Strong tidal encounters behind cracks on icy moons: Study

Strong tidal encounters may be responsible for the cracks on icy moons such as Pluto's Charon, Saturn's Dione and Tethys, and Uranus's Ariel, says a study.

Until now, it was thought that the cracks were the result of geodynamical processes, such as plate tectonics, but the new computer model developed by University of Rochester researchers suggests that a close encounter with another body might have been the cause.

By devising and running the model, professor Alice Quillen showed that the tidal pull exerted by another, similar object could be strong enough to crack the surface of such icy moons.

The key factor in determining if a crack is going to occur is the strain rate, the rate of pull from another body that would have caused the moons to deform at a rate that the top, icy layer could not sustain - leading to cracks, said the study.

The findings will be published in a forthcoming issue of the journal Icarus.

Astronomers have long known that the craters visible on moons were caused by the impact of other bodies, billions of years ago.

But for every crash and graze, there would have been many more close encounters.

Quillen also thinks that "it might even offer a possible explanation for the crack on Mars, but that's much harder to model".

--IANS

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