Category: Saturn

Saturn’s moon Tethys glides past in its orbit. Image credit: NASA/JPL/SSI Click to enlarge
The majesty of Saturn overwhelms in this image from Cassini. Saturn’s moon Tethys glides past in its orbit, and the icy rings mask the frigid northern latitudes with their shadows. Tethys is 1,071 kilometers (665 miles) across.
The image was taken in visible green light with the Cassini spacecraft wide-angle camera on June 10, 2005, at a distance of approximately 1.4 million kilometers (900,000 miles) from Saturn. The image scale is 80 kilometers (50 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 . The Cassini imaging team homepage is at http://ciclops.org .

Original Source: NASA/JPL/SSI News Release

Prometheus and Pandora above the dark side of Saturn’s rings. Image credit: NASA/JPL/SSI. Click to enlarge
Saturn’s moons Prometheus and Pandora are captured here in a single image taken from less than a degree above the dark side of Saturn’s rings. Pandora is on the right, and Prometheus is on the left. Prometheus is 102 kilometers (63 miles) across. Pandora is 84 kilometers (52 miles) across.
The two moons are separated by about 69,000 kilometers (43,000 miles) in this view.

The F ring, extending farthest to the right, contains a great deal of fine, icy material that is more the size of dust than the boulders thought to comprise the dense B ring. These tiny particles are particularly bright from this viewing geometry, especially at right near the ansa, or edge.

At left of center, a couple of ringlets within the Encke gap (325 kilometers, or 200 miles wide) can also be easily seen due to their fine dust-sized material. The other dark features in the rings are density waves and bending waves.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Feb. 20, 2005, when Cassini was a mean distance of 1.85 million kilometers (1.15 million miles) from the moons. The image scale is about 11 kilometers (7 miles) per pixel on both 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 team is based at the Space Science Institute, 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 .

Original Source: NASA/JPL/SSI News Release

Unusual bright spot offers Titan mystery. Image credit: NASA/JPL/SSI. Click to enlarge
During a recent pass of Saturn’s moon Titan, one of more than 40 during Cassini’s planned four-year mission, the spacecraft acquired this infrared view of the bright Xanadu region and the moon’s south pole. Titan is 5,150 kilometers (3,200 miles) across.

Southeast of Xanadu (and above the center in this view) is a peculiar semi-circular feature informally referred to by imaging scientists as “the Smile.” This surface feature is the brightest spot on Titan’s surface, not only to the imaging science subsystem cameras, but also to the visual and infrared mapping spectrometer instrument, which sees the surface at even longer wavelengths. The Smile is 560 kilometers (345 miles) wide.

At the landing site of the successful Huygens probe mission, brighter regions correspond to icy upland areas, while the darker regions are lowlands that possess a higher proportion of the organic byproducts of Titan’s atmospheric photochemistry. Those results seem to confirm the long-standing hypothesis that Xanadu is a relatively high region of less contaminated ice. However, the cause of the even brighter Smile is a mystery that is still under study.

Farther south, a field of bright clouds arcs around the pole, moving at a few meters per second. Around the limb (edge), Cassini peers through Titan’s smoggy, nitrogen-rich atmosphere.

North in this image is toward the upper left.

The image was taken with the Cassini spacecraft narrow-angle camera on June 4, 2005, at a distance of approximately 1.2 million kilometers (700,000 miles) from Titan using a spectral filter sensitive to wavelengths of infrared light centered at 938 nanometers. The image scale is 7 kilometers (4 miles) per pixel.

Original Source: NASA Astrobiology

Saturn’s shepherd moon Prometheus hovers between the A and F rings. Image credit; NASA/JPL/SSI. Click to enlarge
Saturn’s shepherd moon Prometheus hovers between the A and F rings as if suspended on an invisible thread, while bright clouds drift in Saturn’s atmosphere approximately 130,000 kilometers (81,000 miles) beyond. It is noteworthy that such clouds are visible here in the shadows cast by the rings. Prometheus is 102 kilometers (63 miles) across.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on June 3, 2005, at a distance of approximately 2.1 million kilometers (1.3 million miles) from Saturn. The image scale is 13 kilometers (8 miles) per pixel. This view was processed to enhance fine details.

