Originally created 12/30/00

Infrared cuts dust of Milky Way



Astronomers wanting to peer farther into space to see stars, planets and other things in the Milky Way galaxy haven't been able to because of clouds of gas and dust that obscure the view like a dirty windshield.

But new technology scheduled to blast into orbit in 2002 is expected to allow stargazers to see as far as they want and learn more about the galaxy we call home.

A team from the University of Wisconsin-Madison will be the first to get a gander at the Milky Way and help map the two-thirds of the galaxy that astronomers don't know much about. UW-Madison researchers have won a major contract with NASA to perform a detailed survey of the inner regions of the Milky Way using the Space Infrared Telescope Facility, which will be launched into orbit around the sun in July 2002, an official said this week.

Scientists will look at stars through infrared, which cuts through the dust and clouds like a pair of X-ray glasses. The $600 million telescope will sample light in the infrared region of the electromagnetic spectrum.

Infra red light, which is invisible to unaided human eyes, is given off by stars, planets, nebulas and other objects. This means astronomers can squint into a region rich in star clusters, brown dwarfs, luminous nebulas and dark planet-sized things called substellar objects.

Brown dwarfs are objects with too little mass to be stars, while nebulas are clouds of interstellar dust.

"We expect to uncover hundreds of new regions where stars are being formed, which is a big deal since these stars will really determine the future evolution of our galaxy," said Edward Churchwell, a UW-Madison astronomer.

Information gleaned from the telescope will help answer fundamental questions such as how stars are formed and what kind of stars occur in certain areas of the galaxy.

Scientists know there are stellar nurseries, where new stars are born, inside the inner regions of the Milky Way galaxy. But they're hidden by a curtain of gas and dust, which the Space Infrared Telescope Facility will be able to open.

"At optical wavelengths, you can't see further than a few thousand light years away because of obscuring dust," Churchwell said. "But the infrared is different. You can see right through it."

Sent aloft via an unmanned rocket, the telescope will begin its journey approximately 9 million miles away from Earth. As time goes on, it will lag further behind our planet as it orbits the sun in the same orbit path as Earth, Churchwell said.

The telescope will get tossed into space behind Earth, where the skies are the most black and give the best view of the inner galaxy. The project has a five-year life span, although UW-Madison scientists expect to get most of their information in the first two years. After five years, the telescope will literally run out of gas - the fuel used to fire off jets to orient itself in space - and drift out the end of its days.

Once the information begins streaming into computers, "that's when the fun be gins and we start to do some science," Churchwell said. "We'll look at these stellar nurseries and try to determine how many stars are being born. There are signatures in the infra red where we can actually date the stars pretty well through the distribution of radiation."

Scientists expect to see about 100 million stars in the inner two- thirds of the galaxy. Surveying stars and star clusters, noticing density and where stars are distributed will help astronomers map out the Milky Way.