Six teams of scientists led by NASA's Marshall Space Flight Center in Huntsville, Ala., will monitor the annual Leonids meteor shower this month when the phenomenon is brightest over the North American continent.
Part of the monitoring activities will include the launch of a weather balloon carrying video and audio equipment which will allow scientists and the public to actually hear what a meteor sounds like as it crashes into Earth¡¦s atmosphere.
The public, particularly along the East Coast, also will be able to look up and, depending on weather conditions, see perhaps 700 or more shooting stars per hour.
Three peak times for the showers are forecast for the East Coast -- Nov. 17 at about 3 a.m. EST and again at 11 p.m. EST, and Nov. 18 at about 3 a.m. EST -- according to Bill Cooke, senior computer scientist at the Marshall Center.
A Leonids shower happens every year when Earth passes close to the orbit of the comet Tempel-Tuttle and the debris left in the comet's path. As Earth travels through the comet dust, the debris burns up in the Earth's atmosphere resulting in shooting stars or meteors. Some of these dust streams actually broke away from the comet long ago. Meteors visible this year date to 1932, 1866 and 1733.
"This year, the Moon will be in the constellation Leo -- practically on top of the Leonids radiant," said Mitzi Adams, a Marshall Center astronomer. "Moonlight will make fainter meteors hard to spot, but if there's a strong outburst, stargazers could see plenty of Leonids in spite of the bright Moon."
Because this year's peak meteor activity is not projected to reach storm level -- at least 1,000 meteors per hour -- Marshall scientists will use the opportunity to test their accuracy at predicting Leonids intensity.
In 1999, a true "storm" occurred when up to 3,700 meteors per hour were recorded over Israel.
"We can predict within minutes the time the meteors will peak," said Marshall Space Environment Team researcher Dr. Rob Suggs. "What we have trouble with is predicting the intensity."
If the intensity of a Leonids shower can be accurately predicted, scientists will know which way orbiting satellites should be turned to keep them operating smoothly during meteor activity.
"Satellites are an integral part of our lives now, so anything that affects these satellites directly affects our lives," Suggs said, citing as examples communications and television satellites.
To help protect these satellites from the fast-travelling meteors, Marshall scientists will analyze information from the various monitoring teams and pass it along to satellite operators.
Although a typical meteor is smaller than a grain of sand, it travels 12 miles (20 kilometers) per second. Leonids are the fastest of all meteors -- traveling at about 44 miles (71 kilometers) per second. At that speed, a Leonids meteor could travel from New York to Los Angeles in about one minute.
Heavy Leonids meteor storms are predicted for 2001 and 2002.
"We are getting predictions from models for next year in excess of 10,000 meteors per hour over East Asia and Mongolia," Suggs said. "In 2002, predictions are in excess of 25,000 meteors per hour over the East Coast of the United States."
The Marshall Center is NASA's lead center for monitoring and forecasting meteor showers. Huntsville scientists will begin monitoring Nov. 16, using two image-intensified camera systems and recording the meteors onto videotape.
"This year we also have a forward-scatter radar that will allow us to 'hear' the meteors," Suggs said, explaining that the noises are caused by the meteors interacting with ionized gas or plasma in the Earth's atmosphere.
Besides monitoring the Leonids from Huntsville, Marshall scientists also will coordinate monitoring teams at the following locations:
* Mount Allison Observatory in New Brunswick, Canada.
* Elginfield Observatory at the University of Western Ontario, in London, Ontario.
* The University of Regina in Saskatchewan, Canada.
* U.S. Air Force LINEAR (Lincoln Near-Earth Asteroid Research) Observatory in Socorro, N.M.
* Calar Alto Observatory near Almeria, Spain.
In addition to the observing teams, Marshall scientists, weather permitting, will launch a 10-foot (3-meter) diameter weather balloon from Marshall's Atmospheric Research Facility at 12:30 a.m. CST on Nov. 18. The balloon will ascend approximately 20 miles (32 kilometers), carrying a sensitive camera for capturing high-resolution television pictures of the meteors. During the three-to- four-hour flight, the television pictures can be viewed online at the Marshall Center's Science Directorate Web site at http://www.leonidslive.com
The balloon also will carry a very low frequency radio receiver that will allow visitors to the Web site to hear the "whistlers" and other bizarre noises that meteors might make as they enter the Earth's atmosphere. On-board transmitters will allow local amateur radio operators, or "hams," to track and retrieve the balloon.
Materials provided by NASA's Marshall Space Flight Center. Note: Content may be edited for style and length.
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