Gas around the black hole of galaxy M87

[Olias]

Good Paper if anyone is interested:http://uk.arxiv.org/abs/gr-qc/0408008

The paper deals with some aspects for Entropy Conservation for Dynamical Blackholes, from the abstract :An effective gravitational-radiation energy tensor is obtained, providing measures of both ingoing and outgoing, transverse and longitudinal gravitational radiation on and near a black hole. Corresponding energy-tensor forms of the first law involve a preferred time vector which plays the role for dynamical black holes which the stationary Killing vector plays for stationary black holes.

There are a number of top notch theorists producing some heavyweight papers recently, this is really great.

 

[ZZ Boson]

From my desktop it seems that a BH is the coldest integral body in the universe, and its BEC-like existence demands it maintain a temperature of somewhere around one-millionth K, depending on its size.

Encircling the BH, there is often an accretion disk of extreme, increasing thermal energy, but the material/mass being acquired by the BH must be cool enough, so that its low internal temperature can be maintained.

Is there an E-M-thermal "exchange of information" that only allows cool materials IN and expells the hotest materials away in high speed plasma jets?

 

[Orion1]

NASA has launched its Swift satellite, which will track huge explosions of gamma rays.

Scientists hope the satellite will provide insights into black holes.

The rays emanate from astonishingly powerful phenomena, such as supernovae - massive stars that, when all their fuel has expired, perish in a violent explosion.

Some think these blasts could be generated by colliding neutron stars, which are tiny, astonishingly dense stars, born in the rubble of a supernova.

The gravitational force of the neutron stars compresses the equivalent matter of our Sun into a radius of only 20 kilometres.

Neutron stars themselves can collapse if their mass becomes too great and then form black holes - the mighty maws of space that suck up everything, even light, and are only detectable thanks to the radiation they spray across the Universe.

Swift is a $US250 million mission, which is going ahead with British and Italian participation.

NASA says the Delta rocket launcher lifted of from Cape Canaveral at 12:16pm local time.

It was slated to enter Earth orbit one hour and 20 minutes later at an altitude of 600 kilometres.

In 1991, NASA put in orbit the 6-tonne Compton Gamma Ray Observatory, which determined that the powerful cosmic blasts originated above all outside our own galaxy.

On October 17, the European Space Agency launched its own gamma-ray telescope.

The the International Gamma-Ray Astrophysics Laboratory (Integral), was launched from the Baikonur Cosmodrome in Kazakhstan.

Reference:
http://www.abc.net.au/reslib/200411/r35954_89789.jpg
http://www.abc.net.au/news/newsitems/200411/s1248011.htm

 

[Crosson]

I'm taking a course on cosmology, my first Astro course, and we are going over all the standard Friedman equation stuff. The assumptions that the universe is homogenous and isotropic seem to be sufficient to narrow things down to 3 possibilities: +1, -1, and zero curvature.

I would like to develop a cosmological model in which the universe is isotropic and homogenously full of black holes. I think the singularities are important because they are topological properties of spacetime (and I think the topology of spacetime should affect the expansion of the universe as much as the curvature does).

Conceptually, I plan to do this by expressing both the metric and the stress-energy tensor as periodic functions of space involving the scwarchild solution, and then solving for expansion parameters. It may be hokey, but that's Cosmology

Do you guys think this could work? Has it been done? 25% of our grade is a special project, and I want to come up with something good, any suggestions would be great.

