaged portion of Mercury’s surface during MESSENGER’s second Mercury flyby has uncommonly dark material within and surrounding the crater. The material is darker than the neighboring terrain such that this crater with a diameter of 180 kilometers (110 miles) is easily identified even in a distant global image of Mercury; it is located just south of the equator near the limb of the planet in this previously released Wide Angle Camera (WAC) image (PIA11245). The dark halo may be material with a mineralogical composition different from the majority of Mercury’s visible surface. Craters with similar dark material on or near their rims were seen on the floor of the Caloris basin during MESSENGER’s first flyby (PIA10603). Images acquired though the 11 different narrow-band color filters of the WAC during MESSENGER’s second flyby will be crucial to an understanding of the nature of this newly seen, unusual feature.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131774051
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 540 meters/pixel (0.34 miles/pixel)
Scale: This image is about 550 kilometers across (340 miles)
Spacecraft Altitude: 21,000 kilometers (13,000 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11357: An Intriguing Dark Halo sur le site de la NASA.
As the MESSENGER spacecraft drew closer to Mercury for its historic first flyby, the spacecraft's Narrow Angle Camera (NAC) on the Mercury Dual Imaging System (MDIS) acquired an image mosaic of the sunlit portion of the planet. This image is one of those mosaic frames and was acquired on January 14, 2008, 18:10 UTC, when the spacecraft was about 18,000 kilometers (11,000 miles) from the surface of Mercury, about 55 minutes before MESSENGER's closest approach to the planet.
The image shows a variety of surface textures, including smooth plains at the center of the image, many impact craters (some with central peaks), and rough material that appears to have been ejected from the large crater to the lower right. This large 200-kilometer-wide (about 120 miles) crater was seen in less detail by Mariner 10 more than three decades ago and was named Sholem Aleichem for the Yiddish writer. In this MESSENGER image, it can be seen that the plains deposits filling the crater's interior have been deformed by linear ridges. The shadowed area on the right of the image is the day-night boundary, known as the terminator. Altogether, MESSENGER acquired over 1200 images of Mercury, which the science team members are now examining in detail to learn about the history and evolution of the innermost planet.
Mission Elapsed Time (MET) of image: 108821596
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10176: MESSENGER Views Mercury's Horizon sur le site de la NASA.
One of the more dramatic craters seen by MESSENGER during its first flyby of Mercury this past January was Vivaldi (see PIA10175). Right at the day/night terminator, the crater was slipping away into darkness as Mercury slowly rotated. Two days ago, MESSENGER made its second flyby of the innermost planet, and once again captured a view of Vivaldi, this time at sunrise. Long shadows are draped across the floor of this feature, which is actually considered a “small” double-ring basin despite having a diameter of 213 kilometers (133 miles). The low Sun illumination also highlights ridges, valleys, and chains of craters radiating away from Vivaldi.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131771928
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 250 meters/pixel (0.16 miles/pixel)
Scale: The diameter of Vivaldi crater is 213 kilometers (133 miles)
Spacecraft Altitude: 9,600 kilometers (6,000 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11350: Vivaldi: At Sunset and Now at Sunrise sur le site de la NASA.
Click on the image for movie of
Rendezvous with Mercury
As the MESSENGER spacecraft approached Mercury for its first flyby, the Narrow Angle Camera, part of the Mercury Dual Imaging System (MDIS) instrument, acquired a series of images of the planet in support of spacecraft navigation. The nine images shown here were taken from January 9 to 13, 2008, as MESSENGER closed to between 2.7 million kilometers and 760,000 kilometers (1.7 million miles and 470,000 miles) from Mercury. These nine images can also be viewed in sequence by clicking on the image above.
At the beginning of the image sequence, Mercury was no more than a bright crescent in the blackness of space. As MESSENGER drew closer, surface features began to be resolved. The image from January 13 (bottom right) has the highest spatial resolution of this sequence (20 kilometers/pixel, 12 miles/pixel). In this image, bright markings are visible, and impact craters can be seen near the terminator (the line between Mercury's day side, to the left, and the night side to the right).
During MESSENGER's closest pass by Mercury yesterday, January 14, 2008, extensive scientific observations were executed. Today, the last of these planned observations will be completed, and at noon EST, the spacecraft will begin to transmit the data gathered during the flyby to Earth. This exciting new dataset will be used to address fundamental questions about the origin and evolution of the planet Mercury and our solar system. Currently, the MESSENGER team is anxiously awaiting the arrival of this dataset.
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10171: Rendezvous with Mercury sur le site de la NASA.
When Mariner 10 flew by Mercury in 1974, morning sunlight was just striking Mozart crater so that most of the feature was hidden in darkness near the terminator. During MESSENGER's Mercury flyby on January 14, 2008, Mozart was in full sunlight, allowing the crater to be seen in detail for the first time, as shown in this image snapped by the Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS). Named in honor of the classical composer Wolfgang Amadeus Mozart, Mozart is the large crater near the center of the image. The crater's diameter is about 225 kilometers (140 miles). The arc of dark hills visible on the crater's floor probably represents remnants of a central peak ring, similar to that shown in the January 30 image release (PIA10378). Clues to the origin of the dark material on the peak ring and the curious dark streaks radiating outward from the crater will be provided by 11-color image data collected by the spacecraft's Wide Angle Camera (WAC). A close inspection of the area around Mozart crater shows many long chains of secondary craters, formed by impact of material thrown out during the formation of the main crater. Mozart crater is located just south of the Caloris basin and can be identified in the false color image previously released (PIA10398). Members of the MESSENGER Science Team are currently studying and characterizing the small craters on Mercury in order to provide new insight into the cratering process as it operates on the different planets in the Solar System.
Image Mission Elapsed Time (MET): 108830250
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10607: Appreciating Mozart in a New Light sur le site de la NASA.
When MESSENGER flew by Mercury on January 14, 2008, the Mercury Dual Imaging System (MDIS) snapped images of a large portion of Mercury's surface that had not been previously seen by spacecraft. On these images, new examples of long cliffs were identified and viewed for the first time. This image, taken by the Narrow Angle Camera (NAC), shows one of those cliffs in the bottom right corner. The cliff can be followed from the bottom edge of the image, cutting through and deforming an impact crater, and curving out of the image frame on the middle right edge. This cliff is the northern continuation of the cliff visible in the images previously released on January 16 (PIA10174) and January 27 (PIA10194). This image shows an area of Mercury's surface about 200 kilometers (125 miles) across, and by tracing this cliff through the three images, it can be seen that it extends for hundreds of kilometers.
Cliffs that mark geologic escarpments on Mercury are called "rupes," which is simply the Latin word for cliff. On Mercury, rupes are named after the ships of famous explorers, and names include Discovery Rupes, for a ship of Captain Cook, Santa Maria Rupes, for a ship of Christopher Columbus, and Victoria Rupes, for a ship of Ferdinand Magellan. (The word rupes is both singular and plural). The MESSENGER team proposed to the International Astronomical Union, which has the final say on all names of landforms on planets and satellites, that this cliff be named the Beagle Rupes, after the ship on which naturalist Charles Darwin sailed around the world. Today the MESSENGER team received word that the proposed name has received formal approval.
Image Mission Elapsed Time (MET): 108827037
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10609: Discovering New Rupes on Mercury sur le site de la NASA.
Click on image for larger annotated version
About 69 minutes after MESSENGER’s closest approach to Mercury during the mission’s second flyby, the NAC acquired this image of a portion of Mercury’s surface also seen during the Mariner 10 mission. Toward the lower portion of the image, Arecibo Vallis is visible. Vallis is the Latin word for valley, and valles (the plural of vallis) on Mercury are named for radio telescope observatories. Arecibo Observatory is located in Puerto Rico and has been used to conduct Earth-based studies of Mercury with important results, including the detection of radar-bright materials at Mercury’s poles that may be water ice trapped in permanently shadowed craters. Arecibo also observed some bright, rayed craters that have now been better resolved by MESSENGER’s latest images (PIA11356). Lately, Arecibo’s unique radar capabilities have been threatened with closure due to changed funding priorities. The craters Ibsen (named for the Norwegian playwright) and Petrarch (named for the Italian poet) are also visible in this image. Bright rays from Kuiper crater extend down from the top of the image (PIA11355).
