Researchers have long theorized about the origin of Mars' moons, and whether there has ever been a ring around the "Red Planet." According to research published by scientists at Purdue University in March 2017, it is believed that the Martian moon Phobos has repeatedly broken apart into a ring of debris and then coalesced back into a moon. If that theory is correct, then 70 million years from now, Mars will have a new set of planetary rings and one less moon.
Astronomers think that about 4.3 billion years ago, Mars collided with a large object that disintegrated and formed planetary rings. Scientists believe these rings eventually formed into Mars' current moons, Phobos and Deimos. However, due to the tidal forces of the planet, Phobos has been gradually decaying and shrinking. They hypothesize that in about 70 million years, Phobos will break apart to form a new set of planetary rings.
More about planetary rings:
- The "Roche limit" is the minimum distance at which a moon orbiting a celestial body can remain intact. Phobos will break apart once it surpasses this limit.
- Planetary rings are most often associated with the Jovian planets: Jupiter, Saturn, Uranus, and Neptune.
- Planetary rings are composed of rock, ice, and dust particles of varying sizes.