Will Mars ever get rings?
One of the Red Planet’s two moons is on a death spiral towards it
Mars has two moons, Phobos and Deimos, and scientists think the former’s days are numbered. In about 10 to 50 million years, Phobos is expected to break apart and possibly form a ring around Mars. Why? Well, Phobos is slowly falling towards the Red Planet due to the gravitational pull of Mars. It orbits just 6,000 kilometres above the surface (in comparison, our Moon is 384,000 kilometres away) and is getting closer to Mars by 1.8 centimetres a year.
Eventually, the weakest, most damaged material will be pulled from the moon. Scientists aren’t sure if it will then fall towards Mars and impact the surface, or if the fragments will form a ring. Either way, it should be pretty spectacular.
Put a ring on it
How Phobos might break apart in Martian orbit
1. Orbit
Phobos currently orbits about 6,000 kilometres above Mars, but is falling by 1.8 centimetres every year due to the gravitational force from the Red Planet.
2. Break up
In about 10 million years, Phobos might begin to break up as Mars’ gravity pulls it apart. This will depend on if it is rubble-like rather than solid inside.
3. Ring
The moon’s dusty outer layer may form a temporary ring around Mars in just a week. Its more solid chunks, however, will likely impact the surface of Mars.
4. Spectacle
Scientists predict Mars may keep this ring for 1 to 100 million years, leaving Deimos – which will not go through a similar process – as the planet’s only moon.
This article was originally published in How It Works issue 098, written by Jonathan O’Callaghan
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