Strange Posted September 11, 2017 Posted September 11, 2017 24 minutes ago, Handy andy said: How would a quantum black hole compare with a big black hole? Can it absorb and emit radiation in the same way suggested by Hawking. As far as we know. But a theory of quantum gravity might change this. 24 minutes ago, Handy andy said: Is space at the quantum level still viewed as smooth There are several theories that attempt to combine GR and quantum theory where space is quantised. But all test of quantised space have shown it to be smooth. 24 minutes ago, Handy andy said: At the quantum level could a black hole be the cause of entanglement, like a wormhole. ? The hypothesis is that there is some fundamental similarity between wormholes (which are purely hypothetical) and entanglement. If this turns out to be the case, I expect it will be because a theory of quantum gravity gives us a different understanding of both wormholes and entanglement. 1
MigL Posted September 11, 2017 Posted September 11, 2017 All depends on what you mean by 'quantum' Black Holes. A quantum sized BH, could have a huge amount of energy/mass. Assuming GR works to exceedingly small separations, then there should be no limits to the minimum size of a BH, other than extreme amounts of Hawking Radiation due to extreme temperature, and as a result, extremely short life of the BH. But we know that isn't the case. IIRC, intrinsic angular momentum ( spin ) conservation laws require that curved space-time has 'torsion' ( see Einstein- Cartan theory ), and this 'torsion' gives a minimum size to particles ( see Dirac's equation in a gravitational field ). IE, quantum effects modify GR to give a limiting size to BHs. A workable Quantum Gravity Theory will go a long way to clear up matters. The 'no limit' scenario would have made tiny BHs in the LHC ( as was feared by some ), but the 'minimum size' scenario means we need orders of magnitude greater energies than the LHC can provide in order to create tiny BHs. 1
Handy andy Posted September 11, 2017 Posted September 11, 2017 Thanks for the replies. You can have a laugh now:) The reason for my question is based on what I think space is perceived to be full off. Space as I understand it is absolutely full of particles (virtual and real) waves of one form or another. Every point in space has some form of matter or gravitational potential gradient associated with it. I was wondering if a quantum black hole was a lack of something filling a point in space allowing other matter to flow in to fill the empty space. I also was wondering about the shape of space to allow quantum entanglement to take place. I have an half baked idea that as quantum particles come into existence they create a 3 dimensional space for a short period before popping out of existence again, possibly into a black hole. Within that 3 dimensional space occupied by a quantum particle I visualise a 4th spatial dimension allowing all points in space to be directly connected to it. It occurred to me that this might be connected to a black hole. There is as you are aware a theory of black holes losing matter through a wormhole to a white hole, which as strange pointed out has never been observed. I was partly wondering if empty space (space full of quantum activity and gradients)is partly like a white hole constantly ejecting and absorbing matter and radiation. You will be aware I don't believe in gods, unless they are misunderstood ET's , beginnings of time or singularities, I do however understand the concept of continual creation and destruction, spatial contraction and expansion. What I am probing around for is a way matter can violate the 2nd law of thermodynamics and come into existence, providing matter for a big bang. I view the quantum world as being a chaotic unstable interlinked system, whereby peaks in energy will I think inevitably happen resulting in quarks being produced in space. I think the production of a single quark that combines with other quarks to produce hydrogen, is far more likely than all matter suddenly appearing out of a mind boggling big bang. A Big bang might have happened in the past, but where did the matter and heat it exploded into space come from. If space produces matter, and black holes destroy or redistribute it, it kind of makes sense. The big bang or god as the source of all matter is a little religious for me to accept. Something was behind it and it might have been a infinite quantum entangled computing god that produced matter form the vacuum, ie made everything.
Strange Posted September 11, 2017 Posted September 11, 2017 2 minutes ago, Handy andy said: The reason for my question is based on what I think space is perceived to be full off. Space as I understand it is absolutely full of particles (virtual and real) waves of one form or another. Every point in space has some form of matter or gravitational potential gradient associated with it. I was wondering if a quantum black hole was a lack of something filling a point in space allowing other matter to flow in to fill the empty space. That is actually quite an interesting idea (although nothing to do with black holes!) You are suggesting something like the equivalent of holes in semiconductors; a point with lower energy than the vacuum (zero point) energy. I have no idea if such a thing is possible or has been hypothesised, though. Quote The big bang or god as the source of all matter is a little religious for me to accept. The Big Bang is not the source of all matter. It is just a model describing the universe expanding and cooling over time.
