(Photo: NASA/JPL/Space Science Institute)
That would be Saturn's moons, offering ringside seats to the most sublime views in the solar system, the rings of the second-largest planet.
It won't happen anytime soon, but NASA may have boosted the chances of folks enjoying these views up close someday by awarding a $17.8 million contract this week to Bigelow Aerospace to install an inflatable "space habitat" aboard the International Space Station in 2015. Bigelow Aerospace is owned by a hotel magnate, billionaire Robert Bigelow, who has long harbored hopes of hosting honeymooners in space.
And the vista around Saturn would be worth the trip. With the international Cassini spacecraft mission now eight years into its tour of the ringed planet and its moons, the views of Saturn those moguls may enjoy someday have only gotten better. And some of the mysteries about Saturn's satellites, from the spouting geysers of Enceladus to the frozen lakes of Titan, have only grown deeper.
The latest puzzler comes from Dione, Saturn's fourth-largest moon, some 700 miles wide, an ice-crusted rock first spotted by the original Cassini, astronomer Giovanni Cassini of the Paris Observatory, in 1672. His namesake probe first flew over the moon in 2004 and revealed that "wispy terrain" long observed on the frozen moon was actually a series of ridges and cliffs, hundreds of feet high, cutting across one side of the moon.
How did Dione's eggshell end up cracked? A team led by Noah Hammond of the SETI Institute in Mountain View, Calif., looks at this riddle in an upcoming study in the journal Icarus.
One clue comes from the craters on Dione. Planetary scientists use craters to estimate the ages of moons and asteroids throughout the solar system. The leading face of Dione as it circles Saturn is pockmarked with impact divots, for example, some 6 miles or so deep. On the trailing side, however, the surface is smoother, with fewer of these craters. Estimates are that the heavily cratered side's surface represents changes that date to 4 billion years ago, based on the number of divots, while the cliff-riven surface got its facelift about 2 billion years ago, based on its smoother appearance.