Saturn’s Moon Enceladus May Have Tipped Over: Cassini Mission Finds The Reason

NASA’s Cassini mission’s latest research suggests that Saturn’s ice-covered moon Enceladus may have tipped over in the distant past.

Researchers associated with the Cassini mission studied the images it took and found proof that the Enceladus’ spin axis was reoriented, which was likely a result of a collision with a tinier celestial body such as an asteroid. The spin axis is the imaginary line that goes through the North and South Pole of a planet or its satellite.

Saturn’s Moon Enceladus May Have Tipped Over

During the evaluation of Enceladus’ surface features, the researchers showed that Saturn’s satellite may have slanted away from its original spin axis by roughly 55 degrees. If the calculations are correct, then it means that Saturn’s icy moon rolled away onto its other side by over 50 percent.

“We found a chain of low areas, or basins, that trace a belt across the moon’s surface that we believe are the fossil remnants of an earlier, previous equator and poles,” the study’s lead author Radwan Tajeddine, also an associate from Cassini’s imaging team, shared.

Cassini Observations Help Researchers

The researchers drew the conclusion that Saturn’s moon may have tipped over by observing the geological activity in Enceladus’ South Pole. The current South Pole of Saturn’s ice-covered moon is an internally active zone, featuring remarkable linear and long fractures or tiger stripes on the satellite’s surface. These fractures run parallel to each other.

Tajeddine and his team believe that in the past, an asteroid possibly collided with the satellite in this region, when it was nearer to the equator. They opined that the collision may have led to Enceladus getting tipped over from its original spin axis. This may have occurred as the scientists think that the geological activity in the particular area did not start internally.

Tajeddine and the team think that an external impact was necessary to bring about such a huge reorientation in Enceladus’ positioning. The researchers feel that the external collision in the satellite’s current South Pole area may have led to the redistribution of some of Enceladus’ mass, resulting in its rotation becoming unstable and wobbly.

Based on the Cassini’s new observations, it can be concluded that the rotations eventually stabilized over millions of years, but resulted in the reorientation of the Saturn moon’s north-south axis. The researchers call this mechanism “true polar wander.”

The Polar Wander Theory

The polar wander theory explains why the two current poles of Enceladus are drastically different from each other. While the South Pole is a geologically young active region, the North Pole is filled with craters and is much older than its southern counterpart.

If the collision that tipped Enceladus over would not have taken place, the satellite’s poles would have been similar in features and characteristics.

The study’s results were published in the online journal Icarus on Tuesday, May 30.

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