Acehtsunami

The twin STEREO spacecraft confirmed their reality in February 2009 when sunspot 11012 unexpectedly erupted. The blast hurled a billion-ton cloud of gas (a coronal mass ejection, or CME) into space and sent a tsunami racing along the sun’s surface.

STEREO recorded the wave from two positions separated by 90 degrees, giving researchers an unprecedented view of the event.

“It was definitely a wave,” says Spiros Patsourakos of George Mason University, lead author of a paper reporting the finding in Astrophysical Journal Letters. “Not a wave of water, but a giant wave of hot plasma and magnetism.”