Newspaper article The Christian Science Monitor

On the Trail of Missing Matter ; X-Ray Astronomy Opens Up Some of the Universe's Most Violent and Creative Processes

Newspaper article The Christian Science Monitor

On the Trail of Missing Matter ; X-Ray Astronomy Opens Up Some of the Universe's Most Violent and Creative Processes

Article excerpt

At first glance, the narrow, 8-meter-long truss resting on its side in an assembly hall here at NASA's Goddard Space Flight Center hardly looks like a telescope - no highly polished glass mirror to focus starlight. And in an age when pixels have replaced pupils, certainly no eye-piece.

Yet the instruments mounted on the truss represent key stepping stones toward an orbiting observatory that astronomers say is critical to helping them pick up the trail of the universe's missing matter, observe the origin and evolution of chemical elements, and unravel the mysteries behind black holes - objects with gravity so intense that light fails to escape.

Known as Constellation-X, the observatory is designed to study X- ray emissions from some of the most energetic - and bizarre - objects and processes in the universe.

"The nice thing about X-ray astronomy in general is that virtually every object we study is weird," says Robert Petre, who heads up the X-ray astrophysics branch of Goddard's Laboratory for High Energy Astrophysics and is deeply involved in the Constellation-X project.

Yet, Dr. Petre adds, understanding the processes driving such objects - from neutron stars cannibalizing the matter of companion stars to the highly energetic cores of distant galaxies - is vital to understanding how the universe evolved since it burst into existence 15 billion years ago. Nor is he alone in that view.

Last May, the National Research Council published a report laying out astronomy and astrophysics projects for the next decade. Constellation-X was high on the list of "major initiatives."

Astrophysicists certainly don't lack highly capable orbiting X- ray telescopes. In 1999, the National Aeronautics and Space Administration launched the Chandra X-Ray Observatory, one of its Great Observatory series, which includes the Hubble Space Telescope.

Chandra has been a stunning success so far. For example, it has helped determine the source of X-ray emissions from the Crab Nebula, a supernova remnant in our own galaxy. And just last week, researchers using Chandra announced that they've bagged the most distant cluster of galaxies ever seen via X-rays. The cluster lies 10 billion light years from Earth. According to Harvey Tanabaum, director of the Chandra Observatory Center at the Harvard- Smithsonian Center for Astrophysics and chairman of Constellation- X's science team, Constellation-X will serve a different purpose.

More light, please

Chandra, he says, is analogous to the Hubble Space Telescope, which "does an amazing job of providing highly detailed, beautiful images from space." Yet at 2.4 meters across, Hubble's light- gathering mirror fails to capture enough light to allow astronomers to conduct detailed studies of the distant objects it images. That task falls to large ground-based "light buckets" such as the twin 10-meter Keck telescopes on Hawaii's Mauna Kea.

Constellation-X is designed to be the X-ray version of these light buckets. And its spectrograph will be able to pick more details out of the emissions it detects than can Chandra's. …

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