 

[marcus]

http://arxiv.org/abs/astro-ph/0603204

Getting a kick out of numerical relativity
John G. Baker, Joan Centrella, Dae-Il Choi, Michael Koppitz, James R. van Meter, M. Coleman Miller
15 pages, 2 figures, submitted to ApJ Letters
"Recent developments in numerical relativity have made it possible to follow reliably the coalescence of two black holes from near the innermost stable circular orbit to final ringdown. This opens up a wide variety of exciting astrophysical applications of these simulations. Chief among these is the net kick received when two unequal mass or spinning black holes merge. The magnitude of this kick has bearing on the production and growth of supermassive black holes during the epoch of structure formation, and on the retention of black holes in stellar clusters. Here we report the first accurate numerical calculation of this kick, for two nonspinning black holes in a 1.5:1 mass ratio, which is expected based on analytic considerations to give a significant fraction of the maximum possible recoil. Our estimated kick is 105 km/s with an error of less than 10%. This is intermediate between the estimates from two recent post-Newtonian analyses and suggests that at redshifts z > 10, halos with masses < 10^9 M_sun will have difficulty retaining coalesced black holes after major mergers."

 

[Klitwo]

Yo...Is this the mother of all Black Holes? Doubtful. Remember, there is 'No' upper limit for a Black Hole.

I found an article in 'NewScientist.com news service' where it states that the biggest Black Hole to date has been discovered. Weighing in at over 18 billion solar masses and lurking at the core of a distant Quasar called OJ287 at a distance of 3.5 billion light years. To make this article even more interesting, another 100 million solar mass Black Hole orbits it's larger brother and is expected to merge with it in another 10,000 years. It comes close enough to punch through the disc of matter twice each orbit surrounding the larger one, causing a pair of outbursts that makes OJ287 suddenly brighten. In the case of OJ287, the tremendous gravitational field of the larger Black Hole causes the the smaller Black Hole's orbit to precess at an incredible 39 degrees each orbit. The precession changes where and when the smaller Black Hole crashes through the disc surrounding it's larger sibling.

Klitwo

 

[Sci1]

There is a lot of great astrophysics now available for casual readers and viewers like me, and it is fun to speculate and cross reference ideas. The episode of the Universe (History Channel) on black holes describes that at some point matter that gets too close is stretched, rotated, and heated into a plasma around the black hole. If the black hole is supermassive then this process is speculated to also occur inside the event horizon around the singularity. Could all the space being warped around the singularity provide room for the heat to dissipate (but not escape), so that as matter approaches the singularity it loses its motional energy and the singularity itself becomes a Bose–Einstein condensate? From watching the Nova (PBS) episode on Bose–Einstein condensate, matter in such a state loses its particle nature and behaves as overlapping waves. Perhaps the singularity can be infinitely small because it is no longer a point of dense particles, but a point of overlapping waves that, unlike light, has mass and gravity. A black hole being the ultimate super heated plasma surrounding the ultimate Bose–Einstein condensate, has nice symmetry and reminded me of Dante's Inferno where the center of hell is cold.

 

[HarryWertM]

What is the understanding of PhysicsForums gurus regarding the possible shapes of black holes?

A rapidly spinning black hole should "frame drag" matter just outside the "equator" of the spinning hole, which would mean such matter would not pass any event horizon until closer to the axis of rotation. In other words, a rapidly spinning BH should "pull in" around its axis of rotation, becoming elliptical.

I found one abstract from Tanabe Makoto [[a brane theorist]] regarding elliptical black holes.

Additionally, if a heavy mass such as a neutron star passes thru the event horizon there should be a "local bulge" in the EV in the vicinity of the swallowed mass, since such mass clearly aids gravitational capture and such gravitational field change cannot propagate throughout the hole at infinite speed.
-Harry Wertmuller

 

[ACG]

A spacecraft creates two entangled particles. One of them falls into a black hole, past the event horizon.

Inside the black hole, the entangled particle interacts with a piece of matter (and if all else fails the singularity). This forces a measurement on it.

Does the wave function of the particle outside the event horizon collapse? There probably isn't any way to check if it's collapsed (because the check will collapse it for you and you'll read a collapsed result ni both cases). However, it's an interesting question...

ACG

 

[Dima6666]

As I have already stated before Opposite Thermodynamic Arrows of Time is, in my opinion, the better alternative model of thermodynamic BH comparing to perpetual mobile of Hawking radiation. So you can see below the first part of my work which was start up of that idea.

