Mars Surveyor Data
The images and science data from NASA's Mars Global
Surveyor spacecraft show a climatically diverse yet
lifeless world where a mountain soars 17 miles high
and a canyon cuts 11 miles deep into the surface.
"We are seeing a very interesting planet in that we have
no idea of how it got into that form," said David Smith
of NASA's Goddard Space Flight Center in Greenbelt, Md.,
principal investigator for the instrument that measure's
the planet's elevations.
So far, Surveyor has shown that Mars is an ever-changing
world with dust devils swirling five miles high into
rainless skies, clouds of ice hover over giant volcanoes
and layers of frost settle on rust-colored sand dunes.
Mars is shaped like a pear, its mountainous southern half
nearly two miles higher than its flat northern hemisphere.
Its surface has the highest, lowest and smoothest land
forms found in the solar system.
So far, there is no evidence from the Surveyor mission
that life existed or could exist on Mars. Findings from
an instrument that studies the composition of surface
minerals has so far found no rocks from which the building
blocks of life could develop, according to Dr. Arden Albee
of the California Institute of Technology. "Things that we
thought would be the precursors of life have not shown up,"
he said.
The mapping also will help other mission managers determine
where to land. A landing site for the next Mars probe, which
arrives on Mars in December, will be determined over the next
few months using Surveyor data.
Magnetic Strips Discovered
Instruments aboard the Mars Global Surveyor have detected
magnetic striations that closely resemble the magnetic
signature of crustal spreading and continental drift on
the Earth. This may mean the very young Mars resembled
the very young Earth, but that Mars depleted its internal
energy sources and became a geologically dead planet early
in its history, said Norman F. Ness of the University of
Delaware and co-author of the study. "The data suggests
that Mars was once magnetic and was far more similar to
Earth's global magnetic field than had previously assumed,"
Ness said.
Evidence of this magnetic field is frozen in rocks that
were molten when the magnetic field existed. When the
rocks hardened they retained the original magnetism and
that now has been detected and mapped by the spacecraft.
"At the present time there is no evidence of a global
magnetic field on Mars," said Ness. "That means the dynamo
died and what is left is the memory of that dynamo, stored
in the crustal rocks like a magnetic tape recording."
The discovery of Martian magnetic striations suggests that
Mars may also have had continent-sized plates that split
apart on the surface of the planet and inched apart, pushed
by the flow of magma bubbling up through crustal rifts. Ness
said the energy that heated the rock apparently ran out
within a few hundred million years and Mars became a dead
planet geologically.
To see the latest images sent back
by the Mars Global Surveyor,
visit the mission's Web site:
Mars Exploration Program
