NASA's New Observatory

0 Comments | Insight on the News, Oct 4, 1999 | by Rebecca Wyatt

An X-ray telescope orbiting Earth has sent back stellar photos from deep space.

The National Aeronautics and Space Administration has released the first images captured by the orbiting Chandra X-ray Observatory, expressing relief that the $1.5 billion telescope works as advertised and optimism in its research potential.

The space telescope sent back two sharp images: one of the Cassiopeia A supernova, a star in the Milky Way galaxy that exploded about 300 years ago; the other of an "X-ray jet" streaming deep into intergalactic space from a quasar. According to Robert Kirshner, a Harvard astronomer, Chandra's ability to make high-quality X-ray images of the universe "will have an impact on virtually every area of astronomy."

Chandra was never a sure thing. Technical snags caused delays, and the 50,000 pound, 45-foot-long, gold-and silver-colored telescope was the heaviest payload yet for a shuttle mission. Scientists were not sure whether Chandra would work or even survive in space once it reached orbit.

"It's been like a roller-coaster ride," says Martin Weisskopf, a NASA scientist. "The buildup to the top of the hill has been a long, steep climb." He and his colleagues at NASA wax ebullient at the early results, however. "When I saw the first image, I knew that the dream had been realized," says Weisskopf. "This observatory is ready to take its place in the history of spectacular scientific achievements."

Chandra does not capture visual, light-based images but X-rays emitted from stars and fields of hot gas, such as those that might surround a black hole. Heated heavy elements in space give off X-rays of specific intensities. Chandra is able to measure those intensities and identify specific elements, shedding new light on fundamental processes in the universe.

The telescope is in an oval orbit that puts it at 6,000 miles altitude at its closest and 86,400 miles at its farthest, allowing its sensitive X-ray equipment to escape the radiation of the Earth's atmosphere to record accurately.

The image of the Cassiopeia supernova contains such exacting detail of the explosion and its surrounding cloud -- being hurled outward at 10 billion mph -- that scientists have detected near its center evidence of what may be a black hole, a superdense kernel of collapsed stellar matter -- "like a huge garbage compactor in the center of the star," says NASA scientist Harvey Tananbaum.

The other image captures an X-ray jet about 200,000 light-years in length, being emitted by a quasar some 6 billion light-years away. (A light-year is the distance light travels across space in a year, nearly 6 trillion miles.) The quasar itself throws out visible light of 10 trillion suns, according to NASA researchers.

Chandra's estimated life span is five years, and the results will be entered into a public archive on the Internet for anyone to access. The orbiting observatory was named in honor of Subrahmanyan Chandrasekhar, a pioneer astronomer at the University of Chicago and Nobel Prize winner.