Since 2004, the sophisticated Cassini
spacecraft has been orbiting Saturn, sending back remarkable pictures of the
planet, its rings, and its moons. Now, with its fuel running out, the little
spacecraft is being directed closer to Saturn’s rings, to get us even better
views of this spectacular region (before Cassini does a Kamikaze dive into
Saturn Sept. 15th.)
The image above is a fantastic close-up
of one of the strangest moons we have ever seen. The small moon Pan orbits inside the Encke
Gap, an emptier region in Saturn’s bright A ring (Saturn’s different rings are
given letter names.) Pan looks like a “flying
saucer” – with a set of high ridges around its equator. It's about 22
miles across at its widest point.
Astronomers think that Pan formed inside
Saturn’s ring and, as it grew, its gravity helped clear out the material in the
gap which it now rules. But there was
enough material still in the flat ring neighborhood that it fell onto Pan’s
equator and made the giant ridges that make Pan so distinctive.
Over the next few months, as scientist
program Cassini to dive again and again into the space between Saturn’s and its
rings, we will continue to get better images of “things in the rings” (sounds
like Dr. Seuss) than we ever have before.
It’s a fitting finale for a spectacular space mission.
The image below shows you the neighborhood. You can see Pan, its shadow, the Encke gap, and the A ring.
