Whole sun imaged for the first time

On February 6, NASA's twin STEREO probes moved into position on polar opposite sides of the sun and started beaming back the first images to capture the star's entire surface (see video above).

"For the first time ever, we can watch solar activity in its full 3-dimensional glory," says Angelos Vourlidas, a member of the STEREO science team at the Naval Research Lab in Washington, DC. 

This new ability should improve forecasts of solar eruptions. These violent magnetic events can wreak havoc with satellites and even power lines and railway signals on Earth. But without a view of the sun's entire surface, charged solar emissions can end up hurtling through space,even towards Earth, without warning. 

The twin probes left Earth in 2006, heading for the positions they have now reached. They are expected to beam back images of the entire sun for the next 8 years.