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131773984
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 530 meters/pixel (0.33 miles/pixel)
Scale: Ibsen crater is 159 kilometers in diameter (99 miles)
Spacecraft Altitude: 21,000 kilometers (13,000 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11359: MESSENGER Observes Arecibo sur le site de la NASA.
On January 14, 2008, the MESSENGER spacecraft observed about half of the hemisphere not seen by Mariner 10. These images, mosaicked together by the MESSENGER team, were taken by the Narrow Angle Camera (NAC), part of the Mercury Dual Imaging System (MDIS) instrument, about 20 minutes after MESSENGER's closest approach to Mercury (2:04 pm EST), when the spacecraft was at a distance of about 5,000 kilometers (about 3,100 miles). The image shows features as small as 400 meters (0.25 miles) in size and is about 370 kilometers (230 miles) across.
The image shows part of a large, fresh crater with secondary crater chains located near Mercury's equator on the side of the planet newly imaged by MESSENGER. Large, flat-floored craters often have terraced rims from post-impact collapse of their newly formed walls. The hundreds of secondary impactors that are excavated from the planet's surface by the incoming object create long, linear crater chains radial to the main crater. These chains, in addition to the rest of the ejecta blanket, create the complicated, hilly terrain surrounding the primary crater. By counting craters on the ejecta blanket that have formed since the impact event, the age of the crater can be estimated. This count can then be compared with a similar count for the crater floor to determine whether any material has partially filled the crater since its formation. With their large size and production of abundant secondary craters, these flat-floored craters both illuminate and confound the study of the geological history of Mercury.
Mission Elapsed Times (MET) of images: 108826040, 108826045
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10178: Mercury's Complex Cratering History sur le site de la NASA.
About 58 minutes before MESSENGER’s closest approach to Mercury, the NAC captured this close-up image of a portion of Mercury’s surface imaged by spacecraft for the first time during this flyby. This image is one of 44 in a high-resolution NAC mosaic taken of the approaching crescent-shaped Mercury, as seen at lower resolution in the optical navigation images (PIA11244) and the approach WAC color image set (PIA11247). The features in the foreground, near the right side of the image, are close to the terminator, the line between the sunlit dayside and dark night side of the planet, so shadows are long and prominent. Two very long scarps are visible in this region, and the scarps appear to crosscut each other. The easternmost scarp also cuts through a crater, showing that it formed after the impact that created the crater. Other neighboring impact craters, such as in the upper left of this image, appear to be filled with smooth plains material. The MESSENGER team has only had a few hours to examine these intriguing features, and, currently, more images from the flyby are still streaming back to Earth.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131766396
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: about 0.5 kilometers/pixel (0.3 miles/pixel) in the upper right portion of the image
Scale: The crater near the upper right of the image is about 50 kilometers (30 miles) in diameter
Spacecraft Altitude: 17,100 kilometers (10,600 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11248: A Close-Up View of Previously Unseen Terrain sur le site de la NASA.
Two weeks ago, on January 14, 2008, MESSENGER became the first spacecraft to see the side of Mercury shown in this image. The first image transmitted back to Earth following the flyby of Mercury (PIA10172), and then released to the web within hours, shows the historic first look at the previously unseen side. This image, taken by the Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS), shows a closer view of much of that territory.
Just above and to the left of center of this image is a small crater with a pronounced set of bright rays extending across Mercury's surface away from the crater. Bright rays are commonly made in a crater-forming explosion when an asteroid strikes the surface of an airless body like the Moon or Mercury. But rays fade with time as tiny meteoroids and particles from the solar wind strike the surface and darken the rays. The prominence of these rays implies that the small crater at the center of the ray pattern formed comparatively recently.
This image is one in a planned set of 99. Nine different views of Mercury were snapped in this set to create a mosaic pattern with images in 3 rows and 3 columns. The WAC is equipped with 11 narrow-band color filters, and each of the 9 different views was acquired through all 11 filters. This image was taken in filter 7, which is sensitive to light near the red end of the visible spectrum (750 nm), and shows features as small as about 6 kilometers (4 miles) in size. The MESSENGER team is studying this previously unseen side of Mercury in detail to map and identify new geologic features and to construct the planet's geological history.
Mission Elapsed Time (MET) of image: 108827618
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10195: A Closer Look at the Previously Unseen Side sur le site de la NASA.
To the human eye, Mercury shows little color variation, especially in comparison to a colorful planet like Earth. But when images taken through many color filters are used in combination, differences in the properties of Mercury’s surface can create a strikingly colorful view of the innermost planet. Shown here are two color images of Thakur, named for the Bengali poet, novelist, and Nobel laureate influential in the late 19th and early 20th centuries. The image on the left was produced by combining images from three WAC filters into red, green, and blue channels, as a general representation of the color seen by the human eye (though every person sees color slightly differently, as discussed for the full-planet color images PIA11364). The right image was created by statistically comparing and contrasting images taken through all 11 of the WAC’s narrow-band color filters, which are sensitive to light not only in the visible portion of the spectrum but also to light that the human eye cannot see. This method greatly enhances subtle color differences in the rocks of Mercury’s surface, providing insight into the compositional variations present on Mercury and the geologic processes that created those color differences. Visible on the floor of Thākur crater is the intersection of two ridges, seen here in unprecedented detail for the first time with MESSENGER’s newly obtained images.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131770496 - 131770546
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 460 meters/pixel (0.29 miles/pixel)
Scale: Thākur crater is 118 kilometers in diameter (73 miles)
Spacecraft Altitude: 2,500 kilometers (1,600 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11365: Exposing Mercury’s Colors sur le site de la NASA.
This WAC image was acquired 9 minutes and 14 seconds after MESSENGER’s closest approach to Mercury, when the spacecraft was moving at 6.1 kilometers/second (3.8 miles/second). The image, centered at about 2.4ºS, 290ºE, is one in a sequence of 55: a five-frame mosaic with each frame in the mosaic acquired in all 11 of the WAC filters. This portion of Mercury’s surface was previously imaged under different lighting conditions by Mariner 10, but this new MESSENGER image mosaic is the highest-resolution color imaging ever acquired of any portion of Mercury’s surface. Additionally, some of the images in this mosaic overlap with flyby data acquired by the Mercury Atmospheric and Surface Composition Spectrometer (MASCS) and Mercury Laser Altimeter (MLA) instruments, resulting in the first time that these three instruments have gathered data of the same area of Mercury. The combination of these three datasets will enable unprecedented studies of this region of Mercury’s surface.
The largest impact feature at the top of the image is about 133 kilometers (83 miles) in diameter and is named Polygnotus, after a Greek painter from the 5th century B.C. This basin has a central peak ring and is embayed with smooth plains material, which is very different in texture from the surrounding terrain. A second, comparably large crater at the top left of the image, named Boethius after the 6th century Roman philosopher, also appears to be almost filled with smooth plains, which were subsequently deformed during the formation of a prominent scarp.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131770421
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC Filter: 3 (480 nanometers)
Resolution: 330 meters/pixel (0.21 miles/pixel)
Scale: This image is about 340 kilometers across (210 miles)
Spacecraft Altitude: 1,800 kilometers (1,100 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11246: MESSENGER Gathers Unprecedented Data about Mercury’s Surface sur le site de la NASA.
"The spider" now has an official name: Pantheon Fossae. As first presented at the NASA press conference on January 30 (see PIA10397), when MESSENGER flew by Mercury on January 14, 2008, the Mercury Dual Imaging System (MDIS) snapped images of an intriguing and previously unknown feature on the surface of Mercury. Near the center of the Caloris basin, a set of troughs (called graben by geologists) was observed to radiate outward in a pattern unlike anything ever seen on Mercury. The Science Team nicknamed this unique feature "the spider." The International Astronomical Union (IAU) recently approved the official name of Pantheon Fossae, as detailed in the MESSENGER press release issued last week.
