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METEOR SHOWER UPDATE:
The Orionid meteor shower is still
active. According to the International Meteor
Organization, observers are now counting as many as 35 Orionids
per hour. If it's dark where you live, go outside and look
up. You might see a meteor every few minutes or so. Rates
will be highest during the hours just before local sunrise.
The shower is caused by dusty debris from Halley's Comet,
which litters the October portion of Earth's orbit. On Oct.
20th, a fragment of Halley cut across the skies of New Mexico
where amateur radio astronomer Thomas
Ashcraft operates an all-sky camera and forward scatter
meteor radar. Click on the image to play a movie with soundtrack:
The eerie sound you just heard was a radio echo--a distant
TV signal reflected from the meteor's ionized trail. Ashcraft
records the reflections at 61.250 MHz and 55.250 MHz using
a VHF antenna co-located with his all-sky camera. He says
he'll be updating his radio
fireball gallery as the shower intensifies.
Meanwhile at the Marshall Space Flight Center (MSFC) in Alabama,
NASA astronomers have been monitoring Orionid activity using
a two-station observatory with cameras separated by more than
100 miles. When a meteor is captured by both cameras, triangulation
yields the meteor's height,
direction
and speed.
"We find that most Orionids are hitting the atmosphere
at about 140,000 mph," says lead researcher Bill Cooke.
This high speed accounts for the rapidity with which Orionids
flit across the sky. "They are very fast meteors,"
he says.
For the past three years, Orionid rates have been unusually
high, with reports of 60 or more meteors per hour. Researchers
believe this is a result of some very old and rich debris
from Comet Halley drifting across Earth's orbit. Computer
models suggest that this debris is still nearby, so the trend
of "good Orionids" should continue in 2009.
UPDATED:
2009
Orionid Photo Gallery
[full
story] [sky
map] [previous years: 2006,
2008]
Sept.
2009 Aurora Gallery
[previous Septembers: 2008, 2007, 2006, 2005, 2004, 2002, 2001]
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