صورة اليوم الفلکیة
Phobos: Doomed Moon of Mars
Image Credit:
HiRISE,
MRO,
LPL (U. Arizona),
NASA
Explanation:
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
our Solar System.
The larger moon, Phobos, is indeed seen
to be a cratered, asteroid-like object in this
stunning color image from the robotic
Mars Reconnaissance Orbiter,
with objects as small as 10 meters visible.
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 perhaps 50 million years,
Phobos is expected to disintegrate
into a ring of debris.