Category: Saturn

Here’s a photograph of Saturn’s moon Titan, captured by NASA’s Cassini spacecraft. The image was captured on May 13, 2007 at a distance of approximately 104,000 kilometers (65,000 miles) from Titan, when the spacecraft was on a flyby. The bright clouds on the lower part of the moon show how Titan’s methane atmosphere cycles around.

Original Source: NASA/JPL/SSI News Release

One of Cassini’s greatest discoveries has been the ice geysers pouring out of Saturn’s moon Enceladus. It appears, that this icy moon isn’t alone. Two other Saturnian moons are generating great gouts of icy particles too, suggesting that they might be active geologically.

In addition to the particles tracked back to Enceladus, Cassini’s instruments picked up a stream of particles that originated from Tethys and Dione.

Future flybys are planned for Tethys and Dione, so Cassini will be able to get a closer look in the future. Until then, researchers will have to go back and take another look at the data gathered when the spacecraft made its flybys in 2005.

Original Source: ESA News Release

New observations from NASA’s Cassini spacecraft have revealed that Saturn’s largest ring isn’t a smooth distribution of particles like it looks in photographs. Instead, it’s actually made up of tightly packed clumps of material surrounded by empty spaces.

According to researchers, these clumps of material are constantly colliding, breaking up, and reforming. And these clumps have hidden the mass of Saturn’s rings. Scientists originally estimated the mass of Saturn’s rings, assuming that particles were evenly distributed. But taking these clumps into account, the rings could be two or more times previous estimates.

To make the calculation, astronomers measured the brightness of a stars as they passed behind the rings. This allowed Cassini to measure the amount of material obscuring the stars, and so scientists could determine the thickness of the rings. Instead of fading gradually, the stars flickered in brightness as they passed behind these clumps.

These observations confirm that theory that the particles in Saturn’s rings gravitationally attract one another, bunching up into “self-gravity wakes”. If they were further from Saturn, the clumps would eventually form moons. But Saturn’s gravity tears them apart, halting their growth when they get larger than 30 to 50 meters (about 100 to 160 feet) across.

Original source: NASA/JPL/University of Colorado News Release

I thought I’d highlight this recent Cassini image of Saturn, it’s just so cool looking. What you’re seeing is a view of Saturn from high above the planet’s northern latitudes, providing nearly a full view of the main rings, from the C ring to the A ring.

Why are the rings blue? Cassini captured this image in three different wavelengths of infrared light, and then they were matched on computer to the colours red, green and blue. So, this isn’t what you’d see with your eyes, but it helps reveal subtle differences on the planet and its rings.

The image was captured on April 5, 2007 when Cassini was approximately 1.4 million kilometers (900,000 miles) from Saturn.

Original Source: NASA/JPL/SSI News Release

Just the way you can rub your hands together on a cold day to warm them up, the process of frictional heating can warm up an object in space. We see this through Jupiter’s interactions with Io, and now, astronomers report, that’s the same process that’s causing geysers of ice to erupt on Saturn’s moon Enceladus.

New research from the University of California, Santa Cruz, proposes that the gravitational interaction between Enceladus and Saturn causes the moon to flex as it orbits. Enceladus’ orbit is eccentric, varying its distance to Saturn, and it’s this eccentricity that creates the flexing. The faults on Enceladus to rub together, producing enough heat to transform solid ice into plumes of water vapour and ice crystals.

The researchers calculated how much heat could be generated by this flexing, and determined that it matches the observations made by NASA’s Cassini spacecraft during its flybys. Cassini detected tiger striped fissures around the Enceladus’ southern pole, and these geysers of water ice.

Another promising prediction is that Enceladus must have an ocean of liquid water beneath the icy shell for this flexing process to work at all. If the moon had a solid rock interior, it wouldn’t flex, and wouldn’t generate the ice geysers. This is good news for astrobiologists, since life on Earth exists wherever there are quantities of liquid water. This ice shell has to be at least 5 km (3 miles) thick, and is probably much thicker.

Original Source: UCSC News Release

This photograph of Saturn looks as if it was painted, or carved from a block of sandstone. That’s because it was heavily processed on computer to bring out detail in the Ringed Planet’s cloud structure. You lose the smooth natural look, but you get to see sharp detail in the atmospheric bands. The image was captured by NASA’s Cassini spacecraft using a combination of spectral filters. Different wavelengths of infrared radiation represent different colours in the image.

Cassini captured the image on August 19, 2005 when it was approximately 492,000 kilometers (306,000 miles) from Saturn.

Original Source: NASA/JPL/SSI News Release