The word fossa is Latin and means trench. The term is used in planetary geology to name features that are long, narrow, shallow depressions. Fossae, the plural of fossa, have been named on planetary bodies including Mars, Venus, and the Moon, but Pantheon Fossae are the first to be named on Mercury. The name is taken from the Pantheon in Rome, an ancient temple with a classic domed roof. The dome of the Pantheon has a series of sunken panels that radiate from a central circular opening at the top of the dome, and Mercury's Pantheon Fossae is reminiscent of this pattern. Consequently, the crater near the center of Pantheon Fossae is now named Apollodorus, who is credited by some as being the architect of the Pantheon. Apollodorus, shown in the middle of this Narrow Angle Camera (NAC) image, has a diameter of 41 kilometers (25 miles). MESSENGER scientists are debating whether Apollodorus played a role in the formation of Pantheon Fossae or whether the crater is simply from a later impact that occurred close to the center of the radial pattern.
Image Mission Elapsed Time (MET): 108828901
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10635: Mercury's First Fossae sur le site de la NASA.
During MESSENGER's flyby of Mercury on January 14, 2008, part of the planned sequence of observations included taking images of the same portion of Mercury's surface from five different viewing angles. The first view from this sequence was taken just after MESSENGER made its closest approach to Mercury, from a low viewing angle; an image of the first view (PIA10184) was released on January 19. The image released here, acquired with the Wide Angle Camera (WAC) on the Mercury Dual Imaging System (MDIS), was snapped 13 minutes after MESSENGER's closest approach with Mercury. The lower two-thirds of this image shows much of the same terrain seen in the first view, but from a much higher viewing angle, as the spacecraft began to pass nearly overhead. At the time of this image, MESSENGER was at a distance of about 3000 kilometers (about 2000 miles) from Mercury.
A comparison of the images taken at different viewing angles provides important information about the properties of the materials that make up Mercury's surface. In addition, each view was taken through all 11 of the WAC's narrow-band color filters. The image shown here is from filter 7, which is sensitive to light near the red end of the visible spectrum (750 nm). The MESSENGER team is working to compare these images taken from different perspectives and in different colors to understand surface properties on Mercury. In addition, knowledge of the variation of image properties with viewing angle in this region will permit a more confident comparison of images of other portions of the surface taken at different illumination and viewing angles.
This image is about 1000 kilometers (about 600 miles) across.
Image Mission Elapsed Time (MET): 108825632
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10192: MESSENGER's Different Views sur le site de la NASA.
When a meteoroid strikes the surface of a planet, material from the surface is ejected outward at high velocity, often creating rays that extend over distances far greater than the size of the crater formed by the impact. During MESSENGER’s second Mercury flyby, MDIS captured images of impressive rays on Mercury, such as the ejecta prominent around Kuiper crater (PIA11355) and the extensive ray system associated with a newly imaged crater in Mercury’s northern latitudes (PIA11356). In both of those examples, the rays appear bright, which is characteristic of freshly pulverized rock and indicates that the rays are younger than much of Mercury’s surface. In contrast, in the upper portion of this NAC image, a set of dark rays is seen emerging from a small crater. Dark rays are rare on Mercury, but other occurrences have been identified, such as at Mozart crater (PIA11024) imaged during MESSENGER’s first Mercury flyby). Mozart crater is interpreted to have excavated dark material from depth during the impact event, creating dark streamers. The dark rays from the crater shown here may have a similar origin, and color imaging from the Wide Angle Camera (WAC) gathered during the flyby is being used to explore the nature of these unusual dark rays further.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131773885
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 520 meters/pixel (0.32 miles/pixel)
Scale: The top of this image is about 530 kilometers across (330 miles)
Spacecraft Altitude: 20,000 kilometers (12,000 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11362: Dark Rays on Mercury sur le site de la NASA.
Click on image for larger annotated version
MESSENGER’s second Mercury flyby passed over the opposite side of the planet from that seen during the mission’s first Mercury encounter. Thus, if one could follow this view obtained by the NAC during the second flyby toward the south, beyond Mercury’s south pole, it would lead to the surface seen in an image from MESSENGER’s first Mercury flyby (PIA10187). Visible in the recently obtained image shown here are many features also seen by Mariner 10: Shevchenko crater named for the 19th century Ukrainian poet, Khansa for the Arabic poet of the 7th century, Rabelais for the Renaissance French writer, Holberg for the Norwegian-Danish writer of the 18th century, Spitteler for the Swiss epic poet who won the Nobel Prize for Literature in 1919, Rameau for the Baroque-era French composer, Puccini for the Italian composer of the late 1800s and early 1900s, and Horace for the ancient Roman poet. Discovery Rupes cuts through Rameau and is named for the ship of English explorer Captain James Cook.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131773823
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 510 meters/pixel (0.32 miles/pixel) at the top of the image
Scale: Shevchenko crater is 137 kilometers (85 miles) in diameter
Spacecraft Altitude: 20,000 kilometers (12,400 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11374: A View to the South…from the Other Side of Mercury sur le site de la NASA.
Just nine minutes after the MESSENGER spacecraft passed 200 kilometers (124 miles) above the surface of Mercury, its closest distance to the planet during the January 14, 2008, flyby, the Wide Angle Camera (WAC) on the Mercury Dual Imaging System (MDIS) snapped this image. The WAC is equipped with 11 different narrow-band filters, and this image was taken in filter 7, which is sensitive to light near the red end of the visible spectrum (750 nm). This view, also imaged through the remaining 10 WAC filters, is from the first set of images taken following MESSENGER's closest approach with Mercury.
The image shows Mercury's surface as seen from a low viewing angle, looking over the surface and off the limb of the planet on the right side of the image. The cratered terrain in the image is on the side of Mercury unseen by spacecraft prior to this MESSENGER flyby. This scene was imaged at multiple viewing angles as MESSENGER sped away from Mercury, and these multiple views of the same surface features from different perspectives and in different colors will be used to help understand the properties of Mercury's surface.
Mission Elapsed Time (MET) of image: 108825371
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10184: MESSENGER's First Image after Closest Approach sur le site de la NASA.
Recently named for the French photographer Eugène Atget, Atget crater, seen in the middle of the lower portion of this NAC image, is distinctive on Mercury's surface due to its dark color. Atget crater is located within Caloris basin, near Apollodorus crater and Pantheon Fossae, which are also both visible in this image to the northwest of Atget. The dark color of the floor of Atget is in contrast to other craters within Caloris basin that exhibit bright materials on their floors, such as the craters Kertész and Sander. Other craters on Mercury, such as Basho and Neruda, have halos of dark material but the dark material does not cover the crater floors. Understanding the variety of bright and dark materials associated with different craters will provide insight into Mercury's composition and the processes that acted on Mercury's surface.
Date Acquired: January 14, 2008
Image Mission Elapsed Time (MET: 108828540
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 520 meters/pixel (0.32 miles/pixel)
Scale: This image shows a scene about 530 kilometers (330 miles) across
Spacecraft Altitude: 20,300 kilometers (12,600 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10934: Voilà! Mercury's Atget sur le site de la NASA.
Click on image for
larger annotated version
Located in the western edge of Mercury's giant Caloris basin (PIA10383), Kertész crater (recently named for André Kertész, a Hungarian-born American photographer) has some unusual, bright material located on its floor. Sander crater (PIA10603), located in the northwestern edge of Caloris basin, also shows bright material on its floor. The MESSENGER Science Team is investigating the nature and composition of these bright materials and making comparisons between these two craters both located at the edges of Caloris basin. Just northeast of Kertész, a small crater has very bright rays and ejecta in this image, indicating that the crater is young.
