NASA Spacecraft Observe Nov. 20 Solar Eruption

Experimental NASA research models, based on observations from the Solar Terrestrial Relations Observatory (STEREO), show that the Nov. 20 CME left the sun at speeds of 450 miles per second, which is a slow to average speed for CMEs.

CMEs can cause a space weather phenomenon called a geomagnetic storm, which occurs when CMEs successfully connect up with the outside of the Earth's magnetic envelope, the magnetosphere, for an extended period of time.

In the past, CMEs of this speed have not usually caused substantial geomagnetic storms. They have caused auroras near the poles but are unlikely to cause disruptions to electrical systems on Earth or interfere with GPS or satellite-based communications systems.

NOAA's Space Weather Prediction Center (http://swpc.noaa.gov) is the United States government's official source for space weather forecasts.

What is a CME?

For answers to this and other space weather questions, please visit the Spaceweather Frequently Asked Questions page:

http://www.nasa.gov/mission_pages/sunearth/spaceweather/index.html

Karen C. Fox
NASA's Goddard Space Flight Center, Greenbelt, Md.