Using Bose-Einstein condensation, the scientists created a black hole for sound waves. The new research may help scientists learn more about galactic black holes and confirm the existence of Hawking radiation, which has not yet been discovered.
A black hole created by a scientist at the Technion won't destroy the Earth, but it might dampen some of the noise on its surface.
Using Bose-Einstein condensation, the scientists created a black hole for sound waves. The new research may help scientists learn more about galactic black holes and confirm the existence of Hawking radiation, which has not yet been discovered.
One of the motivations for the construction of the large particle accelerator - LHC, located near Geneva, which was activated last September, is the desire to test the correctness of Stephen Hawking's well-known statement, which has not yet been proven, according to which black holes, despite their definition as celestial bodies that do not emit anything, emit radiation, including particles light. But, if the operators of the LHC fail to return to operation quickly, it is possible to find what is known as "Hawking radiation" in an experiment recently carried out in a laboratory at the Faculty of Physics in Haifa.
"A sonic black hole is similar to a galactic black hole because the waves are sucked in and cannot escape," said Dr. Jeff Steinhauer, head of the research group. "The only difference is that here we use sound waves instead of light waves."
In order to create the sonic black hole, the scientists had to first create a Bose-Einstein condensation - a cloud of atoms cooled to almost absolute zero. These atoms behave like a light wave. The Israeli scientists actually created two clouds of rubidium 87 atoms, cooled to a few nano-kelvins and separated by a small gap.
Profit is the secret. This gain, known as "density inversion", creates an area of very low density, which allows atoms to move between the two clouds, without interruption, at a speed of about three millimeters per second - more than 4 times the speed of sound. This is an inversion because unlike the Earth's atmosphere, where the clouds are lighter than the air below them, the clouds in the Bose-Einstein condensation are denser than the space below them. Since the atoms that move between the clouds are faster than sound, any sound wave that tries to escape outside will be left behind, and will not be able to pass beyond what is known as the "event horizon" - the language that defines the boundaries of the black hole. "It's like someone trying to move slowly against a fast current", according to Dr. Steinhauer. "The sound waves lag because the current moves faster than the waves".
Scientists watched the sonic black hole for eight milliseconds, using lasers. Since it is a sonic black hole, and not a true black hole, light waves, which travel at a much higher speed than sound waves, can escape from it and allow the observation of the phenomenon.
According to James Anglin, a professor at the Technische Universitat Kaiserslautern, scientists in Germany, the US and Australia have been trying to create a sonic black hole since Canadian physicist Bill Unro theorized the issue. But Steinhauer and his colleagues were the first to actually create such a hole.
"Jeff's experiment confirms that it is indeed possible to create a stable supersonic flow in a superfluid gas," says Anglin. "The research will give us a new perspective on some deep issues related to quantum mechanics, thermodynamics and gravity."
Hawking radiation, first predicted by the physicist Stephen Hawking in 1974, is radiation emitted, theoretically, from the event horizon region of the black hole. Its existence means that matter can escape from a true black hole. In such a situation, if the amount of matter ejected from a black hole is greater than the amount of incoming mass, the black hole will eventually disappear. Despite long and many efforts, scientists have so far failed to prove the existence of Hawking radiation. According to the theory, Hawking radiation is slightly lower than the temperature of the background radiation in space, and is therefore difficult to detect.
Dr. Steinhauer plans to use the sonic black hole to confirm the existence of Hawking radiation, which, as mentioned, was predicted but not yet observed.
A sonic black hole, the equivalent of Hawking radiation is a cloud of phonons, which are loose bundles of energy that behave like particles. Phonons escaping from a black hole can be easily detected, as a small cloud between the two large clouds of a Bose-Einstein condensate, or in a more difficult way, as one cloud lying on top of another cloud. "The discovery of such a phonon cloud would not be absolute proof of Hawking radiation, but it would add experimental evidence for its existence," says Dr. Steinhauer.
"It's about understanding the basic laws of physics," he adds. "It is not clear to me how useful the research will be for everyday life, but we, as human beings, want to understand how the universe works."
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Elbentzo,
Thanks
Nitzan,
The answer is "yes", "no" and "don't know", depending on how you look at it. Let's start with the most correct of the three - we don't know. There is a lot to be said about black holes theoretically (by mathematical analysis of their structure within the framework of gravity theories available to us, first and foremost general relativity) but observationally we are quite limited. Black holes are in space very far away from us - even if they were close, there are fundamental problems with observing them precisely because of their black nature. So there are a lot of assumptions and ideas we have about black holes that we just can't prove or disprove experimentally. This is exactly the tremendous importance of creating such sonic black holes - they allow us to do experiments in a controlled laboratory on objects that are very similar to black holes in space.
