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# Black Holes - Science topic

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I just watched the Leonard Susskind lecture at Berkeley,
and I wish somebody could answer me a question.
Do entangled Black holes exist in the real world?
Because it seems to me that it's pretty hard for particles (lots of them) to first become entangled and then go on to separately form 2 distinct Black holes.
And I also guess that not all the particles that comprise the two Black holes would have been entangled prior to the Black holes formation. How does that affect the entanglement of the Black holes? Let's say that only 10% of the particles that formed the 2 Black holes were entangled at their formation. Will the Black holes still be entangled. And will they be fully or partially entangled?
Remains to be worked out what the possible signal could be. Insofar as they are objects in space and time, they can be entangled; however, just like for ordinary objects, observing this can be very hard.
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Mathematically, it is posited that the cosmic or local black hole singularity must someday become of infinite density and zero size. But this is unimaginable. If an infinite-density stuff should exist, it should already have existed.
Hence, in my opinion, this kind of mathematical necessities are to be the limiting cases of physics. IS THIS NOT THE STARTING POINT TO DETERMINE WHERE MATHEMATICS AND PHYSICAL SCIENCE MUST PART WAYS?
Stam Nicolis, you have been telling me how the problem is being considered in GTR, Cosmology, etc. This is known already.
The question I have posed is for considerations towards new attempts to discuss the problem rationally and to come to possible further conclusions that might help us understand the very problems better
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In the gravitational collapsing phenomenon, if density and Kretschmann curvature scalar diverges uniformly at t-> infinity.
Is it a singularity?
if yes, then what is the nature of singularity -Black hole, Naked or eternally collapse?
if density and Kretschmann curvature scalar diverges uniformly at t-> infinity then you have a singularity. Whether it is a black hole or a naked singularity, depends on the formation or not of a regular horizon.
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Are there any other theories similar to Participatory Universe or SuperDeterministic Universe?
The universe, just like the universe of your mind... There is such a difference between the universe and the universe of your mind: the universe of your mind is subjective, A mirror image of the universe which is objective, in it the appearance of reality like thoughs in your mind... Regards,
unfortunately I have a book in connection to your question, in Hungarian did have its digital form:
There is only one essay on RG:
What is primary, being or consciousness?
Regards,
Laszlo
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It is known to all that the propagation of gravitational field is not instant.
So for black holes, the gravitational field generated by the singularity of the black holes needs time to travel before exerting gravitational pulling forces on other celestial bodies.
According to gravitational time dilation, the time near black holes are extremely dilated to infinity.
This indicates, given the limited age of the universe, the gravitational field generated by the singularity of any black holes have NOT exert any pulling forces on any celestial bodies yet.
Thus, we can conclude, it is impossible for any current celestial body to be pulled by the gravity of any black hole and orbit around a black hole. actually there should be no celestial bodies now gravitationally pulled by any black holes at all.
But, this conclusion is apparently absurd.
Any professor can explain this please?
Dear Professor Preston Guynn,
Thank you very much for your kind reply. Yes, I then try to find independent reviews. Again, I am genuinely grateful to you for your kind helps.
BR
Albert
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DARK MATTER AND DARK ENERGY
Dark Matter cannot be detected by any device invented till the date.
Dark matter is so light and spread over the universe indefinitely.
Dark Energy is much more faster than light.
Dark energy is also cannot be detected by any devices.
Dark Energy is Transparent to all other matter.
Dark Matter and dark energy emitted simultaneously when a matter converted to any type of detectable energy. This may cause the quantum tunnelling, a chance transporting detectable particle with dark energy.
• Atoms do not have empty space; all the empty space we consider are occupied by dark matter.
• Atoms- nuclear force controlled by dark matter present in the nucleus.
• Dark matter particles actually repel each other, But at certain condition(P/T) it may come close each other and make other normal particle to coagulate.
• In Black hole Dark matter also absorbed and helps to convert another type of new elements by fusion reaction of the matter in black hole.
• Finally, all black hole will collapse and converted to singularity.
• Then A new universe will form after another big bang, the second universe
• The new universe may consist of new elements which are not in the periodic table available now.
• The next generation universe may contain electromagnetic energy without LIGHT ENERGY.
Dark matter come from "vacuum". It's formed inside some mass distribution when ordinary matter separate the exterior space(vacuum) from interior space(vacuum). The interior "cut off vacuum" undergoes a phase tranformation, become attaractive. This is my idea...
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Incoming material approaching the event horizon of a black hole when viewed from a stationary object somewhere outside the hole travels at the speed of light. At the same time, the event horizon of a black hole rotates at speeds close to the speed of light. How do these factors relate to the dynamics at the black hole's surface? What is the relationship between incoming matter and centripetal force?
Charles Wohl Very interesting link. 84% of the speed of light which is around 252,000 km/sec. I am not clear what they think is moving at this speed. Is it at the surface of the neutron star inside the black hole?
Looking at the link and other links related to the same galaxy black hole I am sceptical about their conclusion of 84% of the speed of light.
We know that it is possible for objects like stars to orbit a black hole. That is how the Milky Way galaxy black hole was found. This is a bit like what you were proposing where rotational velocity and gravitational pull cancels. But is not in a particular place like a skin because it depends on the rotational velocity.
They do talk about an ergosphere around a black hole. I find it difficult to distinguish in some of these articles between speculation and solid science but it is all most interesting.
I think we still haven’t resolved the question of why matter should be falling into a black hole at the speed of light. Do you think this is correct and necessarily so in all cases?
Richard
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I have not directly studied Hauwking's radiation, I only know what my teachers told me about it and which is constantly repeated in popular science texts.
It says: If a pair of virtual particles materializes on the black hole's event horizon, one of them may move away, while the other falls into the hole, so that the black hole emits a radiation and gradually evaporates.
I don't understand this evaporation process as in the process the black hole gains a particle, so that its mass increases instead of decreasing. Worse, the universe outside the hole is also gaining mass to the detriment of the void.
Could somebody help?
Preston Guynn In your referenced articles you mentioned a mismatch between the amount of dark matter needed for the galaxy rotation curves and that needed for gravitational lensing.
I think the problem is that the assumption of 2 radii of the visible galaxy is too restrictive. The dark matter halo of the Milky Way galaxy is believed to be out to a radius of more than a million light years.
I think if the dark matter halo size for each galaxy were increased then the rotation curves and the gravitational lensing will be consistent.
I take the view that the laws of physics and the values of the physical constants will be the same everywhere and for all time. This is a feature of the model presented here:
Richard
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We assume this to be true and this may be the reason why the rule,
[Two 3D bodies of different shapes cannot have the same volume to area ratio unless both have the same volume and area?]
applies to half-spheres but not full spheres.
Richard yes, gravitational singularity is a myth.....we have to leave it behind.
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We know that the massive stars at the ends of their lives turn up to be black holes, and we know that in the center of each galaxy there's a massive or super massive black hole. Does this mean that we can say that the galaxy is a remnant of that star after it exploded?
Yeah.. The central black hole of galaxies are supermassive.. when star explode it turns into black hole but there are few stars which turns into supermassive black hole depends on the mass of the star..
Basically these supermassive black hole surrounds all near space stuff to its gravitational field even stars , small black holes , pulsars.. which makes whole galaxy.
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Singularity in a center of a black hole is a wrong idea. Here is my preprint https://zenodo.org/record/7276801
After one month of intense research, I did not find one article that would give proof of astronomical observation has confirmed the singularity of a black hole.
A black hole is a singlar state of time, where the observer's time stops. No any observations of this exist.
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Black holes do not emite light/radiation because light/radiation cannot scape from them or because light is not generated in a black hole - since the strong gravitacional field and time change compications do not permit the energy level transition of electrons/nuclear particles (energy level colapse)?
Altair de Assis: The field equation of the GTR without the cosmological constant tells us that the STC should be radially expanding analogous to a sphere of gas cloud due to the stress/negative pressure present in the stress-energy-momentum tensor. this means the geodesics/orbits naturally are expanding resulting in non-keplerian open orbits. this is seen as precession of the orbits which is most pronounced at the perihelion. the cosmological constant was introduced by Einstein as an ad hoc fudge factor to prevent this expansion of the STC. it is the cosmological constant that is "attractive" in the classical/Newtonian sense of gravity. without it the gravity (=geometry of the STC) of GTR is "repulsive"! it is the cosmological constant, given the misnomer of having anti-gravitational effect, that is responsible for the collapse of massive stars into hyperdense objects including black holes. without it there cannot be stars let alone hyperdense objects and black holes. Einstein also assumed the gravitational field energy density to be infinitesimal due to the the extremely small value of the Gravitational Constant in order to change a 3D spatial volume, with one dimension of time, into a 2D surface with a one dimension of time (Minkowski space to apply STR) locally. This allowed him to use the Riemannian geometry and make the geodesic a 1D spatial metric (the Ricci-Einstein metric). This also allowed him to create gravitational waves moving at C when massive objects collided as they carried away energy and momentum from the collisions similar to the EM waves. The GF energy density of the GTR is infinitesimal or almost zero similar to or close to a photon. the stress/negative pressure part of the tensor on the right side of the field equation is the tension of the geodesics as they are slowly expanding. Einstein could not give a non-infinitesimal energy density to the GF as that would result in the energy density having it's own GF which in turn will have it's GF ad infinitum and thereby resulting in a GF with infinite energy density. All these and more fudging was carefully done by him because he wanted to fit the theory to his preconceived ideas about gravity. when he realized that the STC became unstable by becoming naturally expansive he again fudged the left side of his field equation, describing the geometry of the STC, by adding the cosmological constant. the reason the cosmological constant is mistakenly said to have anti-gravitational effect (or DM/DE) is because the it's effect in the interstellar and intergalactic space is to prevent stars and galaxies from disintegrating due to their centrifugal forces. thanks, Mustafa.
