Invading black holes explain cosmic flashes
September 18, 2009
(PhysOrg.com) -- Black holes are invading stars, providing a radical explanation to bright flashes in the universe that are one of the biggest mysteries in astronomy today.
The flashes, known as gamma ray bursts, are beams of high energy radiation - similar to the radiation emitted by explosions of nuclear weapons - produced by jets of plasma from massive dying stars.
The orthodox model for this cosmic jet engine involves plasma being heated by neutrinos in a disk of matter that forms around a black hole, which is created when a star collapses.
But mathematicians at the University of Leeds have come up with a different explanation: the jets come directly from black holes, which can dive into nearby massive stars and devour them.
Their theory is based on recent observations by the Swift satellite which indicates that the central jet engine operates for up to 10,000 seconds - much longer than the neutrino model can explain.
Mathematicians believe that this is evidence for an electromagnetic origin of the jets, i.e. that the jets come directly from a rotating black hole, and that it is the magnetic stresses caused by the rotation that focus and accelerate the jet's flow.
For the mechanism to operate the collapsing star has to be rotating extremely rapidly. This increases the duration of the star's collapse as the gravity is opposed by strong centrifugal forces.
One particularly peculiar way of creating the right conditions involves not a collapsing star but a star invaded by its black hole companion in a binary system. The black hole acts like a parasite, diving into the normal star, spinning it with gravitational forces on its way to the star's centre, and finally eating it from the inside.
"The neutrino model cannot explain very long gamma ray bursts and the Swift observations, as the rate at which the black hole swallows the star becomes rather low quite quickly, rendering the neutrino mechanism inefficient, but the magnetic mechanism can," says Professor Komissarov from the School of Mathematics at the University of Leeds.
"Our knowledge of the amount of the matter that collects around the black hole and the rotation speed of the star allow us to calculate how long these long flashes will be - and the results correlate very well with observations from satellites," he adds.
More information: The research is published in the Monthly Notices of the Royal Astronomical Society.
Source: University of Leeds (news : web)
Jun 27, 2007 |
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From the same reason the belief, we could survive black hole formation in LHC many years at the case, when black hole would fall into Earth core appears pretty naive for me. We would evaporate in much faster way.
It seems that if it remained in existence long enough to come into contact with anything solid, then it would very, very quickly-perhaps in only a few minutes make it to the gravitationally stable center of the planet. One would expect that soon after, the planet would begin to break apart or implode. Great movie idea, but how real is this proposed sequence of events? Anyone?
One piece of evidence, which is generally considered quite convincing, is that the Earth is constantly being bombarded with cosmic rays with far more energy than could ever be achieved by the LHC. The fact that the Earth still exists makes the evaporation model a high statistical probability, even without the accompanying logical argument.
Note: It's not just the Earth either - if BHs didn't evaporate, one would expect the Sun or any of the other planets to have been destroyed by now. The fact that they, and the many bodies in our stellar neighborhood still exist lends further credence to black hole evaporation.
http://www.physor...766.html
If scientists are searching for theories, which would violate existing theories, which predict black hole evaporation, they shouldn't be surprised in near future.
Safety is the main concern of LHC experiments. You can be perfectly sure, LHC experiments are safe because of many theories. After all, the main purpose of these experiments is to verify these theories.
Isn't the only purpose of LHC to verify it's own safety at the very end? Is it really enough for everybody?
Says WHO?
Don't magnets have positive and negative charged parts in equilibrium? So why would a galaxy need an imbalance in charged particles to have a strong magnetic field?
There is evidence of a galactic magnetic field. It is very weak, but it constrains sources of cosmic rays.
I just feel sorry for the hundreds of thousands of "scientists" who are forced to propagate the myths.
It's not science at all. And I condemn those trying to suppress and ignore Crothers work for the sake of jobs, reputations, false pride and money.