Mini-Jets in Saturn's F-Ring

New images from the Cassini spacecraft reveal rogue kilometer-sized objects punching through Saturn's F-ring as the source of 'mini-jets' seen emanating from the ring.

Saturn's narrow F-ring is already known to host a variety of dynamic features including channels, ripples and 'snowballs' that are created by the gravitational influence of nearby moon Prometheus. While some snowballs are likely broken up by collisions and tidal forces, the new images reveal five hundred separate cases where small surviving fragments punch through the F-ring, dragging icy ring particles with them.

The objects collide with the ring at low speeds of around two meters per second, resulting in 'mini-jets' that extend between 40 and 180 kilometers from the ring. In some cases the snowball impacts occur in groups, creating exotic patterns as they drag through the ring.

Video credit: NASA/JPL-Caltech/SSI/QMUL; text credit: ESA

Note: There are quite a few recent articles about this story; see:
* Cassini Movie Shows Blazing Trails in Saturn's F-ring
* Blazing Trails in Saturn’s F-ring Seen by Cassini
* PIA15500: Glittering Trail in Saturn's F Ring
* PIA15501: F Ring Patterns
* PIA15502: Small Trail at Saturn Orbit Insertion
* PIA15503: Classic Trails or Mini-Jets
* PIA15504: Exotic Trails or Mini-Jets
* PIA15505: Wavy, Wiggly Ring
* Cassini Sees Objects Blazing Trails in Saturn Ring

The Face of Phoebe

Phoebe's true nature is revealed in startling clarity in this mosaic of two images taken during Cassini's flyby on June 11, 2004. The image shows evidence for the emerging view that Phoebe may be an ice-rich body coated with a thin layer of dark material. Small bright craters in the image are probably fairly young features. This phenomenon has been observed on other icy satellites, such as Ganymede at Jupiter. When impactors slammed into the surface of Phoebe, the collisions excavated fresh, bright material -- probably ice -- underlying the surface layer. Further evidence for this can be seen on some crater walls where the darker material appears to have slid downwards, exposing more light-colored material. Some areas of the image that are particularly bright - especially near lower right - are over-exposed.

An accurate determination of Phoebe's density -- a forthcoming result from the flyby -- will help Cassini mission scientists understand how much of the little moon is comprised of ices.

This spectacular view was obtained at a phase, or Sun-Phoebe-spacecraft, angle of 84 degrees, and from a distance of approximately 32,500 kilometers (20,200 miles). The image scale is approximately 190 meters (624 feet) per pixel. No enhancement was performed on this image.

Photo credit: NASA/JPL-Caltech/Space Science Institute

Phoebe

This panel of images shows the nearly spherical shape of Saturn's moon Phoebe, as derived from imaging obtained from NASA's Cassini spacecraft. Each image represents a 90-degree turn.

Photo credit: NASA/JPL-Caltech/SSI/Cornell

Note: For more information, see Cassini Finds Saturn Moon has Planet-Like Qualities.

Rhea

Cassini looks over the heavily cratered surface of Rhea during the spacecraft's flyby of the moon on March 10, 2012.

See PIA08909 and PIA06553 to learn more about the impacts that have shaped the surface of Rhea (949 miles, or 1,528 kilometers across). This view is centered on terrain at 58 degrees north latitude, 84 degrees west longitude on Rhea.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera. The view was obtained at a distance of approximately 27,000 miles (43,000 kilometers) from Rhea and at a Sun-Rhea-spacecraft, or phase, angle of 67 degrees. Image scale is 827 feet (252 meters) per pixel.

Photo credit: NASA/JPL-Caltech/Space Science Institute

Ephemeral Lakes on Titan and Earth

Ontario Lacus is Titan's largest lake in its southern hemisphere. It is an ephemeral lake that resembles Etosha Pan in Namibia, Africa. On Titan the liquid is made of hydrocarbons, whereas on Earth it is made of water.

