Saturn's expansive rings separate the moon's Tethys (at the top) from Dione (at the bottom). Even in this distant view, it is easy to see that the moons' surfaces, and likely their evolutionary histories, are very different.
Both moons are on the far side of the rings in this scene, which shows their Saturn-facing hemispheres (terrain centered on 0 degrees longitude). The dark shadow across the rings is cast by Saturn's southern hemisphere.
The diameter of Tethys is 1,071 kilometers (665 miles) and the diameter of Dione is 1,126 kilometers (700 miles).
This image was taken in visible light with the Cassini spacecraft narrow-angle camera on Sept. 12, 2005, at a distance of approximately 2.4 million kilometers (1.5 million miles) from Saturn. The image scale is about 17 kilometers (11 miles) per pixel on the two moons.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.
For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov. The Cassini imaging team homepage is at http://ciclops.org.
This movie, showing six of Saturn's small ring-region moons as they raced around the planet, was made from images taken by the Cassini spacecraft on Nov. 15, 2004.
The moons appear in following order (their diameters are given in parentheses): Janus (181 kilometers, or 113 miles), Atlas (32 kilometers, or 20 miles), Epimetheus (116 kilometers, or 72 miles), Prometheus (102 kilometers, or 63 miles), Pandora (84 kilometers, or 52 miles) and Pan (20 kilometers, or 12 miles). Each moon is marked by a colored circle that corresponds to the key at lower left.
While little detail on the moons is visible, it is possible to discern the irregular shapes of the larger ones seen in this movie. The rings are overexposed due to the long exposure times used (2 seconds per image): doing so makes the smaller, fainter moons (especially Pan) easier to detect. The direction of the moons' motion is prograde, or clockwise as seen from Cassini's vantage point beneath the ring plane.
In addition to the moons, knots in the F ring are visible here, as are several faint ringlets on both sides of that ring's bright core. Faint knots also appear sporadically within the narrow Encke gap, where tiny Pan resides.
The movie consists of 73 images and spans a period of just over 14.5 hours, about an orbital period of the particles in the F ring.
The individual frames were taken at 12 minute intervals in visible light with Cassini's narrow angle camera. The spacecraft was about 4.5 million kilometers (2.8 million miles) from Saturn when the images were taken. Image scale is approximately 26.5 kilometers (16.5 miles) per pixel.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.
For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov. For images visit the Cassini imaging team home page http://ciclops.org.
Saturn wears a halo of four moons in this wide angle camera image taken by the Cassini spacecraft on August 18, 2004.
Satellites visible in this image are (clockwise from upper left): Tethys (1060 kilometers, or 659 miles wide); Dione (1118 kilometers or 695 miles wide); Enceladus (499 kilometers or 310 miles wide); and Mimas (398 kilometers or 247 miles wide).
The image was taken in visible red light at a distance of 8.9 million kilometers (5.5 million miles) from Saturn. The image scale is 529 kilometers (329 miles) per pixel.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Office of Space Science, Washington, D.C. The Cassini orbiter and its two onboard cameras, were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.
For more information, about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org.
A scene straight out of science fiction, this fantastic view shows, from left to right, Saturn's moon's Mimas, Dione and Rhea, on the far side of Saturn's nearly edge-on rings.
The trailing hemispheres of all three moons are sunlit here, and wispy markings can be seen on the limbs of both Dione and Rhea. The diameter of Mimas is 397 kilometers (247 miles), Dione is 1,118 kilometers (695 miles) and Rhea is 1,528 kilometers (949 miles).
The image was taken in visible blue light with the Cassini spacecraft narrow-angle camera on March 15, 2005, at a distance of approximately 2.4 million kilometers (1.5 million miles) from Saturn. The image scale is 14 kilometers (9 miles) per pixel.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.
For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org.
This fanciful view spies the Saturnian moons, Dione and Enceladus, from just beneath the ringplane. Enceladus (505 kilometers, or 314 miles across) is on the near side of the rings with respect to Cassini, and Dione (1,126 kilometers, or 700 miles across) is on the far side.
