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X-ray telescope design tested

Astronomers have developed a design for an X-ray telescope so staggeringly powerful that it could see black holes gulping matter in distant galaxies.

Government and university scientists successfully tested a small prototype at NASA's Marshall Space Flight Center in Huntsville, Ala. A full-size instrument based on the new design would be a million times more powerful than today's observatories, the researchers said.

The preliminary results were published in today's issue of the journal Nature.

"It will make it easier than previously thought to obtain a black hole image," said physicist Nicholas White of NASA's Goddard Space Flight Center, who reviewed the study.

A black hole is an extremely dense object at the center of a galaxy with such powerful gravitational pull that not even light can escape. That is why black holes are invisible to conventional telescopes that use visible light.

To find them, astronomers observe stars and gas swirling around the center of a galaxy before they fall into the cauldron of its invisible core. The matter is condensed and heated during its journey, generating X-rays.

X-rays can directly penetrate conventional flat mirrors. So to catch them, telescopes must use ultrasmooth mirrors in creative designs.

The $1.5-billion Chandra observatory is the most powerful X-ray telescope. Orbiting Earth since July, it uses four cylindrical nesting mirrors to funnel incoming X-rays. Computers process the data into images.

The new telescope design was developed at the University of Colorado. It uses an approach known as interferometry, in which multiple flat mirrors gently steer the fringes of the incoming X-rays. Two sets of mirrors mix and amplify these beams, producing sharper images.