Earth's Magnetosphere

Earth's Magnetosphere

A visualization of Earth's magnetosphere.

NCAR High Altitude Observatory (HAO)

Earth's magnetic field generates a sort of "magnetic bubble" in space around our planet. This region is called the magnetosphere. Earth's magnetosphere is a bit like a magnetic force field that surrounds our planet. The magnetosphere protects our planet from some types of radiation from the Sun.

Earth’s weather is produced by heat, moisture, and wind, but space weather is a result of electromagnetic and particle radiation. The Sun’s magnetic field releases energy in its atmosphere, generating many forms of solar activity. Bursts of radiation and highly energized particles can race into interplanetary space. This solar wind flows around the Earth’s magnetic field (the magnetosphere), drawing the field out into a comet-like tail.

Earth's Dipole Magnetic Field

The magnetosphere can be visualized as magnetic field lines produced by a giant bar magnet, tilted about 11o from Earth’s rotation axis (as seen in the COMET Program's image to the right). One magnetic pole is located in northern Canada, and the other pole is located in Antarctica. The magnetic field above the poles extends far into space and shields the Earth from many of the energetic charged particles coming from the Sun and more distant sources in the galaxy.

When the solar wind reaches Earth’s upper atmosphere, it can energize charged particles. The result is colorful auroras that encircle the magnetic poles at heights of around 60–125 miles (100–200 kilometers) in the atmosphere. In the Northern Hemisphere, these are also called the northern lights. Collisions of electrons with oxygen produce red and green aurora, while collisions with nitrogen produce red, blue, and violet aurora.

Severe space weather can injure astronauts and satellites in orbit; disrupt radio, GPS, and airline communication systems; and damage power grids on Earth’s surface. Longer-term variations in solar magnetic activity can affect Earth’s climate and space environment. Continued observations of solar activity help society anticipate and prepare for solar storms, so we can learn to live with our changing Sun.

© 2012 UCAR