The moons of Mars explained.

Mars has two moons, Phobos and Deimos.

They are really tiny. How tiny?

Compared to Mars or our own Moon,

pretty tiny.

Although ‘tiny’ is a matter of opinion.

Their surface area is up close to some
of the smallest states on Earth,

like Luxembourg and Malta.

Although Phobos and Deimos are
in no way lightweight,

in reality, their gravitational pull
isn’t even strong enough

to bring them into spherical form.

So they look more like huge
potatoes than moons.

The most popular theory of their origin

is that they were once
part of the asteroid belt,

until Jupiter’s massive gravity
kicked them out of it,

so Mars could catch them.

Phobos orbits Mars at a average distance
of 9,400 kilometres, once every 7½ hours.

It’s on a collision course, and gets
2 metres closer to Mars every year.

In 50 to 100 million years, it will either
be ripped to pieces by Mars’s gravity

and be transformed into a beautiful ring,

or it will crash into Mars.

The energy released in this collision
would kill everything on the small planet.

So, if there are humans on Mars by then,
they should build very strong bunkers.

Smaller Deimos, on the other
hand, is slowly escaping Mars.

Eventually, it will fly off into space
and leave a lonely red planet behind.

So, in a few hundred million years,
Mars will be moonless and on its own.

Unless it manages to catch
itself another asteroid.