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How would we go about specifying the position of our solar system in the universe, let us say
to an intelligence residing in an unknown part of the universe (assuming for simplicity that we can neglect the sun's motion in our galaxy).
Are there any objects or "landmarks" in the universe that could be used as known points of reference that could be used to specify our location to other intelligent beings residing in a distant part of the universe ? I am thinking of an exact analogue of longitude and latitude for the earth's surface.
An obvious answer would be simply to specify the aspect of the sky (and all known data) as seen from earth or the sun. But would this really be helpful, even if this did specify uniquely our position ?
Relativistic considerations further complicate matters.
The gold plaque on the Pioneer and Voyager craft did this using pulsars as reference points:
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I invite anyone to participate to an open discussion on the latest “findings” on Black-Holes' research. The motive of this thread is a set of articles appeared in the issue of September 2022 (p. 26-51) of Scientific American magazine under the title “Black Hole Mysteries solved”.
I have proposed a new way of thinking about Nature/Reality NCS(Natural Coordinate System) (https://www.researchgate.net/publication/324206515_Natural_Coordinate_System_A_new_way_of_seeing_Nature?channel=doi&linkId=5c0e3a7d299bf139c74dbe81&showFulltext=true) and I would ask whether you recognize any basic distinction between the above preprint(and the following Appendices) and the articles of Sci. Am.. This thread is intended to be an open– in respect to time and subject - discussion forum for the latest results of Black Hole research in order to advance new perspectives based on NCS and to put the proposals of NCS to the public assessment.
In order to seed points of arguments, I picked up some phrases from the articles of SciAm in comparison to phrases or references from NCS preprint.
1. “Paradox Resolved” by G. Musser. “Space looks three-dimensional but acts as if it were two-dimensional.” (p.30) → NCS (p.11-13, 49-52).
2. - “It says that one of the spacial dimensions we experience is not fundamental to nature but instead emerges from quantum dynamics” (p.31) → NCS (p.11-13).
3. - “Meanwhile theorists think that what goes for black holes may go for the universe as a whole” (p.31) → NCS (p.31-38, 46-47).
4. “Black Holes, Wormholes and Entanglement” by A. Almheiri- “The island itself becomes nonlocally mapped to the outside” (p.39) → NCS (p.44-47), https://www.researchgate.net/publication/345761430_APPENDIX_18_About_Black_Holes?channel=doi&linkId=5facf0fe299bf18c5b6a0d4d&showFulltext=true .
5. “A Tale of Two Horizons” by E. Shaghoulian- The whole article is about BH-Horizon, Holographic Principle, Observer, and Entropy → NCS (p.31-38, 44-47, 54-61, 6-7), https://www.researchgate.net/post/What_is_Entropy_about_Could_the_concept_of_Entropy_or_the_evaluation_of_its_magnitude_lead_us_to_the_equilibrium_state_of_a_system .
6. “Portrait of a Black Hole” by S. Fletcer- The article is about the history of the observation of Sagittarius A* (the BH at the center of Milky Way galaxy). There is no obvious connection with NCS.
PS. This discussion is NOT open for new “pet-theories” apart from NCS.(!!!)
All the articles mentioned are just essays about how not to do the calculation that has to be done-summing over metrics-and trying to guess the answer. Unfortunately the guesses, as expected, fail at some point.
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There are some famous corollaries of the equivalence principle:
1. Unruh effect is locally equivalent to Hawking radiation near the horizon, therefore "static" observer outside a blackhole will see radiation, while a free-fall observer will not.
2. Firewall, i.e., a free-fall observer will be evaporated at the horizon, is forbidden by the equivalence principle.
However, there is no physical law saying that no inertial observer will see thermal radiation or Firewall (it is bizarre, but not forbidden) in flat spacetime. The problem is the equivalence principle only restricts the evolution rule of the system but has no hint on boundary conditions. When people are using the above corollaries, are they assuming some particular boundary conditions?
How can we apply the equivalence principle in general?
Draw a curve and notice that it looks flat when observed through a microscope. In this flat domain, general relativity becomes teleparallel equivalent general relativity. Down here, the covariant spin connection is used to regularize quantum general relativity and the renormalized action becomes just the integral of the mass over time. Einstein chose to use curvature, and not torsion, to define general relativity for the sole purpose of elevating the equivalence principle. Down here we separate gravity from inertia and quantize just gravity, using the covariant spin connection as a regulator. Down here the equivalence principle is replaced by a new boson, dubbed the Lorentz boson, that couples to fermion number at gravitational strength. Down here Bell’s theorem is broken by torsion. Down here becomes macroscopic, and macroscopic entanglement is produced, before fermions localize and couple to Lorentz bosons, forcing entanglement entropy to become causal. That all happens down here. Just have a look through the microscope.
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The uniform accelerated observer sees isotropic thermal radiation with no net energy flux.(Gerlach, Ulrich H. 1983 as an example) However, people naturally believe Hawking radiation causes blackhole evaporation, assuming non-vanishing energy flux for an outside observer. The only difference is blackholes do not have a uniform gravity field, but I cannot see why it causes anisotropic radiation.
By the way, even if there is some correction causing anisotropic radiation, can we still observe some thermal radiation moving from infinity to the blackhole, which is implied by the Unruh effect?
The reason Hawking radiation from astrophysical black holes hasn't been observed and can't be observed is quantitative: The Hawking temperature is given by the expression
T/μK=0.12M_Sun/M_BH
which means that it is so low that it is drowned out.
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This finding has caused quite a stir in the physics community, as it seems to imply that information can be lost forever in a black hole. However, Hawking has since proposed a solution to this problem, known as the "information paradox." According to Hawking, the information that falls into a black hole is not actually lost, but is instead encoded on the event horizon of the black hole.
As Einstein correctly pointed out in a 1939 paper, black holes cannot form in a universe of finite age because gravitational time dilation reliably prevents the formation of an event horizon during gravitational collapse. His conclusion was respected until, some years after his death, the academic community decided that anything goes in physics. The trouble was, the pesky physics of the universe remained unchanged - and the academic community totally lost all sense of humility.
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LIGO and Virgo consortium has published results in which the mass of a merged black hole is always less than the sum of masses from the binary black holes.
GR can predict this mass loss in the Bondi-Sachs Formalism, often in the range of 5% loss while the merged event horizon is not spherical.
Not everyone agrees with published mass loss. See Tables 5.2 and 5.3 for no mass loss.
References are given for mass loss.
In my publications I compare the LIGO mass loss to theory of Polarizable Vacuum extended for high speed with reasonable agreement. In other threads I asked the question if high speed might cause part of mc2 energy to convert to pc energy. It is not widely accepted, but is allowed in the popular energy momentum equations for GR situations where curvature cannot be ignored.
In Black Hole Mergers Does Part Of Mass Energy mc2 Convert To Momentum Energy pc?
Jerry Decker Regarding super massive black holes at the centre of a galaxy it is clear that these must form as part of the galaxy formation process.
In the paper on the evolution of the universe I propose that matter formation takes place in a series of individual galaxy formation events. All matter is initially formed as neutrons but around 85% of the neutrons bond in pairs to form dineutrons which are the dark matter particle. The remaining 15% of neutrons decay to protons and electrons leading to the formation of hydrogen and helium.
Now this cloud of hydrogen and helium and dark matter will be affected by the expansion of space and by gravitational acceleration towards the centre of the galaxy. Typically around one thousandth of the total mass of the galaxy ends up forming a super massive neutron star at the centre of the galaxy. Because the Swarzschild radius lies well outside the surface of the super massive neutron star it is a super massive black hole.
Richard
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We all are told that any object (even light or information) that reaches at Black Hole's (BH's) event-Horizon can not escape from inserting into the BH.
What is the velocity at the point of passing the event-horizon?
