- WASHINGTON (Reuters) - Sky-watchers get a once-in-a-generation chance to
see a spectacular show of shooting stars next month, astronomers said Monday.
Sky and Telescope magazine said a shower of meteors known as the Leonid
stream, which comes around only every 33 years, should be at its peak this
November.
-
- "Every year around November 17,
Earth's orbit around the Sun carries us though the Leonid meteor stream,
which originates from Comet 55P/Tempel-Tuttle," the magazine said
in a statement.
-
- Usually, the Earth passes through a thin
area, with little to see. But every 33 years, the Earth and the comet pass
very close to one another and it is possible to see the meteroids that
accompany it.
-
- "When our planet happens to pass
through the debris trail shortly before or after the comet has gone by,
we plunge right through this rich concentration of meteoroids, and the
normal Leonid drizzle can be replaced by a torrential meteor storm in which
thousands of shooting stars might flash overhead every minute," the
statement said.
-
- Meteoroids, usually only the size of
a pebble or a grain of sand, cause flashes of light in the sky that people
often call falling stars or shooting stars. The flash of light comes as
the object hits the atmosphere, causing a fire and usually burning up before
it hits the ground.
-
- Satellites are vulnerable to the bits
of rock and dust, which are traveling at great speed and which, although
tiny, can cause serious damage. Many satellites and the Hubble Space Telescope
will be turned away from the direction of the shower.
-
- The last great Leonid meteor storm was
in 1966, so the Earth is due for a good one this year or next. Sky and
Telescope recommends that sky-watchers get up just before dawn on Nov.
17 and 18 to see the show.
-
- The best viewing opportunities this year,
it says, will be in Asia.
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- __________________
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-
- Meteor Storm To
Light Sky & Jolt Satellites
By Keay Davidson
San Francisco Examiner 10-6-98
-
-
- A spectacular meteor storm will ignite
the heavens in mid-November, possibly "sandblasting" satellites
and threatening everyday services from cell phones to TV shows to data
communications.
-
- The last great meteor barrage came in
1966, when space satellites were far less common - and far less essential
to everyday life. Back then, thousands of meteors per minute shot across
the North American sky.
-
- Today, the skies are jammed with satellites
that aid in weather forecasting, relay data communications and TV signals,
and enable military surveillance.
-
- The world's satellite network is a juicy
target for the blistering celestial rain.
-
- Although the meteors are smaller than
grains of sand, they travel tremendously fast - more than 40 miles per
second, equivalent to a 10-second flight from San Francisco to Los Angeles.
As a results, they could knock out or disrupt some satellites' delicate
electronics.
-
- "This meteoroid storm will be the
largest such threat ever experienced by our critical orbiting satellite
constellations," William H. Ailor, director of the Center for Orbital
and Re-entry Debris Studies at the Aerospace Corp. in El Segundo, told
the House Science Committee on May 21.
-
- The 1966 storm appeared over continental
North America, but this year's main aerial assault will be visible from
Japan, China, the Philippines and other parts of east Asia, and possibly
Hawaii. The meteors are debris from a comet, Temple-Tuttle.
-
- Scientists from NASA's Ames Research
Center in Mountain View, Calif., hope to study the shower from aircraft
flying out of Okinawa, said Ames principal investigator Peter Jenniskens.
They hope to broadcast live TV images of the shower over the World Wide
Web.
-
- (ships)
-
- But every 30-plus years, our planet crosses
a particularly dense part of the Leonoid cloud. So the "shower"
becomes a "storm," with up to 40 meteors per second and sometimes
50,000 per hour.
-
- Although very tiny, the particles move
so fast that the friction with Earth's atmosphere will cause them to burn
and glow. Visible from hundreds of miles away, they will make the sky
look like fireworks are going off.
-
- NASA plans to turn the Hubble Space Telescope
away from the storm of meteors that hit the giant orbital telescope will
miss its super-delicate mirror, said NASA spokesman Don Savage.
-
- "NASA is taking (the shower) seriously,"
Savage said. "We have been assessing what we need to do to ensure
our satellites in Earth orbit are going to be operated in a safe manner
during this meteor shower."
-
- Other satellites might be temporarily
reoriented so that they present the narrowest "cross section"
- the smallest target.
-
- "We are concerned, and we have been
in meetings and making plans concerning the Leonoid shower," said
U.S. Army Maj. Mike Birmingham, a spokesman for the U.S. Space Command
in Colorado, which monitors American military and spy satellites.
-
- In his congressional testimony, Ailor
said that "because of the very high speed of the particles - they
will be moving at speeds of over . . . 155,000 mph - the storm poses an
even greater and somewhat unknown threat."
-
- "Fortunately, most of the particles
. . . are very small, smaller than the diameter of a human hair, and
won't survive passage through the Earth's atmosphere," Ailor said.
"Our satellites, however, are (in space and) not protected by the
atmosphere, so they will be sandblasted by very small particles traveling
more than 100 times faster than a bullet.
-
- "At these speeds, even a tiny particle
can cause damage or electrical problems," Ailor said. "While
major holes and physical damage to solar panels and structures are very
unlikely, impacts of small particles will create an electrically charged
plasma which can induce electrical shorts and failures in sensitive electronic
components."
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