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.
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.)
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