I argue that this should be equal to c (light velocity), because if it was less than c it could be pushed, under special circumstances, with a strong, but finite, force in order to get a velocity away from BH's horizon. The result would be, at list for a small period of time, to depart from it (horizon) that is, by definition, not possible. The only way this to be avoided is the object would have velocity c when passing the horizon.
“…Formula rS=2GM/c2However, who knows whether M, G and/or c are changing with time (and how) in response to BH proximity?...”
- in the formula for the Schwarzschild radius of event horizon of an extremely exotic cosmological object “black hole” the fundamental constant c fundamentally doesn’t change, however the values of M and G can differ dependently on M, in certain sense, though, since
- in concrete cases the mass M is determined by also by gravitational mass defect 2GM2/5c2, and,
- if a mass is extremely large, then rather probably Gravity Force acts as having its strength’s value being lesser than is determined by standard G value. Description of all these, and not only, points is rather complex task, which, besides, can be solved only if in physics the really correct theory of the fundamental Nature Gravity force will be developed, with well non-zero probability it must be based on the SS&VT 2007 initial Gravity model, see https://www.researchgate.net/publication/354418793_The_Informational_Conception_and_the_Base_of_Physics , section 2.9 “Mediation of the forces in complex systems.
“…..PS: Please keep yourself as close as you can to the subject (e.g. escape velocity is irrelevant to BH horizon).……”
- that is rather strange claim; the BH /event horizon radius, etc., is the solution of the GR equations just at the initial condition that the escape velocity of some mass on this surface is equal to c. Provided this condition the GR equations solution for some mass is a black hole, radius of the surface of which is the formula above.
Again, analogously such exotic material objects exist in Newton’s gravity, by the same condition above, which have in this case the surface radius rN=GM/c2.
Again, the “black holes” are rather complex physical objects, properties of which rather essentially depend on their masses, and small [~ star mass] BH very essentially differ from larger masses. First of all in that if small BH’s real radius and the GR “event horizon” radius are practically equal, but at the mass increasing rS becomes to be more and more larger than the compact object in the center of BH, which has the mass M.
Say, the radius of the central compact mass in Milky Way SMBH is lesser than the event horizon radius rS at least in 10000 times; and, besides, in this case particles on the event horizon surface have well non-exotic energy. Say, an electron that moved from infinity to this SMBH crosses the event horizon surface having energy ~ 250 keV, i.e. moves with Lorentz factor ~ 1.5, what differs not too much from electrons on K-shell of Uranium [binding energy ~ 100 keV]. Lorentz factor of some moving with the speed of light particle is infinite, what is well larger than1.5.
Cheers
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One of the alleged difficulties of producing a so-called quantum gravity theory is due to the Heisenberg's uncertainty principle.
To probe ever tinier distances, we need ever greater energies. The problem is that if you concentrate too much mass/energy in a tiny space, the gravity of such a space becomes so huge that tiny black holes form, making the measurement impossible. Even though that assumes GR holds in the microscopic realm.
This is my question. How do we know that a high energy allocated to a tiny subatomic region of space would create a tiny black hole, since we don't have any proven UV-complete theory of quantum gravity to begin with?
How do scientists know that a high energy concentration in a tiny space would lead to a tiny black hole?
Here's a precise description of this issue (it starts at the very right time where professor Matt O'dowd explains the issue):
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Could Vaidya space-time be regarded as the evaporation of black holes? we know that ingoing Vaidya is considered as the formation of black holes. How about the outgoing Vaidya as the evaporation?
Valery Borisovich Morozov how do you consider GR without the energy conservation?
and why do you believe that BH are meaningless?
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The recent development of EHT images influenced us to study the shadow of a BH in more detail, as we can extract some information about the source. But I feel there is no strong evidence or support for determining the spin of the compact source.
Einstein: Gravitation is acceleration and geometry, without gravitons.
Ferent: Gravitation is a force mediated by gravitons.
“Black Holes emit Gravitons with negative momentum”
What is a Black Hole?
“Black Hole is Dark Matter that emits Gravitons that change Matter into Dark Matter”
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Hello everyone,
I did some research on the internet about analogies between nonlinear optics (NLO) and general relativity (GR), e.g. https://arxiv.org/pdf/0711.4796.pdf. That's already a very nice result, but is it possible to go even futher? It's a stupid idea, but since both GR and NLO are nonlinear field theories, is there any mapping between these two say at least for special solutions to the Einstein field equations? So more generally asking: Is it possible to simulate and study black holes (or other GR scenarios) with nonlinear optical setups in a earth-based laboratory? I'm really excited about this. Thanks a lot!
Philip
A recent overview, Optical analogues of black hole horizons", might be useful, too:
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We all know that accretion disks around BHs are presumably be magnetized in nature. If we consider ideal MHD, we know magnetic fields are frozen within the plasmas. Now, magnetic fields are turbulent, so can they help in raising the temperature of the disk? And is it significant?
The Boltzmann interpretation of temperature is that it is related to particle velocity. Considering that many of the particles in an accretion disk are expected to be electrically charged the magnetic field would be expected to cause a geometrically anisotropic distribution of temperature and associated thermal effects. This obviously complicates analysis of the thermal profile.
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How are calculations, the mathematics used to find astronomical objects?
Hi, I agree with Preston concerning the different methods used for planets detection. Now, concerning L1, L2 and L3, if you are talking about the Lagrange points of the Restricted Three-Body Problem. Their positions can be approximated by some simple computations. You can refer to existing literature, for e.g.:
Victor G. Szebehely and F. T. Geyling, "Theory of Orbits: The Restricted Problem of Three Bodies", 1967.
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Black Holes out of a galaxy: do they exist??? ➣➣The question is as follow.
Are there black holes outside the confines of a galaxy{*}, in the spaces between one galaxy and another???
{*}Galaxy is not meant only the Milky Way but any type of galaxy. In what way can be identified and/or measured these hypothetical extragalactic black holes???
➢➢Il quesito è il seguente.
Esistono buchi neri al di fuori dei confini di una galassia{*}, negli spazi tra una galassia e l'altra???
{*}Galassia non viene intesa la sola Via Lattea ma qualsiasi tipo di galassia.
in che modo possono essere individuati e/o misurati questi ipotetici buchi neri extragalattici???
Previous POSTS:
IF there are free floating black holes, then it is very likely that there could also be extra-galactic ones??
What are the implications for the total mass of the Universe??
🔻🔻🔻🔻🔻🔻🔻🔻🔻🔻🔻🔻🔻🔻🔻🔻🔻
First ever free-floating black hole found roaming through interstellar space. PHYS•org.
An international team of researchers has confirmed that a possible microlensing event witnessed in 2011 was due to the presence of a free-floating black hole roaming through interstellar space—the first of its kind ever observed. The group has published a paper describing their findings on the arXiv⁂preprint server.
Scientists have assumed for some time that there are many black holes wandering around in interstellar space, but until now they had not found one. This is due to the very nature of a black hole—they are difficult to spot against the black backdrop of space. Still, the evidence for their existence was strong. Prior research has shown that black holes are often formed when stars reach the end of their lives and their cores collapse, generally producing a supernova. And because many such supernova have been observed, it seemed clear that many black holes must have been created as a result.
But finding them has meant looking for lensing effects, when light from stars is bent by the pull of the black hole. Given the great distances, the lensing effect is slight, making it nearly impossible to detect using even the best modern telescopes. But luck prevailed in 2011 when two project teams looking for such lensing spotted a star that appeared to brighten for no apparent reason. Intrigued, the researchers with this new effort began analyzing the data from Hubble. For six years, they watched as the light changed, hoping that the change was due to magnification from a black hole. Then, they found something else—the position of the star appeared to change. The researchers suggest the change could only be due to an unseen moving object exerting a force that was pulling on the light as it passed by—an interstellar black hole. The researchers continued to study the star and its light, and eventually ruled out the possibility of any light coming from the lensing and also confirmed that the magnification had a long duration, both of which are prerequisites to confirming the existence of a black hole.
Taken altogether, the evidence is strong enough to confirm the sighting of a free-floating black hole. The researchers were even able to measure its size, at seven solar masses. They also found that it is traveling at approximately 45 km/second.
