NASA’s twin Solar Terrestrial Relations Observatories (STEREO) sent back their first images of the sun this week and with them a view into the sun’s mounting activity.
A close up of loops in a magnetic active region. These loops, observed by STEREO’s SECCHI/EUVI telescope, are at a million degrees C. This powerful active region, AR903, observed here, produced a series of intense flares over the next few days.