Universe, Big Bang, time and black holes - a position of the layman

“God does not play dice”

Albert Einstein

Introduction

The revolution was started almost four hundred years ago by Galilee and continued by Newton, who showed that some parts of the Universe behave not arbitrarily, and submit to exact mathematical laws. For the last years scientists have received the mathematical laws describing almost all areas of the Universe.

Nevertheless, till now in the opinion of the usual person Universe - is a riddle that is moving to understanding and the analysis, but that about which it is possible to receive only intuitive representation.

In given article I have tried to compare proceedings known to me and intuitive representation and have made a number of far not indisputable conclusions. Essentially I have not used a mathematical apparatus, except elementary formulas familiar to us from a school course of physics. Leaving behind brackets, coordination of statements of this work with existing cosmology, the theory of gravitation and statements of known authors, I have tried to include in it as much as possible positions and citations from my favorite Albert Einstein, Nobert Wiener, Azik Azimov, Stephen Hawking.


1. Look at the sky

I would like to begin the work with position expressed by Nobert Wiener in the beginning of his the most known book «Cybernetics or management and communication in animal and car». I will not declare, what contribution was made by Nobert Wiener's positions in creation of computers, but this work is interesting to us by the comparative characteristic of two sciences of astronomy and meteorology.

There is a small hymn or a song familiar to each German child:


Weiβlt du, wieviel Sternlein stehen

An dem blauen Himmelszelt?

Weiβlt du, wieviel Wolken gehen

Weithin ũber alle Welt?

Cott, der Herr, hat sie gezahlet,

Daβ ihm auch nicht eines fehlet

An der ganzen, groβen Zahl

V.Gey

In translation it means: whether “You know, how many asterisks are on a dark blue tent of heavens? Whether you know, how many clouds pass the whole world? The Lord has counted them in a purpose not to lose any of them”.

This song is interesting for the philosopher and for the historian of a science because two branches of knowledge having that similarity that both are about heavenly arch are compared in it, but absolutely different in all other relations: the astronomy, one of the most ancient science, and the meteorology, one of the youngest sciences, only now beginning to deserve the name of science. The usual astronomical phenomena can be predicted for many centuries, and exact weather forecasting for tomorrow, generally speaking, is inconvenient and in many cases is very rough.

As to a poem it is necessary to answer the first question that in certain borders we really know how many stars are in the sky. Laying aside the small disputable details, concerning some double and variable stars, it is possible to tell that a star – quite certain object rather convenient for the account and cataloguing; and if human search of stars as we can name these catalogues, stops on stars of not too weak size the thought that a certain divine search can go in this direction much further, not seems to us too ridiculous.

On the contrary, if you ask the meteorologist to give similar catalogue of clouds he will burst out laughing or, perhaps, will patiently explain that in meteorology there is concept of a cloud as not certain object remaining always more or less identical, and that if that existed, the meteorologist, does not have means to count clouds, and, in essence, he is not interested in it. The meteorologist with propensity to topology, perhaps, could define a cloud as coherent area of space in which density of water which is available in firm or a liquid state, surpasses some value. But this definition would not have for anybody the slightest value and would describe at the best rather passing condition. The meteorologist is interested actually only in statistical statements, for example: “Boston, on January, 17th, 1950, overcast of 38 %, cirrocumulus clouds”. However, there is a section of astronomy dealing, so to say, with space meteorology – research of galaxies, fogs, star congestions and their statistics, where Chandrasekhar is engaged, for example. But it is very young section of astronomy, younger then meteorology, and it lies a little away from the basic direction of classical astronomy which, outside the limits of pure classification and search, originally was engaged more in Solar system, than in the world of fixed stars. The astronomy of Solar system is closely connected with Kopernik, Kepler's, Galilee and Newton names and was the wet nurse of modern physics.

It is ideally simple science. Even before occurrence of any dynamic theory in Babylon understood that eclipses occur through the correct, predicted periods and that it is possible to learn their approach in the past and in the future. People have understood that it is better to measure time by movement of stars through their ways. In Solar system rotation of a wheel or of some wheels, as in Ptolemy’s theories of epicycles or in Kopernik theories of orbits was considered as model of all events; and in any such theory the future somewhat repeated the past. Music of spheres – palindrome – and the astronomy book are readable equally in direct and return directions. Direct and return movements of a planetarium differ with only initial positions and directions of movement of stars. At last, when Newton has reduced all it to formal system of postulates and to the closed mechanics, it has been established that organic laws do not change at replacement of a variable of time t on–t.

Thus, if to shoot a film about the accelerated movement of planets in such way that change of their position were appreciable, and then to start up this film in the opposite direction the picture of movement of planets would be nevertheless possible and concordant with Newton's mechanics. On the contrary, if we have made a movie about whirling motion of clouds in the field of front of a thunder-storm and would start up this film in the opposite direction absolutely incorrect picture would turn out. We would see descending currents there where should be ascending; the sizes of turbulent formations would increase; the lightning would precede those changes of a structure of a cloud which it usually follows, etc. indefinitely.

Where is the distinction of the nature of the astronomical and meteorological phenomena, causing all these features, and in particular why in astronomy time so obviously is reversible, and in meteorology it is so obviously irreversible? Has put first of all that the meteorological system always contains a great number of approximately identical particles, and some of them are very closely connected among themselves. On the contrary, astronomical, namely the Solar system contains only rather a small number of particles, besides rather various sizes and connection among themselves is so weak that communications of the second order do not change the general character of a picture observed by us, and communications of the higher usages can’t be considered at all. Planets moves under the conditions, more favorable to isolation of some limited system of forces, than under conditions of any physical experience which we can put in laboratory. Planets and even the Sun in comparison with distances between them are the real points. Elastic and plastic deformations of planets are so small that it is possible to consider planets as absolutely firm bodies; and even if it and not so then, internal forces of planets have rather small value by consideration of relative movement of their centers. Space in which planets move, is almost absolutely free from the substance, obstructing their traffic, and by consideration of a mutual attraction of planets it is quite possible to consider that their weights are concentrated in the centers and are constant. Deviations of gravity from the law of return proportionality to a distance square are absolutely insignificant. Positions, speeds and weights of bodies of Solar system are at any moment known with exclusive accuracy, and their future and last positions are calculated easily and precisely – at least basically, if and not always in practice. On the contrary, in meteorology the number of considered particles is so great that exact record of their initial positions and speeds is absolutely impossible, and even if we would make such record and calculate the future positions and speeds of all particles we will receive only vast set of figures which would need to be rethought radically before we could use them. Terms "cloud", "temperature", "turbulence" etc. concern not a separate physical condition, but distribution of possible conditions from which one is realized only. If we collect all simultaneous supervisions of all meteorological stations of the world these supervisions will not make one milliard share of the data necessary for the description of an instant condition of atmosphere in Newton sense. They will give only some constants compatible to infinite number of various atmospheres and at the best capable – at some aprioristic assumptions – to define in the form of distribution of probabilities only some measure on set of possible atmospheres. By means of Newton's laws or any other system of causal laws we can predict for the future moment only distribution of probabilities for constants of meteorological system, and reliability of even this prediction decreases with time increase …. »


Here I am compelled for time to distract the reader from remarkable Cybernetic of Nobert Wiener as the great scientist, have not interested in questions of cosmology and further we should try continuing a narration independently.

For this purpose, we should add Universe to objects already considered above, researches of terrestrial atmosphere and solar system.

The Universe - astronomical system, but thus, the number of objects in the Universe should be certainly very great. Proceeding this, it would be possible to assume, what the Universe system is chaotic in much bigger degree, than solar system and as object for research is closer to atmosphere, than to solar system, is it so actually?

