Scientists have creatively combined pictures of the Sun to make the first 3D view of a massive eruption on the Sun. It should improve understanding of the stormy events that can disrupt radio communications on Earth and threaten satellites and power grids.

The 3D images of a coronal mass ejection (CME) were generated from data collected by the Solar and Heliospheric Observatory (SOHO) spacecraft.

"We need to see the structure of CMEs in three dimensions to fully understand their origin and the process that launches them from the Sun," said Thomas Moran of the Catholic University of America, Washington, DC. "Views in three dimensions will help to better predict CME arrival times and impact angles at the Earth."

Moran developed the analysis technique, described in the July 6 issue of the journal Science.

CMEs sometimes accompany solar flares and involve billions of tons of electrified gas being blasted from the Sun's atmosphere into space at millions of miles (kilometers) per hour. Researchers believe CMEs are launched when solar magnetic fields become strained and suddenly "snap" to a new configuration, like a rubber band that has been twisted to the breaking point. But the exact mechanism is not well understood.

Complex and distorted magnetic fields travel with the CME cloud and sometimes interact with the Earth's own magnetic field to pour tremendous amounts of energy into the space near Earth.

The 3D images were created by combining three separate observations of a CME taken at different angles. The results confirm that an Earth-directed CME is an expanding arcade of loops, rather than a bubble or rope-like structure. Although the CME eventually disconnects from the Sun, Moran's team also discovered that the loops remained connected to the source region for an unexpectedly long time, at least as long as the CME was visible to the SOHO instrument.