Aurora Alert A blast of solar wind from the sun on October 21
is creating strong geomagnetic storm conditions a day later
Oct 22, 1999: At 9:00 a.m. MDT (1500 UT), NOAA's Space Environment Center reported that a strong geomagnetic storm was in progress. The storm is possibly the result of a shock observed in the solar wind on Oct 21 at 01:38UT (Oct 20 at 07:38 p.m. MDT), originating from a mass ejection on the Sun Oct 18. The shock front struck Earth's magnetosphere around 0240 UT on October 21.
The Ultraviolet Imager on NASA's polar spacecraft captured dramatic images this morning of an aurora borealis in progress over the northern United States. Aurorae -- sometimes called Northern Lights -- are luminous multi-colored curtains of light most often seen in the skies at very high northern and southern latitudes. They occur because Earth's magnetic field interacts with the solar wind, a tenuous mix of charged particles blowing away from the sun. Auroral light results from electrons and protons striking molecules in the Earth's upper atmosphere.
Right: These images were captured by the Ultraviolet Imager on NASA's Polar spacecraft's on Friday, October 22. They show UV emissions from aurora borealis during a strong geomagnetic storm. Click for a more detailed animation (2.8MB animated gif). For movies of last night's aurora as seen by the visible camera on Polar click here.
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Indeed, it appears that many observers did spot the Northern Lights early this morning. The Solar Terrestrial Dispatch reports widespread sightings ranging from Washington State in the west to New York in the east, and as far south as Ohio. Click for the latest reports.
Gary Heckman, a space weather forecaster at NOAA's Space Environment Center says it's hard to predict whether the auroral activity will continue through the night of October 22, but for residents of the northern US it's worth taking a look. Tonight's bright full moon could make faint auroral emissions difficult to see, but strong auroral activity might be visible despite lunar interference. The best time to observe is near local midnight.
|Parents and Educators: Please visit Thursday's Classroom for lesson plans and activities related to this story.|
Right: What does an aurora look like? This colorful picture taken in January 1998 shows a spectacular aurora borealis above a frozen landscape of snow-covered spruce trees in Alaska. Auroral light results from solar electrons and protons striking molecules in the Earth's atmosphere. Aurorae rarely reach below 60 kilometers, and can range up to 1000 kilometers. Frequently, when viewed from space, a complete aurora will appear as a circle around one of the Earth's magnetic poles. [Picture credits]
For more information about space weather and current solar activity, including official alerts, warnings, and forecasts, please see NOAA's Space Environment Center web site at http://www.sec.noaa.gov/.
Solar Cycle Update October 14, 1999. Updated predictions from NASA scientists place the solar maximum in mid-2000.
Our Sun's Sizzling Corona September 2, 1999. Something funny's going on in our Sun's outer atmosphere. Read all about the mystery that made scientists flock to the path of totality for the August 11, 1999 solar eclipse.
Seasons of the Sun July 22, 1999. Predicting solar activity is a bit like forecasting the weather here on Earth. It's tricky! Nevertheless, NASA scientists have developed methods to predict the time and date of the next solar maximum.
Surfing Magnetic Waves in the Solar Atmosphere July 8, 1999. How the Solar Wind Gets Up to Speed
Solar Flares Show Their True Colors June 2, 1999. New research points to a common mechanism for spectral behavior in Solar Flares
"Cool" microflares could be solar hot spots May 31, 1999. Secret of coronal heating may be multitude of tiny blasts.
Finding the smoking gun before it fires March 9, 1999. Physicists discover a new tool for predicting solar eruptions.
Recent stories on the August '99 Eclipse
Allais Experiment Update - October 12, 1999, At any given spot along its path, the Aug. 11, 1999, total eclipse offered up to 2-1/2 spectacular minutes of total lunar coverage of the sun. But for two NASA researchers, the show's not over. They're just getting started probing a 50-year-old mystery.
This Eclipse is History - August 12, 1999, A NASA scientist views the event from the foothills of Transylvania, home of ancient legends and modern science.
Decrypting the Eclipse - August 6, 1999, scientists around the world explore the possible and mysterious effect of eclipses on the motion of Foucault's pendulum.
There goes the Sun - August 5, 1999, features general information about the August 11, 1999 solar eclipse, including the effect of eclipses on the birds and the bees, and eclipses on other planets.
Audio eclipse may fill the sky - August 4, 1999 story on investigations of ionization and radio propagation in Earth's atmosphere during the eclipse
Peering through a Hole in the Sky - June 17, 1999 story on exotic gravity measurements to be carried out during the eclipse
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Dr. John M. Horack , Director of Science Communications
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