2006-12-05 05:39:57 · 3 answers · asked by Steel 2 in Science & Mathematics ➔ Astronomy & Space
Gamma-ray bursts are short-lived bursts of gamma-ray photons, the most energetic form of light. At least some of them are associated with a special type of supernovae, the explosions marking the deaths of especially massive stars.
Lasting anywhere from a few milliseconds to several minutes, gamma-ray bursts (GRBs) shine hundreds of times brighter than a typical supernova and about a million trillion times as bright as the Sun, making them briefly the brightest source of cosmic gamma-ray photons in the observable Universe. GRBs are detected roughly once per day from wholly random directions of the sky.
Until recently, GRBs were arguably the biggest mystery in high-energy astronomy. They were discovered serendipitously in the late 1960s by U.S. military satellites which were on the look out for Soviet nuclear testing in violation of the atmospheric nuclear test ban treaty. These satellites carried gamma ray detectors since a nuclear explosion produces gamma rays. As recently as the early 1990s, astronomers didn't even know if GRBs originated at the edge of our solar system, in our Milky Way Galaxy or incredibly far away near the edge of the observable Universe. (That is, they didn't know how far away GRBs were to within a factor of a few billion light years!) But now a slew of satellite observations, follow-up ground-based observations, and theoretical work have allowed astronomers to link GRBs to supernovae in distant galaxies.
In this series of articles we will explore what what astronomers know about gamma-ray bursts, what they think causes them, the evidence for the theories, and the lingering mysteries. Along the way we'll encounter powerful hypernovas and strange Wolf-Rayet stars.
Gamma-ray bursts (GRBs) pose one of the greatest mysteries of modern astronomy. About once a day, the sky lights up with a spectacular flash, or burst, of gamma-rays. More often than not, this burst out shines all of the other sources of cosmic gamma-rays added together. The source of the burst then disappears altogether. No one can predict when the next burst will occur or from what direction in the sky it will come. At present, we don't exactly know what causes these flashes, and we've only recently determined how far away they are!
2006-12-05 05:42:58 · answer #1 · answered by DOOM 2 · 2⤊ 0⤋
Gamma Ray Burst
2006-12-05 13:42:42 · answer #2 · answered by Anonymous · 2⤊ 0⤋