Jeremie Vaubaillon of the California Institute of Technology is banking on a spectacular display, although he's tempered his enthusiasm in public—even halving his forecast to a hundred meteors an hour in a recent press release.
"I wanted to be cautious," he told National Geographic News. "I think what has to be remembered is there are a lot of uncertainties."
"We have so little experience with ancient debris from long-period comets," added Bill Cooke at NASA's Marshall Space Flight Center in Hunstville, Alabama.
"Almost anything could happen—from a fizzle to a beautiful meteor shower."
Ready and Waiting
The meteors are castoffs from comet Kiess, which astronomers believe first buzzed the sun around A.D. 4, leaving behind a trail of dusty debris.
Earth has three times before encountered that dust trail—in 1935, 1986, and 1994.
But unlike previous sightings, a strong network of amateur and professional astronomers stands ready to capture all the information the Aurigids reveal this time around.
"You can follow a meteor shower through hundreds of observations," Caltech's Vaubaillon said.
And that's a good thing, because he has plenty of questions about Keiss and its castoffs.
He hopes to better nail down the orbit of Keiss and calibrate computer models that predict its position.
The shooting stars themselves will be a rare window into the composition of comets in the poorly understood Oort Cloud, a spherical cloud of comets thought to extend from far beyond Pluto's orbit to nearly a light-year from the sun.
"What is cool is we have a piece of comet that was ejected at least 2,000 years ago—we're going to see it being destroyed in the atmosphere," Vaubaillon said.
(Get more comet facts.)
Once in a Lifetime
Astronomers realize it's important not to miss this chance
Comet Keiss visited the inner solar system again only in 1911, after completing a single orbit in the nearly 2,000 intervening years.
Other long-period comets also have such lazy orbits around the sun, passing by once in a thousand or even millions of years and only rarely traveling through the path of Earth's orbit.
For example, Keiss' dust trail will move in and out of Earth's orbit over the next 50 years but will not hit Earth itself again, wrote Vaubaillon and a colleague, Peter Jenniskens at the SETI Institute, in the August issue of the journal Eos.
In fact, no other known long-period comet tail is predicted to make a showing in the foreseeable future.
"At present," the scientists wrote, "the 1 September Aurigid shower seems to be the only sure deal in the next 50 years."
Free Email News Updates
Sign up for our Inside National Geographic newsletter. Every two weeks we'll send you our top stories and pictures (see sample).
|
SOURCES AND RELATED WEB SITES
|
