Hawking proved that black holes do emit a certain type of particle
A physicist from the University of North Carolina claims to have mathematically proven that black holes cannot exist. Black holes are bodies formed when certain stars collapse in on themselves, and their gravity is so strong that nothing is emitted from them, including light.
The British physicist Stephen Hawking proved about 40 years ago that black holes do emit a certain type of particles, and they are called "Hawking radiation" after him.
However, Professor Laura Mersini Houghton says that her calculations show that with the emission of radiation, the collapsing star also loses mass, and therefore cannot form a black hole. The calculations are detailed in a preliminary publication of her article, which was distributed on the Internet.
Physicists have not yet been able to definitively prove the existence of black holes, but in recent years a wealth of indirect evidence has been collected for the presence of such bodies in the centers of many galaxies.
Editor's Note - The Universe Today website was devoted to this study A skeptical opinion column, at the end he poses a question, if there is no black hole in the center of the Milky Way, how can their motion be explained As it looks in the picture in the link.
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I don't fully understand why the question should be converted to entropy. In any case, there is an answer to this question and that is inflation. In super abstracts it can be said that inflation driven by a scalar field creates a de Sitter space with a very small cosmological horizon, resulting in a very small entropy. Any initial configuration will reach this state very quickly due to entropic-thermal considerations (this is the solution with the highest entropy in relation to the parameters).
Regarding the "factor that changed the values of the point", I really don't understand the question. If you are asking what caused a singular point to expand into space on a finite scale, then the answer is exactly what I wrote in the first post. Classically there is no answer because it is impossible to study anything too close to the singularity. From a quantum point of view, it is still not clear - there are a number of ideas within the framework of string theory, for example, but none of them are supported by empirical evidence and neither are they completely closed as mathematical models.
The question should be converted to entropy. How did the universe have such low entropy in the beginning.
Socrates
No way. I was simply born in a country where the Russian language was also spoken. Despite the mosque that was in front of my house, I actually learned more Russian than Arabic.
Einstein
Where did your proficiency in the Russian language come from? Did you do your doctorate at Patrice Lumumba Moscow University?
Albanzo
Ok, now I understand what you mean.
Of course there is no debate about that.
But it is actually a description of a singular point. And hence my question was: What was the factor (in other words: how/how) that caused the change in the values of the point? Out of chaos, symmetry was created, how? gravitation? How - on the quantum level - did gravity change creation?
In modern physics, gravity is described by space being curved. That is, if you solve a physical problem while completely ignoring gravity (which is fine for 99% of physics in the world) then you simply put the problem in flat space - that is, three directions of space and one direction of time when the relationship between the directions of space is exactly like a Cartesian axis system. If we want a mathematical description, it is a space where distances are measured according to the following metric:
ds^2 = -dt^2 +dx^2 +dy^2 +dz^2
One of the most important and interesting theorems in physics is Nether's theorem (named after Emi Nether, a brilliant mathematician from the beginning of the 20th century) which says that every symmetry in physics is accompanied by a conserved magnitude. In the matrix we wrote above, there is symmetry for moving in time (that is, if we perform an experiment at t=0 and repeat it at t=1, the physics will not change and we expect to get the same result). The conserved quantity associated with this symmetry is called energy.
Without going too much into the mathematical details, in the Big Bang the matrix collapses and ceases to have necessary properties for the definition of energy (and again - if we go into mathematics for a moment - the matrix is not asymptotically flat, nor is it stationary).
The definition is simply not valid. If a size is not defined unambiguously, it cannot be called infinite...
Albanzo
OK. There is an understanding. We agree on everything.
Only one thing:
What do you mean that "the energy cannot be said to be infinite."? – Can you elaborate? Mathematical descriptions will also help. (Because in previous comments you claimed that the space is infinite, therefore I did not understand your intention).
The mathematical singularity appears at t=0, i.e. when the size of the universe is 0. It is indeed smaller than the Planck length - and this is also what I said in the previous response. Just before we get to the geometric singularity, we have a problem with the classical physical theory, so general relativity really has nothing to say about the big bang itself, but only about everything that happened a fraction of a second after it.
I don't understand the sentence "Planck length is created from it". Can you explain what you mean? Planck length is a characteristic size in nature, some number. If you meant a Planck size restoration obtained by an inflation starting from the singularity, then this is indeed the classical approach to the problem. How quantum mechanics affects the answer is still not entirely clear.
And yes, you have one mistake. Energy cannot be said to be infinite. Energy is a much more elusive quantity than we are used to in the everyday physics we encounter. In curved spaces, the definition of energy is much more tortuous. Specifically at the singular point, energy is not a well-defined quantity (does not go into the mathematical details), and it certainly cannot be said that energy is infinite.
And no, I don't know the person you mentioned.
Albanzo
How did you infer that I didn't read your comment carefully..? Well no matter.
The explanation you gave is familiar to me and I certainly accept the claim. Except for one thing:
As far as I know, the singular point is smaller than the Planck length. and from it the Planck length is formed. Its space is smaller than the Planck length. And the energy is infinite. Is there any mistake here?
