By Tim Binnall
An intriguing new study concerning Mars' moon Deimos suggests that the Red Planet was once encircled by a ring. The thought-provoking theory arose when scientists took a closer look at a particular peculiarity possessed by the lunar body. "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," said the SETI Institute's Matija Cuk, who led the research,"but once we had a big new idea and we looked at it with new eyes, Deimos' orbital tilt revealed its big secret."
Specifically, Cuk and his colleagues observed that Mars' other moon, Phobos, was orbiting in a manner which will ultimately result in the celestial body being broken apart by the Red Planet's gravitational pull and forming a ring of debris that would eventually come together to create a new moon. This led to the notion that perhaps that future event will merely be the latest iteration in what has been an ongoing pattern which the researchers dubbed the 'cyclic Martian moon theory.'
The hypothesis, they argue, would explain the unique orbit of Deimos as it has an odd tilt that one would expect to have come from "an outward-moving moon" being pushed out of the ring and slightly influencing the characteristics of the celestial body. That theoretical moon, the researchers believe, likely existed "over 3 billion years ago" and underwent the cycle of lunar destruction and rebirth that formed Phobos, which is considerably younger than Deimos.
Taking this new theory into consideration, the researchers postulated that "for much of its history, Mars possessed a prominent ring" and we just so happen to exist in a period when it does not. The team hope to put their idea to the test in the future as a craft from the Japanese space agency JAXA is set to land on Phobos in 2024 and bring samples of the moon back to Earth. This, they believe, may provide some new clues about the history of the celestial body which should inform their hypothesis.