This image illustrates one way in which the magnetometer instrument studies the planet.
Click on image for full size
Image from: NASA/JPL
The Martian Magnetosphere
An important new result from the Mars Global Surveyor (MGS) mission is the definite confirmation of the presence of a magnetic field near Mars. The magnetic field leads to the formation of a magnetosphere, as shown in this drawing. A magnetosphere helps protect a planet from the solar
wind, however, the Martian magnetosphere may be too small to do that very well. In this picture, MGS can be seen going around Mars.
The magnetosphere can be found outside of, but somewhat overlapping the planet's atmosphere. Particles of the atmosphere can sometimes enter the magnetosphere and particles of the magnetosphere can sometimes enter the atmosphere.
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