Date Acquired: January 14, 2008
Image Mission Elapsed Time (MET): 108826812
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 260 meters/pixel (0.16 miles/pixel
Scale: Kertész crater is 34 kilometers (21 miles) in diameter
Spacecraft Altitude: 10,200 kilometers (6,340 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10933: MESSENGER Captures a Shot of Kertész sur le site de la NASA.
With just one day until MESSENGER's historic flyby of Mercury, MESSENGER has Mercury clearly in its sights. The Narrow Angle Camera, part of the Mercury Dual Imaging System (MDIS), took this image on January 12, 2008, when MESSENGER was about 1.2 million kilometers (750,000 miles) away from Mercury. Mercury has a diameter of about 4880 kilometers (3030 miles), and this image has a resolution of about 31 kilometers/pixel (19 miles/pixel).
Tomorrow, Monday, January 14, 2008, at 19:04:39 UTC (2:04:39 pm EST), MESSENGER will pass a mere 200 kilometers (124 miles) above the surface of Mercury and will be the first spacecraft to visit Mercury in nearly a third of a century, since Mariner 10 flew by Mercury in 1974 and 1975. Among the extensive scientific observations planned during the flyby is imaging a large portion of Mercury's surface that was not visible to the Mariner 10 mission. MESSENGER's flyby tomorrow will yield the first spacecraft images ever of these regions of Mercury's surface.
Image acquired on January 12, 2008, 09:06 UTC.
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10169: MESSENGER has Mercury in its Sights sur le site de la NASA.
MESSENGER images have revealed intriguing albedo and color variations on Mercury, providing insight into the compositional differences in the rocks found on Mercury's surface and the processes that have acted on them. The term albedo simply refers to the fraction of light reflected by a material. For example, charcoal has a very low albedo while snow has a very high albedo. This figure, recently published in Science magazine, highlights some of these variations.
A: The bright rays of Basho crater (diameter about 80 kilometers, 50 miles) likely are made of immature material, while the darker material near the rim is thought also to be immature material but of a different composition. Surface materials on Mercury are believed to change color and albedo over time as a result of bombardment by micrometeoroids and energetic particles from the solar wind. They eventually reach an unchanging, "mature" state. If the surface is disturbed, for instance by a cratering impact, underlying material is freshly exposed on the surface. It is termed "immature" if the disturbance was sufficiently recent that there hasn't yet been time for the exposed material to gain maturity.
B: Two craters within PIA10383 Caloris basin have dark crater walls, and the crater at upper right, PIA10603 Sander (diameter about 50 kilometers, 30 miles), has bright patches on its floor. Unlike the rays of Basho crater, the bright areas are not believed to be immature but are inherently bright.
C: PIA10607 Mozart crater (diameter about 220 kilometers, 140 miles) shows linear dark streamers (unlabeled arrows), which are thought to be material excavated from depth during the crater-forming impact. Similarly colored dark patches can also be seen in the crater wall (arrows labeled W) and in the central peak (arrow labeled P) and may be derived from the same underground layer.
D: The smooth plains (labeled SP) interior to Tolstoj basin are superimposed on the darker areas shown with unlabeled arrows. Materials with these two color and albedo characteristics are common on Mercury's surface. This image is 825 kilometers (513 miles) wide.
E: This image was generated by comparing and contrasting WAC images taken in 11 different color filters and choosing a color scheme to highlight differences on Mercury's surface. The image shows the dark streamers of Mozart crater (white arrows) and a young impact crater with fresh, immature rays (black arrow). The image is about 800 kilometers (500 miles) wide.
F: Using a similar color scheme, this image of a segment of the edge and rim of Caloris basin (white arrows) clearly shows that the rocks present on the basin's floor differ from those exterior to the basin. This image is about 600 kilometers (370 miles) wide.
Date Acquired: January 14, 2008
Image Mission Elapsed Time (MET): A: 108828233. B: 108826687. C: 108827022. D: 108828337, 108828342. E, F: 108829678-108829728.
Instrument: (A-D) Narrow Angle Camera (NAC) and (E-F) Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11024: A Closer Look at Albedo and Color Variations on Mercury sur le site de la NASA.
These two images, published in the July 4 issue of Science magazine, illustrate the power of using MESSENGER’s WAC multi-spectral images to study compositional variations across the surface of Mercury. Both images shown here were generated using a statistical method known as principal component analysis. In this analysis, images taken through the WAC’s 11 different narrow-band color filters are compared and contrasted to discover significant variations. The image on the left shows Mercury in one of the resulting principal components that enhances the largest color differences on Mercury’s surface. The Caloris basin (labeled with a C) is shown to be considerably different from the surrounding areas in this view. Dark craters within Caloris (shown with white arrows), such as Atget crater, are clearly distinct. Mozart crater (labeled with an M) and the Tolstoj basin and material ejected from it (basin labeled with Tsp; ejecta labeled with a T) also show significant color signatures. The image on the right was created by displaying the negative of the left image in red, a different principal component in green, and a ratio of images taken in two WAC filters (430 nm/560 nm) in blue. The white arrows identify areas of Mercury’s surface that are interpreted to be relatively young volcanic plains, and the black arrows point to reddish areas interpreted to be volcanoes. Most of the color differences studied here are believed to indicate variations in the mineral composition and physical state of the rocks at different places on Mercury.
Date Acquired: January 14, 2008
Image Mission Elapsed Time (MET): 108829678 - 108829728
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
Scale: Mercury’s diameter is 4880 kilometers (3030 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11219: Exploring Mercury’s Surface with MESSENGER’s Color Images sur le site de la NASA.
The International Astronomical Union (IAU) recently approved new names for features on Mercury that were all seen for the first time in images taken by MESSENGER during the spacecraft's first flyby of the planet. Read the full press release for additional details about the naming process and the origin of the names, and visit the U.S. Geological Survey website, the Gazetteer of Planetary Nomenclature, to learn about all of the named planetary features in the Solar System.
This image, produced by mosaicking many Narrow Angle Camera (NAC) images together, shows the locations of the newly named features, along with the craters Basho, Mozart, and Tolstoj, first seen by the Mariner 10 mission. Close-up views of many of these features are available in the MESSENGER website image gallery. In particular, look at these previous releases for NAC high-resolution images of Apollodorus, Beagle Rupes, Eminescu, Mozart, Neruda, Pantheon Fossae, Raditladi, and Sander.
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10611: New Names for Features on Mercury sur le site de la NASA.
The MESSENGER spacecraft continues to speed toward Mercury, preparing for its closest approach to the planet on Monday, January 14, 2008, at 19:04:39 UTC (2:04:39 pm EST). This image was snapped with the Narrow Angle Camera, one half of MESSENGER's Mercury Dual Imaging System (MDIS), on January 10, 2008, when MESSENGER was a distance of just less than 2 million kilometers (1.2 million miles) from the planet. Mercury is about 4880 kilometers (3030 miles) in diameter, and this image has a resolution of about 50 kilometers/pixel (31 miles/pixel).
During the flyby on January 14, 2008, extensive scientific observations are planned. Beginning 30 hours prior to the closest encounter, when the spacecraft will pass a mere 200 kilometers (124 miles) above the surface, MDIS will begin to acquire images regularly of Mercury and continue until about 22 hours following the closest approach. MESSENGER will then start to transmit the new data to Earth once all of the scientific measurements are completed. This exciting new data set will be the first spacecraft data returned from Mercury in over 30 years, since the three Mariner 10 flybys in 1974 and 1975.
Image acquired on January 10, 2008, 21:06 UTC.
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10167: MESSENGER Closes in on Mercury sur le site de la NASA.