(By the way, do you know Gili Naman-Marom?)
Socrates
Did you mean: Zavetra Zabstovka?
If so, the interpretation is: strike tomorrow.
First of all, it is neither matter nor energy, it is the space that has dimension 0. I used the word "matter" because I was answering a commenter who spoke in terms of matter. If you read my response carefully, you would understand that nothing is really grouped into a point - the matter, the energy, whataber - everything is spread over an infinite space whose size is 0.
Regarding the "creation" of the time space. So in classical Big Bang theory, spacetime did not emerge from the singularity. Space-time exists but its scale changes in time and the big bang is the point (mathematically singular and therefore called the "singularity") where the scale is 0. Close to this point, when the scale is the Planck length, general relativity ceases to be a reliable theory and therefore cannot tell us exactly what happened Name. For this you need a theory that explains gravity in a quantum way.
Within the framework of string theory, which is quantum gravity theory, there are several hypotheses for the big bang mechanism. None of them is proven or supported by enough evidence to have a consensus about it. Examples of works in this field are the collision of membranes (extended objects in string theory with multiple dimensions), or emergent space time. That is, mathematical structures that in a certain approximation (say, low energies) form geometry. It is a bit difficult to explain the idea without going into its mathematics, but it is actually interesting and holds that space is not a fundamental characteristic of our universe but rather the result of more abstract physical processes.
Einstein
One of the commenters told me that you speak Russian about Buria. Not long ago I heard the phrase Zafra Zabtowska, maybe you know what the phrase means? I would be happy to receive your answer.
Albanzo
By the way, it is not matter that is concentrated in a point, but energy.
Albanzo
How is space time created from the singular point?
All the idiots and fools who attack science do not notice that the computer they use to attack science is a purely scientific product.
And about the "proof". Man in the past I wrote black black cannot exist in the present, always only in the future. Because time slows down due to a compressed body. Apparently its result is exactly what I claimed already so that by the time the future comes the black hole will have already evaporated.
In any case, bodies that go towards collapsing into an ideal black hole (which does not exist in reality) can be considered a black hole for any other purpose.
Gabriel,
The Big Bang is a non-trivial physical idea, and oversimplifying it as an explosion is incorrect and will of course cause confusion. A little deeper look at the model shows that it is not correct to say that all the matter was concentrated in one point at the time of the bang, but rather that the matter was spread over a flat and infinite space (in the simplest models of the big bang) but at the time of the bang this entire space was of zero size (or of the order of Planck size) ). I know it sounds confusing, but if you look at the mathematical model, then the difference between what you say (all matter is compressed at a point and therefore there should be a gravitational collapse that prevents matter from escaping) and what the model actually says, becomes much clearer.
Gabriel
The material did not "escape" from the hole. The hole itself grows and grows and continues to grow.
Imagine we were living on a really small balloon. Now - start to inflate the balloon. We cannot escape from the rubber of the balloon and yet we see everything moving away from us. In the universe the rubber of the balloon is three-dimensional, and the inflation is along a fourth axis - the axis of time.
I'm not a physicist, but this explanation helps me imagine what really happened.
I'm not a physicist though
If a lot of matter is collected at a certain point in space then it collapses in on itself and becomes a black hole
And that black hole nothing can escape out of it not even light
So how does it happen that at the beginning of the creation of the universe there was at least an almost infinite mass grouped in one place
Then there was the big bang from which the whole universe was created
After all, at this point there had to be a black hole from which nothing escapes
Even the big bang
There is no connection between the singularity of the big bang and the singularity that sits at the origin of a black hole. Besides, as was said here before, all that is shown in the article (assuming that everything in it is true) is that a specific collapse process that was commonly thought to lead to a black hole, does not really lead to this final result. This in no way means that there are no gravitational singularities.
Your explanation is quite accurate to the article as a layman (me) reads it.
However, yes, if she is right, and this is subject to the examination of the community, that recently things are not completely closed there, there is a problem regarding the formation of our universe, because if on the way to the formation of a black hole it was not formed, then it is not clear how there was a big bang. Because there was no singularity. Obviously, she has not been declared right yet.
I think the title is really exaggerated and in the meantime the black holes should not be buried - I will explain.
What is the article actually about?
First, I recommend everyone to read the introduction of the article in question (to which Yossi referred). Although the article itself is written for physicists dealing with the subject, from the introduction it is certainly possible to learn at least what the discussion is about. For those who don't read below, my very unqualified summary:
When the space is curved, particles from different particles are created from the empty space - these are ejected out and thus carry energy with them - this is Beckenstein-Hawking radiation. If there is an old, stable black hole, the space around it is curved in a known way and in such a situation one knows how to calculate the emitted radiation (this calculation from quantum considerations is Hawking's contribution to Beckenstein-Hawking radiation).
