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No one would put Mars in the list of planets with rings, but millions of years ago the red planet could belong to this exclusive group of the worlds jewels. Scientists from the SETI Institute and the Purdue University believe that the orbit unusually inclined Deimos , one of its two moons, is a new test that different past. A past that is repeated cyclically, and that it is very possible for it to return.

Mars has two small moons and deformed as tubers, Deimos and Phobos , discovered in 1877. For a long time scientists believed that they were asteroids captured. However, given that their orbits are nearly in the same plane as the martian equator, the satellites had been formed at the same time that Mars. But the orbit of the moon smaller and more distant one, Deimos, is tilted two degrees . It seems very little, but that difference is key.

“The fact that the orbit of Deimos is not exactly in-plane with the equator of Mars, it was not considered important, and no one tried to explain it,” says Matija Ćuk, a researcher at the SETI Institute and lead author of the study, recently presented at the virtual meeting of the Astronomical Society of america and whose publication has been accepted in the journal “Astrophysical Journal Letters”. “But once we had a great new idea and we look at it with new eyes, the orbital inclination of Deimos revealed his great secret,” he says.

Moons destroyed

This new idea to which it refers Ćuk was submitted in 2017 by his colleague, David Minton, a professor at Purdue University and then graduate student Andrew Hesselbrock. Hesselbrock and Minton proposed that Phobos, the moon interior of Mars, is caught in a cycle of destruction and rebirth, each time produces the rings on the red planet. During thousands of millions of years, generations of moons on mars have been destroyed in rings. And each time, the ring would give rise to a new moon and smaller which repeats the cycle again. The researchers came to this conclusion by noticing that the moon interior of Mars, Phobos is losing altitude as its small gravity interacts with the balloon to a martian. Within tens of millions of years, soon, in astronomical terms, Phobos will not withstand the gravitational pull and it will end up shattered to create a new ring around the planet.

This theory is cyclic of the martian moon has a crucial element that makes it possible for the inclination of Deimos: a moon new born to 20 times more massive than the current Phobos would be pushed out by the ring, marciano would have a resonance orbital 3:1 with Deimos, which means that the orbital period of Deimos is three times higher than that of the other moon. This caused the inclination of two degrees of Deimos.

That moon huge, he could have been the “grandmother” of Phobos a little more than 3,000 million years. Followed by two more cycles of ring-moon as the last moon Phobos.

The test, in 2024

According to the researchers, the discovery of the resonance orbital practically confirms the theory of the cyclic moon-ring for Mars. Implies that during most of its history, Mars had a ring prominent. While Deimos has thousands of millions of years, Ćuk and its partners believe that Phobos is young in astronomical terms. Perhaps formed only 200 million years ago, just in time to the dinosaurs.

These theories can be tested in some years since the space agency, the japanese JAXA plans to send a spacecraft to Phobos in 2024 to collect samples from the moon’s surface and return them to the Earth. Ćuk has the hope that this will give us firm answers about the dark past of the moons on mars. As he expresses, “the theoretical calculations are good, but are tested in the real world is even better.”