Mars to get planetary ring set to rival Saturn, with moon Phobos set to break up from tidal stress
Mars is destined to get a spectacular new planetary ring system to rival that of Saturn, but don’t hold your breath because it will not be for another 30 million years or so, according to scientists.
The findings, published in the journal Nature Geoscience, are based on a new study to determine the fate destined to befall the diminutive Martian moon Phobos.
Over time Phobos is creeping inwards towards Mars at a couple of centimetres per year.Dr Benjamin Black
“We found that Phobos is too weak to withstand tidal stresses from Mars and we expect it to break apart in a few tens of millions of years and form a ring around Mars,” the study’s lead author Dr Benjamin Black of the University of California said.
Only the giant planets of the outer solar system have rings at the moment.
Phobos — the larger of the two moons circling Mars — orbits just 6,000 kilometres above the surface of the red planet, closer than any other moon in the solar system.
“Over time Phobos is creeping inwards towards Mars at a couple of centimetres per year,” Dr Black said.
“We wanted to figure out whether Phobos crashes into Mars or breaks apart to form a ring, so we needed to know how strong it was — is it going to be able to stand the increasing tidal stresses that are going to be pulling this little moon apart, or will it eventually succumb to these forces?”
Dr Black and co-author Tushar Mittal found that Phobos will be pulled apart by the red planet’s gravitational tidal forces in about 20 to 40 million years’ time.
“We concluded that Phobos would break apart between 2.4 and about 1.1 Mars radii, somewhere between 8,500 kilometres down to around 4,000 kilometres or so,” Dr Black said.