MESSENGER successfully flew by Mercury yesterday, using Mercury’s gravity to perturb the probe’s path and to help put it on track to become, in March 2011, the first spacecraft ever to orbit the innermost planet in the Solar System. This image, acquired about 89 minutes before the craft’s closest approach to Mercury, resembles the optical navigation images taken leading up to the flyby. The resolution of this image is slightly better than that obtained by the final optical navigation image set (see PIA11244), and the surface visible is newly imaged terrain that was not previously seen by either Mariner 10 or during MESSENGER’s first flyby. However, the added resolution is not the main scientific advancement that will be provided by this image. This WAC image is one of 11 viewed through different narrow-band color filters, the set of which will enable detailed color studies of this newly imaged area. In addition, the Narrow Angle Camera (NAC) acquired a high-resolution mosaic of most of this thin crescent view of Mercury at a resolution better than 0.5 kilometers/pixel (0.3 miles/pixel) that will enable the MESSENGER team to explore this newly imaged region of Mercury’s surface in more detail. Images acquired during the flyby are currently still being transmitted to Earth, and the MESSENGER team is busy examining each of the 1223 as it arrives. When combined with the 64 optical navigation images previously obtained, MDIS acquired a total of 1287 images during the flyby encounter.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131764550
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC Filter: 1 (700 nanometers)
Resolution: 5 kilometers/pixel (3 miles/pixel)
Scale: Mercury’s diameter is 4880 kilometers (3030 miles)
Spacecraft Altitude: 27,000 kilometers (17,000 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11247: MESSENGER Encounters the Innermost Planet sur le site de la NASA.
As MESSENGER sped by Mercury on January 14, 2008, the Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS) captured this shot looking toward Mercury's north pole. The surface shown in this image is from the side of Mercury not previously seen by spacecraft. The top right of this image shows the limb of the planet, which transitions into the terminator (the line between the sunlit, day side and the dark, night side) on the top left of the image. Near the terminator, the Sun illuminates surface features at a low angle, casting long shadows and causing height differences of the surface to appear more prominent in this region.
It is interesting to compare MESSENGER's view to the north with the image looking toward the south pole, (PIA10187) released on January 21. Comparing these two images, it can be seen that the terrain near the south pole is more heavily cratered while some of the region near the north pole shows less cratered, smooth plains material, consistent with the general observations of the poles made by Mariner 10. MESSENGER acquired over 1200 images of Mercury's surface during its flyby, and the MESSENGER team is busy examining all of those images in detail, to understand the geologic history of the planet as a whole, from pole to pole.
>This image was acquired about 94 minutes after MESSENGER's closest approach to Mercury, when the spacecraft was at a distance of about 32,000 kilometers (20,000 miles).
Mission Elapsed Time (MET) of image: 108830513
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10193: MESSENGER Looks to the North sur le site de la NASA.
One week ago, no spacecraft had ever seen the majority of the surface visible in this image. Today, one week after MESSENGER’s successful second Mercury flyby, about 95% of Mercury’s surface has been viewed by spacecraft, resulting in nearly global spacecraft imaging coverage of Mercury’s surface for the first time. This WAC image is just one of 99 in a set of 3 columns by 3 rows by 11 color filters that is being combined into a color mosaic of the departing planet. Kuiper crater (PIA11355), with its bright ejecta rays, is visible on the left edge of the image and was seen by Mariner 10, but most of the terrain east of Kuiper was not. A newly imaged crater with an unusual halo of dark material (PIA11357) is visible at about the same latitude but toward Mercury’s limb. The long, bright rays that can be seen extending across the surface emanate from a crater just north of this image (PIA11356).
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131772818
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC Filter: 1 (700 nanometers)
Resolution: 2.6 kilometers/pixel (1.6 miles/pixel)
Scale: The left side of the image is about 2,700 kilometers tall (1,700 miles)
Spacecraft Altitude: 15,000 kilometers (9,300 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11363: What a Difference a Week Can Make sur le site de la NASA.
As the MESSENGER team continues to study the high-resolution images taken during the Mercury flyby encounter on January 14, 2008, scarps (cliffs) that extend for long distances are discovered. This frame, taken by the Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS), shows a region of Mercury's surface previously unseen by spacecraft and a large scarp crossing vertically through the scene, on the far right of the image. This scarp is the northern continuation of the one seen in the NAC image released on January 16 (PIA10174). The width of this image is about 200 kilometers (about 125 miles), showing that these scarps can be hundreds of kilometers long on Mercury.
The presence of many long and high scarps, as discovered from pictures from the Mariner 10 mission in 1974 and 1975, suggests a history for Mercury that is unlike that of any of the other planets in the solar system. These giant scarps are believed to have formed when Mercury's interior cooled and the entire planet shrank slightly as a result. However, Mariner 10 was able to view less than half the planet, so the global extent of these scarps has been unknown. MESSENGER images, like this one, are providing the first high-resolution looks at many areas on Mercury's surface, and science team members are busy mapping these newly discovered scarps to see whether they are common everywhere on the planet.
Mission Elapsed Time (MET) of image: 108826206
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10194: Mercury's Long Cliffs sur le site de la NASA.
Given the WAC’s ability to take images through 11 narrow-band color filters, it is natural to wonder what does Mercury look like in “true” color such as would be seen by the human eye. However, creating such a natural color view is not as simple as it may seem. Shown here are four images of Mercury. The image in the top left is the previously released grayscale monochrome single WAC filter (430-nanometer) image (PIA11245); the remaining three images are three-color composites, produced by placing the same three WAC filter images with peak sensitivities at 480, 560, and 630 nanometers in the blue, green, and red channels, respectively. The differences between the color representations result from how the brightness and contrast of each individual WAC filter image was adjusted before it was combined into a color picture. In the top right view, all of the three filter images were stretched using the same brightness and contrast settings. In the bottom left picture, the brightness and contrast of each of the three filter images were determined independent of the others. In the bottom right, the brightness and contrast settings used in the upper right version were slightly adjusted to make each of the three filter images span a similar range of brightness and contrast values.
So which color representation is “correct” for Mercury? The answer to that would indeed depend on the eye of the beholder. Every individual sees color differently; the human eye has a range of sensitivities that vary from person to person, resulting in different perceptions of “true” color. In addition, the three MDIS filter bands are narrow, and light at wavelengths between their peaks is not detected, unlike the human eye. In general, in light visible to the human eye, Mercury’s surface shows only very subtle color variations, as seen in the three images here. However, when images from all 11 WAC filters are statistically compared and contrasted, these subtle color variations can be greatly enhanced, resulting in extremely colorful representations of Mercury’s surface, such as seen in a high-resolution image of Thākur crater (PIA11365).
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131775256, 131775260, 131775264, 131775268
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 5 kilometers/pixel (3 miles/pixel)
Scale: Mercury’s diameter is 4880 kilometers (3030 miles)
Spacecraft Altitude: 27,000 kilometers (17,000 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11364: Mercury’s “True” Color is in the Eye of the Beholder sur le site de la NASA.
This scene was imaged by MESSENGER's Narrow Angle Camera (NAC) on the Mercury Dual Imaging System (MDIS) during the spacecraft's flyby of Mercury on January 14, 2008. The scene is part of a mosaic that covers a portion of the hemisphere not viewed by Mariner 10 during any of its three flybys (1974-1975). The surface of Mercury is revealed at a resolution of about 250 meters/pixel (about 820 feet/pixel). For this image, the Sun is illuminating the scene from the top and north is to the left.
The outer diameter of the large double ring crater at the center of the scene is about 260 km (about 160 miles). The crater appears to be filled with smooth plains material that may be volcanic in nature. Multiple chains of smaller secondary craters are also seen extending radially outward from the double ring crater. Double or multiple rings form in craters with very large diameters, often referred to as impact basins. On Mercury, double ring basins begin to form when the crater diameter exceeds about 200 km (about 125 miles); at such an onset diameter the inner rings are typically low, partial, or discontinuous. The transition diameter at which craters begin to form rings is not the same on all bodies and, although it depends primarily on the surface gravity of the planet or moon, the transition diameter can also reveal important information about the physical characteristics of surface materials. Studying impact craters, such as this one, in the more than 1200 images returned from this flyby will provide clues to the physical properties of Mercury's surface and its geological history.
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10378: Double Ring Crater sur le site de la NASA.
