On August 1, 2010, an entire hemisphere of the sun erupted. It consisted of over a dozen shock waves, flares, filament eruptions, and coronal mass ejections that covered half of the sun’s surface and took place over a period of 28 hours. It was big, really big.

The event was recorded in unprecedented detail by NASA’s Solar Dynamics Observatory and twin STEREO spacecraft: scientists had plenty of data. Karel Schrijver and fellow Lockheed-Martin solar physicist Alan Title presented their findings about the “Great Eruption” at a press conference at the American Geophysical Union meeting in San Francisco.

© K. Schrijver & A. Title

They reveal that solar activity is interconnected by magnetism over astounding distances; explosions on the sun are not localized or isolated events. This implies that the surface magnetic field of the entire sun has to be know to predict eruptions and make space weather forecasts more accurate.

Solar physicists now have to find out more about the cause and effect – was the event a big chain-reaction, or was everything triggered at once by a change in the sun’s global magnetic field? Further analysis may reveal the origin of the phenomenon.

The video below shows the Great Eruption in extreme ultraviolet; the different colors represent a range of plasma temperatures: