It Came From the Sun

On January 6, at 11 A.M. Eastern Standard Time, a huge bubble of hot magnetized gas burst from the sun. The bubble, in the form of a giant cloud, rushed toward Earth at some 900,000 miles per hour. By the time the cloud enveloped Earth four days later, it had expanded to a width of about 20 million miles. Despite its enormity, the cloud was by no means unusual. Every four months or so, magnetic disturbances on the sun give rise to similar space-faring clouds as well as solar flares and other phenomena. One such massive storm in 1989 knocked out a power grid in Quebec. Yet this particular cloud was unique in one respect: it was the first to be intercepted by a fleet of three NASA satellites that tracked its every move, from the first hint of strange happenings on the sun to the passage through space, over Earth, and beyond. Together they gave researchers their first coherent picture of how a magnetic cloud interacts with Earth’s magnetic field.