Rhea, Dione and the Rings

The Cassini spacecraft looks past the cratered south polar area of Saturn's moon Rhea to spy the moon Dione and the planet's rings in the distance.

Dione's "wispy" terrain can be seen on the trailing hemisphere of that moon. See PIA10560 to learn more.

This view looks toward the south polar area of the anti-Saturn side of Rhea (1,528 kilometers, or 949 miles across) and the Saturn-facing side of Dione (1,123 kilometers, or 698 miles across). North on the moons is up.

This view looks toward the northern, sunlit side of the rings from just above the ringplane. The rings, closer to Cassini than Dione is, obscure the view of the south of Dione.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on January 11, 2011. The view was acquired at a distance of approximately 61,000 kilometers (38,000 miles) from Rhea and at a Sun-Rhea-spacecraft, or phase, angle of 15 degrees. The view was acquired at a distance of approximately 924,000 kilometers (574,000 miles) from Dione and at a Sun-Dione-spacecraft, or phase, angle of 15 degrees. Image scale is 358 meters (1,175 feet) per pixel on Rhea and 6 kilometers (4 miles) per pixel on Dione.

Photo credit: NASA/JPL/Space Science Institute

Thin Line, Broad Shadows

Saturn's rings appear as only a thin line seen edge-on in the middle of this Cassini view, but the rings cast broad shadows on the southern hemisphere of the planet in the lower left of the image.

This view looks toward the southern, unilluminated side of the rings from just below the ringplane.

The image was taken with the Cassini spacecraft wide-angle camera on January 9, 2011 using a spectral filter sensitive to wavelengths of near-infrared light centered at 728 nanometers. The view was acquired at a distance of approximately 796,000 kilometers (494,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 147 degrees. Image scale is 44 kilometers (27 miles) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Enceladus and Saturn's Rings

The Cassini spacecraft looks over cratered and tectonically deformed terrain on Saturn's moon Enceladus as the camera also catches a glimpse of the planet's rings in the background. The image was captured during the spacecraft's flyby of Enceladus on November 30, 2010.

Geologically young terrain in the middle latitudes of the moon gives way to older, cratered terrain in the northern latitudes. See PIA11685 to learn more. This view is centered on terrain at 41 degrees north latitude, 202 degrees west longitude. North on Enceladus (504 kilometers, or 313 miles, across) is up and rotated 28 degrees to the right.

This view looks toward the northern, sunlit side of the rings from less than a degree above the ringplane.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera. The view was acquired at a distance of approximately 46,000 kilometers (29,000 miles) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 14 degrees. Image scale is 276 meters (906 feet) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Hyperion

The Cassini spacecraft captures a view of the southern latitudes of Saturn's tumbling moon Hyperion.

To learn more about this spongy moon and how it tumbles in its orbit, see PIA06243, PIA07761 and PIA07740. Lit terrain seen here is mostly in the southern hemisphere of Hyperion (270 kilometers, or 168 miles across). The south pole of the moon is near the bottom of the illuminated terrain seen here.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on November 28, 2010. The view was obtained at a distance of approximately 80,000 kilometers (50,000 miles) from Hyperion and at a Sun-Hyperion-spacecraft, or phase, angle of 98 degrees. Image scale is 476 meters (1,562 feet) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Dione and Enceladus

On the top right of this Cassini spacecraft image, Saturn's moon Dione may appear closer to the spacecraft because it is larger than the moon Enceladus in the lower left. However, Enceladus was actually closer to the spacecraft when this image was captured.

Dione (1,123 kilometers, or 698 miles, across) is actually more than twice the size of Enceladus (504 kilometers, or 313 miles, across). Dione's bright "wispy" terrain can be seen here. See PIA10560 and PIA06163 to learn more about this terrain. This view looks toward the area between the trailing hemisphere and Saturn-facing side of Dione.

The highly reflective surface of Enceladus also stands out here. This view looks toward the trailing hemisphere of Enceladus.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on December 1, 2010. The view was acquired at a distance of approximately 510,000 kilometers (317,000 miles) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 7 degrees. The view was acquired at a distance of approximately 830,000 kilometers (516,000 miles) from Dione and at a Sun-Dione-spacecraft, or phase, angle of 8 degrees. Image scale is 3 kilometers (2 miles) per pixel on Enceladus and 5 kilometers (3 miles) per pixel on Dione.

Photo credit: NASA/JPL/Space Science Institute

Enceladus

Saturn's moon Enceladus brightly reflects sunlight before a backdrop of the planet's rings and the rings' shadows cast onto the planet.

The Cassini spacecraft captured this snapshot during its flyby of the moon on November 30, 2010. This view looks toward the anti-Saturn side of Enceladus (504 kilometers, or 313 miles across). North on Enceladus is up and rotated 28 degrees to the right.

This view looks toward the northern, sunlit side of the rings from less than a degree above the ringplane.

The image was taken in visible light with the Cassini spacecraft wide-angle camera. The view was obtained at a distance of approximately 53,000 kilometers (33,000 miles) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 14 degrees. Image scale is 3 kilometers (2 miles) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Rhea's Northern Craters

The Cassini spacecraft captured this high-resolution view of the cratered surface of Saturn's moon Rhea as the spacecraft flew by the moon on October 17, 2010.

For closer views of Rhea's surface from earlier flybys, see PIA07765 and PIA08402. This view is centered on terrain at 60 degrees North latitude, 251 degrees West longitude on Rhea (1,528 kilometers, 949 miles across).

The image was taken in visible light with the Cassini spacecraft's narrow-angle camera. The view was acquired at a distance of approximately 40,000 kilometers (25,000 miles) from Rhea and at a Sun-Rhea-spacecraft, or phase, angle of 88 degrees. Image scale is 238 meters (781 feet) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Saturn's Plasma and Radio Waves, as Seen by Cassini

This animation, derived from data obtained by NASA's Cassini spacecraft, shows how plasma swirling around Saturn is correlated to bursts of radio waves emanating from the planet. The data shown on the upper portion of the screen were obtained by the ion and neutral camera, part of the magnetospheric imaging instrument. When the plasma gets hot, it goes from red to white. The bottom part of the screen shows data from Cassini's radio and plasma wave subsystem. The data were obtained from 12:01 a.m. UTC to 11:55 a.m. UTC on October 7, 2008.

Video credit: NASA/JPL/JHUAPL/University of Iowa

Saturn's Hot Plasma Explosions

This animation based on data obtained by NASA's Cassini spacecraft shows how the "explosions" of hot plasma on the night side (orange and white) periodically inflate Saturn's magnetic field (white lines). Cassini scientists have been able to compute the "pressure" that the hot plasma exerts on the surrounding magnetic field by using remote images of the previously invisible hot plasma taken by the ion and neutral camera, part of the magnetospheric imaging instrument on board Cassini.

These enormous clouds of hot plasma recur in the part of the magnetosphere known as the magnetotail roughly every 10 to 11 hours. They rotate around Saturn at a distance of about eight to 15 times the radius of Saturn. Scientists have finally been able to demonstrate that the pressure contained in these clouds is sufficient to inflate the magnetic field in a manner that is consistent with the periodic magnetic field signals that have puzzled them for so long. As the high- and low-pressure systems of atmospheric weather on Earth produce winds, pressures in space produce huge electrical currents, which in turn distort the magnetic field.

The animation is based on data that were collected from December 17 to 18, 2004.

Video credit: NASA/JPL/JHUAPL/University of Iowa

Note: For more information, see Hot Plasma Explosions Inflate Saturn's Magnetic Field.

Rhea's Western Wisps

Icy fractures on Saturn's moon Rhea reflect sunlight brightly in this high-resolution mosaic created from images captured by NASA's Cassini spacecraft during its March 2, 2010, flyby. This flyby was the closest flyby of Rhea up to then.

This mosaic of six images shows the westernmost portion of the moon's "wispy" terrain. (See PIA06578 and PIA08120 to learn more.) Among the interesting features depicted here is a very straight east-west fracture near the top center of the mosaic that intersects two north-south fractures. The large crater at the bottom left of the mosaic is Inmar (55 kilometers, 34 miles across).

The closest approach of the spacecraft to Rhea during this encounter was 100 kilometers (62 miles). These images were obtained approximately half an hour later at an altitude of about 16,000 kilometers (10,000 miles).

This mosaic shows part of the side of Rhea (1528 kilometers, 949 miles across) that always faces Saturn. The images were re-projected in an orthographic projection centered on terrain at 7 degrees North latitude, 296 degrees West longitude. The mosaic itself shows terrain centered on terrain at 6 degrees North latitude, 293 degrees West longitude. North on Rhea is roughly up in the image.

The images were taken with the Cassini spacecraft narrow-angle camera. The view was obtained at a Sun-Rhea-spacecraft, or phase, angle of 2 degrees. So, Cassini was almost directly between Rhea and the Sun as it acquired these images. Image scale is 85 meters (280 feet) per pixel.

Photo credit: NASA/JPL/Space Science Institute