Meteors to put on quite a show - if skies are clear

Posted: Friday, November 13, 1998

Chinese astronomers in 902 A.D. described stars that fell like rain. In 1833, Boston residents saw ``majestic fireballs'' in the sky.

In 1965, lost from sight for almost 100 years, the ancient showers returned, raining more than 40 meteors per second over the central and western United States.

Leonid meteors shower every November, as Earth hurtles through debris from the comet Tempel-Tuttle, in its orbit around the sun. But every 33 years, for more than a millennium, showers intensify as Earth enters the most densely packed debris pocket of the returning comet.

Star watchers and scientists around the globe are readying telescopes for this year's showers, expected to fall between this weekend and Nov. 20, peaking on Tuesday morning. Those dependent on satellites will also pay attention, because the meteors could damage orbiting equipment.

The best meteor views will be from Asia, but Hawaii may get a good show as well.

Some showers may be visible in Juneau, if clear skies prevail. But if there are clouds, there won't be much excitement. The forecast isn't encouraging.

``It looks like it will be cloudy,'' said Leif Lie, meteorologist in charge with the National Weather Service in Juneau. ``And if it's cloudy we won't be able to see it.''

Mike Orelove, a volunteer at the Marie Drake Planetarium, may travel north to Whitehorse, in hopes of a better view. Skies may be clearer there, he said.

``It's more than a meteor shower. It's a meteor storm,'' Orelove said. ``It's worth setting your alarm clock for, or staying up late.''

Meteors appear when Earth, in its annual journey around the sun, passes through countless bits of rock, dirt and dust particles strewn along the paths of comets.

Sucked into Earth's gravity and vaporized, the particles produce brief and dramatic streaks of light, often called shooting or falling stars. Leonid meteors, named for Leo the Lion, the constellation from which they appear to emanate, have produced some of history's most notable light shows.

This year, scientists expect viewers in Eastern Asia could possibly see several thousand meteors per hour.

Leonid particles, likened to grains of sand or pebbles, are small. Still, rocks and dust speeding through space at 160,000 mph can damage orbiting satellites.

Satellites continually weather dust and debris, but this is the first time a major Leonid shower will meet the numerous crafts placed in space to deliver broadcasts, global positioning information and communications data.

``There's been a lot of attention given to this,'' said Steve Hall, an engineer with AT&T Alascom. ``It hasn't happened during the time communication has been based on satellite communications.''

The showers have some operators worried. The Hubble Space Telescope will turn away from the debris, in hopes of protecting its more vulnerable apparatus.

Not much else can be done, said David Morris, senior manager for General Communication Inc. The company leases space for telecommunications services on the satellite Galaxy Nine.

``There's not a thing we can do about it,'' Morris said. ``You can't predict where these things are going to come down.''

Hall said AT&T will rotate its satellite solar panels away from the particle stream. The risk of being hit during the storm has been assessed as equal to the normal risk of orbiting for 30 days, he said.

``Electronic components on the spacecraft that aren't essential will be turned off for a period of time,'' Hall said, lessening the risk of damage from electrostatic particle discharge.

Satellite transmissions provide a number of services to Juneau residents: television and radio broadcasts, long-distance telephone service, cable TV links and cell phone and pager services, to name a few.

Hall said it's unlikely any services will be interrupted as a result of the Leonid meteor shower.

``We're hoping that it doesn't affect communications here at all,'' he said. ``(The risk is) higher than it would (normally) be, but the probability of an impact is assessed to be small.''

Local phone service is provided by ground connections and microwave links, Morris said. Long-distance calling is most at risk if a satellite sustains damage.

Local users remain largely unalarmed.

Wendell Wassmann, air traffic manager at the Federal Aviation Administration office, said he hasn't received any alerts.

``If the communications gurus knew anything they probably would have told us by now,'' he said.

Local astronomers remain low-key as well.

``With the expected weather we have, I don't see any reason to make any plans,'' said University of Alaska Professor Don Greenberg, adding he hadn't heard of any star-watching parties for early Tuesday morning. ``But they're predicting a pretty good show this year.''





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