Copyright =A9 1996 Reuter Information Service
PARIS (May 2, 1996 3:36 p.m. EDT) -- A new space observatory shows that the sun spews out unexpectedly powerful flames in images which may help explain climate shifts on earth, the European Space Agency said on Thursday.
Scientists operating the so-called Solar and Heliospheric Observatory (SOHO), 1.5 million km (940,000 miles) from the sunward face of the earth , said its data may also help explain mysteries like the structure of the s un and sun spots.
A joint project by ESA and NASA, it was launched in December 1995 and became fully operational last month. Scientists involved in the project s aid all instruments on the 3.8-metre (four-yard) long observatory were workin g well. First images show the the sun is unexpectedly turbulent in what should be a calm period in an 11-year cycle of activity, ESA said. SOHO's images show the star sometimes belches out billions of tonnes of gas in vast fiery pl umes invisible to earth-based observatories.
Temperatures in the sun's upper atmosphere soar to about two million degrees Celsius, far hotter than its visible surface. "By the end of the mission we shall know the sun far better than we do now. Then we shall understand the stars better too," ESA's Director of Science Roger Bonnet said in a statement. "And we shall be able to comment with much more confidence on important but puzzling aspects of solar behaviour that affect our lives on earth, whether in short-lived magnetic storms or long-lasting changes of climate ," he said.
Guenter Brueckner of the U.S. Naval Research Laboratory in Washington said he believed some of SOHO's ultraviolet images could provide advance warning of sudden vast ejections of gas linked to magnetic shifts inside the sun. If confirmed "we should be able to give advance warning of outbursts from the sun which endanger low-flying satellites and can harm power distribution systems on the earth," he said.
SOHO is also probing the sun's interior structure with instruments that detect variations in the intensity of light or its wavelength -- caused b y ultra-low frequency sound waves inside the star.
"Soon we shall make the first movies of the sun's interior," said Philip Scherrer of Stanford University, California. "And by relating what we see there to our measurements of surface magnetic fields we may begin to solve the mystery of why dark sun spots occur, and why they become most numerous every eleven years or so," he added.
SOHO is in a so-called halo orbit at the point between the sun and the ea rth where the gravitational pull of the two cancel each other out.