It turns out that NASA has just found a rather sizeable underground ocean on one of Saturn’s moons, and not the moon they were expecting. Yes, ocean as in bigger than lake.
The Cassini gravity measurements show a negative gravity anomaly at the south pole that however is not as large as expected from the deep depression detected by the onboard camera. Hence the conclusion that there must be a denser material at depth that compensates the missing mass: very likely liquid water, which is seven percent denser than ice. The magnitude of the anomaly gave us the size of the water reservoir.
The gravity measurements suggest a large, possibly regional, ocean about 6 miles (10 kilometers) deep, beneath an ice shell about 19 to 25 miles (30 to 40 kilometers) thick. The subsurface ocean evidence supports the inclusion of Enceladus among the most likely places in our solar system to host microbial life. Before Cassini reached Saturn in July 2004, no version of that short list included this icy moon, barely 300 miles (500 kilometers) in diameter.
On a related note from Wired, “Astronomers Surprised to Find Asteroid With Rings”:
For the first time ever, astronomers have discovered a ring system surrounding an asteroid. The finding is a complete surprise to planetary scientists, who are yet unsure exactly how such rings could have formed.
The cosmic bling was found around an object named Chariklo, which orbits in a region between Saturn and Uranus. At 155 miles across, or about the length of Massachusetts, Chariklo is the largest known asteroid in its neighborhood.
There are only four other known ring systems in our solar system — around Jupiter, Uranus, Neptune and, most dramatically, Saturn — and all the other ones have formed around planets. Astronomers aren’t yet sure if Chariklo’s ring system makes it unique among asteroids. In recent decades, more than 10 other objects in its neighborhood have been searched using a technique similar to Chariklo’s stellar eclipse but have not shown any rings
Both are very cool discoveries, and this is one of the great things about science, we keep finding things that don’t match up with our previous understanding of the universe (ie that only planets have rings), and that opens the door to new possibilities and considerations.
And of course this also puts us one step closer to actually finding life on other planets, possibly in our own solar system! Maybe not sentient life, but still pretty cool.