⁂An Isolated Stellar-Mass Black Hole Detected Through Astrometric Microlensing. arXiv:2201.13296v1. https://arxiv.org/abs/2201.13296We report the first unambiguous detection and mass measurement of an isolated stellar-mass black hole (BH). We used the Hubble Space Telescope (HST) to carry out precise astrometry of the source star of the long-duration (t_E ~ 270 days), high-magnification microlensing event MOA-2011-BLG-191/OGLE-2011-BLG-0462, in the direction of the Galactic bulge. HST imaging, conducted at eight epochs over an interval of six years, reveals a clear relativistic astrometric deflection of the background star's apparent position. Ground-based photometry shows a parallactic signature of the effect of the Earth's motion on the microlensing light curve. Combining the HST astrometry with the ground-based light curve and the derived parallax, we obtain a lens mass of 7.1 +/- 1.3 M_Sun and a distance of 1.58 +/- 0.18 kpc. We show that the lens emits no detectable light, which, along with having a mass higher than is possible for a white dwarf or neutron star, confirms its BH nature. Our analysis also provides an absolute proper motion for the BH. The proper motion is offset from the mean motion of Galactic-disk stars at similar distances by an amount corresponding to a transverse space velocity of ~45 km/s, suggesting that the BH received a modest natal 'kick' from its supernova explosion. Previous mass determinations for stellar-mass BHs have come from radial-velocity measurements of Galactic X-ray binaries, and from gravitational radiation emitted by merging BHs in binary systems in external galaxies. Our mass measurement is the first ever for an isolated stellar-mass BH using any technique.
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Dear Researchers in the field :
Does anyone know what the KAGRA Gravitational Waves Observatory it's been up to ?
KAGRA announced at the end of last year (2019) that they were ready for the kick off. And that in February this year (2020) they were turn to the sky for the first (real) observations and be ready to joing the efforts of the LIGO-Virgo collaboration.
But I haven't hear anything about KAGRA since that time.
I'm sure they had to close due to the COVID-19 pandemic, probably since March.
But, now in December, almost the end of the year, I would have expected to hear news about Observatory.
Does anyone know what is it status nowadays ? Maybe the explanation is that the facilities kept shut down almost the whole year since the pandemic.
If someone know fresh news, I'll appreciate the sharing.
Best Regards all ! :)
Discovered the following publications which i shall be reviewing and highly recommend the members here to as well. From KAGRA.
[2201.01397] Inferring Astrophysical Parameters of Core-Collapse Supernovae from their Gravitational-Wave Emission (arxiv.org)
Phys. Rev. D 105, 023004 (2022) - Merger rate density of stellar-mass binary black holes from young massive clusters, open clusters, and isolated binaries: Comparisons with LIGO-Virgo-KAGRA results (aps.org)
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I doubt a long day.
This is an imaginary suspicion!
Quantum Entanglement, if we understand it better and use it like a live tv through technology,
""" that means it's ( Quantum Entanglement ) transfer information fast like rather than light.
And note: near the black hole (where time goes much shorter than Earth) """
Now if I look from near the black hole, at things happening on Earth through a live camera that works with this Quantum entanglement technology/like, can I see things on Earth as fast-forwarded video of things happening on Earth? Or whatever else happens.
As well as watching "things near the black hole" from Earth that sounds like slow motion video?
My understanding of quantum entanglement is based on the concepts of the Spacetime Wave theory. When two particles become entangled they should be considered as a single system spread out in space. When one of the particles is measured the system collapses and the particles are no longer entangled. As a result it is found that the measurement of one of the entangled pairs affects the outcome of a measurement of the second particle.
This effect is propagated through the medium of space in the space rest frame (the frame of reference in which light travels):
The effect can be expected to propagate at the speed of light since the collapse of the system is an effect taking place with waves in the medium of space.
Richard
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Recently, black-holes were demonstrated to exert a pressure on their adjacent surrounding space (see: https://scitechdaily.com/physicists-total-surprise-discover-black-holes-exert-a-pressure-on-their-environment/amp/"Physicists’ Total Surprise: Discover Black Holes Exert a Pressure on Their Environment – SciTechDaily")
Reference: “Quantum gravitational corrections to the entropy of a Schwarzschild black hole” by Xavier Calmet and Folkert Kuipers, 9 September 2021, Physical Review D. DOI: 10.1103/PhysRevD.104.066012
In two old preprints of mine (2018 and 2020), I've also predicted that all black-holes exert a mechanical pressure on their adjacent environment which I've defined as being actually a reaction(al) force produced by a predicted universal black-hole-associated Casimir force.
More precisely, a black-hole (bh) limits the spontaneous appearance of virtual pairs (VPs) inside it and that creates a gradient between the outer and inner VPs (a positive gradient between the number of VPs per unit of volume outside vs inside that bh), a gradient translated in a (bh-associated) Casimir force (bhaCF) exerting an additional out-to-in pressure on that bh (which bhaCF also generates a reactional force that acts from inside to outside that bh, manifesting as a pressure exerted by that bh on its adjacent surrounding space). See the two preprints cited next:
[1] “(eZEH working paper - version 1.0 - 10 pages - 2.08.2018) An extended zero-energy hypothesis: on some possible quantum implications of a zero-energy universe, including the existence of negative-energy spin-1 gravitons (as the main spacetime “creators”) and a (macrocosmic) black-hole (bh) Casimir effect (bhCE) which may explain the accelerated expansion of our universe”:
[2] “(bhCE-HR-AE-ObU - version 1.0 - 18.11.2020- 2 A4 pages without references) A proposed black-hole-associated Casimir effect (bhCE) possibly inhibiting Hawking radiation (HR) and creating a spatial expansion around any macro/micro black-hole (possibly driving the global accelerated expansion of our observable universe)”:
What do you think of my proposed black-hole-associated Casimir force and its reactional force (manifested as a pressure exerted by black-holes on their surrounding space)?
If black matter is actually the sum of all existing primordial black holes (pBHs) (https://scitechdaily.com/black-holes-could-be-dark-matter-and-may-have-existed-since-the-beginning-of-the-universe/), THEN my proposed bhCE would more plausibly explain the universal accelerated expansion of our universe by the pressure exerted by all these pBHs (which pressure is the reaction force of my B-associated Casimir force).
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Doesn't the angular momentum of a BH indicate that it is not a singularity, but an extended object?
If angular momentum is conserved, where does the moment of the BH accretion disk go?
The answers I have found do not explain what rotates.
Saying that it is the black hole what rotates does not explain it.
I have read that Kerr metric black holes don't have point singularities, but this refers to mathematical equations, not physical reality.
Thank you.
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Gibbons and various other people (including myself) claim that there is no higher force value than
c^4/4G = 3.0 * 10^43 N
and no higher power than
c^5/4G = 9.1 * 10^51 W
in any physical system in nature. Research so far has shown that boosts cannot help to exceed the limit, neither do black holes, nor quasars. In all cases explored so far, horizons, in combination with the proper dimension of the bodies involved, prevent exceeding the limits. Recent attempt to construct counter-examples, found on arxiv, have been shown to contain mistakes. The maximum power radiated from the brightest black hole mergers observed so far is about 200 times smaller than the limit. Even the highest electric or magnetic forces are much smaller. The limits also appear to be related to general relativity, so that higher values might be possible in alternative theories of gravity.
What counter-example or paradox comes to mind?
How could one try to achieve a larger force or power value?
Any suggestion is of interest. The question is interesting also for another reason: it resembles the question whether there is no higher speed that c = 3.0 * 10^8 m/s for physical systems.
The issue
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HU (the Hypergeometrical Universe Theory) proposed a new model for the creation of the Universe, called The Big Pop Cosmogenesis.
Big Pop Cosmogenesis proposed that the Universe started as a Hyperspherical Metric Fluctuation, which upon partial recombination, decays into an Inner Dilation Layer and the outermost Contraction Layer.
Upon motion (at the speed of light), the Universe (Outermost Dilation) fragmented into a Blackholium (a hyperspherical hypersuperficial Black Hole). The Blackholium expanded until a phase transition into the Neutronium (neutron star density hyperspherical hypersuperficial Neutron Star).
That phase transition led to the triggering of hyperspherical harmonic acoustic oscillations. These Neutronium Acoustic Oscillations were frozen by a further reduction in density.
These frozen hyperspherical harmonic acoustic modes are what we see in the Cosmic Microwave Background.
HU uses Planck CMB observation to extract the hyperspherical harmonic acoustic modes composition.
Once one has that composition, one can calculate the density fluctuation anywhere.
The video contains the initial density fluctuation (1:100,000) that after billions of years, should create a corresponding galaxy density across ALL observable and unobservable Universe.
This means that starting from our CMB, one can create a map (based on observations of the CMB at different positions within the hyperspherical hypersuperficial Universe) that would tell you where you are anywhere where the Universe exists.
This video is less ambitious and only displays our 3D observable Universe.
I am in agreement with your implied conclusion that the Big Bang theory is not correct. I have found in my analysis that there are three assumptions in the Big Bang theory that have to be discarded:
1) The cosmological principle.
2) The assumption that all matter formed at the same time.
3) The explanation for the cause of the Cosmic Microwave Background radiation.
Once these assumptions are discarded there is considerable freedom to choose an evolution path with the age of the universe being much greater.
