Three years after we watched the Death Star kill a planet on the silver screen, the twin Voyager spacecraft flew past Mimas and spotted its iconic crater. Nearly 40 years later, NASA’s Cassini spacecraft is bidding farewell to the moons of Saturn as it inches closer to its fiery demise.
On January 30th, Cassini made its final close approach to Mimas. 28,000 miles away, the spacecraft snapped the last close-up images of Mimas until NASA decides to send another spacecraft to the Saturn system. Here’s how it looked if we were floating alongside Cassini.
And here it is with the brightness slider cranked up.
Cassini’s imaging team combined ten narrow-angle camera images to create the mosaics we see above.
Our last close-up of Mimas is missing its most famous crater. Herschel Crater, or the Death Star as most of us know it. We can see the small moon has seen its fair share of asteroid impacts. But the asteroid that made Herschel Crater was nearly a moon killer. The crater measures 86 miles across and is nearly one-third the diameter of the moon.
Scientists believe if the asteroid that created this crater were any bigger, Mimas would have met the same fate as its Death Star nickname.
Another image shows the huge mountain peak stretching above the center of the crater.
Scientists estimate the peak is nearly as tall as Mount Everest.
Another water world?
It’s possible. A few years ago, researchers took a closer look at what was going on inside the small moon. “The data suggest that something is not right, so to speak, inside Mimas,” Radwan Tajeddine (lead author on the research) said at the time. “The amount of wobble we measured is double what was predicted.”
Which leads to an exciting possibility. An ocean could be lurking deep beneath Mimas’ surface. The models say the ocean would have to sit 15 to 20 miles below the surface. Plus, because Mimas is too small to have kept hold of internal heat from its formation, some other energy source would be needed for the liquid ocean.
There is another possible reason for the wobble researchers observed. Instead of a frozen core that resembles a sphere, it could look more like a football.
More papers will be written about the mysteries of Mimas and the rest of the Saturn system. Cassini might be bidding farewell to the small moon, but this won’t be the last we hear about Mimas.