How did Mars become the
planet we see today? What accounts for the differences and
similarities between Earth and Mars? These questions will be
addressed by studying Mars' geology. As part of the Mars
Exploration Program, we want to understand how the relative
roles of wind, water, volcanism, tectonics, cratering and other
processes have acted to form and modify the Martian surface.
For example, Mars is home to incredibly large volcanoes, which can be 10 to 100 times larger than those on Earth. One reason for this difference is that the crust on Mars doesn't move the way it does on Earth. That means the total volume of lava piles up into one, very large volcano.
The Magnetism of Mars Gives Clues to the Planet's Interior and More
A recent discovery by the
Mars Global Surveyor spacecraft of large areas of magnetic
materials on Mars indicates that the planet once had a magnetic
field, much like Earth does today. Because magnetic fields in
general act to shield planets from many forms of cosmic radiation,
this discovery has important implications for the prospects
for finding evidence of past life on the Martian surface. Study
of the ancient magnetic field also provides important information
about the interior structure, temperature and composition of
Mars in the past. The presence of magnetic fields also suggests that Mars was once more of a dynamic Earth-like planet than it is today.
Rocks on Mars Can Tell Us About the Planet's History and Its Potential for Harboring Life
Of fundamental importance
are the age and composition of different types of rocks on the
Martian surface. Geologists use the age of rocks to determine
the sequence of events in a planet's history. Composition
information tells them what happened over time. Particularly
important is the identification of rocks and minerals formed in
the presence of water. Water is one of the keys to whether life
might have started on Mars.
What other materials might be
trapped in those rocks with information about the planet's
history? How are the different rock types distributed across
the surface? Future orbiting and landed missions will carry
special tools designed to help answer these questions.
Twelve Mars meteorites discovered on Earth can also give us
clues about the planet. Learn more about
Meteorites from Mars
from the Johnson Space Center.