Richard
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I was doing pictures. It was possible to extend the numerical solution for the place that people call the Schwarzschild radius. Now you can describe how g_ {00} behaves,
1. Somewhere around 50 Schwarzschild radius it graphically merges with Schwarzschild's solution.
2. There are no peculiarities in the area of ​​the Schwarzschild radius.
3. The solution apparently exists everywhere, except for the origin.
4. g_ {00} is strictly positive (time does not stop).
5. Somewhere around 0 <r <3.4rg quickly decreases to almost zero. This is exactly close to the estimated radius of neutron stars. Time in this area almost stops.
6. So far, the solution has been extended to 0.98. The value for g_ {00} is about 10 ^ (- 260).
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To begin with, where is the mass of a black hole? If we are not able to define a location in spacetime for that mass, we could think just about the deformation of spacetime around the event horizon.
How does Hawking radiation reduce the energy and mass of the black hole? Talking about particle pairs, does the negative energy particles annihilate with the particles inside the event horizon and if so, could that interaction which occurs inside the event horizon affect the event horizon radius?
In response to your assertion "I want to discuss about the evidence for the existence of black holes," made on this ResearchGate discussion thread on August 10, 2019, I am sharing a fairly recent illustrated article which you may access by clicking on the SOURCE LINK below.
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As we know that planck's constant is universal constant so some Theoretical aspect shows the existence of particle having mass of Planck mass and dimensions having planck's length
So if you know something or any idea please feel free to express it will help me
Dear Kunal Rai
You can find Planck's formula of the Planck length at Wikipedia.
The formula shows that Planck used 2 physical quantities, de constant speed of light (c) and the gravitational constant (G). The problem is Planck's use of the gravitational constant.
If the differences between the primary forces in the universe (Standard Model) are absolute, our universe cannot transform continuously without any hitch or hike. Actually, we know that there is a unification of the primary forces. The unification will show that all the primary forces have the same origin. Thus the differences between the primary forces are related to our concept of forces and that determines the way we measure forces.
Thus Planck's use of the gravitational constant is meaningless. It is founded on unrealistic assumptions. For example gravity seems to be a vector force and vectors have no spatial dimension (1-dimensional).
So forget the Planck units. Nevertheless, Planck's constant (h), the quantum of energy, exists without any doubt.
With kind regards, Sydney
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If a black hole swallows an object of mass "m" and the initial mass of the black hole being "M", then does the total mass of black hole be = M + m?
Will the Schwarzschild radius change accordingly?
Your explanations about processes in the interior of stars uses terms of ideal gas theory. But actually, nuclear physics terms are needed.
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The paper describes the insides - the basic concepts of the Math Microscope, demonstrates the results of Super-Resolution images obtained from the Event Horizon Telescope and analyzes the results of the movement of clusters of stars that go around the Black Hole. The presence of point objects - single stars in the SR image allowed us to implement a new breakthrough approach in the problem of SR images of Powehi Black Hole in the concept of MM. In the paper, we reviewed and illustrated new concepts: Invertability Indicators and Adequacy Characteristics of discrete Models of Apparatus Functions. With these new concepts, in the inverse problem, for the first time, we were able to answer simple questions: What are we dealing with? Moreover, have we solved the inverse problem? The paper demonstrates the “manual solution” of the problem of Reconstruction of AFs and Super-Resolution on MM. In the Discussion at the end of the paper, we pose the problem of creating two Artificial Intelligences for the automated solution of the R&SR problem with the interpretation of the SR results of BH images from EHT.
Dear Pr Evgeni Terentiev,
A very interesting subject, thank you for sharing with us your experience.
Best regards,
Pr Hambaba
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Does anyone know the answer to this question: Can Black holes be a recycling process of old stellar material to produce a new one?
So the idea that I've proposed in my question we recently confirmed:
First detection of light from behind a black hole https://phys.org/news/2021-07-black-hole.html via @physorg_com
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Due to the Unruh effect the vacuum energy for the uniformly accelerated observer looks like as the equilibrium background with the Hawking-Unruh temperature $T=\hbar a/2\pi ck_B$, where $a$ is the acceleration. So we can conclude that the vacuum energy specifies a noninertial frame of reference with respect to which one can define an acceleration of any particle (note that vacuum energy does not specify any inertial frame of reference because it is uniformly distributed in a four-dimensional continuum so that all four directions for it are identical). But as it follow from Freedmann's equations a relative acceleration of two galaxies (observers) which currently are on distance R from each other is equal to $a= (\Omega_{\Lambda}-\Omega_m)H_0^2R/2$. So if in some point of the Universe the Hawking-Unruh temperature is equal to zero for the other points it is not so. Such way the vacuum energy specifies on an existence of a center of the Universe contrary to the cosmological principle which claims that the properties of the Universe are the same for all observers. In this situation it does not matter whether we can observe the Unruh radiation or not. This means that our knowledge about the Universe and the vacuum energy are incompatible.
To solve this conflict one can assume that the Universe is a hypersphere which isotropically expands on the background of 4D Euclidean space. In such case the accelerations (with respect to background) of all points belonging to hypersphere would be equal. As an alternative, we also can assume that vacuum energy does not exist in reality. Unfortunately both of these assumptions lie beyond the standard model of physics. Can someone help me solve this puzzle?
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Is gravitational waves really exist ? This is a humble declaration of Einstein that GTR is a wrong theory, then why should we blame him. It is human nature every one wants show that they are intelligent and make the best effort to impress the scientific community and the society. The same thing he also did. It is a survival tactics but when they have reached the goal usually they try to correct their wrong by some way or other to remove their guilt. So it is high time that we should forgive Einstein by declaring that his theory was wrong and that there is no gravitational waves by agreeing with his later results. We should council (both Scientifically and Psychologically ) the people who detected the gravitational waves, that they are merely weak radio waves. All students from the school level itself, should be asked to take oath that they should fall into this black hole since we need give Einstein's soul a rest.
Transcript of dialogical exchange regarding disputed recommendation I made:
[Unedited Copy-and-Paste Quoted material follows]
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• 📷Christian Cordato you22 hours agoDear Miss Watanabe, I do not know you. Thus, can you kindly clarify why did you recommend the crackpottery of Mr. Stefan Ruster against me? Regards, Prof. C. Corda
• 📷Nancy Ann Watanabe11 hours agoChristian Corda, I would like to answer your inquiry; however, I have to ask that you clarify the dialogical exchange to which you refer. A cut-and-paste will suffice. In general, I agree with the ResearchGate rule with respect to the use of polite, proper, and scientifically referential language. Your diction in the subject heading to your inquiry suggests a breach of social propriety because it looks just like name-calling. ResearchGate is a platform designed and intended to provide scientists with different opportunities and venues for social networking. Dr. Nancy Ann Watanabe, Ph.D. June 22, 2021, reply to inquiry of C. Corda
• 📷Christian Cordato you2 hours agoDear Nancy Ann Watanabe, You recommended the statement of Mr. Ruster: "Dear Christian, no more comment from my side to your nonsense." Which was a reply to my previous comment: "Mr. Soosaleon dos not know the basics of Riemannian geometry and of a lot of other things. The same happens for Mr. Ruster....." Notice that both Mr. Ruster and Mr. Soosaleon are two crackpots who claim that Einstein's theory of relativity is wrong (sic) while I am a known expert of that theory. Respecting the use of polite, proper, and scientifically referential language is different than endorsing crackpottery. Best wishes, Prof. C. Corda
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Most people would answer this question ad hoc: What a redundant question, of course a negative energy density cannot exist. But all these “ad hoc “-people oversee that the gravitational field around a mass indeed has a negative energy density. The next ad hoc remark is then, what is the sense of this question if the negative energy density of gravitational fields is fact.
After this remark we get closer to the point. The only possibility to avoid a negative energy density around a mass is the existence of a gravitational field with positive energy density, which overlays all gravitational fields around masses.
The existence of such a gravitational field, omnipresent, with a positive energy density, and nearly homogenous in the whole universe, now has consequences, which we consider with the following points.
(1) The existence of such a field requires a closed finite universe. A positive energy density cannot fill an infinite volume.
(2) A gravitational field with a positive energy density X allows the propagation of gravitational waves with a wave pressure p and an energy density E with p=√(EX). This is a result of wave theory.
(3) Every grain of mass, including atomic nuclei, electrons, and photons moves a small dent through the homogenous background field with energy density X. This movement leads to post pulse oscillations. “Generation of post pulse oscillations” is a wave excitation mechanism completely different from “quadrupole radiation”, which currently is proposed as mechanism for gravitational wave generation.
(4) The post pulse mechanism is much more efficient. It leads to the general effect that any mechanic or electrodynamic activity generates gravitational waves. This means that X in a closed universe, is continuously growing.
(5) X as a medium, which supports wave propagation has a density, a wave pressure component, and a kinetic component. The pressure and the kinetic component are the result of wave excitation.