Data of supervision shows that behavior of the Universe in very big scale is simple and not random. In 1929 Edvin Hubble has opened that remote galaxies move from us - the Universe expands. With accuracy not worse than 99,999 % micro wave background is identical in all directions. It is possible only in case if the average density of the Universe and speed of its expansion everywhere are identical. Any deviation of average density or speed of expansion in the big area would lead to differences in the background in different directions. As so in regular intervals, it is possible to describe Universe expansion by one number – distance between galaxies. Now it increases.

It is necessary to notice that in 1922, some years prior to Edvin Hubble's opening the Russian physicist A. Freedman in accuracy has predicted expansion of the Universe, A. Freedman has made two very simple assumptions concerning the Universe:

1 That it looks equally in every direction

2 Also that the given position is true irrespective of, from what point of the Universe we look

The assumption that the Universe looks equally in any direction, not absolutely represents the facts. For example, as we already know, stars of our galaxy form in the night sky a distinct light strip the Milky Way. But if we look at the remote galaxies, their number more or less equal in all parts of the sky will be similar. The first assumption of Friedman completely proves to be true the data of supervision; nevertheless, we cannot empirically confirm the second assumption of Freedman. A number of scientists, for example Stephen Hawking, even consider that we have no arguments for or against the second hypothesis of Freedman. «For today we accept the second assumption of Freedman from some kind of modesty: the citation from the book the “Shortest history of time” - Chapter 7 the Expanding Universe would seem to us absolutely surprising if the Universe would look equally in all directions only for us, but not for other observers in the Universe».

Meanwhile, in my opinion, the assumption of Freedman is a direct consequence of a principle of a relativity of Einstein taking into account the law of conservation of energy (the first law of thermodynamics).

On a being, unique accessible way for the analysis of a total energy of the Universe is the analysis of radiation coming to us from stars and galaxies etc., but the observer, speed (or which direction of movement has changed) marks change of length and frequency of radiation according to effect of Doppler. According to the General theory of a relativity the given supervision is invariant in relation to readout system, in other words, the observer cannot be assured, if he was accelerated, whether the total energy of observable object has changed. According to the theory of a relativity the total energy is equal to the sum of energy of rest (taking into account parity E=m*C^2) and kinetic energy.

For descriptive reasons we will imagine the elementary example, the observer is in a rocket A and flies in a direction of extremely massive star B (which weight is infinitely great in comparison with the Rocket) and brakes.

---------------------------------А----------------------------------В

Except a rocket and a massive star, the observer can find out nothing and according to it, considers that the rocket, he and a star is the whole Universe. According to the general theory of the relativity, that fact that the observer brakes should be invariant to increase in a total energy of a star B, in other words, according to the general theory of a relativity, there should not be a way on basis of which, it would be possible to assert that the observer has braked, instead of the total energy of a star B has increased. Really, observer, during the time when he brakes, feels acceleration in a star B direction, that can be caused both the braking fact, and that fact that the weight, and accordingly total energy (with the account of equation E=m*C ** 2) stars has increased. Similarly, at decrease in speed the observer notices shift of radiation of a star B in the red party as the length of a wave of radiation increases that can be equivalent to the fact of increase in a gravitational field, namely weights (so also a total energy) of B star. But if a B star is the Universe it contradicts the law of conservation of energy as the Universe total energy should not change. The observer knows the first law of thermodynamics in Universe terms (for the first time formulated thus Rudolf Julius Emmanuel) – namely: the Universe Total energy is constant value and makes the assumption that the system is not closed also he should find in a direction opposite to his movement other star (we name it D) with weight more or less equivalent to weight of a star B. Thus, the observer which speed varies faces a dilemma, General Theory of relativity or First law of thermodynamics is not true; or somewhere in a direction opposite to his movement there should be D star. As you understand, in a reality, the observer does not face such dilemma, as the Universe is homogeneous in any direction. Thus, we establish that positions of Freedman operate in any part of the Universe where General Theory of relativity and First law of thermodynamics operates.