Saturn's shadow stretches beyond the outermost reaches of the main rings, causing them to disappear at left.
The image was taken with the Cassini narrow-angle camera using spectral filters sensitive to polarized green light on Oct. 15, 2005 at a distance of approximately 2.1 million kilometers (1.3 million miles) from Dione and 1.5 million kilometers (900,000 miles) from Enceladus. The image scale is 12 kilometers (7 miles) per pixel on Dione and 9 kilometers (6 miles) per pixel on Enceladus.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.
For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov. The Cassini imaging team homepage is at http://ciclops.org.The moons Dione and Tethys face each other across the gulf of Saturn's rings. Here, the Cassini spacecraft looks on the Saturn-facing hemisphere of Tethys below and the anti-Saturn side of Dione above. The dark groove in the rings is the Cassini Division.
Tethys is 1,071 kilometers (665 miles) across, while Dione is 1,126 kilometers (700 miles) across.
This image was taken in visible light with the Cassini spacecraft narrow-angle camera on Sept. 22, 2005, at a distance of approximately 860,000 kilometers (530,000 miles) from Dione. Tethys was on the far side of the rings, 1.5 million kilometers (900,000 miles) from Cassini. The image scale is 5 kilometers (3 miles) per pixel on Dione and 9 kilometers (6 miles) per pixel on Tethys.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.
For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov. The Cassini imaging team homepage is at http://ciclops.org.
Saturn's peaceful beauty invites the Cassini spacecraft for a closer look in this natural color view, taken during the spacecraft's approach to the planet. By this point in the approach sequence, Saturn was large enough that two narrow angle camera images were required to capture an end-to-end view of the planet, its delicate rings and several of its icy moons. The composite is made entire from these two images.
Moons visible in this mosaic: Epimetheus (116 kilometers, 72 miles across), Pandora (84 kilometers, 52 miles across) and Mimas (398 kilometers, 247 miles across) at left of Saturn; Prometheus (102 kilometers, 63 miles across), Janus (181 kilometers, 113 miles across) and Enceladus (499 kilometers, 310 miles across) at right of Saturn.
The images were taken on May 7, 2004 from a distance of 28.2 million kilometers (17.6 million miles) from Saturn. The image scale is 169 kilometers (105 miles) per pixel. Moons in the image have been brightened for visibility.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Office of Space Science, Washington, D.C. The Cassini orbiter and its two onboard cameras, were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.
For more information, about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org.
Saturn's atmosphere is prominently shown with the rings emerging from behind the planet at upper right. The two moons on the left of the image are Mimas and Enceladus.
This image was taken on August 8, 2004, with the Cassini spacecraft narrow angle camera in red, green, and blue filters. This image was taken 8.5 million kilometers (5.3 million miles) from Saturn. Contrast has been enhanced to aid visibility.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL.
For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov.
This image shows Saturn's moon Tethys partially occulting the moon Dione. The difference in the surface brightness of the two moons is immediately apparent.
The diameter of Tethys is 1,071 kilometers (665 miles), while Dione is 1,126 kilometers (700 miles) across.
This still image was acquired on Sept. 16, 2005, at a distance of 2.1 million kilometers (1.3 million miles) from Dione and 2.7 million kilometers (1.7 million miles) from Tethys. Resolution in the original images was 13 kilometers (8 miles) per pixel on Dione and 16 kilometers (10 miles) per pixel on Tethys. The still image was magnified by a factor of two to aid visibility of surface features.
A brief movie of is also available (see PIA07620).
Voir l'image PIA07621: Tethys Meets Dione sur le site de la NASA.
This excellent grouping of three moons -- Dione, Tethys and Pandora -- near the rings provides a sampling of the diversity of worlds that exists in Saturn's realm.
A 330-kilometer-wide (205 mile) impact basin can be seen near the bottom right on Dione (at left). Ithaca Chasma and the region imaged during the Cassini spacecraft's Sept. 24, 2005, flyby can be seen on Tethys (middle). Little Pandora makes a good showing here as well, displaying a hint of surface detail.
Tethys is on the far side of the rings in this view; Dione and Pandora are much nearer to the Cassini spacecraft.