Handy andy Posted September 11, 2017 Posted September 11, 2017 5 minutes ago, Strange said: That is actually quite an interesting idea (although nothing to do with black holes!) You are suggesting something like the equivalent of holes in semiconductors; a point with lower energy than the vacuum (zero point) energy. I have no idea if such a thing is possible or has been hypothesised, though. The Big Bang is not the source of all matter. It is just a model describing the universe expanding and cooling over time. Thanks now I need to drag out of storage all my old semiconductor notes.
Mordred Posted September 12, 2017 Author Posted September 12, 2017 (edited) 7 hours ago, Handy andy said: Thanks now I need to drag out of storage all my old semiconductor notes. While your at it, think about "Observer limits and range of validity within a given metric or function. Then think about observer limits to different observers, when it comes to BH's and if you understand particles as field excitations. Think about observer limits/range of validity of the metric. A model is only accurate within its range of validity, with field treatments observer limits is the effective cutoffs of a given metric. ( the above is needed to understand Hawking properly under different coordinate systems. (also applies to semiconductors in the emitter/observer limits) Edited September 12, 2017 by Mordred
Handy andy Posted September 12, 2017 Posted September 12, 2017 6 hours ago, Mordred said: While your at it, think about "Observer limits and range of validity within a given metric or function. Then think about observer limits to different observers, when it comes to BH's and if you understand particles as field excitations. Think about observer limits/range of validity of the metric. A model is only accurate within its range of validity, with field treatments observer limits is the effective cutoffs of a given metric. ( the above is needed to understand Hawking properly under different coordinate systems. (also applies to semiconductors in the emitter/observer limits) Yep lots to read and believe in, maybe I will start an OU course when I stop travelling.
Albert Einstine Posted October 31, 2017 Posted October 31, 2017 (edited) to strange a reply to your quotation of me the substance of a black hole's properties in the "observable universe" it has to be something as it sucks all light and is therefore invisible and this is the "observable universe" and only incompasses things visible so no invisible thing exists in the "observable universe" (<-technically) so it is nothingness(in the observable universe) and something in the actual universe (where things our eyes cant see exist) factoid there might be an infinitely abundant object we don't know about due to the infinity of this universe it both must exist and might'nt A literal ten year old. On 8/24/2017 at 1:58 PM, Albert Einstine said: Quote Edited October 31, 2017 by Albert Einstine -1
Strange Posted November 1, 2017 Posted November 1, 2017 (edited) 10 hours ago, Albert Einstine said: to strange a reply to your quotation of me the substance of a black hole's properties in the "observable universe" it has to be something as it sucks all light and is therefore invisible and this is the "observable universe" and only incompasses things visible so no invisible thing exists in the "observable universe" (<-technically) so it is nothingness(in the observable universe) and something in the actual universe (where things our eyes cant see exist) factoid there might be an infinitely abundant object we don't know about due to the infinity of this universe it both must exist and might'nt A literal ten year old. A black hole doesn't suck all light. It prevents light escaping, which isn't quite the same thing. We can see stars orbiting the black hole at the centre of our galaxy so it isn't sucking all their light. Also, "observable universe" isn't a description of things that are visible around us it is about the greatest distance lighten reach us from. So black holes and dark matter cannot be seen but they are still in the observable universe (if they are less than 47 billion light years away). Edited November 1, 2017 by Strange
Albert Einstine Posted November 2, 2017 Posted November 2, 2017 On 11/1/2017 at 9:20 AM, Strange said: A black hole doesn't suck all light. It prevents light escaping, which isn't quite the same thing. We can see stars orbiting the black hole at the centre of our galaxy so it isn't sucking all their light. Also, "observable universe" isn't a description of things that are visible around us it is about the greatest distance lighten reach us from. So black holes and dark matter cannot be seen but they are still in the observable universe (if they are less than 47 billion light years away). observable i'm using a new interpretation(that i made up) that means only thing observable by the human eye exist in it and black holes basically suck light it "prevents" it escaping but it look like its not there so in my new interpretation it dosent exist -2
