NASA: Gamma-ray burst was aimed at Earth

Washington -- The U.S. space agency says scientific data shows a gamma ray burst from a powerful March 19 stellar explosion was aimed nearly directly at the Earth.

The National Aeronautics and Space Administration said its Swift satellite and observatories around the world detected the explosion at 2:13 a.m. EDT that morning in the constellation Bootes.

Judith Racusin of Penn State University and a team of 92 scientists recorded observations across the spectrum that began 30 minutes before the explosion and then followed its afterglow for months. The team concluded the burst's extraordinary brightness arose from a jet that shot material directly toward Earth at close to the speed of light.

At the same moment Swift saw the burst, the Russian KONUS instrument on NASA's Wind satellite also sensed the gamma rays.

Within the next 15 seconds, the burst brightened enough to be visible in a dark sky to human eyes. It briefly crested at a magnitude of 5.3 on the astronomical brightness scale although the dying star was 7.5 billion light-years from Earth.

Racusin and colleagues report their findings in the Thursday issue of the journal Nature.

Copyright 2008 by United Press International.