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 . The Cassini imaging team homepage is at http://ciclops.org.

Original Source: NASA/JPL/SSI News Release

Saturn’s unusual moon, Hyperion. Image credit: NASA/JPL/SSI. Click to enlarge.
Two new Cassini views of Saturn’s tumbling moon Hyperion offer the best looks yet at one of the icy, irregularly-shaped moons that orbit the giant, ringed planet.

The image products released today include a movie sequence and a 3D view, and are available at , and .

The views were acquired between June 9 and June 11, 2005, during Cassini’s first brush with Hyperion.

Hyperion is decidedly non-spherical and its unusual shape is easy to see in the movie, which was acquired over the course of two and a half days. Jagged outlines visible on the moon’s surface are indicators of large impacts that have chipped away at its shape like a sculptor.

Preliminary estimates of its density show that Hyperion is only about 60 percent as dense as solid water ice, indicating that much of its interior (40 percent or more) must be empty space. This makes the moon more like an icy rubble pile than a solid body.

In both the movie and the 3D image, craters are visible on the moon?s surface down to the limit of resolution, about 1 kilometer (0.6 mile) per pixel. The fresh appearance of most of these craters, combined with their high spatial density, makes Hyperion look something like a sponge.

The moon’s spongy-looking exterior is an interesting coincidence, as much of Hyperion?s interior appears to consist of voids. Hyperion is close to the size limit where, like a child compacting a snowball, internal pressure due to the moon?s own gravity will begin to crush weak materials like ice, closing pore spaces and eventually creating a more nearly spherical shape.

The images used to create these views were obtained with Cassini’s narrow-angle camera at distances ranging from approximately 815,000 to 168,000 kilometers (506,000 to 104,000 miles) from Hyperion. Cassini will fly within 510 kilometers (317 miles) of Hyperion on Sept. 26, 2005.

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.

Original Source: NASA News Release

An unusual feature on the surface of Titan that could be a hydrocarbon lake. Image credit: NASA/JPL/SSI. Click to enlarge.
This view of Titan?s south polar region reveals an intriguing dark feature that may be the site of a past or present lake of liquid hydrocarbons.

The true nature of this feature, seen here at left of center, is not yet known, but the shore-like smoothness of its perimeter and its presence in an area where frequent convective storm clouds have been observed by Cassini and Earth-based astronomers make it the best candidate thus far for an open body of liquid on Titan.

If this interpretation is correct, then other very dark but smaller features seen in the south polar region, some of which are captured in this image, may also be the sites of liquid hydrocarbon reservoirs.

In addition to the notion that the dark feature is or was a lake filled with liquid hydrocarbons, scientists have speculated about other possibilities. For instance, it is plausible that the ‘lake’ is simply a broad depression filled by dark, solid hydrocarbons falling from the atmosphere onto Titan?s surface. In this case, the smoothed outline might be the result of a process unrelated to rainfall, such as a sinkhole or a volcanic caldera.

A red cross below center in the scene marks the pole. The brightest features seen here are methane clouds. A movie sequence showing the evolution of bright clouds in the region during the same flyby is also available (see PIA06241).

This view is a composite of three narrow angle camera images, taken over several minutes during Cassini’s distant June 6, 2005 flyby. The images were combined to produce a sharper view of Titan?s surface. The images were taken using a combination of spectral filters sensitive to wavelengths of polarized infrared light. The images were acquired from approximately 450,000 kilometers (279,000 miles) from Titan. Resolution in the scene is approximately 3 kilometers (2 miles) per pixel. The view has been contrast enhanced to improve the overall visibility of surface features.

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 imaging team is based at the Space Science Institute, Boulder, Colorado.

For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org.

Original Source: CICLOPS News Release

Close up view of Saturn’s moon Janus. Image credit: NASA/JPL/SSI. Click to enlarge.
This close-up look at Saturn’s moon Janus reveals spots on the moon’s surface which may be dark material exposed by impacts. If the dark markings within bright terrain are indeed impact features, then Janus’ surface represents a contrast with that of Saturn’s moon Phoebe, where impacts have uncovered bright material beneath a darker overlying layer. Janus is 181 kilometers (113 miles) across.

