What’s The Reason Behind Stronger than Expected Wobble of Saturn’s Moon, Mimas

Mimas, Saturn’s smaller ice moon was often believed as the most dullest satellite. But recently a new study revealed that, the humdrum space boulder could have hidden secrets.

According to the recent study published in the ‘Science’ journal; Like other moons, Mimas has been orbiting Saturn for the last ten years under the influence of its parent planet, though there is a difference that Mimas’ orbit wobbles is quite large.

A team of astronomers have been studying the moon using the Cassini-Huygens spacecraft. Radwan Tajeddine, Cornell research associate in astronomy and lead author of the study stated that, “After carefully examining Mimas, we discovered it librates, it delicately wobbles around the moon’s polar axis.”

“We are really excited about this measurement because it may specify much about the satellite’s insides. Nature is basically enabling 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.”

The researchers used data collected from Cassini-Huygens spacecraft to create a 3D model of the moon’s orbit and found it wobbles twice as much as it ought. Such wobbles can be caused by the gravity of passing of planetary masses, but Mimas’ motion points to two other possibilities.

The first thing is that the moon’s rocky surface is hiding an ocean deep within the planet. With only 400kms in diameter Mimas won’t have enough mass to have a hot core, but tidal kneading caused by the close proximity of Saturn could provide enough heat for some of the moon’s innards to be liquids. On the basis of 3D modeling, we found that the ocean would have to be around 24 to 31kms beneath the surface of the moon’s crust to account for the wobble. Secondly, the Mimas’ birth left it somewhat abnormal. Mimas is believed to be the smallest body in the solar system to be rounded due to self-gravitation. It has enough mass to shape into a ball without being frayed apart.

According to the astronomers, if a subsurface ocean is present, then it would require a source of interior heat to keep it liquid. But yet again, the moon’s surface does not display any sign of such heating. Instead of internal heat, a possible mechanism leading to a subsurface ocean might be a gravitational effect that Saturn has on Mimas.