Solar magnetic cloud expands by 20% before reaching Earth

A University of Iowa-led physics team has detailed the extreme expansion of a magnetic cloud that originated from a huge, gaseous explosion on the sun. In a new study, the researchers describe the inflated magnetic cloud as recorded by spacecraft in separate, fortuitous locations as the cloud approached Earth. During that interval—spanning some 13 million miles (21 million kilometers)—the cloud expanded by a fifth of its original size during its approach to Earth, as plasma inside the super-expanded bubble heated up. The researchers termed the striking increase in size a "super expansion."