New Delhi: Researchers have found new evidence indicating the presence of a subsurface ocean of Miranda, a moon of Uranus. Previous research had indicated subsurface oceans on the largest moons of Uranus, Titania, Oberon, Ariel and Umbriel, but not Miranda. The Voyager 2 spacecraft is the only probe to have observed the Uranian system from up close, and it only managed to capture images of the southern hemisphere of Miranda. The terrain is a hodgepodge of grooves interrupted by craters and rough scraps. Researchers suspect that these features are a result of tidal heating, as the ice giant squeezes the moon in its orbit.
Grooves, ridges and craters on Miranda captured by Voyager 2. (Image Credit: NASA).
Researchers attempt to reverse-engineer the surface features to uncover the interior of the moon using sophisticated computer modelling. The researchers tested several possible interior compositions that could give rise to the observed features. The best match for the predicted stress patterns and the observed features suggests that a vast ocean formed beneath the surface of Miranda between 100 and 500 million years ago, at least 100 kilometres in depth. The research indicates that the subsurface ocean is beneath an ice crust that can be a maximum of 30 kilometres in thickness.
Tidal forces provided the energy to form the ocean on Miranda
The formation of the ocean was driven by the tidal heating because of the gravitational heating of Uranus itself, as well as four larger moons of Uranus that all orbit at greater distances than Miranda. The friction from the tidal flexing also causes the stress cracks on the surface, resulting in the rich tapestry of geologic features observed on Miranda. Miranda is an old and small moon, and scientists had not previously expected this world to harbor a subsurface ocean. A paper describing the findings has been published in The Planetary Science Journal.