(6) What is the current amount of X? This amount is presumably above the range of the gravitational field around a neutron star. The Tolman-Oppenheimer-Volkoff-limit determines the value.
(7) Black holes slightly exceed this limit. But they cannot really exceed it because there remains nothing to be exceeded.
(8) Black holes become clouds of matter in a strange condition surrounded by a zone of zero gravity.
(9) The zone of zero gravity shields the cloud of matter from the oscillating background field with energy density X.
(10) The field X penetrates all kinds of matter except the extremely dense matter inside black holes. The energetic interaction of field X with normal matter including neutron star matter is a small one-way street towards X. But the matter inside a black hole is in a much denser state, susceptible for excited matter X with a pressure- and a kinetic component.
(11) The excitation of field X with gravitational waves shrinks the zone without gravitation around black hole matter. If the field X reaches the matter, the port of energy flow from X to the black hole matter is open.
(12) The consequence is that after a few million years the black hole matter becomes transformed into a widespread cloud of atomic hydrogen which provides new star fuel for the next life cycle of the universe.
If nature does not allow a negative energy density, the points (1) to (5) above are mandatory consequences. The points (6) to (12) are speculations about the amount of the gravitational energy density which surrounds us. However, the most remarkable point is that the “nonexistence of negative energy density” leads to a new model of the universe, fundamentally different to the big bang theory.
Dear Wolfgang,
It was a quick example of Energy as force for distance, the medium is indifferent. If you want density, divide it by volume and that's it.
All the negative energies that you have seen will be something similar, it is not a true negative energy in which the distance goes in the opposite direction to the force.
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Hello,
If LIGO can detect stellar to supermassive blackholes why is it difficult to detect intermediate black holes?
It appears it has only ever detected one so far: (https://www.google.com.au/amp/s/www.space.com/amp/black-hole-intermediate-size-ligo-gravitational-waves-discovery.html intermediate-size-ligo-gravitational-waves-discovery.html)
Initially I thought it was because LIGO was incapable of detecting intermediate black holes but it seems the reason is to do with black holes and not LIGO?
Im not a space scientist just curious!
Our theory about black hole is wrong, if light is not detected by certain bodies then it is electromagnetically isolated one, it is not because of any space time singularity. Space is not real and the time is measurement by EM waves and therefore analysing a body with EM waves is only by EM theory not by a pseudo theory like differential geometry which is useful only for understanding the field geometry not the space geometry as we think. Actually space is a mathematical entity and we assume accordingly to the need of the problem, may be Euclidian or non Euclidian. Trying to realise the space is the best stupidity of scientific community. I don't believe a rational mind will accept this nonsense.
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for an external observer the negative energy of the virtual particle may have positive energy relative to an observer inside the horizon. So, the energy sign (-) is frame dependent. How can I see that clearly ?
I know that for understanding this situation, we must note that the Hamiltonian is the generator of time translations. But I need more explanations.
thanks.
N.M
Nabil Mehdaoui why has it to do with the hamiltonian and its role as the generator of time translation?
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We know gravitational field distorts time and space as well as the path of the light wave. Due to this distortion, some space objects may be hidden from our observations. Is it possible even if the objects don't have high mass density like a black hole say a solar system size star system to be invisible due to the gravitational fields of other nearby objects?
Gerges Francis Tawdrous
"Let's ask another question to support this discussion
Can Uranus effect on the Earth moon motion?"
That is not even remotely related to this discussion.
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Many conservation laws are found in references, also selection rules and exclusion rules. Time passage is taken for granted, but I don't find any law that compels time to pass.
Discussions in other threads explored that possibility that passage of time is started by creating particle pairs with mass out of a swarm of photons. Mass experiences the passage of time while photons do not.
Consider an end of time. In theory all the mass would convert to photons including black holes. Entropy the arrow of time would go to zero. Distances could not be measured, and might not continue to exist. This begins to sound much like descriptions of our early universe many researchers have given, which is the reason for this question.
Roger Penrose in the book Cycles of Time and in many speeches has a dilemma that enormous length of time is required for black holes to evaporate in the manner of Stephen Hawking. A remedy might be found in some other mechanism for time to stop passing sooner.
Comparing other laws, it seems likely that time should continue to pass unless something causal occurs or a permissive is lost in physical cosmos.
In other threads topics were explored about possible ways time might stop by natural processes, and other possibilities that human activities working with extreme high energy densities might cause time to stop locally in a bubble of quantum modified space.
Researchers debate what might happen to a modified bubble, and how large it would need to be before it could begin to expand uncontrollably to fill the cosmos. Also they make theories about how a bubble might be stopped. A few researchers look to such bubbles as a source of dark energy.
The question is asking if researchers have other information or theories about passage of time.
Does Any Law Of Science Require Time To Continue Passing?
This question is closely related to Hume's paradox (David Hume, Enquiry Concerning Human Understanding). Hume asks: How do we know the future resembles the past? Because it always has in the past? That is assuming the very point in question!
Hume decided there was no rational argument for assuming the future resembles the past. The same could be said about the assumption time will continue. Schroedinger answered Hume's paradox by stating that we assume the future resembles the past because, if we hadn't, we would not have survived natural selection.
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You can see in this picture. That the magnetic effect of a black hole reflects the rotating optical magnetic force. And we can name the magnetic effect, the optical magnet effect.
Dear @RayButler,
I showed this picture so that you can know about it. And no theory is analyzed. and would be linked to one or more theories. For example, to get an equation, different numbers are needed. Similarly it is also. This is only discusion. Not an article or research item.
.
I hope you have understood.
.
Thank you...
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We did not identify the black hole in full detail yet. Does  it has an event horizon or apparent horizon. We are trying to modify our theory to resolve the problem of singularity. Is the black hole without singularity still be a black hole? What is the main character of the black hole, the singularity or the event horizon.
the singularity is unphysical. your answer can only be answered by a quantum gravity, which avoids singularities. .the singularity of a black hole is nothing but another word for the failure of geneal relativity at the planck scale. hence it makes no sense to ask for.the natue of the singularity
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How can we establish the age of a black hole? I think that black holes are the oldest and the most massive objects in the Universe. Am I right? Since nothing gets out from a black hole we cannot know the age of the matter inside it. Am I right?
If it is true that they are the oldest objects in the universe, knowing their age may give us information about the age of the universe, and, MAYBE, about when the Big Bang occurred. For instance, the Big Bang couldn't have occurred after the black holes were formed. Also, it may be that a black hole is a shard from the the object that exploded and produced the Big Bang.
I appologize, ny question may seem naive, cosmology is not my domain of competence.
A black hole is a place in space containing an enormous amount of mass packed very tightly together. These objects have so much mass — and therefore gravity — that nothing can escape them, not even light. https://t.co/NLZseL8kA3
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My question is this: One of the most extraordinary predictions of general relativity is the prediction of the singularities of black holes, where this theory stops making sense. For example, there are the classical solutions to the Einstein equations, such as the Schwarzschild, Kerr, Reissner-Nordström, and Kerr-Newman solution; and, even more, the Penrose works. But general relativity predicts them by going beyond general relativity, since at the point of singularity itself, physics and even mathematics itself lose their meaning (not to mention philosophical-conceptual aspects, such as a mass and/or electric charge concentrated at a dimensionless point). Well, as we know, general relativity is built on the mathematical foundation of differential geometry, with a manifold that must be C ^ n differentiable. Or is it that we can perhaps consider general relativity as a limit case of a more general theory that can explain the paradox of the singular point and where we can to accept a hypothesis of that explanation coincides with the infinite mathematical limit to which the theory of general relativity tends in said singularity? Or perhaps in this possible more general theory the limit of gravitational collapse is not allowed due to the existence of a minimum spatial scale?, for example, string theory or theories of discrete space-times, with a minimum spatial length, which it could be the length of Plank. I hope you can clarify this question for me. Thanks.
Carlos Oscar Rodríguez Leal This is a good question and my answer is this: General Relativity does not predict a singularity at the centre of a black hole. If you take a look at the book by Paul Dirac titled General Relativity he covers black holes and the Schwarzschild radius. There is no mathematical requirement for there to be a singularity at the centre of the sphere defined by the event horizon.
The idea of singularities in physics is to be avoided because they represent places where the laws of physics break down and we need laws of physics which apply everywhere. Singularities occur in maths but not physics.
So how did the idea of a singularity in a black hole come about? It seems that some assumptions were made in considering the collapse of stars using a concept of "pressureless dust". I heard about this concept when I watch the Nobel prize lecture video by Sir Roger Penrose. A pressureless dust will keep collapsing to a higher and higher density until all the mass is concentrated at the centre. However, pressureless dust is not the way matter behaves and there is a certain maximum density that matter can attain. This density corresponds to the density of the neutron particle.