The question now is what happens when a star collapses and a black hole is formed, in such a situation space is curved, but also changes in time and then it is not trivial to do the above calculation and a priori there is the possibility that the particles created are energetic enough to prevent the collapse and thus the formation of the black hole.
This article basically discusses the question of what are the characteristics of the radiation created when a black hole is created and whether it may prevent the creation - under the assumptions of the article the author claims that black holes are not created.
What is my opinion on the subject and why I don't worry about the black holes:
First of all, you have to wait and see that the article is accepted and no technical errors are found in it,
In any case, even if so, there are some fundamental problems in the assumptions regarding the star of the course that make it irrelevant in reality:
- The star that is placed is made of dust - that is, it is made of gas at a temperature of 0 without any pressure no matter what the density. Needless to say, it's not that realistic for a real star.
- The solution was tested for numerical symmetry and the stability of the solution was not tested. This is a very significant flaw because if the solution is unstable this means that if one atom deviates from numerical symmetry the entire solution will collapse and a black hole will be created. Therefore the question of stability is critical to the truth of the solution.
It is important to note that these two flaws are mentioned right in the summary of the article which, in a rather modest way, states that in fact the star being discussed is a mathematical object and not necessarily a physical one.
In my opinion, there is another rather critical flaw in the libraries' assumption
As mentioned, the star that is assumed to be spheroidal, that is, the star does not rotate and forms a spinless black hole. This is a very strange case since as of today the popular opinion is that stellar black holes are created from rotating stars with high spin in very energetic events called long GRBs (long gamma ray bursts). These events are very non-spherical-symmetric and we see the black holes that form in them with a very high spin. As for black holes that form straight out of spin, there may be a process that would create it but so far I don't know of an astrophysical event linked to such a creation.
in brief,
The article does not pretend to rule out black holes but only to offer a solution for a simple case of very simple black holes in a not so physical but solvable case. In light of this, it is really excessive to dismiss the existence of black holes based on an article like this.
I saw a movie on the science channel with amazing shots of the center of the Milky Way showing huge stars spinning at high speed around….. nothing. These are many stars (I saw at least a dozen) that surround "nothing" at different spatial angles. (From right to left, from top to bottom, and inside out at different angles.
If the scientist mentioned above is right - perhaps it is a slow disintegration of a black hole. time will tell.
It's in Kenstein!! Not Hawking
I really don't give a shit
The original article for those who want to download it
http://arxiv.org/pdf/1406.1525v1.pdf
A short 4 page article that is worth reading. Not arrogant, calculating. I'm not saying she's right, only that physics is sometimes seen as a concept and maybe she's right.
I don't understand enough.
As is the habit of science, what starts with a belief about what a black hole is (Hawking) later turns into another belief that a black hole exists, but actually something a little different from what we thought, and so on. For those who feel and for those who don't, science is a form of faith and it changes and evolves. Today is not far, I believe, for science to come to the conclusion that the Big Bang is actually not what we "thought until today", nor is evolution what we thought about until today. Happy holiday
And what happens if two gray holes merge?
The title is misleading.
What is claimed in the article is not that black holes do not exist, but that those that do exist were not created by the collapse of massive suns.
The claim in the article does not contradict the possibility that new black holes can be created by other processes (unknown to us), or that there are black holes that have always existed, or that there are black holes that were created when the universe was created (subject to physical conditions that we do not understand today).
The source of the misunderstanding is that until today there was only a known theory for the formation of a black hole from the gravitational collapse of a sun with a massive mass (above a certain size), no one has proposed other theories for the formation of black holes.
The fact that there are black holes is almost certain according to observations (since there are parts of the universe from which there is no emission of radiation). The fact that the formation of those dark parts cannot be explained does not prove that they do not exist.
The meaning in the original article is that "not a black hole" is a very massive body, but a little larger than the Schwarzschild radius which is the radius of the "event horizon". And if mass is added so that the size does reach this radius, then mass comes out in the form of Hawkins radiation, these are particles that are formed in the Schwarzschild radius area and go out, and thus the mass of the body decreases. That is, when the body is formed, there is a competition between mass collection and mass ejection so that the body grows and grows but never grows fast enough to achieve the Schwarzschild radius.
I don't understand the calculations well enough, but if this is the case, then in the center of the Milky Way there is a body of enormous mass, but it is not a black hole because its radius is slightly above the Schwarzschild radius. So there is no contradiction to the photographs of the stars that revolve around the body, only a change in the details of this massive body structure and in the process of its formation. It is impossible to see Mila because of layers of dust and star fragments that circulate around the body and hide it. Maybe someday there will be suitable telescopic technology.
Well, the esteemed professor did not prove that "black blacks" do not exist, but only that those objects of his lose their valence over time.... This does not contradict Hawking.. I don't understand where the big discovery is here?.... Can someone explain to me?
I have always argued that there is no proof of the formation of black holes because the laws of physics that are used have not been proven in the extreme environment of the black hole, therefore we cannot know how the mass and radiation will behave in the final stages of the formation of the "black hole"
Happy holiday
Yehuda Sabdarmish