Cosmic flashbulb effect caused by 'black-hole invaders' Boffins at Leeds Uni say they have come up with a new explanation for the mysterious astronomical phenomena known as "gamma ray bursts" (GRBs) because they consist of bursts of gamma rays. GRBs, originally noted by US military spy sats looking for evidence of surreptitious commie nuke tests, are puzzling because of their …
So how does this fit with desktop blackholes evaporating before they get big enough to become stable.
So the end of the world, will be.
1. Fire up the LHC
2. Black forms and falls into the center of the earth.
3....
4. Profit.
However I believe step 3 involves selling tickets to interplanetary gawkers, laughing at how a complete planet is killed by extreme G while the planet speeds up.
DJ
Beer 6 pints, 2 bags of peanuts and a towel.
Firstly the copy on the arxiv is a preprint (that's what the arxiv is for). Preprints generally have spelling mistakes and far worse in. Further to that I'm sure Dr Barkov and Prof Komissarov are perfectly proficient in their native Russian, and for Russians their standard of Eeenglish is pretty damn good. Try reading a preprint by some Chinese authors (with no non-Chinese co-authors) - it's worth a laugh (though can be painful if you're actually trying to extract some useful information - running it backwards and forwards through google translate sometimes gives you a clue).
I reread the paragraphs in question, and it does make sense:
Once the black hole is *inside* the star, slurping up fusioning material like a rugrat with a inbreed predisposition to runaway brain freeze on an Orange Julius, the combined mass of the resulting body is hugely increased. Bodies with increased mass (but same volume) rotate faster, resulting in a temporarily stable, but ultimately destructive state. The star appears to increase in mass greatly, spin at an exetremely accellerated rate, spewing out GRBs (and X-Rays, etc) until its "surface" mass becomes too ephermal and collapses completely into the black hole that ate the star from the inside out.
Cosmic cancer, anyone?
"The mysterious cosmic flashbulbs pop off about once a day from random directions in the sky, and boffins have struggled to work out what causes them ever since they were detected in the 1960s"
Umm, sounds like art has been imitating life again!
I believe this phenomenon is common at so-called gala-h events with copious quantities of red carpet in view.
OK, I'm on my way
Hugo - in principle yes and lots of work has been done on lensing of GRBs for several reasons, but it's not thought to be a useful mechanism for the long/short burst dichotomy.
In practice the differential path lengths from a typical single-galaxy lens (the sort of "Einstein Cross" setup that provides pretty HST pics) are of order hours to months. So a single short-duration GRB would appear as multiple short bursts separated by that timescale - I don't think such a GRB has ever been unambiguously observed, and I think that's consistent with the rarity of the very close source-lens alignment you would need.
Many a GRB, though, lies on a line-of-sight that skirts nearby a foreground galaxy, usually evidenced by absorption lines in the GRB optical spectrum. In such cases micro-lensing by individual stars in the foreground galaxy would be expected to occur, but if IIRC that can only give you fractions of a second of temporal smearing - not enough to make a 100-second long-duration burst from an intrinsically short one.
(And of course the near-alignment will also cause some magnification too - there's been some controversy here recently because of a claim that "GRBs are more frequently lensed than quasars" - but as always the devil is in the detail and there's still plenty of head-scratching going on!)
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