The Magnetic Tail of the Earth
February 05, 2001
This is a false color image of the transparent, electrified gas (plasma) trapped inside Earth's magnetic field collected by NASA's Imager for Magnetopause to Aurora Global Exploration (IMAGE) spacecraft. By tracking the motion of this plasma, scientists are getting the first large-scale, global views of the Earth's magnetic field and magnetic storms. The IMAGE spacecraft is looking down at the Earth from above the north pole. The Sun is outside the picture area towards the top right corner (note the shadow cast by the Earth in its own plasma cloud at the bottom left of the blue image).
The blue represents the ultraviolet glow from relatively cold plasma as seen by the Extreme Ultraviolet imager (EUV) instrument on board IMAGE. A hook-shaped "tail" of plasma streaming toward the Sun can be seen at the top left of the picture. Note also the small, faint circle near the center of the image - this is the ultraviolet glow from the aurora, also known as the northern lights. The region laced by Earth's magnetic field, called the magnetosphere, dominates the behavior of electrically charged particles in space near Earth and shields the planet from the solar wind. Explosive events on the Sun can charge the magnetosphere with energy, generating magnetic storms that occasionally affect satellites, communications and power systems.