Strange Posted November 2, 2017 Posted November 2, 2017 3 minutes ago, Albert Einstine said: observable i'm using a new interpretation(that i made up) that means only thing observable by the human eye exist in it and black holes basically suck light it "prevents" it escaping but it look like its not there so in my new interpretation it dosent exist There are lots of other things that we can't see for a variety of reasons. We can't see dark matter, neutrinos, the bodies in the Oort Cloud, stars inside the Horse Head Nebula, and on and on. Does that mean all those things don't exist? BTW, there is a project to image the black hole at the centre of our galaxy: http://www.sciencemag.org/news/2017/03/global-telescope-may-finally-see-event-horizon-our-galaxys-giant-black-hole
Albert Einstine Posted November 3, 2017 Posted November 3, 2017 (edited) k i'm wrong but did u read that i'm ten also in my universe they don't. and if a black hole were to be in my universe it would not exist (my universe is hypothetical ergo there is not much info 4 u to say i'm wrong about) actually i just made up my universe at the first post in this discussion i was incorrect but im arrogant so i tried to make myself right, i may have succeeded but at first i was incorrect sorry btw these were seperate but it merged them On 11/1/2017 at 9:20 AM, Strange said: A black hole doesn't suck all light. It prevents light escaping, which isn't quite the same thing. We can see stars orbiting the black hole at the centre of our galaxy so it isn't sucking all their light. true yet if some of their light were suck in then prevented from escaping over time i would have sucked all the light (assumaably) Edited November 3, 2017 by Albert Einstine
Strange Posted November 3, 2017 Posted November 3, 2017 32 minutes ago, Albert Einstine said: k i'm wrong but did u read that i'm ten I did see that you were ten, and I didn't;t really make any allowance for that. So sorry if I came over as a bit tough. But I think it is great that you are interested in science and imaginative to come up with ideas. Keep it up. But remember that science is quite strict about ideas being tested against evidence, so coming up with ideas is the easy bit. Good luck with your future studies. It's OK to be wrong. In fact, science is all about being wrong; that is how it progresses! Actually, growing up is all about being wrong, as well. 36 minutes ago, Albert Einstine said: true yet if some of their light were suck in then prevented from escaping over time i would have sucked all the light (assumaably) The fact we can see them means that some of the light escapes and is never sucked in. 2
Albert Einstine Posted November 3, 2017 Posted November 3, 2017 4 hours ago, Strange said: So sorry if I came over as a bit tough. i dont mind
beecee Posted November 3, 2017 Posted November 3, 2017 On 11/1/2017 at 10:05 AM, Albert Einstine said: to strange a reply to your quotation of me the substance of a black hole's properties in the "observable universe" it has to be something as it sucks all light and is therefore invisible and this is the "observable universe" and only incompasses things visible so no invisible thing exists in the "observable universe" (<-technically) so it is nothingness(in the observable universe) and something in the actual universe (where things our eyes cant see exist) factoid there might be an infinitely abundant object we don't know about due to the infinity of this universe it both must exist and might'nt A literal ten year old. A BH has what is known as a "Photon Sphere" that is a region where light/photons can actually orbit and exists at 1.5 Schwarzchild radius. eg: If you were at this position, and you shone a torch directly ahead, it would orbit and hit you on the back of the head! Stars that we see, and accretion disks actually orbit outside the photon sphere and matter is spiraled in towards the BH. For any body to maintain an orbit at 1.5 Schwarzchild radius, it must be travelling at "c" therefor any orbit within 1.5 Schwarzchild radius is impossible. A great site for knowledge, facts about BHs can be found at http://casa.colorado.edu/~ajsh/ On 9/12/2017 at 4:55 AM, Handy andy said: The big bang or god as the source of all matter is a little religious for me to accept. Something was behind it and it might have been a infinite quantum entangled computing god that produced matter form the vacuum, ie made everything. The difference being of course is that we have evidence for the BB, and the evolution of space and time, (spacetime) from t+10-43 seconds. Plus then we are able to reasonably speculate before that 10-43 seconds, and show how it could be possible for the BB to arise from nothing...https://www.astrosociety.org/publication/a-universe-from-nothing/ or http://www.phys.hawaii.edu/~dumand/post/dumandexternal/1990/HDC-3-90.pdf The point is that the universe is here, and while the above links cover speculative elements as to how it arose, I find it far far more reasonable then any magical supernatural being that supposedly is eternal.
interested Posted May 8, 2018 Posted May 8, 2018 Sorry for the question. In a black hole according to relativity time slows or stops. From a photons perspective time stops and space is reduced towards zero. Does the space inside a black hole cease to exist or become a gateway to another dimension or white hole perhaps existing in the future. If time stops in normal space time, or time ceased to exist does space cease to exist also.
