How powerful is the magnetic field of the Earth in space?

At the surface of the Earth, the magnetic field has a strength of about 0.5 Gauss units (50000 nano-Teslas, or 50000 nT). In comparison, a typical toy magnet, or one used on your refrigerator, produces about 100 Gauss.

The strength of the earth's magnetic field at any point in 'geospace' out to 30,000 kilometers can be estimated from detailed models of the shape of the magnetic 'dipole field' of the Earth...a field pattern that was originally proposed by Gilbert in the 1600's.

If you visit the International Geophysical Reference Field web site, you can create a plot of the change in the magnetic field strength with height from the earth's surface by using their interactive form. At the orbit of the Space Shuttle, the field has a strength of 0.35 Gauss, and declines to 0.037 Gauss ( 3700 nT) by 7000 kilometers. Additional resources about the Earth's magnetic field can be found at the IMAGE/POETRY magnetosphere resource page.

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