Fireball sightings on the rise!
November 3, 2005
November
3, 2005: "I thought some wise guy was shining a spotlight at
me," says Josh Bowers of New Germany, Pennsylvania. "Then I realized
what it was: a fireball in the southern sky. I was doing some backyard
astronomy around 9 p.m. on Halloween (Oct. 31, 2005), and this meteor was so
bright it made me lose my night vision.”
Bowers wasn't the
only one who saw the fireball. Lots of people were outdoors Trick or Treating.
They saw what Bowers saw ... and more. Before the night was over, reports of
meteors "brighter than a full moon" were streaming in from coast to
coast.
Astronomers have
taken to calling these the "Halloween fireballs." But there's more
to it than Halloween. The display has been going on for days.
On Oct. 30th, for
example, Bill Plaskon of Jonesport,
Maine, was "observing Mars through a 10-inch telescope at 10:04 p.m. EST
when a brilliant fireball lit up the sky and left a short corkscrew-like smoke
trail that lasted about 1 minute."
On Oct 28th, Lance
Taylor of Edmonton, Alberta, woke up early to go fishing with five friends. At
about 6 a.m. they "noticed a nice fireball. Then 20 minutes later there
was another," he says
On Nov. 2nd in the
Netherlands, "The sky lit up very bright," reports Koen
Miskotte. "In the corner of my eye I saw a
fireball about as bright [as a crescent moon]."
And so on….
What's happening?
"People are probably seeing the Taurid meteor
shower," says meteor expert David Asher of the Armagh
Observatory in Northern Ireland.
Every year in late
October and early November, he explains, Earth passes through a river of space
dust associated with Comet Encke. Tiny grains hit
our atmosphere at 65,000 mph. At that speed, even a tiny smidgen of dust makes
a vivid streak of light--a meteor--when it disintegrates. Because these
meteors shoot out of the constellation Taurus, they're called Taurids.
Most years the
shower is weak, producing no more than five rather dim meteors every hour. But
occasionally, the Taurids put on quite a show.
Fireballs streak across the sky, ruining night vision and interrupting fishing
trips.
Asher thinks 2005
could be such a year.
According to Asher,
the fireballs come from a swarm of particles bigger than the usual dust
grains. "They're about the size of pebbles or small stones," he
says. (It may seem unbelievable that a pebble can produce a fireball as bright
as the Moon, but remember, these things hit the
atmosphere at very high speed.) The rocky swarm moves within the greater Taurid
dust stream, sometimes hitting Earth, sometimes not.
"In the early
1990s, when Victor Clube was supervising my PhD
work on Taurids," recalls Asher, "we
came up with this model of a swarm within the Taurid
stream to explain enhanced numbers of bright Taurid
meteors being observed in particular years." They listed "swarm
years" in a 1993 paper in the Quarterly Journal of the Royal
Astronomical Society and predicted an encounter in 2005.
It seems to be
happening.
When should you
look? You might see a fireball flitting across the sky any time Taurus is
above the horizon. At this time of year, the Bull rises in the east at sunset.
The odds of seeing a bright meteor improve as the constellation climbs higher.
By midnight, Taurus is nearly overhead, so that is a particularly good time.
According to the
International Meteor Organization, the Taurid
shower peaks between Nov. 5th and Nov. 12th. "Earth takes a
week or two to traverse the swarm," notes Asher. "This comparatively
long duration means you don't get spectacular outbursts like a Leonid meteor
storm." It's more of a slow drizzle--"maybe one every few
hours," says Asher.
A drizzle of fireballs,
however, is nothing to sneeze at. So keep an eye on the sky this month for Taurids.
SOURCE: Space.com
Also, read this story from Science@NASA.