Black Hole, Event horizon

Discussion in 'Science and Technology' started by Dalia, Jul 9, 2019.

  1. james bond
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    james bond Silver Member

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    There is some evidence for this as the black hole describes a void. A void is where nothing exists even light. It is different from a vacuum where space exists and particles do not.
     
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  2. Dalia
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    Dalia Platinum Member

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    I want to give you very long information that comes from a link in French that i will translate the best possible for you and the theory of spaghetti is part of it.

    Suppose a person (Alice) observes a black hole at a great distance, safely, and sees an elephant inadvertently heading straight for that gravitational trap. She will see him approaching closer and closer to the horizon of events, slowing down due to the time dilation effects consistent with general relativity. However, she will never see him cross the horizon. Instead, she sees him stop at the edge, just as the poor pachyderm is vaporized by Hawking radiation and reduced to ashes that scatter in space. From Alice's point of view, all the information about the elephant is contained in these ashes.

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    And that's where the story is getting difficult. Alice suddenly realizes that her friend Bob was on the back of the elephant when it plunged to the black hole. When Bob himself crossed the horizon of events, the theory of relativity tells us that he did not even notice it. The horizon is not a brick wall in space. It is simply the point beyond which an observer outside the black hole can not see light escape. For Bob, who is in free fall, it looks like any other place in the universe; the attraction of gravity itself will not be sensitive to it for perhaps millions of years. Finally, when he approaches the singularity, where the curvature of space-time is taken furious madness, the gravitation master Bob, and he and his elephant will be scattered in a thousand pieces. But so far, from his point of view also the information will be preserved.

    [​IMG]

    Neither story ends well, but which one is right? According to Alice, the elephant has never crossed the horizon; she saw him approach the black hole and merge with the Hawking radiation. According to Bob, the elephant passed through and continued to glide happily for eons until it turned into spaghetti. The laws of physics require that both stories be true, yet they contradict each other. So where is the elephant, inside or outside?

    Susskind's answer is - we'll have guessed it - both. The elephant is both inside and outside the black hole; the answer depends on who the pose. "What we have discovered is that we can not talk about what is behind the horizon AND what is ahead of the horizon," says Susskind. "Quantum mechanics always forces us to substitute the word AND by the word OR Light is a wave WHERE light is a particle, according to the experiment we realize.An electron has a position OR it has an impulse, according to the same thing happens with the black holes, or the matter is said to have fallen into a black hole, looking behind the horizon, or it is described in terms of the Hawking radiation coming out of it. ".

    [​IMG]

    But, maybe there are two copies of the information? Maybe when the elephant crosses the horizon, a copy is made, and one version comes out as radiation while the other moves inside the black hole? No, because a fundamental law called the "impossibility of quantum cloning" theorem eliminates this possibility. If we could reproduce the information, we could avoid the principle of uncertainty, which nature forbids. As Susskind says, "there is no quantum photocopier". Also the same elephant must be in two places simultaneously: living inside the horizon and dead somewhere in a heap of radiant ash outside.

    The consequences are quite disturbing, to say the least. Of course, quantum mechanics tells us that the position of an object can not always be exactly indicated. But this applies to electrons for example, not to elephants! And this usually involves tiny distances, not light-years! It is this large scale that is surprising, says Susskind. In principle, if the black hole were big enough, both versions of the same elephant could be separated by billions of light-years. "It has always been thought that quantum ambiguities are a very small phenomenon," he adds. "We discover that the greater the quantum gravity becomes, the more the scales in which these ambiguities intervene become enormous".

    The fact is that the position of an object in space-time is no longer undeniable. Susskind calls this "a new kind of relativity". Einstein considered factors that were supposed to be invariable - the length of an object and the course of time - and proved that they were relative to the movement of the observer. The position of an object in space or time could only be defined relative to that observer, but its position in space-time was guaranteed. Henceforth this notion is annihilated, says Susskind, and the position of an object in space-time depends on the state of the observer's movement relative to a horizon.

    And what's more, this new type of "non-locality" only concerns black holes. It occurs anywhere a boundary separates regions of the universe that can not communicate with each other. Such horizons are more common than one might think. Any object in acceleration - the Earth, the Solar System, the Milky Way - produces a horizon. There are regions of space-time from which light will never reach us. These inaccessible regions are beyond our horizon.

    As researchers progress in their quest to unify quantum mechanics and gravitation, non-locality could point the way forward. For example, quantum gravitation should obey the holographic principle. This means that there may be redundant information and less large space-time dimensions in the theory. "This must be part of the understanding of quantum gravity," says Giddings. "It is possible that this paradox of black hole information leads to a revolution at least as profound as that generated by quantum mechanics".

    And that's not all. The acceleration of space-time itself, that is to say the fact that the expansion of the universe is accelerating, also causes a horizon. Just as we might discover that an elephant is hiding inside a black hole by decoding the Hawking radiation, perhaps we could discover what exists beyond our cosmic horizon by decoding its emissions. How? According to Susskind, the cosmic microwave background that surrounds us could be even more important than we thought. Cosmologists study this radiation because its variations tell us about the early days of the universe, but Susskind speculates that it could be a kind of Hawking radiation from the edge of our universe. If that were the case, he could teach us some things about elephants on the other side of the universe ...