Machaut is the name of a crater, approximately 106 kilometers (66 miles) in diameter, first seen under high-Sun conditions by Mariner 10 in the 1970s. The crater is named for the medieval French composer and poet Guillaume de Machaut. This NAC image shows an amazing new view of Machaut taken during MESSENGER’s second flyby of Mercury. The slanting rays of the Sun cast shadows that reveal numerous small craters and intricate features. The largest crater within Machaut appears to have been inundated by lava flows similar to those that have filled most of the floor of the larger feature. The adjacent, slightly smaller crater was formed at a later time and excavated material below the lava-formed surface. MESSENGER science team members will also be studying the shallow ridges that crisscross Machaut’s floor.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131770808
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 100 meters/pixel (0.06 miles/pixel)
Scale: This image is about 100 kilometers across (60 miles)
Spacecraft Altitude: 3,900 kilometers (2,400 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11249: Detailed Look within a Previously Known Crater sur le site de la NASA.
Extending from the left edge of this image downward toward the lower right corner is a long cliff face. This cliff runs through a large ancient crater in the center of the frame. Cliffs such as this one, referred to as rupes on Mercury, have been identified on other areas of the planet, such as Beagle Rupes (PIA10939) imaged during MESSENGER’s first flyby. This rupes is being seen for the first time, as this portion of Mercury’s surface is located within the “gap” present in the Mariner 10 dataset (PIA11354). This cliff may have been created when, in Mercury’s past, the entire planet cooled and the surface consequently contracted.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131771143
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 150 meters/pixel (0.09 miles/pixel)
Scale: The bottom of this image is about 150 kilometers across (93 miles)
Spacecraft Altitude: 5,700 kilometers (3,500 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11358: A Cliff Runs Through It sur le site de la NASA.
As MESSENGER neared Mercury on January 14, 2008, the spacecraft's Wide Angle Camera on the Mercury Dual Imaging System (MDIS) took images of the planet through each of its 11 filters. This image of the planet's full crescent was taken using the 7th filter, in light near the far-red end of the visible spectrum (750 nm). The image shows portions of Mercury previously seen by Mariner 10, but when Mariner 10 flew by the planet at each of its encounters the Sun was nearly overhead. For this MESSENGER flyby, in contrast, the Sun is shining obliquely on regions near the day/night boundary (called the terminator) on the right-hand side of the crescent, revealing the surface topography in sharp relief. This image illustrates how MESSENGER, during its future flybys and subsequent orbital mission, will teach us much about the portion of Mercury already imaged by Mariner 10, and not just because of its superior camera and close proximity to the planet. The solar lighting geometry makes an enormous difference.
This picture provides a global context for the MDIS Narrow Angle Camera (NAC) images taken while MESSENGER was inbound. For example, the NAC image of the crater Vivaldi (PIA10175), released earlier this week, would fit as a small patch on the terminator just above the center of the crescent. The already released image that includes the crater Sholem Aleichem (PIA10176) shows a part of Mercury near the top of the crescent. More NAC images of the incoming crescent will be released in the future.
This image was taken about 80 minutes before closest approach from a distance of about 27,000 kilometers (17,000 miles) and shows features as small as 10 kilometers (6 miles).
Mission Elapsed Time (MET) of image: 108820027
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10179: An Overview of Mercury as MESSENGER Approached sur le site de la NASA.
This image was taken about 54 minutes before MESSENGER’s closest approach to Mercury during the mission’s second flyby of the innermost planet in the Solar System. The striking image shows a view looking over Mercury’s horizon into the darkness of space. The surface in this image is located in the northern portion of the sunlit, crescent-shaped planet seen as the spacecraft approached Mercury (see PIA11247). The low Sun angle creates distinct shadows, enhancing the visibility of the roughness of the surface, which is especially prominent for material ejected from, and surrounding, the impact crater cut by the left edge of this image.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131766595
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 410 meters/pixel (0.25 miles/pixel) near the bottom of the image
Scale: The bottom length of the image is about 420 kilometers (260 miles)
Spacecraft Altitude: 16,000 kilometers (9,900 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11351: A View Over Mercury’s Horizon sur le site de la NASA.
Today, January 14, 2008, at 19:04:39 UTC (2:04:39 pm EST), MESSENGER will experience its closest approach to Mercury, passing just 200 kilometers (124 miles) above the planet's surface. As the MESSENGER spacecraft continues to speed toward Mercury, the Narrow Angle Camera, part of the Mercury Dual Imaging System (MDIS) instrument, acquired this crescent view of Mercury. The image was taken on January 13, 2008, when the spacecraft was at a distance of about 760,000 kilometers (470,000 miles) from Mercury. Mercury is about 4880 kilometers (about 3030 miles) in diameter, and this image has a resolution of about 20 kilometers/pixel (12 miles/pixel).
During the historic flyby encounter today, extensive scientific data will be gathered. The MDIS instrument will acquire over 1200 images of Mercury, including images of portions of the surface never before viewed by a spacecraft. The MDIS instrument is just one member of a whole suite of instruments that will be used to study Mercury during the flyby. The Mercury Atmospheric and Surface Composition Spectrometer (MASCS) will observe Mercury's surface as well as its tenuous atmosphere. The MESSENGER Magnetometer (MAG) will accurately measure Mercury's magnetic field, and the Energetic Particle and Plasma Spectrometer (EPPS) will characterize Mercury's space environment and interactions with the solar wind. The Mercury Laser Altimeter (MLA) will sense surface topography along a narrow profile. The Gamma-Ray and Neutron Spectrometer (GRNS) and X-Ray Spectrometer (XRS) will make the first measurements of Mercury's surface elemental composition.
MESSENGER will begin to transmit the new data to Earth once all of the scientific measurements are completed, about 22 hours after the spacecraft's closest approach to Mercury. These flyby data will shed light on fundamental scientific questions related to the formation and evolution of the planet Mercury. As scientists analyze the data, the MESSENGER spacecraft will continue on its planned journey, which includes two more encounters of Mercury in October 2008 and September 2009, before entering an orbit around Mercury in March 2011.
Image acquired on January 13, 2008, 06:34 UTC.
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10170: Countdown to MESSENGER's Closest Approach with Mercury sur le site de la NASA.
The Caloris basin on Mercury is one of the youngest large impact basins in the Solar System, and MESSENGER images are enabling scientists to study it in ways not previously possible. This image, acquired by the Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS), was taken on January 14, 2008, and shows an area that is about 280 kilometers across (about 170 miles) on the floor of the basin. Bright rays from a young impact crater extend into the image from the top right corner. This bright-rayed crater is located slightly left of the center of the basin and is easily spotted on the previously released image that shows the entire Caloris basin (PIA10383).
The spectacular fractures seen cutting the floor of the basin, as visible in this image, show that extensional (pull-apart) forces deformed Mercury's crust in the ancient past. Impact craters can be observed on top of the fractures and the fractures do not deform the craters, indicating that the fractures are ancient. The fractures are observed in the smooth plains material that fills the Caloris basin, are found near the outer edges of the basin, and are oriented roughly concentric with the basin's rim. This orientation is in contrast to a series of radial fractures located in the center of the Caloris basin (PIA10397). The fractures were likely formed when the floor of the basin was uplifted, causing horizontal stretching and breaking apart of the material that filled the basin. Similar concentric fractures were observed on the eastern side of the basin that was photographed by Mariner 10. By mapping out the extent of these fractures and other tectonic features, MESSENGER scientists are exploring how Mercury's great Caloris basin evolved after it formed.
Image Mission Elapsed Time (MET): 108826817
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10606: Exploring the Evolution of the Caloris Basin sur le site de la NASA.