If we take the assumption that matter cannot be crushed out of existence, then within every black hole there is matter and not a singularity.
Now we conclude that all black holes contain a neutron star of the corresponding mass. Then we can calculate the size of neutron star at which an event horizon will form at the surface and this turns out to be 3.4 solar masses. This leads to the prediction that all black holes will be greater than 3.4 solar masses and all observed neutron stars will be less than 3.4 solar masses. This prediction is confirmed by observation.
The Big Bang singularity is discarded here:
Richard
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As we know that the Law of Newton's Gravitation, gravitational force depends on the masses of interacting particles but not on their energies. And we also know photons are massless, chargeless, energy pockets.
So, there are only two possibilities. The 1st possibility is "Photons do possess trivial masses and the theory about them saying they are massless would be invalid" or the 2nd possibility is "energy can also be influenced by gravity and the law should be reformulated".
according to the interpretation of gravity by general relativity, gravity is interpreted as a property of space-time in that , in general, energy-concentrations form space-time and the geodesics in space-time are the orbits, on which energy-comcentrations move. since photons are energy concentrations, they move on geodesics as well. for black-hole solutions in general relativity, these geodesics lead directly into the center of the black hole.
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Einstein's theory of relativity is now accepted by the scientific community. In 2020, Penrose was awarded one half of the Nobel Prize in Physics for the discovery that black hole formation is a robust prediction of the general theory of relativity.
The idea that the theories of relativity or even Newton;s faulty theory of extraterrestrial gravity (as discussed in the reference above) are essential) for GPS is pure propaganda. It is the same propaganda regarding the navigation of other space exploration vehicles; which use onboard intelligent and/or remote control systems, without any systematic use of theories of gravity (GR included), like modern self-driving cars on earth.. Everything is done by the brilliant engineers, but theoretical physicists insist on their relevance and get engaged unnecessarily for scholastic exercise to big-up the theories of relativity.
The following reference shows a publication (as far back as 1997), by two engineers, who were involved in the early development of GPS.
H.F. Fliegel and R. S. DiEsposti of the GPS Joint Program Office of the Aerospace Corporation conclude:
“Except for the leading γ [gamma] factor [in their final equation], it is the same formula derived in classical physics for the signal travel time from the GPS satellite to the ground station. As we have shown, introducing the γ factor makes a change of only 2 or 3 millimeters to the classical result. In short there are no ‘missing relativity terms.’ They cancel out.” General Relativity Theory is not needed."
And the following is what our shameless mega-propagandist theoretical physicists spout out:
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The total energy of two bodies in gravitational interaction must be
(m1 + m2) c^2 - G m1 m2 / r ,
where r is the distance between them. When r is  G/c^2 times the reduced mass, the total energy and hence the total mass vanish! It is the Schwarzschild radius, so a black hole may form. Does it necessarily have zero mass? Is this not contradictory?
Recognizing the simple theory of the electron radius https://wikimili.com/en/Classical_electron_radius they only have the mass deficiency. Let the Black Hole be a matter sphere. Than its gravitational energy due to self interaction is E_g = - (3/5) G M^2/ r If r is the Schwarzschild radius than G M m /r = m c^2 /2 for the probe mass m so r = 2 G M / c^2 so we have E_g = - 3/10 M c^2. Now let M be the nuclear (rest) energy of all matter at infinity which would build the Black Hole sphere than we have:
M c^2 - 3/10 Md c^2 = Md c^2 where now Md is the dressed Black Hole Mass. So finally Md = 10/13 M so 3/13 of the constituent infinity mass deficiency.
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If quantum information is stored on the Event horizon of the black hole (according to the Holographic principle), What happens to information when black holes evaporate or merge?
Have a look at
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The black hole is a thermal system as defined by the Hawking radiation hypothesis. The black hole emits radiation at a very low temperature. I would like to know how one defines its thermal conductivity?
Dear researcher
This publication describes Some Simple Black Hole Thermodynamics by Michael C. LoPresto ( DOI: 10.1119/1.1571268)
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According to Einstein-Rosen bridge theory, shortcuts in space time where if galaxies or multiverses come close to each other, due to excess increase in electro magnetic waving some fructures like holes or tubes, not to be confused with Black holes, form as shortcut tunnels in space time where the observer can see the destination he will be arriving if he goes into the hole when he looks into the worm hole. Having strength as a theory, somehow the worm holes must be detectable, but they are not. What do Physicists think? Are worm holes detectable?
A wormhole has never been observed either directly or indirectly, but wormholes do exist in the sense that they arise in solutions to Einstein's general relativity field equations. What that means for those of us who don’t deal in Jacobian matrices every day is that we can break down the universe into its many different parts and then use mathematical equations to describe how those pieces fit together.
Those field equations are like the scaffolding or that the universe is built upon. The equations that describe how general relativity or gravity works don’t require that wormholes exist but they do allow for their existence. In other words, one possible solution to the general relativity field equations is a wormhole connecting two points in spacetime.
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According to general relativity, it is well known, and notably confirmed by Penrose and Dirac, that in the broader reference frame of the universe---that is, the reference frame astronomers use to describe their observations---a black hole would take forever to form through gravitational collapse. Yet many astrophysicists assume without qualification that supermassive black holes exist at the centers of galaxies and can be indirectly detected at the present time.
Are these theorists contradicting general relativity? Or do they assume such black holes are primordial, or were formed through unlikely non-gravitational processes? Unless primordial, it seems more consistent to assume supermassive quark or neutron stars reside at the cores of galaxies.
In fact, there is no test that would establish the presence of a black hole.
I am of Einstein's opinion that singular solutions of Einstein's equation have no physical meaning in the region where the equation is not defined, i.e. are mathematically meaningless.
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How does one combine the basis of Quantum Physics that the information cannot be destroyed with the GR statement that black holes destroy the info?
Indeed, some of these topics are open: they are connected with the theory of quantum gravity, yet to be constructed (string theory and holography, with the AdS/CFT correspondence, or loop quantum gravity are only attempts).
However, I think that the "black hole information paradox" is surrounded by too much hype. The reason is, of course, the attraction of Hawking's public figure and his wager. There was much theatre in Hawking's conceding that black hole evaporation in fact preserves information.
The paradox arises because the initial matter configuration is assumed to be constructed as a pure quantum state. As I have already remarked, this is unphysical. The article in Wikipedia about the "black hole information paradox" cites Penrose saying that the loss of unitarity in quantum systems is not a problem and that quantum systems do not evolve unitarily as soon as gravitation comes into play. This is most patent in theories of cosmological inflation.
Of course, the definitive answer to Natalia S Duxbury's question will come with the final theory of quantum gravity. We can keep looking forward to it :-)
Best wishes to the seekers of final theories!
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If the magnetic direction of any two black holes is made equal. So the capacity of attraction decreases to zero? If it becomes zero. So we can make the ability to magnetize / attract other black holes to zero or similar by using such an artificial black hole.
Dear Neeraj Meena,
I am sorry that I can't get the point of your discussion.
Will you please make the discussion more clear ?
Thanks
N Das
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(french version is available on my research profil)
In my last article "The stress energy in fluid mechanics", I explain what is current researches about fluid space-time.
On the one hand, Franck Delplace thinks that this viscosity is high. However, I do not find that coherent at all, in the sense that if a high viscosity existed, the bodies that move in space-time would be slowed by this viscosity. It would be more generally a Newtonian fluid (ie a non-turbulent fluid with a viscosity), and more precisely, a Newtonian superfluid (a non-turbulent fluid with a viscosity almost zero).
I am not an astrophysicist, but that can explain the phenomenon described by Stephano Liberatti and Luca Macione: "they thought that high energy photons that travel a great distance lose a large fraction of their energy". This loss of energy, tiny, is due to this very low viscosity, which has an influence on the movement of the bodies.
In the case of high gravity (as at the beginning of a black hole) space-time bends so much that the photons are "swallowed" in the black hole. In a certain way, space-time, which is globally a Newtonian superfluid, becomes a non-Newtonian superfluid (a turbulent fluid with a near-zero viscosity). A team of physicists then noticed that the lower the viscosity, the more the fluid is turbulent. This is observed at the beginning of a black hole, which is also easily comparable to the great entropy that has black holes.
In conclusion, I think that space-time must be superfluid. If he had a high viscosity, it would risk complicating the theoretical calculations and would require reviewing all the physics, which is not necessary at all. Space-time is a Newtonian superfluid, which becomes non-Newtonian when the gravitational force becomes very large (black hole, neutron star etc ...).
Superfluid have more coefficient of viscosity so viscosity increase and viscosity also depends on general relativity and temperature.
