Saturn moon Mimas, which is commonly referred to as the "Death Star" due to its similar appearance to the Star Wars entity, has an unusual interior, scientists are now learning.

Mimas' Strange Interior

Due to Mimas’ rotation and orbit around Saturn, the satellite appears to rock back and forth and oscillate, not dissimilar to the way in which a pendulum swings, according to an article on Space.com. Typically, such movements, called librations, are the result of the gravitational pull from nearby planets. While a libration isn’t uncommon, Mimas’ is of note because of its strength in one spot.

"We're very excited about this measurement because it may indicate much about the satellite's insides," Cornell University research associate Radwan Tajeddine said in a statement. "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."

The Cassini spacecraft has been capturing images of Mimas, Saturn and the planet’s rings for the past 10 years. From the photos, Tajeddine and his team have been able to mock up a 3D map of the moon to determine how it spins and orbits Saturn. Tajeddine and his team have developed a total of five possible interiors of the satellite, two of which theorectically have more of a chance of being accurate.

The prevailing theory is that Mimas has an “elongated, oval-shaped core.” This could have occurred to do the push and pull of Saturn’s rings. The other theory – that MImas has a subsurface ocean – is less likely.