KEY POINTS

  • Researchers claimed that Mars once had a ring around it
  • The orbit of Deimos supported the theory on Mars' ring
  • An early version of Phobos was destroyed by Mars

A team of researchers came across new evidence that strongly suggests that Mars once had rings around it. The researchers came to this conclusion after studying the behavior of Mars moons Phobos and Deimos.

The new study about Mars was conducted by astronomers from the SETI Institute. They presented their findings in a new paper submitted for publication to The Astrophysical Journal Letters.

In the study, the researchers claimed that like Jupiter, Neptune and Saturn, Mars was also a ringed planet. They made this conclusion after studying the orbit of Deimos, which is the smaller of the two Martian satellites.

According to the researchers, the moon’s orbit around Mars is about 1.8 degrees off the planet’s equator. It also rotates around Mars at an average of 30 hours with low eccentricity. Although the orbit seems pretty normal, the researchers claimed that this was the result of another massive space object that orbited Mars.

Using simulations, the researchers proposed Mars was once orbited by the predecessor of Phobos. As it encircled Mars, it moved closer to the planet. Eventually, the moon got close enough to be ripped apart by the planet’s tidal forces.

As the pieces of debris from the natural satellite orbited Mars, they started to form a ring structure around the planet. The larger fragments, on the other hand, formed into a new natural satellite. As the ring moved closer to the planet, the new moon got pushed away.

According to the researchers, the outward movement of the new moon could have affected the orbital inclination of Deimos around Mars. Deimos’ orbit around the Red Planet tilted by about 1.8 degrees due to the gravitational effect of another Moon.

“The fact that Deimos's orbit is not exactly in plane with Mars's equator was considered unimportant, and nobody cared to try to explain it,” astronomer Matija Cuk, lead author of the study, said in a statement. “But once we had a big new idea and we looked at it with new eyes, Deimos's orbital tilt revealed its big secret.”

The researchers believed that as the debris within the ring fell into Mars, the new moon moved closer to the planet. Eventually, it would start another cycle of getting destroyed by tidal forces and creating a new ring around Mars.

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The moon Phobos snuck into photos the Hubble Space Telescope was taking of its parent planet, Mars. This composite puts together all 13 photos Hubble took. NASA