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Friday the 13th might prove to be a lucky night for area stargazers when
the Geminid meteor shower reaches its peak at 11 p.m.
Many astronomers consider the Geminids to be
more satisfying than other annual meteor showers, which boast many more
visible meteors per hour; because the Geminids produce more spectacular
individual shooting stars that linger longer in the heavens.
The Geminid meteoroids are larger and denser
than the bits of comet dust that supply most meteor showers.
Because the Geminids encounter the Earth's atmosphere at a relatively
slow speed of only 22 miles per second, they appear to travel farther and
burn brighter than average meteors.
Due to their chemical composition, Geminid meteors
typically have a yellowish hue when they burn, while most meteors are
greenish in appearance.
In the book, "Observing Comets, Asteroids,
Meteors and Zodiacal Light," by Stephen Edberg and David Levy, the authors state, "If you have
not seen a mighty Geminid fireball arcing gracefully |
across the expanse
of the night sky, then you have not seen a meteor."
The Geminid meteor shower differs from other
meteor showers, which are generally spawned from the dust of comets,
because (according to some astronomers) it is the only substantial
meteor shower created from the debris of an asteroid.
3200 Phaeton, as the asteroid is known, orbits
the sun approximately every 1.4 years. Because of its highly
elliptical orbit, which atypical of asteroids, there is scientific
debate that it might not really be a true asteroid, but rather an
extinct or dormant comet that no longer produces a tail from solar
heating.
Some doomsayers fear 3200 Phaeton presents a
collision threat to Earth, because in 1997, it passed by our planet
within a close range of less than eight times the distance of the radius
of the orbit of the Moon.
The Geminid meteor shower is so named because
its radiant, which is the point in the sky from which the meteors appear
to emanate, is located near the zodiacal constellation of Gemini.
Friday's peak is predicted to have a Zenithal
Hourly Rate of 120, which means, under ideal conditions, the naked eye
should be able to see
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approximately 120 meteors over a
one-hour period of time when the radiant is directly overhead, or at its
zenith. Patient viewers should expect to see an average of one
shooting star every thirty seconds.
By contrast the Leonid Meteor shower, which
peaked on Nov. 19 was predicted to have a ZHR of 1000+. But such
scientific prognostication is always subject to a margin of error, as
evidenced by the disappointing show of last month's cosmic display.
Yet regional stargazers will recall that last
year's Leonid meteor shower far exceeded experts' predictions, when
during the predawn hour of Nov. 19, 2001, hundreds of visible meteors
fell each minute.
Nevertheless, the Geminid meteor shower has
proven to be reliable, regularly producing many large fireballs, which
often startle amateur observers.
Another advantage of the Geminid meteor shower
is that stargazers have a wide window of opportunity
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to catch the celestial fireworks. It runs from
approximately Dec. 6 through Dec. 19; with the peak occurring tomorrow.
This reporter sighted an early Geminid meteor
on Dec. 3 at approximately 10 p.m., when a large fireball, emanating
from the radiant in Gemini, streaked across the sky and passed through
the constellation of Orion.
Although the peak will occur on Friday at 11
p.m., experts suggest the best viewing will be after 2 a.m. Saturday
when the moon sets and the sky becomes darker.
Visible meteors can be sighted as early as 8
p.m., however, when the constellation of Gemini rises above the
east-northeast horizon.
Observers should seek clearings away from
streetlights or other forms of artificial illumination in order to
appreciate the optimal effect of the cosmic spectacle.
Be sure to dress warmly.
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