In one of the first images transmitted back to Earth following MESSENGER’s second flyby of Mercury, an image of the entire departing planet (PIA11245), a spectacular and extensive system of rays can be seen. This NAC image shows a close-up view of the apparent source of those rays, a crater 110 kilometers (68 miles) in diameter located in the northern region of Mercury. The location of this bright crater is consistent with Earth-based radar images, which suggested a very fresh, rayed impact crater in this area. The amazing extent of this large ray system is visible for the first time in MESSENGER’s newly acquired images.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131774306
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 570 meters/pixel (0.35 miles/pixel) at the bottom left of the image
Scale: The extensively rayed crater is about 110 kilometers in diameter (68 miles)
Spacecraft Altitude: 22,000 kilometers (14,000 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11356: Looking Back to the Source sur le site de la NASA.
Shortly following MESSENGER's closest approach to Mercury on January 14, 2008, the spacecraft's Narrow Angle Camera (NAC) on the Mercury Dual Imaging System (MDIS) instrument acquired this image as part of a mosaic that covers much of the sunlit portion of the hemisphere not viewed by Mariner 10. Images such as this one can be read in terms of a sequence of geological events and provide insight into the relative timing of processes that have acted on Mercury's surface in the past.
The double-ringed crater pictured in the lower left of this image appears to be filled with smooth plains material, perhaps volcanic in nature. This crater was subsequently disrupted by the formation of a prominent scarp (cliff), the surface expression of a major crustal fault system, that runs alongside part of its northern rim and may have led to the uplift seen across a portion of the crater's floor. A smaller crater in the lower right of the image has also been cut by the scarp, showing that the fault beneath the scarp was active after both of these craters had formed. The MESSENGER team is working to combine inferences about the timing of events gained from this image with similar information from the hundreds of other images acquired by MESSENGER to extend and refine the geological history of Mercury previously defined on the basis only of Mariner 10 images.
This MESSENGER image was taken from a distance of about 18,000 kilometers (11,000 miles) from the surface of Mercury, at 20:03 UTC, about 58 minutes after the closest approach point of the flyby. The region shown is about 500 kilometers (300 miles) across, and craters as small as 1 kilometer (0.6 mile) can be seen in this image.
Mission Elapsed Time (MET) of image: 108828359
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10177: MESSENGER Reveals Mercury's Geological History sur le site de la NASA.
One month ago, on January 14, 2008, MESSENGER became the first spacecraft in over three decades to visit Mercury, snapping images of a large portion of Mercury's surface previously unseen by spacecraft. As the spacecraft proceeds on its journey, the science team continues to study the 1213 images returned from the mission's historic first flyby. The probe's trajectory will bring it to a second Mercury flyby on October 6, 2008.
MESSENGER's Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS) captured this image during the flyby one month ago. The Sun is illuminating this region at a low angle, accentuating the modest ridges and other low topography on these nearly flat plains. Low ridges trend from the top-center of the image to the left edge (white arrows). The ghostly remains of craters are visible, filled to their rims by what may have been volcanic lavas (red arrows). The faint remnant of an inner ring within the large crater in the bottom half of this picture can be seen (blue arrow); the area interior to this ring was also flooded, possibly by lava, nearly to the point of disappearance. Clusters of secondary craters on the floor of the large crater and elsewhere (yellow arrows) formed when clumps of material were ejected from large impacts beyond the view of this image, which is about 350 kilometers (220 miles) across.
Image Mission Elapsed Time (MET): 108826972
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10601: One Month Ago… sur le site de la NASA.
This image of Mercury's surface was acquired during MESSENGER's first flyby of the planet on January 14, 2008, through the lens of the Narrow Angle Camera (NAC), part of the Mercury Dual Imaging System (MDIS). The image was acquired when MDIS was 11,588 km (7,200 miles) from Mercury's surface.
Several processes have acted to sculpt Mercury's surface over time, and evidence of them is abundant in this image. This scene shows at least five different events in Mercury's surface history. The large crater to the lower left of the image measures ~230 km (143 miles) in diameter and has a prominent crater, about 85 km (53 miles) across, nestled inside it, south of its center. Both of these craters were subsequently filled with a material that appears to have been emplaced in a relatively fluid form, as evidenced by the fact that the material "embays" or onlaps the ejecta blanket surrounding the rim of the smaller crater. The larger crater is filled almost to its rim with this smooth plains material, which is thought to be of volcanic origin. Subsequent to the plains emplacement was the formation of the linear feature trending southwest to northeast across the lower half of the scene. This feature is a lobate scarp, similar to many others found on Mercury's surface, and thought to originate when compressional stresses crumpled the surface. The last major episode in the history of this region is the impact that formed the large crater at the top of the image. The formation of this crater resulted in impact-derived material, known as ejecta, being thrown out radially for large distances. Some of this ejecta formed chains of "secondary" craters as it impacted back onto the surface; some of these secondary craters are visible atop the lobate scarp.
By careful examination of the relationships among features within images such as these, Mercury's surface history can be teased out, enabling us to better understand the evolution of this planet and other terrestrial worlds.
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10384: Mercury's Violent History sur le site de la NASA.
Last week, the MESSENGER team learned that the impact crater seen in the middle of this Narrow Angle Camera (NAC) image has been officially named Eminescu. The crater was named in honor of Mihai Eminescu, an accomplished and influential poet who is still considered the national poet of Romania. The MESSENGER team proposed the name to the International Astronomical Union (IAU), the authority that officially names surface features on planetary bodies.
Eminescu crater is 125 kilometers (78 miles) in diameter and can be seen just at the top of the image previously released on January 30 (PIA10384). The image shown here was acquired by the Mercury Dual Imaging System (MDIS) on January 14, 2008, and shows a portion of Mercury's surface unseen by spacecraft prior to MESSENGER's historic flyby. Eminescu is a particularly interesting crater for several reasons. Eminescu formed more recently than most of the craters on Mercury, on the grounds that there are very few later craters superposed on it. Moreover, impressive chains of secondary craters, formed by material ejected by the impact explosion that formed the crater, radiate away from Eminescu. The central peaks within the crater are arranged in a circular pattern; geologists call this a "peak ring." The bright peaks inside Eminescu exhibit unusual color characteristics in the 11-color Wide Angle Camera (WAC) images, which the MESSENGER Science Team is currently studying. They show up with a bluish tinge in the previously released false-color image of the entire planet (PIA10398); Eminescu is just north of the equator, near the day/night "terminator" in that image.
Image Mission Elapsed Time (MET): 108828468
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10610: Now Introducing: Eminescu sur le site de la NASA.
On January 9, 2008, the MESSENGER spacecraft snapped one of its first images of Mercury at a distance of about 2.7 million kilometers (1.7 million miles) from the planet. The image was acquired with the Narrow Angle Camera, one half of MESSENGER's Mercury Dual Imaging System (MDIS) instrument. Mercury is about 4880 kilometers (3030 miles) in diameter, and this image has a resolution of about 70 kilometers/pixel (43 miles/pixel). The MESSENGER spacecraft is fast approaching Mercury and will pass within 200 kilometers (124 miles) of the surface at 19:04:39 UTC (2:04:39 pm EST) on January 14, 2008. During this close encounter, MESSENGER will gather extensive scientific data about the planet, including measurements of Mercury's magnetic field, observations of Mercury's thin atmosphere, and images of the hemisphere of Mercury that has never before been viewed by a spacecraft.
MESSENGER is only the second spacecraft to visit the planet Mercury; the first was Mariner 10 in 1974. The data from MESSENGER's first encounter with Mercury will help address key outstanding science questions about this little known planet. The MESSENGER mission will have two additional encounters with Mercury, in October 2008 and September 2009. All three encounters with Mercury provide gravity assists to enable MESSENGER to become the first spacecraft ever to orbit Mercury in March 2011.
Image acquired on January 9, 2008, 11:04 UTC.
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10166: MESSENGER Readies for its Encounter with Mercury sur le site de la NASA.
This image shows details of the Caloris basin, one of the largest impact basins in the solar system. Caloris was discovered in 1974 from the Mariner 10 images, but when Mariner 10 flew by Mercury, only the eastern half of the basin was in daylight. During its first flyby of Mercury, on January 14, 2008, the MESSENGER spacecraft was able to snap the first high-resolution images of the western half of the basin. This image is a compilation of pictures from the Mariner 10 mission (right portion of the image) and images from MESSENGER's Narrow Angle Camera (NAC), part of the Mercury Dual Imaging System (left portion of the image).
