LEONID METEOR SHOWER

The 2009 Leonid Meteor Shower	11.10.2009
+ Play Audio | + Download Audio | + Email to a friend | + Join mailing list   November 10, 2009: This year's Leonid meteor shower  peaks on Tuesday, Nov. 17th. If forecasters are correct,  the shower should produce a mild but pretty sprinkling of  meteors over North America followed by a more intense  outburst over Asia. The phase of the Moon will be new,  setting the stage for what could be one of the best Leonid  showers in years.  "We're predicting 20 to 30 meteors per hour over the  Americas, and as many as 200 to 300 per hour over Asia,"  says Bill Cooke of NASA's Meteoroid Environment Office.  "Our forecast is in good accord with independent theoretical  work by other astronomers."1 Right: A Leonid meteor at dawn, photographed in 2002  by Simon Filiatrault of Quebec, Canada. [larger image] Leonids are bits of debris from Comet Tempel-Tuttle.  Every 33 years the comet visits the inner solar system  and leaves a stream of dusty debris in its wake. Many  of these streams have drifted across the November portion  of Earth's orbit. Whenever we hit one, meteors  come flying out of the constellation Leo. "We can predict when Earth will cross a debris stream  with pretty good accuracy," says Cooke. "The intensity of the display is less certain, though, because we don't know  how much debris is in each stream." Caveat observer! Sign up for EXPRESS SCIENCE NEWS delivery The first stream crossing on Nov. 17th comes around  0900 UT (4 a.m. EST, 1 a.m. PST). The debris is a diffuse  mix of particles from several old streams that should produce  a gentle display of two to three dozen meteors per hour  over North America. Dark skies are recommended for full  effect. "A remarkable feature of this year's shower is that  Leonids will appear to be shooting almost directly  out of the planet Mars," notes Cooke. It's just a coincidence. This year, Mars happens to be  passing by the Leonid radiant at the time of the shower.  The Red Planet is almost twice as bright as a first magnitude  star, so it makes an eye-catching companion for the Leonids:  sky map.The next stream crossing straddles the hour  2100-2200 UT, shortly before dawn in Indonesia and China.  At that time, Earth will pass through a pair of streams laid  down by Comet Tempel-Tuttle in 1466 and 1533 AD. The  double crossing could yield as many as 300 Leonids per hour. Above: This side of Earth will be facing the Leonid debris  stream at the time of the Nov. 17th outburst. Observers in  India, China and Indonesia are favored with dark, pre-dawn  skies. Image credit: Danielle Moser of the NASA Meteoroid  Environment Office. "Even if rates are only half that number, it would still be  one of the best showers of the year," says Cooke. The Leonids are famous for storming, most recently in  1999-2002 when deep crossings of Tempel-Tuttle's debris  streams produced outbursts of more than 1000 meteors  per hour. The Leonids of 2009 won't be like that, but it  only takes one bright Leonid streaking past Mars to make  the night worthwhile. Enjoy the show. Author: Dr. Tony Phillips | Credit: Science@NASA