Saturn’s moon Mimas - level 3
A new study focusing on the inside of Saturn's icy moon Mimas suggests that its cratered surfaces hide one of two intriguing possibilities: either the moon's frozen core is shaped a bit like a rugby ball, or it contains a liquid water ocean.
Researchers used a number of images of Mimas taken by NASA's Cassini Mission to determine how much the moon wobbles, as it orbits Saturn.
They later came to the conclusion that the data suggests that something "isn't right".
An underground ocean is one of two explanations for why the 400-mile diameter moon wobbles.
The other possibility is that Mimas has an oblong or rugby ball-shaped core.
Whilst scientists believe the ocean idea sounds quite unlikely, a closer look at the moon's eccentric orbit suggests gravitational tugging by Saturn as the moon circles closer and then further away could cause enough frictional heating to melt ice and form an ocean.
Difficult words: intriguing (interesting), liquid water ocean (oceans made of water are rare on other planets and moons), determine (find out), wobble (move a little from side to side), oblong (a circle where one side is longer than the other), eccentric (strange), tug (pull).
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