SETI [ASTRO] Space Blobs Create Super-Speedy, Backward Auroras


Larry Klaes (lklaes@bbn.com)
Wed, 02 Jun 1999 15:29:46 -0400


>X-Authentication-Warning: brickbat12.mindspring.com: majordom set sender to owner-astro using -f >Date: Wed, 2 Jun 1999 16:51:40 GMT >From: Ron Baalke <BAALKE@kelvin.jpl.nasa.gov> >To: astro@lists.mindspring.com >Subject: [ASTRO] Space Blobs Create Super-Speedy, Backward Auroras >Sender: owner-astro@brickbat12.mindspring.com >Reply-To: Ron Baalke <BAALKE@kelvin.jpl.nasa.gov> > >MEDIA RELATIONS OFFICE >JET PROPULSION LABORATORY >CALIFORNIA INSTITUTE OF TECHNOLOGY >NATIONAL AERONAUTICS AND SPACE ADMINISTRATION >PASADENA, CALIF. 91109 TELEPHONE (818) 354-5011 >http://www.jpl.nasa.gov > >Contact: Jane Platt (818) 354-0880 > >FOR IMMEDIATE RELEASE June 1, 1999 > >SPACE BLOBS CREATE SUPER-SPEEDY, BACKWARD AURORAS > > Blobs of electrified particles spew violently from the Sun, zoom at >"warp speed" toward Earth's magnetic field, and trigger an unusual form of >aurora, scientists have discovered using an ultraviolet camera on NASA's >Polar spacecraft. > > These electrified blobs, called coronal mass ejections, travel at >more than 1.5 million miles per hour, or 2,000 times the speed of sound, and >create interplanetary shock waves that "ram into" Earth's magnetic field. >This is roughly comparable to the way a supersonic aircraft breaks the sound >barrier and creates a shock wave that we hear as a sonic boom. With the >aurora, the effect of the interplanetary shock wave is not heard, but >instead is seen as a multi-colored display by Polar. > > The more common type of Earth aurora is formed through a process that >begins when the magnetic fields that extend from Earth's Poles are dragged >away from the Sun and Earth by the solar wind. When these magnetic fields >collide, they annihilate each other and ultimately create a hot, electrified >gas that produces an eerie, colorful display near midnight at high and low >latitude locations such as Alaska and Antarctica. We call those displays the >northern and southern lights. > > These newly discovered auroras appear in those same latitude regions >-- but unlike the better known auroras, they appear at high noon, when they >would usually be obscured by the Sun. That would explain why no one on Earth >has reported seeing them yet. In addition, these dayside auroras move much, >much faster and in the opposite direction from ordinary auroras. > > "This sheds new light on the way the Sun's tumultuous activities >affect us here on Earth," said Dr. Bruce Tsurutani of NASA's Jet Propulsion >Laboratory, co-investigator for the Polar camera. "Since this type of aurora >has not been seen by earthlings, it's a prime example of a robotic >spacecraft finding things we'd never know about otherwise." > > "Originally NASA's Wind spacecraft was used to find interplanetary >shocks," said Dr. Xiaoyan Zhou, a National Research Council resident >research associate who is also on the Polar science team. "We wanted to find >out what effect these shocks have on Earth. We were surprised to discover >that they caused these unusual, fast-moving auroras." Polar's instruments >confirmed their existence with a dozen sightings. These latest aurora >findings were based on data gathered during the past two years. > > Now that scientists are aware of the new form of auroras, they hope >professional and amateur Earth observers will look for the phenomenon at >certain locations like Spitzbergen, Norway in the winter, when the skies are >dark at noon. "We're anxious to know what these new auroras look like when >seen from Earth," Tsurutani said. > > More will be learned about these space blobs, or coronal mass >ejections, when NASA's planned Solar Probe spacecraft flies closer to the >Sun's sizzling surface than any previous spacecraft. Solar Probe will launch >in 2007 and will approach to a distance of only 1-1/2 times the Sun's >diameter in 2010, surviving temperatures above 3,700 degrees Fahrenheit. > > "I can hardly wait to see close-up pictures of a coronal mass >ejection when the spacecraft flies through one as it's being formed," said >Tsurutani, who also serves as Solar Probe project scientist. > > The Polar and Wind missions are managed by Goddard Space Flight >Center, Greenbelt, MD, for NASA's Office of Space Science, Washington, DC. >The two spacecraft are part of the International Solar-Terrestrial Physics >program. Solar Probe is managed by JPL as part of the Outer Planets/Solar >Probe project. JPL is a division of the California Institute of Technology, >Pasadena, CA. > > For a picture go to http://www.jpl.nasa.gov/releases/99/aurora.pdf. > (Adobe Acrobat Reader required). > > ##### >



This archive was generated by hypermail 2.0b3 on Sun Jul 11 1999 - 00:43:07 PDT