Phobos: Doomed Moon of Mars
This moon is doomed.
Mars,
the red planet named for the
Roman god of war, has two tiny moons,
Phobos and
Deimos, whose
names are derived from the Greek for Fear and Panic.
These martian moons may well be captured
asteroids
originating in the main asteroid belt between Mars
and Jupiter or perhaps from even more distant reaches
of the Solar System.
The larger moon, Phobos, is indeed seen
to be a cratered, asteroid-like object in this
stunning color image
from the Mars Express spacecraft, recorded at a resolution of about
seven meters per pixel.
But Phobos orbits so close to Mars -
about 5,800 kilometers above the surface compared to 400,000 kilometers
for our Moon - that
gravitational tidal forces are dragging it down.
In 100 million years or so it will likely crash into the
surface or be shattered by stress caused by the
relentless
tidal forces, the debris forming a ring around Mars.