Solar Tsunamis

Sometimes you really can believe your eyes. That's what NASA's STEREO spacecraft are telling researchers about a controversial phenomenon on the sun known as the 'solar tsunami.'

Years ago, when solar physicists first witnessed a towering wave of hot plasma racing along the sun's surface, they doubted their senses. The scale of the thing was staggering. It rose up higher than Earth itself and rippled out from a central point in a circular pattern millions of kilometers in circumference. Skeptical observers suggested it might be a shadow of some kind - a trick of the eye - but surely not a real wave.

The twin STEREO spacecraft confirmed their reality in February 2009 when sunspot 11012 unexpectedly erupted. The blast hurled a billion-ton cloud of gas into space and sent a tsunami racing along the sun's surface.