Put on your knit ski hat,
zip up your winter coat, pour a hot beverage… and just look up. Get away
from street lamps, turn off the porch light and find a patch of dark
sky. It’s time for the Leonid meteor shower peak tonight and into
tomorrow morning.
Like the Perseid meteors in August,
the Leonid shower in November has potential to be interesting, but this
is a year of low strength. Later this evening and past midnight,
astronomy experts predict about 15 to 20 each hour could fly through our
sky. You won’t see all the meteors, but if you see four or five each
hour, you’re doing well.
The meteor shower peak is expected around 3 a.m. ET, Saturday.
If you saw last night’s young crescent moon at dusk in the western
sky, we’re still dealing with a (one-day older) adolescent slim moon. It
sets early enough in the evening to give sky gazers a dark opportunity
to scout more shooting stars.
Meteors are just cosmic trash. When comets fly about the heavens,
they leave dusty trails. Earth, on its own annual cruise around the sun,
sometimes runs into the trails of comet debris left behind. Earth runs
into these ribbons of debris and as these minute pieces of dirt strike
our atmosphere, they burn up. We see them as streaks across our heavens.
Meteor showers get their names from the constellations from which
they appear to emanate. In this case – Leo! With the Leonids, these
comet pieces strike the Earth head on, according to Alastair McBeath in
Guy Ottewell’s Astronomical Calendar 2012. They are quick, bright and
many leave trails behind.
“Leonid meteors are very swift. Meteroids in this stream have the
highest geocentric velocity (44 miles per second) known for any shower,
close to the maximum value theoretically possible,” says Neil Bone in
his book Meteors. “The Leonids are rich in faint meteors, indicating a
high proportion of small particles in the swarm.”
But which comet produces the Leonids? In 1981, Don Yeomans,
astronomer, Jet Propulsion Lab in Pasadena, Calif., confirmed that Comet
Tempel-Tuttle was indeed responsible for the Leonids. Published in
Icarus (September 1981), he suggested that the 1998 return of Comet
Tempel-Tuttle could spawn significant meteor activity in subsequent
years. Yeomans was right, there were heavy meteor showers in subsequent
years. In November 2002, eastern U.S. residents saw clear nights and the
peak produced hundreds of meteors an hour – making it seem like a
fireworks show with a twist.
Rick Baldridge, near Coalinga, Calif., shares the 2001 Leonid meteor
shower. You will see small meteors emanating from near the constellation
Leo. During points (such as at 1:56) in the video, you will see
stronger meteors – with trails.
Beyond showers, the Leonids sometimes sire storms – as it did in 1799
and 1833. Astronomers of the time suggested that the 1866 Leonids
produced between 2000 and 5000 meteors per hour at the peak. One hundred
years later, for a 40 minute period, United States sky gazers in 1966
were treated to a virtual bombardment of an estimated 60,000 Leonid
meteors an hour.
Comet Tempel-Tuttle has a Washington, D.C. connection: Horace P.
Tuttle, an astronomer with the U.S. Naval Observatory, co-discovered the
comet on Jan. 5, 1866 from here. The comet last reached perihelion
(it’s closest point to the sun) in 1998 and it returns in May 2031.
(As a note, Italian astronomer Giovanni Schiaparelli is credited with
being the first theorist to see the connection between meteors and
comets. In 1871, he published “Outline of an Astronomical Theory of
Shooting Stars.” Before this, the topic was hotly debated among
astronomers, as some had suggested meteors came from the moon.)
Sources
Observer’s Handbook 2012, Royal Astronomical Society of Canada;
Meteors, by Neil Bone (1993), Sky Publishing Corporation;
Icarus, (1981) Elsevier publishing
Astronomical Calendar 2012, Guy Ottewell, Universal Workshop
International Meteor Organization, www.imo.net
By
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10:06 AM ET, 11/16/2012
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