|Photo by NASA/IMAGE-EUV/Univ. of Arizona|
No, Earth is not being incinerated. The orange cloud enveloping the planet in this image is sunlight scattering off helium ions in the plasma sphereÑthe extremely rarefied, electrically charged bit of our atmosphere that extends 12,000 miles into space. This infernal view was beamed back by NASA's Imager for Magnetopause to Aurora Global Exploration (IMAGE) satellite, which monitors what happens when solar storms reach Earth.
"We had almost no idea of what the plasmasphere looked like," says James Burch of the Southwest Research Institute in San Antonio, the principal investigator on IMAGE. "We thought it had smooth edges and long tails that extended out into space from the dusk side, but it is actually circular." The scalloped fringes of plasma on the upper left formed after a small magnetic disturbance from the sun passed Earth. "We don't really know why they are there," Burch says, but they appear to form before a full-on solar squall that could disruucommunications. Burch and the rest of the IMAGE team hope their satellite will allow scientists to track space storms, much as weather satellites now monitor thunderstorms.