A team of astronomers have been studying the moon using the Cassini-Huygens spacecraft, which has been orbiting Saturn for the last ten years, and discovered Mimas’ orbit wobbles much more than theoretical models allow.
“After carefully examining Mimas, we found it librates – that is, it subtly wobbles – around the moon’s polar axis,” said Radwan Tajeddine, Cornell research associate in astronomy and lead author of the paper published in Science.
New photos, taken by Nasa, of one of Saturn’s moon’s suggest it has a wobbly surface.
Researchers think the reason for this is either the moon, called Mimas, has got a huge ocean beneath the surface or a weird rocky core, which is weirdly shaped like a rugby ball.
Saturn’s moon officially known as Mimas has a particular wobble to it, meaning it either has an oblong rocky core or is rich with life-encouraging water. Cassini has been investigating Saturn since 1997, a planet with distinct rings and at least 62 moons, 53 of which have been named.
Mimas is nicknamed the Death Star because it looks like the space station seen in the Star Wars films.
“We’re very excited about this measurement because it may indicate much about the satellite’s insides. Nature is essentially allowing us to do the same thing that a child does when she shakes a wrapped gift in hopes of figuring out what’s hidden inside.”
NASA, the European Space Agency and the Italian Space Agency collaborates on the Cassini mission and this study was an international effort with scientists from France, Belgium and the U.S. The study authors believe that, if there is an ocean beneath Mimas’ surface, it is probably 15 to 20 miles down.
“Observing libration can provide useful insights about what is going on inside a body,” Tajeddine said in a statement from NASA. “In this case, it is telling us that this cratered little moon may be more complex than we thought.”