Janus may be a porous body, composed mostly of water ice.

This image was taken in visible light with the Cassini spacecraft narrow-angle camera on May 20, 2005, at a distance of approximately 357,000 kilometers (222,000 miles) from Janus and at a Sun-Janus-spacecraft, or phase, angle of 6 degrees. Resolution in the original image was 2 kilometers (1 mile) per pixel. The view was magnified by a factor of two and contrast-enhanced to aid visibility of the moon’s surface.

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 . The Cassini imaging team homepage is at http://ciclops.org .

Original Source: NASA/JPL/SSI

Blue flashes of X-rays from Chandra on top of an optical image of Saturn. Image credit: NASA. Click to enlarge.
Chandra images reveal that the rings of Saturn sparkle in X-rays (blue dots in this X-ray/optical composite). The likely source for this radiation is the fluorescence caused by solar X-rays striking oxygen atoms in the water molecules that comprise most of the icy rings.

As the image shows, the X-rays in the ring mostly come from the B ring, which is about 25,000 kilometers wide and is about 40,000 kilometers (25,000 miles) above the surface of Saturn (the bright white inner ring in the optical image). There is some evidence for a concentration of X-rays on the morning side (left side, also called the East ansa) of the rings. One possible explanation for this concentration is that the X-rays are associated with optical features called spokes, which are largely confined to the dense B ring and most often seen on the morning side.

Spokes, which appear as radial shadows in the rings, are due to transient clouds of fine ice-dust particles that are lifted off the ring surface, and typically last an hour or so before disappearing. It has been suggested that the spokes are triggered by meteoroid impacts on the rings, which are more likely in the midnight to early morning hours because during that period the relative speed of the rings through a cloud of meteoroids would be greater.

The higher X-ray brightness on the morning side of the rings could be due to the additional solar fluorescence from the transient ice clouds that produce the spokes. This explanation may also account for other Chandra observations of Saturn, which show that the X-ray brightness of the rings varies significantly from one week to the next.

Original Source: Chandra News Release

Saturn’s moon Pan makes ripples in the rings as it orbits the planet. Image credit: NASA/JPL/SSI. Click to enlarge.
Saturn’s moon Pan is seen here orbiting within the Encke Gap in Saturn’s A ring in two differently processed versions of the same Cassini image. The little moon is responsible for clearing and maintaining this gap, named for Johann Franz Encke, who discovered it in 1837. Pan is 20 kilometers (12 miles) across.

The top image reveals two of the faint, dusty ringlets that occupy the gap along with Pan. One of the ringlets occupies nearly the same orbit as Pan, while the other is closer to the gap’s inner edge. Not only do the ringlets vary in brightness, but they also appear to move in and out along their length, resulting in notable “kinks,” which are similar in appearance to those observed in the F ring (see PIA06585). One possible explanation for the complex structure of the ringlets is that Pan may not be the only moonlet in this gap.

Pan is responsible for creating stripes, called ‘wakes,’ in the ring material on either side of it. Since ring particles closer to Saturn than Pan move faster in their orbits, these particles pass the moon and receive a gravitational “kick” from Pan as they do. This kick causes waves to develop in the gap where the particles have recently interacted with Pan (see PIA06099), and also throughout the ring, extending hundreds of kilometers into the rings. These waves intersect downstream to create the wakes, places where ring material has bunched up in an orderly manner thanks to Pan’s gravitational kick.

In the bottom image, the bright stripes or wakes moving diagonally away from the gap’s edges can be easily seen. The particles near the inner gap edge have most recently interacted with Pan and have just passed the moon. Because of this, the disturbances caused by Pan on the inner gap edge are ahead of the moon. The reverse is true at the outer edge: the particles have just been overtaken by Pan, leaving the wakes behind it.

This image was taken in visible light with the Cassini spacecraft narrow-angle camera on May 18, 2005, at a distance of approximately 1.6 million kilometers (1 million miles) from Pan and at a Sun-Pan-spacecraft, or phase, angle of 44 degrees. The image scale is 9 kilometers (6 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 additional images visit the Cassini imaging team homepage http://ciclops.org.

Original Source: NASA/JPL/SSI News Release