Exploratorium Dispatches A Glimpse of Zambia Zambian Geography Zambian Wildlife STEREO Mission International Space Station

Dr. Nahide Craig
Dr. Craig describes coronal mass ejection and the impact of the STEREO mission.  
For starters, scientists aren’t exactly sure how or why CMEs happen, though they seem to be associated with sudden, colossal rearrangements of magnetic fields at the sun’s surface. In the eruptions that result, enormous loops of matter burst from the sun’s surface and travel into space.

Coronal mass ejections are just part of a complicated interplay of forces on the sun. As steady and placid as the sun may seem, in truth it seethes and sputters, its surface an ever-changing landscape of violent activity, little of it well understood.

Stereo 3-D sun
STEREO 3-D sun.  
To study CMEs and other solar activity, scientists at NASA have initiated the STEREO project. The basic idea is to launch two satellites that will give us a stereo view of the sun, much as our two eyes give us a stereo view of the world around us. Three-dimensional images generated by the STEREO project will reveal details about the shape and composition of coronal mass ejections.

Aurora borealis
  Aurora borealis. Photograph by Dick Hutchinson©
Coronal mass ejections aren’t all bad. The charged particles they send our way are responsible for auroras, brilliant light displays created at the north and south poles, (termed aurora borealis and aurora australis, respectively.) In times of greatest solar activity, the "Northern Lights" have been visible from as far south as Arizona.

3D stereo image

Scheduled for launch in 2004, the two satellites of the STEREO project will give us a three-dimensional view of activity on the sun’s surface, including coronal mass ejections.

Both satellites will share earth’s orbit around the sun. One will be slightly ahead of the earth, the other slightly behind. Like a pair of eyes, these satellites will see with "depth perception," providing 3-D images that are far more informative than ordinary "flat" pictures.


©2001 - Exploratorium