Phobos is Mars’s largest moon.
By Dileep Thekkethil
A stunning discovery made by Indian origin researcher and his colleague at the University of California, Berkeley, reveals that Mars, the red planet that we see today in images, will not be the same after a few million years as a new ring, similar to that of Saturn will be formed around it.
The new finding of earth’s closest cousin comes just two weeks after NASA found that Mars’s moon Phobos is moving closer to the planet due to the heavy gravitational pull exerted by it on all nearby objects.
According to Tushar Mittal, Phobos will not make it to the surface of Mars as it will get disintegrated within the Martian orbit resulting in the formation of a ring similar to the one around Saturn. This phenomenon is expected to happen in the next 20-40 million years, says the research team.
‘Phobos will either break apart to form a ring or any large fragment of the moon that is strong enough to escape the tidal stress will eventually collide with Mars in an oblique, low-velocity impact’ said postdoctoral researcher Benjamin Black, of University of California, Berkeley, and graduate student Tushar Mittal.
Phobos, the largest moon of Mars, is positioned 6000 km away from the planet and has been orbiting for many million years, each time inching closer to its parent due to the tidal stress that pulls it towards the host. Of late, the immense gravitational pull has made the core of Phobos weak, causing gradual structural disintegration of the moon as it nears Mars.
The researchers also confirm that this couldn’t be the first instance of a moon disintegrating into a ring as many have suffered similar death in the solar system in the past. They cited the example of Saturn’s iconic ring, which is also believed to be the result of a similar phenomenon. The ring of dust particles and rubbles could stay there for a few hundred years before it gets vanished.
According to Benjamin Black, the slow death of Phobos, which is in its initial stage is a rare chance for researchers to study the process, which could be widespread throughout the solar system. He along with Tushar Mittal authored a paper on ring-system on November 23 in Nature Geoscience.
Phobos, the moon with rubble like core, measures 22 km in radius. It is residing close to Mars and after each year, the Moon comes a centimetre or two closer to its parent due to the gravitational pull.
Mittal and Black did a thorough investigation into the impending death of Phobos and found that the weakest part of Phobos would be the first to shudder off from the core, spreading out and forming a ring in about 20 million years from now.
Once the moon reaches a distance that is too close for it to handle, the process of disintegration would speed up resulting in its complete destruction within days or weeks. “If you were standing on the surface of Mars, you could grab a lawn chair and watch Phobos shearing out and spreading into a big circle,†Black says.
The smaller size of the disintegrated particles will allow it to stay afloat in the Martian orbit for close to 1 – 100 million years before the debris finally fall on the Mars’s surface.
Terry Hurford, a planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland while presenting his work this month at a planetary science conference said the excess gravitational pull experienced by Phobos has already created grooves in the surface of the moon, which is the first sign of tidal failure that will eventually rip the moon into fragments.
Earlier in 2012, a Russian mission to explore the surface of Phobos plummeted back to Earth after a launch failure. According to Mittal and Black, future missions to Phobos could provide more insights into how and when the moon will meet its death.
Deimos, another moon of Mars, which is 6.2 km in radius is 23,460 km away from Mars’s surface, far away from feeling the gravitational pull of the planet.
Deimos, Mars’s other moon, is too far away from the planet to be subject to the same stresses, so won’t break up anytime soon
Mittal says he and Black will be looking for signs of these now-dead moons.