Phobos: Doomed Moon of Mars
Explanation:
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 asteroid belt between
Mars and
Jupiter
or perhaps from even more
distant reaches of the
Solar System.
In this 1977 Viking orbiter image, the largest moon,
Phobos, is seen to be a heavily cratered asteroid-like object.
It is about 17 miles across and zips through the Martian sky completing an
orbit in less than 8 hours. Phobos is doomed. It orbits so close to Mars,
(about 3,600 miles above the surface compared to 250,000 miles for our
Moon)
that gravitational tidal forces are dragging it down. In 100 million
years or so it could crash into the surface or be shattered by stress
caused by the relentless tidal forces, the debris forming a ring around
Mars.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
