Short Gamma-ray Bursts Traced to Colliding Stars 135
Astervitude writes "Collisions of the cosmic kind could be the source of one of nature's most lethal explosions. Astronomers have traced the origin of short-duration gamma-ray bursts, or GRBs, to the merger of neutron stars or other dense bodies. Space.com has a report on the scientific detective work that led to the solution of what has been described as a 35-year-old mystery. "Our observations do not prove the coalescence model, but we surely have found a lady with a smoking gun next to a dead body," said Shri Kulkarni, one of over two dozen astronomers who discovered and investigated two short-duration bursts that took place last May and July. Unlike short-duration GRBs, long-duration GRBs are believed to be produced when extremely massive stars collapse and explode as supernovas."
Re:They explode, hence blackholes are a impossibil (Score:2, Insightful)
people don't believe they exist just because of a GR solution.
they were predicted before GR but believed to be a mathematical trick that would need perfect conditions to form (perfectly symmetrical mass distribution). GR just changed that by removing these conditions (the generation of gravitational waves by mass distributions with a quadrupolar moment means).
anyway, you make it sound like it's just a case of GR for black holes. it's not - it's a huge amount of theory and observations that are all consistent. if you want respect then the first thing to do is acknowledge this work exists, and the second is to provide an alternative explanation that works at least as well.
Re:The summary (Score:4, Insightful)
Which is, of course, nonsense. It should say 'the same amount of energy as the visible Universe'. Big (very, very big) difference!
Re:Astronomy vs Science (Score:3, Insightful)
You have something against sociology? It's a science too. And ALL sciences are practiced by human beings, who need to be convinced by evidence -- as they should.
This, of course, is nonsense. The vast majority of new astrophysical phenomena find explanations within current physics.
And your point is what? There is substantial evidence in favor of these theories, and all competing theories advanced so far have failed. Sometimes new physics is discovered, you know. Just because you want to stick your fingers in your ears and ignore the evidence in its favor, doesn't mean it's not there.
What the hell are you talking about? All of those observations SUPPORT Big Bang cosmology, rather than contradict it. (Except for one mistake on your part: there is no known preferred direction of the CMBR -- but even if there was, there are anisotropic Big Bang cosmologies with preferred directions.)
It is not negative evidence. Theories of neutron stars and black holes make specific predictions of what you will see, and those predictions are supported by observations.
This turns out not to be the case. Ultra high energy cosmic rays, for one, are within the capacity of jets from supermassive black holes. One current goal is to localize the origin of these rays better to see whether they coincide with such sources.
The bigger mystery is not whether mechanisms exist to produce them, but why these rays are appearing to exceed the GZK cutoff, which sets an upper bound on the energy of distant cosmic rays that we can detect. (Some possibilities: the experiments are miscalibrated, which is distinctly possible since HiRES and AGASA's curves look the same except one is shifted by 20%; the cosmic rays are nearer in origin than we think; there is new physics or an unaccounted effect that allows violation of the GZK prediction. All are being investigated, and new expriments such as the Pierre Auger observatory should shed light on this question.)
Oh, I get it, you're a plasma cosmology crank. Well, no, you're wrong: plasma physics gets published in astrophysics journals all the time. Just look at the astro-ph arXiv. However, crank physics which purports to expl
Re:A few questions about GRBs (Score:3, Insightful)
I dont know if we _EVER_ have observed a GRB in our galaxy, the detected ones are very isotropically distributed over the sky and in the _deep_ background. Most have a z>0.1 and are FAR away.
And the killing ratio for a GRB would be more like 100-250 ly. 10 ly away even a normal supernova would be an extinction event.
Just use some fermi logic:
If a GRB is the result of the collision of 2 neutron start, than they are at least twice as rare as supernovas (somewhere those NS have to come from, plus many supernovas dont leave a neutron star).
and after that, there has to be a situation when 2 are able to merge (which 99.9% only happens in close binary start, as 2 neutron start hitting each other has a laughably small propability).
This alone allows to fix the rate of GRBs to at least as rare as once per millenium.