A decade ago, NASA's Cassini spacecraft, the largest and most complex robotic probe yet built, arrived in the Saturn system to begin a marathon exploration of the gas giant, its famous and awe-inspiring rings and what has turned out to be a collection of some of the most eye-opening moons in the solar system.
Cassini's status as a permanent orbiting resident of the ringed giant, as well as its deployment of the ESA's Huygens probe to the surface of the giant moon Titan, has afforded us an up-close-and-personal inspection of much of the Saturn system, yielding orders of magnitude more data and details than the three brief flyby missions, Pioneer 11 and Voyagers 1 and 2, that preceded it 25 years earlier.
So what has Cassini taught us in its decadal odyssey a billion miles from the sun?
The most recent news is that the large moon Titan may be older, in a manner of speaking, than Saturn itself. That is to say, the original building blocks that made Titan may have originated not in the Saturn system, but elsewhere in the primordial nebula from which the solar system formed.