WASHINGTON - The first three-dimensional images of the Sun from a pair of spacecraft orbiting the planet were released today and can begin helping scientists predict when and how hard dangerous solar storms will hit, the US space agency Nasa said.
Such storms can disrupt satellites, communications and sometimes the electricity supply, and may endanger astronauts in Earth orbit as well as commercial airline flights.
The twin Solar Terrestrial Relations Observatory, or STEREO, satellites can create more accurate, real-time views of these storms, called coronal mass ejections, project scientists said.
"The improvement with STEREO's 3-D view is like going from a regular X-ray to a 3-D CAT scan in the medical field," said Michael Kaiser, STEREO Project Scientist at Nasa's Goddard Space Flight Center in Greenbelt, Maryland.
The STEREO spacecraft were launched in October and have now been manoeuvred into their orbits, one slightly ahead of Earth and one slightly behind.
"Just as the slight offset between a person's eyes provides depth perception, the separation of spacecraft allow 3-D images of the sun," Nasa said in a statement.
Solar storms are a conglomeration of charged gases and magnetic forces. When they hit the Earth's magnetic barrier they cause the auroras, the dramatic Northern and Southern lights.
But they can also disrupt satellites, radio communication, and power grids. The radiation they carry is a danger to astronauts.
The orbiting SOHO observatory is providing some information, but the two STEREO spacecraft will be able to triangulate with SOHO and give a much better view of these bursts as they bud off the sun's surface, Nasa said.
"In the solar atmosphere, there are no clues to help us judge distance. Everything appears flat in the 2-D plane of the sky. Having a stereo perspective just makes it so much easier," said Russell Howard of the Naval Research Laboratory.
"Knowing where the front of the coronal mass ejection cloud is will improve estimates of the arrival time from within a day or so to just a few hours," Howard added.
"STEREO also will help forecasters estimate how severe the resulting magnetic storm will be."
More details are available on the internet at: http://www.nasa.gov/mission_pages/stereo/main/index.html