This image illustrates the magnetic field of the planet.
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Image from: NASA/JPL

Mars Global Surveyor Magnetometer findings

An important new result from the Mars Global Surveyor (MGS) mission is the definite confirmation of the presence of a magnetosphere around Mars.

Previous missions made inconclusive measurements of the Martian magnetic field. A determination of the presence of a magnetic field helps scientists understand where the magnetic material of Mars resides, and a little bit about the Martian evolution. It also answers one fundamental question set to be resolved by the Mars Surveyor Program.

Scientists used to think that because the Martian surface contained so much iron, and the Martian magnetic field was so weak, that the early history of Mars was not sufficiently warm for Mars to differentiate, and form a large solid iron core. A large molten iron core, such as that of the Earth, would generate a strong magnetic field. Thus, iron must have stayed mostly on the outside layers of Mars, making the surface red with rust.

Recently, Mars Pathfinder returned a measurement which suggested that Mars has a large iron core. Therefore, if the core of Mars is large and composed of iron as the Mars Pathfinder measurement shows, and there definitely is a magnetic field generated inside as the Mars Global Surveyor measurement shows, then this theory about the evolution of Mars may not be completely correct.

Last modified June 3, 2003 by Randy Russell.

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