While the big space news this week is all about new planets outside of our solar system and the possibility that some may contain life, our next-door neighbor Mars made some news itself with the confirmation of a long-held theory that it is developing a ring and its tiny moon Phobos may eventually become part of it.
When Galileo put his eye to one of the first telescopes, Saturn became the king of rings in our solar system. Stronger telescopes and recent space missions have confirmed that Jupiter, Uranus, and Neptune also have similar but less spectacular rings. Astronomers have theorized that these rings aren’t limited to the giant planets and Mars is a strong candidate to have one or more, possibly made of pieces of its moons Phobos and Deimos. While simulations and models showed the possibility, no telescopes nor Mars missions could find them.
That changed with the Mars Atmosphere and Volatile Evolution (MAVEN) mission in 2013. Initial data from the satellite showed high-altitude dust particles surrounding the planet, but their even distribution implied they were captured from outer space by Martian gravity and not formed from broken or unformed moons or meteorite collisions like other planetary ring systems. However, no definitive proof was found.
New data from MAVEN has changed the picture. According to a study led by Jayesh Pabari of the Physical Research Laboratory in Ahmedabad, India, and published recently in the journal Icarus, a model based on Martian and moon meteorite data suggests that about 0.6 percent of the dust is coagulating into a ring and it’s coming not from the Martian surface but from the breakdown of Phobos and Deimos.
The two Martian moons should actually be called moonlets since Phobos is about 14 miles (22 km) wide and Deimos is a tiny 3.9 miles (6.2 km) in diameter. Phobos is closer to Mars in a fast (circling Mars twice each Martian day) but deteriorating orbit (dropping 6.5 ft (2 meters) per century). While some astronomers believe Phobos will eventually crash into the Martian surface (in 30 to 50 million years), this new model shows it may be breaking apart already and forming a ring.
Unfortunately, we won’t be around to see a Martian ring from Earth but MAVEN’s scientists are not convinced that Pabari’s model is correct. The dust data is limited because MAVEN wasn’t designed to analyze or collect it, says scientist Laila Anderssen of the University of Colorado Boulder who has been studying the dust using MAVEN instruments whose primary purpose is electrical sensing.
To really say anything definitive about the dust, you really need to have a dedicated dust detector. We still haven’t seen a good indication that there is significant material in the vicinity of the moons. So I think it’s a long shot, but one should never say never.
However, one could say that the Dedicated Dust Detectors would be a great name for a band.