Once at 50 years!

Aug 31, 2007 08:46 GMT  ·  By

Tomorrow morning you can take a look at a rare two-hour meteor shower coming from the remote Oort cloud, at the edges of the Solar System.

The Aurigid show will reach its maximum at 4:30 a.m. Pacific daylight time, spotting the night sky with about 200 shooting stars each hour.

The unusual event can be witnessed just once at 50 years and takes place when Earth crosses a dusty tail of comets orbiting our star. But while other comets orbit the sun in about 200 years, the Aurigids are long-period comets that do it in 2,000 years. The meteor shower will allow the researchers to investigate the outer reaches of the solar system, employing wide-field cameras and upper atmosphere techniques. But the shower will be visible with the naked eye, a show of bright burning blue and green meteors. But this is not guaranteed.

In western North America, the shower will be visible from the constellation Auriga.

"We have so little experience with ancient debris from long-period comets. Almost anything could happen-from a fizzle to a beautiful meteor shower," said Bill Cooke at NASA's Marshall Space Flight Center in Hunstville, Alabama.

The meteors come from the comet Kiess, which could have interfered with the solar systen around A.D. 4, producing a trail of dusty debris, visible from Earth three times before: in 1935, 1986, and 1994.

Now, astronomers want to use advanced techniques to better assess the orbit of Keiss and its position.

Oort Cloud, a sphere of comets extending from far beyond Pluto's orbit to nearly a light-year from the sun, is also an enigma.

"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," said Jeremie Vaubaillon of the California Institute of Technology.

Long-period comets orbit the sun so lazily (in a thousand or even millions of years), that crossing the Earth's orbit is indeed an extremely rare event.

"Keiss' dust trail will move in and out of Earth's orbit over the next 50 years but will not hit Earth itself again. At present, the 1 September Aurigid shower seems to be the only sure deal in the next 50 years," wrote Vaubaillon and Peter Jenniskens at the SETI Institute.