Dione is 1,126 kilometers (700 miles) across. Tethys is 1,071 kilometers (665 miles) across and Pandora is 84 kilometers (52 miles) across.
This image was taken in visible blue light with the Cassini spacecraft narrow-angle camera on Sept. 22, 2005, at a distance of approximately 1.2 million kilometers (800,000 miles) from Saturn. The image scale is about 5 kilometers (3 miles) per pixel on Dione and Pandora and 9 kilometers (6 miles) per pixel on Tethys.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.
For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov. The Cassini imaging team homepage is at http://ciclops.org.
1980S26
Outer F-ring
shepherd
120 X 100 1980S1
Leading
co-orbital
220 X 160 1980S25
Trailing
Tethys trojan
radii: 25 1980S28
Outer A
shepherd
radii: 20 1980S27
Inner F-ring
co-orbital
145 X 70 1980S3
Trailing
Tethys trojan
140 X 100 1980S13
Leading
Tethys trojan
radii: 30 1980S6
Leading
Dione trojan
radii: 30 These images have been scaled to show the satellites in true relative sizes. This set of small objects ranges in size from small asteroidal scales to nearly the size of Saturn's moon Mimas. They are probably fragments of somewhat larger bodies broken up during the bombardment period that followed accretion of the Saturnian system. Scientists believe they may be mostly icy bodies with a mixture of meteorite rock. They are somewhat less reflective than the larger satellites, suggesting that thermal evolution of the larger moons "cleaned up" their icy surfaces. The Voyager project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, Calif.
Voir l'image PIA01954: Collage of Saturn's smaller satellites sur le site de la NASA.
A stately Saturn poses for a portrait with five of its moons in this Cassini spacecraft wide angle camera view.
Satellites visible in this image are (clockwise from upper left): Dione (1,118 kilometers or 695 miles wide), Enceladus (499 kilometers or 310 miles wide), Tethys (1,060 kilometers or 659 miles wide), Mimas (398 kilometers or 247 miles wide) and Rhea (1,528 kilometers or 949 miles wide).
The image was taken in visible red light on Aug. 1, 2004, at a distance of 7.8 million kilometers (4.8 million miles) from Saturn. The image scale is 464 kilometers (288 miles) per pixel.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Office of Space Science, Washington, D.C. The Cassini orbiter and its two onboard cameras, were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.
For more information, about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org.
Saturn and its rings are prominently shown in this color image, along with three of Saturn's smaller moons. From left to right, they are Prometheus, Pandora and Janus.
Prometheus and Pandora are often called the "F ring shepherds" as they control and interact with Saturn's interesting F ring, seen between them.
This image was taken on June 18, 2004, with the Cassini spacecraft narrow angle camera 8.2 million kilometers (5.1 million miles) from Saturn. It was created using the red, green, and blue filters. Contrast has been enhanced to aid visibility.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL.
For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov.
This montage shows four major icy moons of Saturn that the Cassini spacecraft visited while surveying the Saturnian system during 2005. Even though all of these bodies are made largely of ice, they exhibit remarkably different geological histories and varied surface features.
Craters from meteorite impacts are common features on all of these moons. But since the major moons of Saturn are thought to have all formed at approximately the same time, the different distribution of sizes, shapes and numbers of craters on each of their surfaces tell scientists a great deal about the differences in their geologic histories.
Rhea and Iapetus are thoroughly peppered by impacts, suggesting their surfaces have been exposed to the shooting gallery of space for eons. Dione appears to have regions of terrain that are smoother, with fewer craters, suggesting a slightly younger surface. Dione also has a large system of bright, braided fractures that suggest tectonic activity took place there some time after the moon first formed.
Enceladus, however, possesses a region of terrain near its south pole (shown here), that is so dramatically devoid of impact sites that scientists suspected it was geologically active in the recent past, and perhaps even today. The discovery this year of material jetting from the pole and creating a great plume of icy particles confirmed these suspicions. See PIA07758 for images of the Enceladus plume.
