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First "Observation" of Hawking Radiation
KentuckyFC writes "Italian physicists are claiming the first observation of Hawking radiation, but not from a black hole. Instead they've spotted it streaming from a sonic horizon in a Bose Einstein Condensate (abstract on the arXiv). That's consistent with previous predictions but they're claiming the 'first' even though the experiment was only a numerical simulation. Does that really count?"
... and they wanted to get First Post?
A numerical model is little more than a highly specific and round off error prone implementation of existing analytical results. All these guys have done, at most, is shown the correctness of Hawking's analysis. If that.
May the Maths Be with you!
That accurately describes about 90% of theoretical physics doesn't it?
If so, then many slashdotters are no longer virgins.
Welcome to the Panopticon. Used to be a prison, now it's your home.
My first thought from the headline was Unruh effect. It's a kind of Hawking radiation you can get in a particle accelerator. It just happens that with black holes, the acceleration is due to gravity, but other sources of acceleration also work. There are huge decelerations from c to nearly 0 at heavy ion collisions, for example.
I first heard of the effect when some fellow physicists were considering the idea of tiny black holes created in particle physics experiments. It turned out that the presence of Hawking-like radiation doesn't necessarily mean a black hole.
Well, it also turns out that this has nothing directly to do with the article, but might be +i, interesting nevertheless.
Escher was the first MC and Giger invented the HR department.
I'm sorry, but I'm with the "no way this counts" camp. Theories have to be tested in the physical world to be proved. Theoretical physics included folks. That's why we have supercolliders and Z-machines, duh! Numerical analysis can help predict physical behavior but it is not law until it is proved in the real world. Sorry guys.
yes, but Hawking radiation is somewhat different, and requires no material in the vicinity. It works like this: there are always opposite particles (say, positron-electron pairs) that spontaneously appear at the subatomic level. But in the normal universe, they immediately re-collide, giving back to the local space whatever energy was used to create them. That's a bad explanation (because I'm not a physicist), but it gives a rough picture. At the edge of an event horizon, however, there is a small - though nonzero - chance that one or the other particle will get sucked down the gravity well before it can remerge with its opposite. Thus the one that survived ambles off into space, no doubt pondering its cosmic parthenogenesis. The energy of the particle is - for reasons unknown to me - taken from the black hole. Also, this process steadily accelerates as the black hole continues to lose mass through the process: it eventually pops out of existence in a burst of gamma radiation.
So, it's a little more complicated/interesting than you described; I'm sure it would be even better if someone here could describe it from an actual background in physics, instead of the armchair variety I can muster.
Not quite, if you imagine the theory as a car then the scientists suspected it might have been a Porsche Cayenne 4x4 and once they had built their simulation ( imagine that as a carwash ) it turned out that it was indeed a Porsche Cayenne 4x4. However the amazing thing was that even though they hadn't considered the driver specifically in their simulation it did indeed turn out the simulated driver was a enormous wanker thus proving beyond doubt the truth of their simulation.
We've got millions of highly vivid simulations!