Ulysses is one of several spacecraft studying the sun, and the only one that passes over the sun's poles. The light from this gigantic flash had traveled 11 billion years before reaching the Earth, and suggests that these explosive objects may provide us with the longest yardsticks yet for detecting and studying galaxies in the early universe. Hurley's colleagues also will report details of the gamma ray observations at a press briefing today in Rome. Results of the observations will appear in a December issue of the European science journal Astronomy and Astrophysics. All objects in the universe are flying away from each other as a result of the Big Bang.
More distant galaxies recede faster from Earth than nearby galaxies.
This is observed as a Doppler effect, best explained by the pitch of a train whistle, which rises as the train approaches and diminishes as the train speeds away. Similarly, if a galaxy is approaching the Earth, all of the wavelengths in the galaxy's spectrum are shifted toward the blue end of the spectrum. Observations of GRB 000131 revealed that it is receding and its light is shifted toward the red end of the spectrum by a factor of 4.5, which is a significant shift, Hurley said. Before these observations were recorded, the most distant gamma-ray burst to be detected was GRB 971214, estimated to be less than 9 billion light years away in the constellation Ursa Major. Still, the fact that such a faint, distant source can produce a burst of gamma rays which appears to be of more or less average intensity from Earth hasn't been explained yet.