Astronomers were particularly concerned that the event was followed by an increase in the flux of sub-atomic particles from the Sun. So the scientists quickly downloaded Internet images of the Sun taken by observatories in the USA, Austria, Australia, and Japan. They then compared images the taken before and after the event.

"Because the data are so distributed and so accessible we were able to identify and track this event," said one astronomer. "Even just a few years ago, this kind of instant international collaboration would have been impossible."  Fortunately, it was soon established that the CME was headed directly away from the Earth - this time.

Preliminary analysis by Dr Simon Plunkett, of the Naval Research Laboratory in the United States, shows that if the CME were travelling towards the Earth, it would have arrived in just two and a half days.