Photo credits: Cassini radar image: JPL/NASA. Envisat radar image: ESA. Composite image: LPGNantes.

Note: For more information, see Far-Off Cousin of Part-Time African Lake Found on Titan. See also Cassini Finds Titan Lake is Like a Namibia Mudflat.

Enceladus, Titan and the Rings

The brightly reflective moon Enceladus appears before Saturn's rings while the larger moon Titan looms in the distance.

Jets of water ice and vapor emanating from the south pole of Enceladus (hinting at a subsurface sea rich in organics), and liquid hydrocarbons ponding on the surface on the surface of Titan make these two of the most fascinating moons in the Saturnian system. See PIA07787 to learn more about these fascinating moons.

Enceladus (313 miles, or 504 kilometers across) is in the center of the image. Titan (3,200 miles, or 5,150 kilometers across) can faintly be seen in the background beyond the rings. This view looks toward the anti-Saturn side of Enceladus and the Saturn-facing side of Titan. The northern, sunlit side of the rings is seen from just above the ringplane.

The image was taken in visible green light with the Cassini spacecraft narrow-angle camera on March 12, 2012. The view was acquired at a distance of approximately 600,000 miles (1 million kilometers) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 36 degrees. Image scale is 4 miles (6 kilometers) per pixel on Enceladus.

Photo credit: NASA/JPL-Caltech/Space Science Institute

The Shadow of Mimas

The shadow of the moon Mimas creates a smudge on the southern hemisphere of Saturn in this view from the Cassini spacecraft.

Mimas does not appear here, but it does cast its shadow on the planet in the lower left of the image. The shadows cast by the rings dominate the upper right of the image. This view looks toward the southern, unilluminated side of the rings from about 1 degree below the ringplane.

The image was taken with the Cassini spacecraft narrow-angle camera on January 21, 2012 using a spectral filter sensitive to wavelengths of near-infrared light centered at 750 nanometers. The view was acquired at a distance of approximately 1.6 million miles (2.6 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 70 degrees. Image scale is 9 miles (15 kilometers) per pixel.

Photo credit: NASA/JPL-Caltech/Space Science Institute

Mimas, Epimetheus, and the Rings

Two of Saturn's moons straddle the planet's rings in this color view.

Mimas (396 kilometers, or 246 miles across) is closest to the Cassini spacecraft here. Epimetheus (113 kilometers, or 70 miles across) is on the far side of the rings. Saturn's shadow cuts across the middle of the rings. This view looks toward the sunlit side of the rings from just above the ringplane.

Images taken using red, green and blue spectral filters were combined to create this natural color view. The images were obtained with the Cassini spacecraft narrow-angle camera on October 24, 2009 at a distance of approximately 2.7 million kilometers (1.7 million miles) from Epimetheus and 2.4 million kilometers (1.5 million miles) from Mimas. Scale on Mimas is 14 kilometers (9 miles) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Titan

Titan's atmosphere makes Saturn's largest moon look like a fuzzy orange ball in this natural color view from the Cassini spacecraft.

Titan's north polar hood is visible at the top of the image, and a faint blue haze also can be detected above the south pole at the bottom of this view. Recent Cassini images suggest Titan's north polar vortex, or hood, is beginning to flip from north to south (see PIA14913). See PIA08137 and PIA12775 to learn more about the moon's atmosphere.

This view looks toward the anti-Saturn side of Titan (3,200 miles, or 5,150 kilometers across). North is up.

Images taken using red, green and blue spectral filters were combined to create this natural color view. The images were obtained with the Cassini spacecraft wide-angle camera on January 30, 2012 at a distance of approximately 119,000 miles (191,000 kilometers) from Titan. Image scale is 7 miles (11 kilometers) per pixel.

Photo credit: NASA/JPL-Caltech/Space Science Institute

Janus

This raw image from NASA's Cassini spacecraft was taken on March 27, 2012. The camera was pointing toward Saturn's moon Janus.

Photo credit: NASA/JPL/Space Science Institute