D--------------------------А--------------------------------------В

In case of presence of star D the observer which speed is slowed down, sees violet displacement concerning star D and the contradiction is eliminated - he can explain his braking by simply redistribution of energy in the Universe.

Generally (non-uniform and not rectilinear movement), it is necessary to consider Mebius's transformations, but the result will not change it.

Better to say, if the Universe would not be homogeneous in all directions the observer, could confirm precisely that it was he who has braked, instead energy (weight) of surrounding stars which has changed that generally speaking departs from postulates of General Theory of relativity a little.

You will ask why, assumptions of Freedman work only in case of the Universe, instead of work in case with solar system, atmosphere or our galaxy. Neither solar system, nor terrestrial atmosphere is the closed systems, but summarized and homogeneous abnormal inclusions.

Thus, we have found out that, despite local anomalies like stars and galaxies our Universe looks homogeneous. Nevertheless, it expands with more and more high speed. It is time to ask a question, why?

 

[Dima6666]

As I have already stated before Opposite Thermodynamic Arrows of Time is, in my opinion, the better alternative model of thermodynamic BH comparing to perpetual mobile of Hawking radiation. So you can see below the second part of my work which was the start up of that idea.


1. Universe expands, why?

As we already wrote, in 1929 supervisions of Edvin Hubble have shown that spectra of the majority of galaxies show red shift – almost all star systems move away from us, moreover, the further from us a galaxy is, the faster it leaves.

To correspond to positions of Freedman, Universe expansion should remind crawling of color stains on a surface of an inflated balloon. With growth of sphere sizes the distance between any two stains increases also, but thus it is impossible to consider any of stains as the expansion centre.

Usually the Big Bang was considered to be the reason of expansion of Universe. And the fact that more remote galaxies have a greater speed can be explained that those galaxies which have received while Big Bang big speeds have departed further. But why the Universe is almost homogeneous and isotropic, but has small indignations of density, the theory of the Big bang does not explain.

Under the scenario of Big Bang the Universe has begun with singularity filled radiation at constant temperature. Thus, I would not wish to stop on the Big Bang theory also because, in singularity the general theory of a relativity is broken and accordingly this theory does not possesses predictive force, on the basis of such theory we can assume that from singularity there can be everything, everything.

If not the big explosion how to explain, process of expansion of the Universe? We will try to return to positions of thermodynamics.

One of cardinal concepts of the statistical mechanics, also application in classical thermodynamics, is the concept of entropy. Entropy is first of all property of areas of phase space; it is expressed by the logarithm from their measure of probability. For systems with a great number of particles and the conditions still remaining within practical discern ability, it means that if to take a condition with entropy below maximum and to observe that will occur, entropy almost always increases. And if to write down second law of thermodynamics in Universe terms second law would sound so - Full entropy of the Universe continuously increases.

Proceeding from definition, entropy can be interpreted as a measure of uniformity of distribution of energy.

Then it is possible to write second law of thermodynamics in a kind – uniformity of distribution of energy continuously increases in the Universe.

And what about weight, you can ask? But the matter is that from the point of view of the theory of a relativity energy and weight are equivalent (we will recollect so known parity E=m*C*C, where weight of rest of a particle, and C – a velocity of light in vacuum). Moreover, you never reflected, that the equations on basis of which processes of an exchange of weight and warmth are calculated are similar so that are usually studied in the same institute course. So, taking into account equivalence of weight of m of energy we will write down first law of thermodynamics in a kind:

Uniformity of distribution of weight (energy) continuously increases in the Universe.

The most obvious example of process of increase in uniformity of distribution of energy (weight) is thermonuclear reaction occurring on the sun, there every second 4 500 000 tons of substance turn to energy which scatters through the Universe with a velocity of light (including, some part of this energy reaches Earths, and allows mankind to exist).

