Blogtrek

Gamma Ray Bursters

At an amateur astronomer's meeting tonight I saw a NOVA video on gamma ray bursters. These are mysterious bursts of radiation, especially gamma rays, coming from some place in the sky that does not usually correspond to any star, galaxy, nebula, or other visible optical instrument. They are so powerful that if one were to occur 100 light years (that's 600 trillion miles) from here, it would wipe out human civilization; it would be like an atom blast everywhere on the Earth simultaneously. So what are they? The theory that came out in the video was that they are caused by really huge stars that collapse into black holes when they die. There are two objections to this argument. One is that usually huge supernovas in which a star (such as a Wolf-Rayet star) could become a black hole usually produce Type 1b or Type 1c supernovas, which are far less powerful than a gamma ray burster. More importantly, if really huge stars that become black holes produce gamma ray bursters ( also called hypernovas) when they die, certainly something like this would have occurred in the 4.6-billion-year history of the earth. That would have wiped out all life. I am alive, and I see all kinds of life around me - people, animals and plants, and the planet is fertile. Therefore, no such explosion could have occurred near here, and that eliminates stars becoming black holes as the cause of gamma-ray bursters. Then what are they? Like many astronomers, I feel I do not know. It is part of the never-ending quest for truth and meaning. Maybe we will know someday.