    Théorie: un trou noir, son horizon des événements et... un éléphant
     
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    Last edited: Jul 11, 2019 at 2:03 AM
  3. james bond
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    james bond Silver Member

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    I think the elephant is vaporized, but comes back as Hawking radiation according to what Hawking believed in quantum theory towards his end of days. It doesn't get stretched unless it is before the event horizon. Hawking didn't believe in the event horizon anymore but an "apparent horizon." Depending on what's pulling it there, likely gravity, but he could not explain the process. I don't think it enters the black hole which is nothing there, but a circular void. It is massless. There may be light reflected from a black hole as an object approaches it as been seen, but Hawking thought it was the radiation that we see. He said the mystery still exists as the full explanation of the process would require a theory that successfully merges gravity with the other fundamental forces of nature. We still do not know how gravity works. If it is due to mass, then the classic theory would seem to be the one most valid.
     
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  4. bear513
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    bear513 Diamond Member

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    We love you..keep posting
     
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  5. fncceo
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    fncceo Gold Member

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    You would kill an elephant in the name of science?! Who do you think you are, Thomas Edison?

    [​IMG]
     
  6. zaangalewa
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    zaangalewa Gold Member

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    abu afak

    As usual you don't have any idea what you try to funny about. This question is a very important question, because in case entanglements exist a black hole is able to cause something outside of its own event horizon - in unlimited speed. Perhaps we can find out in this way what's really going on within a black hole.

     
    Last edited: Jul 12, 2019 at 9:07 AM
  7. Dalia
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    Dalia Platinum Member

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    Yes, and what about the mysterie of dark matter that would make up the Universe at 27%. Many potential candidates to compose it have been analyzed (including axions!), But this remains to be discovered and proved. Therefore, the physicist Verlinde decided to approach the problem differently: perhaps the problem comes from the fact that we do not fully understand the gravity and its operation.

    But dark matter is not the only gravitational incoherence. It should be known that the standard model of physics does not explain the effects of gravity. And this, as well as other known theories of general relativity, do not fit with our understanding of quantum mechanics, leading researchers to try to find a new "theory of everything" that could connect these two elements.

    What Verlinde does is that he has removed the gravity of the equation: he suggests that gravity is not a fundamental force of nature, but rather an emergent phenomenon, just like temperature for example, which stems from the movement of microscopic particles. In other words, gravity is a side effect, not the cause, of what happens in the Universe.
    Verlinde had proposed a radical hypothesis concerning gravity in 2010. But today, it is demonstrated in his new study that when it is considered as a side effect in the Universe and not as a fundamental force, it is not it is more essential to find a new particle that would necessarily make up dark matter: the behavior of galaxies would be sensible, even without it. "We have evidence that this new view of gravity is consistent with observations,"

    He said. "On large scales, it seems that gravity does not behave the way it is described in Einstein's theory," he adds.

    Link in French:
    Une nouvelle étude suggère que notre compréhension de la gravité serait totalement erronée
     
  8. james bond
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    james bond Silver Member

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    I used to think there was a very infinitesmally small and weak particle called the graviton, but enough time has passed and the work at LHC to find it has not been successful. So I agree that we do not fully understand gravity and how it works. If it isn't caused by the mass of an object, then what is it? The closest we came to showing gravity and mass was related was showing how gravitational waves exist in 2015. It backed up Einstein's general theory of relativity.

    "It is hypothesized that gravitational interactions are mediated by an as yet undiscovered elementary particle, dubbed the graviton. The three other known forces of nature are mediated by elementary particles: electromagnetism by the photon, the strong interaction by gluons, and the weak interaction by the W and Z bosons. All three of these forces appear to be accurately described by the standard model of particle physics. In the classical limit, a successful theory of gravitons would reduce to general relativity, which itself reduces to Newton's law of gravitation in the weak-field limit."

    Graviton - Wikipedia

    "Graviton, postulated quantum that is thought to be the carrier of the gravitational field. It is analogous to the well-established photon of the electromagnetic field. Gravitons, like photons, would be massless, electrically uncharged particles traveling at the speed of light. Since gravitons would apparently be identical to their antiparticles, the notion of antigravity is questionable. Gravitons have not been directly observed; as of 2016, observations of weak lensing of distant galaxies have placed the tightest bound on the graviton’s mass as being less than 6 × 10−32 electron volts."

    space-time | Definition & Facts

    "Einstein’s general theory of relativity (1916) again makes use of a four-dimensional space-time, but incorporates gravitational effects. Gravity is no longer thought of as a force, as in the Newtonian system, but as a cause of a “warping” of space-time, an effect described explicitly by a set of equations formulated by Einstein. The result is a “curved” space-time, as opposed to the “flat” Minkowski space-time, where trajectories of particles are straight lines in an inertial coordinate system. In Einstein’s curved space-time, a direct extension of Riemann’s notion of curved space (1854), a particle follows a world line, or geodesic, somewhat analogous to the way a billiard ball on a warped surface would follow a path determined by the warping or curving of the surface. One of the basic tenets of general relativity is that inside a container following a geodesic of space-time, such as an elevator in free-fall, or a satellite orbiting the Earth, the effect would be the same as a total absence of gravity. The paths of light rays are also geodesics of space-time, of a special sort, called “null geodesics.” The speed of light again has the same constant velocity c."

    space-time | Definition & Facts

    What I am doing is laying the groundwork for gravity. With the graviton, we assume that it goes into the 4th dimension of spacetime and is what causes gravitational waves.



    Perhaps we need to understand what the 4th dimension is?



    And also understand how our galaxy works. We have high schoolers who look 12 yrs old with an adult's voice while we have adults who believe in a flat earth. I'll still go with Einstein's GTR and gravitational waves, but beyond that it's still a mystery. Could dark energy and dark matter have something to do with it? I would think the discovery of the graviton would be our evidence for dark matter.
     

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