 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
Data Shows Solar Flares 20 Million Degrees Hotter Than Expected
Columbia - Jun 18, 2003 For scientists who study solar flares, the hottest spots in the solar system just got substantially hotter. The hottest spots in solar flares reach temperatures as much as 20 million degrees Fahrenheit hotter than solar physicists had previously believed, topping out at more than 80 million degrees Fahrenheit. And from about 5 million degrees just before a flare, in less than a minute temperatures in the sun's atmosphere can warm by more than 75 million degrees. Using data gathered by NASA's Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI), scientists from The University of Alabama in Huntsville (UAH), the University of Glasgow and the University of California at Berkeley were able to isolate and measure sources of the most powerful X-rays emitted by a solar flare on July 23, 2002. "Previously the best we could do was look at an average temperature for the entire flare," said Dr. Gordon Emslie, who is scheduled to present the findings today at a meeting of the American Astronomical Society's Solar Physics Division in Columbia, MD. "With RHESSI we get an incredible amount of data. One of the things we can do with that is look at the hottest point sources within a flare. "We have been able to take a picture of the hot spot and the data from that 'ups the ante' considerably." RHESSI images of the flare show a bright "blob" suspended 7,000 miles above the sun. Below it are three hot spots on the solar surface. "This suspended blob is extremely hot," said Emslie, a physics professor at UAH. "That's where the temperature hit 45 million Kelvin -� about 80,000,000 degrees Fahrenheit, give or take a million. We think the other three bright spots are where electrons from that hot blob are being slammed into the surface. And when they hit they release energy in the form of X rays." These findings will force Emslie and other solar physics theorists to re-examine the theories they have developed to explain the most massive explosions in the solar system. "Now we have to stop talking about 30 million Kelvin and start thinking about 40 or 45 million Kelvin," he said. "That represents a bigger concentration of energy, which has to be explained in our theories and our models." The power released by a large solar flare -� such as the one on June 23, 2002 -� would be measured in the billions of trillions of kilowatts. If certain types of flares erupt on the side of the sun facing Earth, waves of electromagnetic energy can disrupt telecommunications, black out power systems, and play havoc with satellites. It might even endanger astronauts working outside a space shuttle or space station. Solar activity has caused power outages in Canada, and blurred TV and telephone signals bounced off satellites. Magnetic storms cause power outages when waves of electromagnetic particles from the sun hit power lines and electrical transformers. Just as electrical power is generated on the sun by the interaction of magnetic fields, electromagnetic fields from the sun induce electrical current in transformers and power lines on Earth. Those extra surges of power can trip circuit breakers and shut down power systems. "If we're ever going to be able to predict these things, we have to understand them better," said Emslie. "And RHESSI is helping us do that." Community Email This Article Comment On This Article Related Links The University of Alabama SpaceDaily Search SpaceDaily Subscribe To SpaceDaily Express Solar Science News at SpaceDaily
From 'Macro' To 'Micro' � Turbulence Seen By Cluster
Paris (ESA) Aug 11, 2005Thanks to measurements by ESA's Cluster mission, a team of European scientists have identified 'micro'-vortices in Earth's magnetosphere. |
|
|
| The content herein, unless otherwise known to be public domain, are Copyright 1995-2006 - SpaceDaily.AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA PortalReports are copyright European Space Agency. All NASA sourced material is public domain. Additionalcopyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement |
