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Goal 3: Characterize the Geology of Mars

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

map of Martian magnetic fields in the southern highlands
Image above: This image is a map of Martian magnetic fields in the southern highlands. It is where magnetic stripes possibly resulting from crustal movement are most prominent. Image credit: NASA/Goddard Space Flight Center
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A 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.

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Editor: Susan Watanabe
NASA Official: Brian Dunbar
Last Updated: November 23, 2007
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