Strange Posted May 8, 2018 Posted May 8, 2018 5 minutes ago, interested said: In a black hole according to relativity time slows or stops. Not really. The time dilation becomes infinite at the event horizon for an observer at infinity. For the person falling in to the black hole, nothing special happens. http://math.ucr.edu/home/baez/physics/Relativity/BlackHoles/fall_in.html 10 minutes ago, interested said: From a photons perspective time stops and space is reduced towards zero. The photon is not a valid frame of reference so this can't really be applied. Quote Does the space inside a black hole cease to exist or become a gateway to another dimension or white hole perhaps existing in the future. Spacetime inside the event horizon is not unlike space-time outside. The fact that the radial direction becomes time probably wouldn't make any difference to our perception - although that explain why you will never see anything falling in ahead of you: because it is in your future. Quote If time stops in normal space time, or time ceased to exist does space cease to exist also. Space & time are inseparable so the question doesn't really have an answer. 1
Taingorz Posted August 4, 2018 Posted August 4, 2018 One thing about space and relativity. Doesn't relativity theory say that 'space' is 'curved'. This seems to be an impossibility to me. 'space' can obviously not 'curve'. That one can calculate nonsense with tensor-calculus doesn't make something automatically true of course! -2
swansont Posted August 4, 2018 Posted August 4, 2018 1 hour ago, Taingorz said: One thing about space and relativity. Doesn't relativity theory say that 'space' is 'curved'. This seems to be an impossibility to me. 'space' can obviously not 'curve'. Fortunately, your comprehension is not the metric we use. Does a spherical or cylindrical coordinate system curve? GR uses non-Euclidean geometry. It is what describes spacetime, and it is curved. 1 hour ago, Taingorz said: That one can calculate nonsense with tensor-calculus doesn't make something automatically true of course! No. What makes it true is that experiment agrees with the theory.
Taingorz Posted August 4, 2018 Posted August 4, 2018 1 minute ago, swansont said: Fortunately, your comprehension is not the metric we use. Does a spherical or cylindrical coordinate system curve? GR uses non-Euclidean geometry. It is what describes spacetime, and it is curved. No. What makes it true is that experiment agrees with the theory. well space time really can't exist but I will leave that for now, And experiments agree? That remains to be seen then.Because it is never about the experiments but about the interpretation of the experiments of course. Just a little logical thinking can show space can not curve. You don't need higher math or experiments. -1
swansont Posted August 4, 2018 Posted August 4, 2018 1 minute ago, Taingorz said: well space time really can't exist but I will leave that for now, And experiments agree? That remains to be seen then.Because it is never about the experiments but about the interpretation of the experiments of course. No, not so much. If the theory predicts a clock will show a certain amount of elapsed time in an experiment, or the frequency will shift a certain amount, and that's what you measure, there's not a lot of room for "interpretation" 1 minute ago, Taingorz said: Just a little logical thinking can show space can not curve. You don't need higher math or experiments. Argument from personal incredulity is about as effective as a nerf® vibrator.
studiot Posted August 4, 2018 Posted August 4, 2018 5 minutes ago, Taingorz said: well space time really can't exist but I will leave that for now, So you don't exist either then? Weren't you the one who ran away from answering my question about shadows? I am still waiting for that answer.
Taingorz Posted August 4, 2018 Posted August 4, 2018 (edited) 1 hour ago, swansont said: Argument from personal incredulity is about as effective as a nerf® vibrator. Just a little logical thinking can show space can not curve. You don't need higher math or experiments. 1 hour ago, swansont said: No, not so much. If the theory predicts a clock will show a certain amount of elapsed time in an experiment, How funny! A clock doens't measure any time, of course. How can it? Time is extremely misunderstood by scientists, still they use something they don't understand all the time. The whole of physics is build on a very weak base. They don't know what 'time', is, nor what 'space' is etc, Still they build theories on this. Personally I call that 'psychotic'. Take time: "Time in physics is defined by its measurement: time is what a clock reads" lol, how circular it all is! Like nearly everything in physics. Edited August 4, 2018 by Taingorz -1
dimreepr Posted August 4, 2018 Posted August 4, 2018 29 minutes ago, Taingorz said: How funny! A clock doens't measure any time, of course. How can it? Your clock doesn't measure my time, how could it?
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