Now, theoretically, it seems that when quantum mechanics comes into play, then the black holes start emitting radiation. Without exaggerating too much, this radiation is actually a very, very "processed" form of the material they ingested before the emission. It is a bit difficult to explain the meaning of the word "processed", but you can think of it as if the black hole is a very large blender - what you put in is also what comes out, but it would be very difficult to look at something that comes out of the blender and say "Oh, it used to be a tomato, a cucumber , a slice of black bread, a pinch of salt and a quarter teaspoon of black pepper." So if a person falls into a black hole, he probably won't be able to come out and tell his experiences (in this sense the answer is "no"), but the material that made him up eventually came out in the form of radiation (and in this sense the answer is "yes").
Of course, even on the theoretical side there is no complete agreement regarding the behavior of black holes. There are several different opinions, several different theories, and several different interpretations for each calculation or thought experiment. But everything I've said so far is more or less in consensus, even if there is disagreement about exactly how it happens.
I didn't understand: "It is radiation emitted, theoretically, from the event horizon region of the black hole. Its existence means that matter can escape from a true black hole. "
Can matter really escape from a black hole? Not only from the Event Horizon area?
From the description of the experiment so far, it is not clear:
1. What is the source that generates the sound waves trapped inside the sonic "black hole"?
2. Where is the measurement performed that confirms that the sound waves are trapped in the sonic "black hole" and do not go out?
3. What happens to the sound waves trapped inside the "black hole" when the experiment is stopped. Is the sound energy suddenly released? And in what way?
Eyal:
I wondered too, but since the middleman is not specified, I assumed that this was the source of the matter.
When you talk about the speed of sound you are actually thinking about the speed of sound in air.
Here we are talking about the speed of sound in the middle between the clouds which is not specified (and I tend to interpret the scripture as if it is the same gas from which the clouds were formed)
"...at a speed of about three millimeters per second - more than 4 times the speed of sound..."
Is it just me or is there a fatal error here.. Is this the origin of the Technion??..
Joseph:
I can understand why you associate it with swelling but that doesn't negate the resemblance to a black hole.
It is, as mentioned, about imagination and not identity, and just as light rays cannot escape from a black hole (which will not expand), so sound waves cannot escape from the cloud (which will not expand).
This is not about the fact that the sound waves escape from the cloud but are not enough to reach the viewer, that the expansion of space makes them farther away faster (and this is what happened in the puff - the light waves left the source towards the destination and moved away from the source without getting closer to the destination) but about the fact that they do not leave the cloud at all .
Here is a link to the original news from the Technion:
http://www1.technion.ac.il/sites/all/includes/blocks/news-items/090624-bhole/news-item.htm
Not everything is clear to me either. For example, it is not clear to me how the whole matter of phonons is connected to Hawking radiation, but this is precisely the reason why I say that it is not clear to me. I don't think it's justified to jump in and claim that it's not true.
Sorry, but there is no connection between the phenomenon described here and the phenomenon calling a black guy.
What is described here is more similar to the inflation process of the universe in the seconds after the big bang. The inflation theory claims that in a certain period of time the universe expanded at a speed greater than the speed of light and this is the reason why we can see today with telescopes to a greater distance than we saw yesterday or even an hour ago. In the process of inflation, some of the matter in the universe (in the form of galaxies, etc.) moved away from us much faster than the speed of light, therefore the light from that matter has not yet reached us. In the future, light will arrive and we will be able to see galaxies that are located further away than the ones we currently perceive in telescopes.
A black hole will not expand, light radiation cannot escape from a black hole because it warps space into itself. That means that whoever advances in a straight line from the black hole onwards will always return into the black hole without being able to escape. This is not what is described here.
What the heck? It's related to the lhc that they said would destroy the earth wow I'm waiting in fear for September what will happen and I'm afraid of what the collisions of protons could do and what the result of such collisions would be because I read about it on all kinds of English sites that the accelerator experiment could cause destruction explain to me what's going on happen in an experiment and what is the black hole this year because I don't understand anything about it and I'm a little afraid.
I also didn't understand what this sonic black hole is because I didn't understand the article that much, what they discovered at the Technion is dangerous
And for those who didn't understand for themselves - this is of course only a metaphor
Speaking of pigs aha,, Noam: "pearls and radishes for pigs" special for you.
Oren, Michael
It seems to me that regarding Hugin the best thing is to adopt the saying:
"Never fight with the pig - you soften and he enjoys it"
See how it 'heard and burst'.. well, black holes are alive-dead, dead-alive...gas seekers.
Really, very interesting how the universe works!!
What happened? You smelled stench and gasped??? Or heard the eruption of some black hole??? Aha Oren.
hello hello long time no hear from you...
"Hoggin" in Hifka and stunt>"Nonsense in tomato juice"
Yes, or the neighbors...
"Black hole" in Hifka and stunt>"Shochar spirit"..
Why won't it help?
I think if he succeeds and makes it commercial it is worth a fortune
Think about a playpen with such a device, how much money parents will agree to pay sleepless nights 😉