This drawing shows the difference between a dipole and a magnetosphere.
Click on image for full size
Image from the AGU Educator's Slide set. Image copyright 1997 by the American Geophysical Union. Further electronic distribution is not allowed.

A Planetary Magnetosphere

A planetary magnetosphere is different from an ordinary dipole. The force of the solar wind, coming from the sun stretches the dipole and creates a nose region in the front of the magnetosphere (facing the sun), and a tail region in the back called a magnetotail.

If it weren't for the solar wind, a planet's magnetic field would extend forever. But because the solar wind presses upon a planet's magnetic field, and encloses it, the magnetic field is forced to stay within a "cavity" called the magnetosphere.

This magnetosphere naturally has an edge and that edge is called the magnetopause.

Last modified June 23, 2010 by Randy Russell.

You might also be interested in:

Cool It! Game

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

The Lobes

The lobes of the magnetosphere are a huge area between the magnetopause and the plasma sheet....more

Magnetosheath

The magnetosheath is the space between the bow shock and the magnetopause. ...more

The Plasmaspheres of Neptune

Neptune has three small plasmaspheres which are greatly affected by Neptune's rings. Particles enter the plasmasphere from Neptune's atmosphere as well as the magnetotail. Particles might leave the plasmasphere...more

Magnetosphere

A magnetosphere has many parts, such as the bow shock, magnetosheath, magnetotail, plasmasheet, lobes, plasmasphere, radiation belts and many electric currents. Particles in the magnetosphere cause aurora...more

AU

AU stands for Astronomical Units. It is an easy way to measure large distances in space. It is the distance between the Earth and the Sun, which is about 93 million miles. For really big distances, we...more

The Spiral of the IMF

The solar wind is formed as the Sun's top layer blows off into space. It carries magnetic fields still attached to the Sun. Streams appear to flow into space as if they are spiraling out from the Sun,...more

Spiral Path of Material

For a planet to be affected by a blob of material being ejected by the sun, the planet must be in the path of the blob, as shown in this picture. The Earth and its magnetosphere are shown in the bottom...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA