Threatening Coronal Mass Ejection

Threatening Coronal Mass Ejection

. A coronal mass ejection is observed billowing out from the Sun on 6 June 2000, using the Large Angle Spectrometric COronagraph, or LASCO, on the Solar and Heliospheric Observatory, SOHO. A central occulting disk blocks out the Sunís intense light to reveal the faint corona, along with background stars and planets. The white circle in the disk denotes the outer edge of the Sunís photosphere. Venus is next to the disk on the right side, while Mars is located at the far left center of the image. This event was a halo mass ejection that grew larger as it expanded, forming a halo around our star, indicating that it was headed toward the Earth. The velocity of the ejected material was at least 900 thousand meters per second. Although coronal mass ejections can occur without a solar flare, this one was accompanied by two intense solar flares (Fig. 8.14). (Courtesy of the SOHO LASCO consortium. SOHO is a project of international collaboration between ESA and NASA.)

Copyright 2010, Professor Kenneth R. Lang, Tufts University