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Giant rivers of plasma seen on the sun
August 28, 1997
Web posted at: 10:32 p.m. EDT (0232 GMT)In this story:
- 'A new era of solar meteorology'
- Weather patterns similar to Earth's
- Sunspots formed by solar 'trade winds'
- NASA sends craft to watch sun
WASHINGTON (CNN) -- American and European astronomers have discovered giant rivers of hot plasma flowing beneath the surface of the sun that may trigger spectacular solar eruptions.
"This is going to enable us to have a much deeper understanding of the dynamics of the sun, and is going to herald, I believe, a new era of solar meteorology," said Douglas Gough of the University of Cambridge.
NASA officials describe the discovery and release SOHO images
16 min., 43 sec. VXtreme streaming video
The scientists hope that a better understanding of the flow of gases on the sun will enable them to predict and anticipate damaging solar storms headed toward Earth.
The scientists said Thursday they discovered the huge, electrically-charged plasma gas currents deep under the sun's surface moving in patterns near the equator and around both poles.
The superheated jet streams were detected by instruments aboard the Solar and Heliospheric Observatory (SOHO), a spacecraft jointly operated by the European Space Agency and NASA.
The craft, which is in orbit one million miles from Earth and 92 million miles from the sun, is the first to keep the sun under almost constant observation.
Weather patterns similar to Earth's
The new data indicate that the sun has complex weather patterns not unlike those on Earth.
Jesper Schou of Stanford University compared the currents circling the solar poles to the jet stream winds that rip through the Earth's upper atmosphere and dramatically affect the weather of the planet. Finding such patterns on the Sun, he said, "is completely unexpected" and not thoroughly understood.
The sun's jet streams form rings at about 75 degrees north and south latitude. The rings are about 17,000 miles across and move 80 miles an hour faster than the surrounding solar material, according to Philip Scherrer of Stanford.
One jet stream circles each pole, while the others migrate toward the solar equator, and according to the scientists, they are huge.
"You can fit almost 100 Earths inside this jet stream," Schou said.
Meanwhile, there are also rivers of hot, electrically charged gases flowing as much as 15,000 miles beneath the surface at the sun's equator. These bands are about 40,000 miles across and move at about 50 miles an hour. At this speed, it takes about a year for material to move from near the equator to the poles, the researchers said.
Sunspots formed by solar 'trade winds'
Migrating between the jet streams at the poles and the gases beneath the surface at the equator, are other bands of gases that the scientists liken to trade winds.
They say sunspots or solar flares appear to form at the edges of these bands in areas where a kind of wind-shear seems to take place.
"Where there's shear," says Stanford's Craig DeForest, "you stretch out magnetic fields and you augment those magnetic fields and produce greater magnetic field intensity, greater magnetic activity. That is where the sunspots form."
Sunspots, which are actually solar eruptions that burst from the sun's surface, occur most frequently near the polar currents, and then move toward the equator.
They can have a dramatic effect on Earth by sending powerful electromagnetic storms that can destroy sensitive electronics on satellites, disrupt radio communication on Earth and even cause blackouts.
Only a few days ago, SOHO spotted an enormous eruption of gas and energy bursting from the sun's surface. It was on a part of the sun, however, that was pointed away from Earth.
NASA sends craft to watch sun
The currents were detected by a radar imager called the Michelson Doppler, which measures vertical motion of plasma on the solar surface at 1 million different points each minute. The measurements are then converted by a computer program to data that resemble the seismic readings that are used to study the interior of the Earth.
Earlier this week, NASA launched a spacecraft called the Advanced Composition Explorer, or ACE, which will join SOHO as it watches the sun. ACE will study the composition of the particles erupting from the sun, and should give scientists a better idea about how damaging a solar storm will be once it reaches Earth.
Correspondent Dick Wilson, The Associated Press and Reuters contributed to this report.
Related stories:
- NASA launches mission to study the sun - August 25, 1997
- New spacecraft to warn of disruptive solar storms - August 14, 1997
- SOHO gives scientists a better look at the sun - July 31, 1997
- Solar flare heading toward Earth - April 8, 1997
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