The processes that power the activity on Enceladus remain elusive, as do those that produced the pronounced equatorial bulge on Iapetus. This feature was imaged for the first time by Cassini during a flyby of Iapetus that began New Year's Day. The bulge on Iapetus reaches 20 kilometers (12 miles) above the surrounding terrain in places, making it one of the tallest features in the solar system.
Like many scientific journeys, Cassini's historic survey of Saturn's moons has raised more questions. For example, why small Enceladus (505 kilometers, or 314 miles across) is presently geologically active while much larger Rhea (1,528 kilometers, or 949 miles across) is not. Fortunately, such puzzles are the most exciting sort for scientists interested in uncovering the secrets of Saturn's realm.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.
For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov. The Cassini imaging team homepage is at http://ciclops.org.Cassini's confirmation that a small moon orbits within the Keeler gap in Saturn's rings is made all the more exciting by this image, in which the disk of the 7 kilometer-wide body (4-miles) is resolved for the first time.
The new body, provisionally named S/2005 S1, was first seen in a time-lapse sequence of images taken on May 1, 2005, as Cassini began its climb to higher elevations in orbit around Saturn (see PIA06238 for the movie). This view was acquired one day after the discovery sequence of images and has allowed scientists to measure the moon's size and brightness.
The Keeler gap edges also bear similarities to the scalloped edges ofthe 322-kilometer-wide (200-mile) Encke gap, where Pan resides. From thesize of the waves seen in the Encke gap, imaging scientists were able toestimate the mass of Pan. They expect to do the same eventually with this new moon.
This image was obtained with the Cassini spacecraft narrow-angle camera on May 2, 2005, at a distance of about 594,000 kilometers (369,000 miles) from Saturn. Cassini was about 525,000 kilometers (326,000 miles) above the ringplane when the image was taken. Resolution in the original image was 3 kilometers (2 miles) per pixel. The image has been magnified by a factor of two, and contrast has been enhanced, to aid visibility of the small moonlet.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.
For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov. For additional images visit the Cassini imaging team homepage http://ciclops.org.
Saturn's moon Dione occults part of Saturn's distant rings while Tethys hovers below. Dione is 1,118 kilometers (695 miles) across, while Tethys is 1,071 kilometers, 665 miles) across.
This image offers excellent contrast with a previously released view (see PIA06629) that showed the bright, wispy markings on Dione's trailing hemisphere. The huge impact structure Odysseus (450 kilometers, or 280 miles across) is near the limb of Tethys. Compared with the battered surface of Tethys, Dione appears much smoother from this distance.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on March 19, 2005, at a distance of approximately 2.7 million kilometers (1.7 million miles) from Saturn. The image scale is approximately 15 kilometers (9 miles) per pixel.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.
For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org.
Saturn hosts its own miniature solar system, with an entourage of more than 30 moons. This image shows Saturn's A and F rings, along with three of the moons that orbit close to them.
From innermost to outermost, tiny Atlas (32 kilometers, or 20 miles, across) orbits just outside of the bright A ring and is seen above center in this view. Prometheus (102 kilometers, or 63 miles, across) is visible near lower right. Prometheus and its smaller cohort, Pandora, shepherd the thin, knotted F ring. Finally Janus (181 kilometers, or 112 miles, across) can be seen near lower left. Janus shares its orbit with the moon Epimetheus.
Density waves due to Janus cause some of the bright bands seen in the A ring in this image. Prometheus and Atlas also produce waves in the rings, but their wave regions are too narrow to be seen here. The interactions of the moons with each other and the rings are a major target of study for the Cassini mission.
The planet's shadow stretches all the way across the main rings in this view. The shadow has an oval shape at present, but over the next few years will become more rectangular as the planet orbits the Sun and the angle at which sunlight strikes the rings decreases. For an example of this from NASA's Voyager mission, see http://photojournal.jpl.nasa.gov/catalog/PIA00335.
The image was taken with the Cassini spacecraft narrow angle camera on Oct. 6, 2004, at a distance of 6.4 million kilometers (4 million miles) from Saturn through a filter sensitive to wavelengths of visible red light. The image scale is 38 kilometers (24 miles) per pixel.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.
For more information, about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org.