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6 October 2020
The Royal Swedish Academy of Sciences has awarded the Nobel Prize in Physics 2020,
with one half to
Roger Penrose
University of Oxford, UK
“for the discovery that black hole formation is a robust prediction of the general theory of relativity”
and the other half jointly to
Reinhard Genzel
Max Planck Institute for Extraterrestrial Physics, Garching, Germany and University of California, Berkeley, USA
and
Andrea Ghez
University of California, Los Angeles, USA
“for the discovery of a supermassive compact object at the centre of our galaxy”
Black holes and the Milky Way’s darkest secret
Three Laureates share this year’s Nobel Prize in Physics for their discoveries about one of the most exotic phenomena in the universe, the black hole. Roger Penrose showed that the general theory of relativity leads to the formation of black holes. Reinhard Genzel and Andrea Ghez discovered that an invisible and extremely heavy object governs the orbits of stars at the centre of our galaxy. A supermassive black hole is the only currently known explanation.
Roger Penrose used ingenious mathematical methods in his proof that black holes are a direct consequence of Albert Einstein’s general theory of relativity. Einstein did not himself believe that black holes really exist, these super-heavyweight monsters that capture everything that enters them. Nothing can escape, not even light.
In January 1965, ten years after Einstein’s death, Roger Penrose proved that black holes really can form and described them in detail; at their heart, black holes hide a singularity in which all the known laws of nature cease. His groundbreaking article is still regarded as the most important contribution to the general theory of relativity since Einstein.
Reinhard Genzel and Andrea Ghez each lead a group of astronomers that, since the early 1990s, has focused on a region called Sagittarius A* at the centre of our galaxy. The orbits of the brightest stars closest to the middle of the Milky Way have been mapped with increasing precision. The measurements of these two groups agree, with both finding an extremely heavy, invisible object that pulls on the jumble of stars, causing them to rush around at dizzying speeds. Around four million solar masses are packed together in a region no larger than our solar system.
Using the world’s largest telescopes, Genzel and Ghez developed methods to see through the huge clouds of interstellar gas and dust to the centre of the Milky Way. Stretching the limits of technology, they refined new techniques to compensate for distortions caused by the Earth’s atmosphere, building unique instruments and committing themselves to long-term research. Their pioneering work has given us the most convincing evidence yet of a supermassive black hole at the centre of the Milky Way.
CONGRATS to these great, blessed and lucky scientists
They are growing desperate to save the theory of relativity against increasing voices that speak against it, and various claims that the theory is false, all of them discarded without an adequate scientific analysis.
Alternative theories to general relativity exist, how about them? maybe some of these are able to explain those phenomena equally good or even better and with more insight. Why these are not taken seriously into consideration, why everything need to be one sided. Scientist are supposed to be open minded.
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Why is nobody talking about Stephen Crothers mathematical refutation of the existence of Black Hole from his study of general relativity? He has been very vocal giving presentation at a conference.
The biggest problem with the study of black holes is that people don’t understand Einstein’s paper on “The Foundations of the General Theory of Relativity”. Scholars don’t understand the physics that underpins his work on gravity. As such the arguments for their existence or otherwise are based around mathematics.
They should be based on the physics. Black hole proponents admit there is no physics to support them. They are a mathematical prediction from solutions to Einstein’s gravitational field equations. They point out it is the most successful theory of gravity ever forwarded. So their prediction must be correct. Then there is the recent images of the Event Horizon Telescope collaboration images. They appear to have the properties attributable to a massive black hole.
Those who want to know the physics underpinning Einstein’s gravity are referred to the following video.
In it, I present the physics of Einstein’s gravity. It requires nothing more than first year university undergraduate mathematics to match some of Einstein’s calculations. It is sufficiently simple that some senior high school students would be able to calculate the precession of Mercury’s perihelion and other effects. When the physics is understood, the mathematics is simple.
It is then relatively easy to go through Einstein’s paper and see the approximations he introduced. Within those approximations, there was nothing wrong with his work. Those criticizing his paper are illustrating they don’t understand his work. His field equations and his calculations were approximations. They did not have to be any more accurate to solve the difference between his predictions and Newton’s predictions for all events within the solar system.
However that does mean that exact solutions to approximations are not exact answers. Einstein never believed in black holes. This presentation shows why he was correct. Black hole believers have made two serious mis-interpretations of Einstein’s work. Consequently their predictions have no meaning. Worse, they are demonstrating a lack of knowledge of basic physics principles.
As for the Event Horizon Telescope images, using exact mathematics derives a metric that predicts their shape. Neither the physics nor mathematics are more complex than early undergraduate university studies in those topics.
@Mr Crothers’ work has the problem that he has uses mathematics that most people don’t understand. There are many other mathematical ways of pointing out the flaws in black hole mathematics.
As for those who want to believe in black holes, slide 42 of the presentation lists a few physics issues that should be addressed before undertaking any mathematical discussion on the work presented in it.
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What capacity can there be. When a black hole attracts a planet or other to itself. There may be a speed.
Since black holes don't exist, for the reason Einstein pointed out in his 1939 paper on the topic, perhaps the only attraction would be a Nobel Prize for doing bad science.
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If the Earth going through space would be close to a black hole, it would be gone to the center of it. Perhaps it is surrounded by low-density air
My questions are:
1. Could exist a black hole there without eating Earth surrounded perhaps by vacuum?
2. If it is possible that the black hole generates a lot of energy in the out border of the event horizon that could explain that the Earth heating is about twice the received sun power?
3. If it could explain the Earth magnetic field
4. It's mass
5. How to detect it
6. If it is true, perhaps earth temperature is higher than several million years before. It is known what was the Earth temperature then?
I make these questions because I am worried about the danger of generating a stable black hole in a scientific test. If one of them were created, it would go to the center of the Earth eating earth generating a thin tunnel.
I agree with dear Joachim Pimiskern
If we recall the TOKOMAK project, then a black hole can be artificially created. Skeptics see this end of the world.
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It is a known fact that nothing can get out of the event horizon of any black hole. If we say that gravitons mediate the gravitational force, then it should mean that gravitons that start from the singularity interact with objects outside to give rise to gravitational force. But from the very principle of black holes, gravitons should not be allowed to escape out of the event horizon. The case of a black hole should have been like that of the strong force, the gravitational force should have confined itself and no gravitational effects should have been observed due to a black hole. Why is this not the case?
:-)
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Congratulation to 2020 Physics Laureates (Roger Penrose, Reinhard Genzel, and Andrea Ghez for their discoveries about black holes).
Penrose, Genzel, and Ghez explained to the world the black holes which are a direct consequence of Einstein’s general theory of relativity. The black holes, in which all the known laws of nature cease, are still not completely understood (at least to me). Why can't light and even time escape from black holes? How are the black holes connected to the creation of galaxies?
All objects of the Universe are built in corresponds to common lows, but structures of galaxies, stars, planets possess especial properties. Every structure is a result of concentration of the Time (energetic world). In other words, every material body is the place of maximal concentration of Time. All material bodies are formed from condensation of different layers, possessing different densities: the top layers possess small densities, and theirs density increase in the direction to the Center. Gravitation is a result of condensation of layers. As known, gravitation of attraction is linked with the temp of Time and temp is linked with the density of Time. The temporal component of Time is g_00 = 1 - r_g/r in the Schwarzshield metric. We see that the Time is stopped by r = r_g = 2GM/c^2. It is the state of collapse: g_00 = 0 --- the Time is stopped. As known, the time in our w0rld flows from the past to the future, where the past is in the Center of every structure. This situation is realized in thr Schwarzshield gravitati0n, which is generalization of Newtonian gravitation of attraction. We cannot be sure that gravitation of repulsion does not exist. We can linked the gravitation of repulsion with the rotation: we know that the rotation decreases attraction: the weight of rotating bodies decreases. We habit in the region with gravitation of attraction therefore the density of layers increases to the Center, therefore the Center of Galaxy is black hole.
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Just curious if someone can provide a good explanation.
With respect to galaxy formation, many astronomers believe in the “bottom-up” model of how matter came together. In this model, small clumps merged repeatedly to form protogalaxies, and further, that many small protogalaxies clumped together to form the larger, normal galaxies we see in the nearby universe today. But others believe giant sheets of matter formed in galaxy superclusters and then broke apart into smaller units. Either way, no one yet knows whether the gas and dust that came together to make galaxies preceded star formation or whether stars formed simultaneously as the first units of matter fell together to form the earliest protogalaxies.
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I am looking for the thermodynamics of the cosmological black hole in scalar-tensor-vector gravity theories. I know how should I write and find the thermodynamical quantities and equations for such a black hole, but I do not know that can I use the Bekenstein-Hawking area law or in this framework, I should find a modified version of it. I looked for it in literature and found out that some authors have said that in this framework, we should find a modified version of this law, and an author has said that we should use the ordinary form of the law. So, what should I do?
There are modifications and how to compute the effects of the additional scalar and vector fields, in certain circumstances, is known. Examples of such calculations may be found here:
and/or here: for instance.
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