Return of the Leonids Dec. 4, 2008: Astronomers from Caltech and
NASA say a strong shower of Leonid meteors is coming in 2009.
Their prediction follows an outburst on Nov. 17, 2008, that
broke several years of "Leonid quiet" and heralds even more
intense activity next November. "On Nov. 17, 2009, we expect the
Leonids to produce upwards of 500 meteors per hour," says Bill
Cooke of the NASA Marshall Space Flight Center. "That's a very
strong display." Forecasters define a meteor storm as 1000 or
more meteors per hour. That would make the 2009 Leonids "a half-
storm," says Jeremie Vaubaillon of Caltech, who successfully
predicted a related outburst just a few weeks ago. Right: A
composite, all-sky image of the 2008 Leonid outburst over
California. Credit: Tony Phillips. On Nov. 17, 2008, Earth
passed through a stream of debris from comet 55P/Tempel-Tuttle.
The gritty, dusty debris stream was laid down by the Leonids'
parent comet more than five hundred years ago in 1466. Almost no
one expected the old stream to