A cycle of moon formation could explain the slightly tilted orbit of Mars' moon Deimos.

Related: Moons of Mars: Amazing Photos of Phobos and Deimos.

"The fact that Deimos' orbit is not exactly in plane with Mars' equator was considered unimportant, and nobody cared to try to explain it," study lead author Matija Cuk, a research scientist at the SETI Institute, said in a statement.

Eventually, Phobos will drop so close to Mars that the gravity of the much larger planet will pull the moon into pieces — forming a ring.

This not only will happen to Phobos, but has happened already other times in the Martian past.

"This cyclic Martian moon theory has one crucial element that makes Deimos’ tilt possible: a newborn moon would move away from the ring and Mars ...

"An outward-migrating moon just outside the rings can encounter a so-called orbital resonance, in which Deimos' orbital period is three times that of the other moon," the institute added.

"We can tell that only an outward-moving moon could have strongly affected Deimos, which means that Mars must have had a ring pushing the inner moon outward.".

This theoretical outward-moving moon would have been huge, at 20 times more massive than Phobos!

The Japanese Aerospace Exploration Agency (JAXA) plans to send a mission to Phobos in 2024, called Martian Moons Exploration (MMX).