When Mariner 10 imaged the Caloris basin, the lighting conditions were very different from those experienced by MESSENGER, as is evidenced by the visible seam created when images from both missions are mosaicked together. Despite the different lighting conditions, the MESSENGER images show that the Caloris basin is even larger than previously believed. On the basis of images from Mariner 10, the rim of the Caloris structure was estimated at about 1300 km (about 800 miles) in diameter, shown as a yellow dotted line in this image. MESSENGER's images, which allow the entire Caloris basin to be seen at high-resolution for the first time, indicate that the basin rim, shown as a blue dotted line in the image, is actually closer to 1550 kilometers (about 960 miles) in diameter. Understanding the formation of this giant basin will provide insight into the early history of major impacts in the inner Solar System, with implications not just for Mercury, but for all the planets, including Earth.
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10383: The Great Caloris Basin on Mercury sur le site de la NASA.
Planetary scientists commonly compare and contrast the geologic features found on different planetary bodies, to learn about the similar processes that operated throughout the Solar System and to understand how each planet is different and unique. This figure, recently published in Science magazine, shows wrinkle-ridge rings on both Mercury (upper image) and Mars (lower image) that look quite similar. Wrinkle ridges arrayed in such a ring are interpreted to trace the rim of an impact crater that was nearly or completely flooded by lavas prior to ridge formation. Wrinkle ridges are created by forces that compress the crust horizontally. A buried crater rim can concentrate the near-surface forces and cause the wrinkle ridges to form a ring. The presence of wrinkle-ridge rings is thus good evidence that volcanism helped to shape the surfaces of both Mars and Mercury.
Date Acquired: January 14, 2008
Image Mission Elapsed Time (MET): A: 108826972
Instrument: A: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Mars Image: B: Mars Express High-Resolution Stereo Camera nadir image h2660_0001
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11025: Wrinkle-Ridge Rings on Mercury and Mars sur le site de la NASA.
With just two days until MESSENGER's closest pass by Mercury, the Mercury Dual Imaging System (MDIS) is acquiring sets of images twice a day. These images are used for optical navigation purposes, to verify that the spacecraft is on the desired course. The images also provide the first glimpse of Mercury by a spacecraft in over 30 years, since the Mariner 10 mission in 1974 and 1975, and hint at the exciting images to come in the next week. This image was snapped on January 11, 2008, when MESSENGER was at a distance of about 1.7 million kilometers (1.1 million miles) from Mercury. The diameter of Mercury is about 4880 kilometers (3030 miles), and this image has a resolution of about 44 kilometers/pixel (27 miles/pixel).
MESSENGER will pass 200 kilometers (124 miles) above Mercury's surface on Monday, January 14, 2008, at 19:04:39 UTC (2:04:39 pm EST). Extensive scientific observations are planned during this historic flyby, including imaging a large portion of Mercury's surface that has never before been seen by a spacecraft. These data will be used to address fundamental questions about Mercury's formation, evolution, and the history of our solar system.
Image acquired on January 11, 2008, 09:06 UTC.
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10168: MESSENGER Nears Mercury sur le site de la NASA.
Mercury's giant Caloris basin is the best-preserved large impact basin known on Mercury, and the high density of craters on its floor indicates that the basin is fairly old and probably formed about 3.8 billion years ago. This NAC image shows an area on the plains that partially fill the Caloris basin floor. On the right portion of this image, the light-colored rays emanating from Cunningham crater (named for the American photographer Imogen Cunningham) show that this crater is relatively young; bright ejecta rays tend to darken with time, as the ejected material is gradually modified by impacting micrometeoroids and solar particles (a suite of different processes that together are called “space weathering”). Relative age relationships such as this one are used to unravel Mercury's geologic history. The similar-sized Kertész crater is also visible on the left side of this image.
Date Acquired: January 14, 2008
Image Mission Elapsed Time (MET:108828535
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 520 meters/pixel (0.32 miles/pixel)
Scale: Diameter of Cunningham crater is 37 kilometers (23 miles)
Spacecraft Altitude: 20,300 kilometers (12,600 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10935: Young Cunningham Crater in Old Caloris Basin sur le site de la NASA.
Though Basho crater is only about 80 kilometers (50 miles) in diameter, its bright rays make it an easily identified feature on Mercury's surface. In addition to the long bright rays, photographs from Mariner 10 showed an intriguing dark halo of material around the crater, which can be seen in the lower right portion of this Narrow Angle Camera (NAC) image snapped by MESSENGER's Mercury Dual Imaging System (MDIS) on January 14, 2008. The MESSENGER Science Team is using the full color data set obtained with the 11 filters of the Wide Angle Camera (WAC) to investigate the nature and composition of this dark material. Basho crater is visible near Mercury's limb in the southeastern portion of the WAC false color image previously released (see PIA10398).
The crater is named for the 17th-century Japanese poet Matsuo Basho, renowned for his many haiku. MESSENGER's images of Mercury's striking landscape have inspired at least one poet; read Stuart Atkinson's poem "MESSENGER's Memories."
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10650: Bright Rays Extending from a Halo of Darkness Gaze upon Basho sur le site de la NASA.
A complex history of geological evolution is recorded in this frame from the Narrow Angle Camera (NAC), part of the Mercury Dual Imaging System (MDIS) instrument, taken during MESSENGER's close flyby of Mercury on January 14, 2008. Part of an old, large crater occupies most of the lower left portion of the frame. An arrangement of ridges and cliffs in the shape of a "Y" crosses the crater's floor. The shadows defining the ridges are cast on the floor of the crater by the Sun shining from the right, indicating a descending stair-step of plains. The main, right-hand branch of the "Y" crosses the crater floor, the crater rim, and continues off the top edge of the picture; it appears to be a classic "lobate scarp" (irregularly shaped cliff) common in all areas of Mercury imaged so far. These lobate scarps were formed during a period when Mercury's crust was contracting as the planet cooled. In contrast, the branch of the Y to the left ends at the crater rim and is restricted to the floor of the crater. Both it and the lighter-colored ridge that extends downward from it resemble "wrinkle ridges" that are common on the large volcanic plains, or "maria," on the Moon. The MESSENGER science team is studying what features like these reveal about the interior cooling history of Mercury.
Ghostly remnants of a few craters are seen on the right side of this image, possibly indicating that once-pristine, bowl-shaped craters (like those on the large crater's floor) have been subsequently flooded by volcanism or some other plains-forming process.
This image was taken 18 minutes after close approach, when MESSENGER was about 5,000 kilometers (about 3,000 miles) away from Mercury. The image is about 200 kilometers (about 125 miles) across, and features as small as about 400 meters (about 400 yards) can be resolved.
Mission Elapsed Time (MET) of image: 108825904
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA10185: Ridges and Cliffs on Mercury's Surface sur le site de la NASA.
The first image taken following MESSENGER’s closest distance to Mercury (PIA11352) during the mission’s recent flyby was a Wide Angle Camera (WAC) image. The image shown here is the first NAC image acquired after closest approach, and since the resolution of the NAC is a factor of seven higher than that of the WAC, this image is the highest-resolution image obtained during MESSENGER’s second Mercury flyby. The image was taken near local dawn, so the shadows are long and many features are shrouded in darkness. The right side of this image overlaps with the left side of the previously released close-up view of Machaut crater (PIA11249), which was taken just five seconds later than this image. This portion of Mercury’s surface is heavily cratered, with small craters visible down to the limits of even this highest-resolution image.
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131770803
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 100 meters/pixel (0.06 miles/pixel)
Scale: This image is about 100 kilometers (60 miles) across
Spacecraft Altitude: 3,800 kilometers (2,400 miles)
These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.
Voir l'image PIA11372: The Highest-resolution Image from MESSENGER’s Second Mercury Flyby sur le site de la NASA.