Certainly, the reader can specify that in the nature it is possible to observe a lot of processes which are characterized by entropy reduction, for example formation of stars similar to the sun, ability to live of live organisms and including the person, but it only means that in practice we can be never assured that we deal with the closed system, yet we do not take for our system something smaller, than all Universe.

If to assume that the Universe has size, and entropy of the Universe (which is a measure of the maintenance of its connected useless energy, energy which cannot be transformed into work) continuously increases, finally, the size of the connected energy will reach points in which it is equal to a total energy. In this condition of the maximum entropy there will be no free energy, no processes which involve a transmission of energy can proceed, there cannot pass any work, Universe will be switched off, will stop its existence.

Let's distract from this pessimistic forecast and return to interpretation of the second law of thermodynamics.

The concept of border for such system as the Universe is not defined (Universe volume is supposed to be infinite) the requirement of increase in uniformity of weight is in essence equivalent, to the requirement of Universe expansion. Thus, taking into account equivalence of weight and energy, and the assumption of infinite volume of the Universe, the second law of thermodynamics can be written down this way:

Uniformity of distribution of weight (energy) continuously increases in the Universe, otherwise, any observer sees expansion of a surveyed part of space, in case if the surveyed part of space is great enough to level influence of local increases in density (in the form of stars and galaxies).

Certainly, this theoretical position is not such visual as the theory of the Big Bang, and many researchers can disagree with it, it has one obvious advantage versus the theory of the Big Bang we do not see in it contradictions with the general theory of a relativity and other laws of physics.

The picture of eternally expanding Universe drawn by us, not chaotic and simple would be so is boring, if not Black holes, and in the following part of work we will consider, this, one of the most interesting natural phenomena from the point of view of physical laws known to us.
3. Black Holes (and now let’s deal with some mysticism)

One of consequences of the General theory of a relativity is the fact of that the matter can bend area in itself so that this area will appear isolated from other Universe. It would turn in something that we name a black hole. Objects could fall in this black hole, but nothing can get out from there and to be pulled out, the object should move with superlight speed. Einstein was disturbed very much by a conclusion about this collapse, and he has refused to believe that it happens. But in 1939 Robert Opengamer has shown that old stars, more than twice exceeding in weight the Sun inevitably collapse when they burn out all nuclear fuel.

Today thanks to telescopes which work in x-ray and scale – ranges, we know that black holes are much more ordinary phenomenon, than was thought earlier there are thousand and thousand of black holes. Astronomers also have found out the massive black hole which weight is a million times more than weight of our sun in the centre of our galaxy.

Now, with pleasure, I will quote Nobert Wiener's well-known Cybernetics once again:

«Very interesting astronomical question concerning time direction arises in connection with astrophysical time. After all in astrophysics, at unitary supervision of the remote heavenly bodies, experience on the essence as though is not unidirectional. Why the unidirectional thermodynamics based on experimental terrestrial supervision, appears so useful in astrophysics? The answer to this question is interesting enough and very simple. We observe stars via beams or the particles of light proceeding from observable object and perceived by us. We can perceive coming light, but we cannot perceive leaving light. At least, perceptions of leaving light cannot be achieved by the same simple and direct experiment, as perceptions of coming light. We perceive coming light by means of an eye or a photographic plate. We prepare them for perception of images, isolating them from the past for some period of time: We look preliminary in darkness to eliminate traces of previous images, and we wrap plates in a black paper in order to avoid fogging. Obviously, only such eyes and such plates can be suitable; to keep the last images – all the same, what to be blind and if we needed to wrap plates in a black paper after their application and to show them before application the photography would be very difficult business. Therefore we can see stars which are letting out light for us and for whole Universe, and if there are stars developing in the opposite direction, they will draw radiations from all heavenly bodies. But gravity of light even proceeding from us, cannot be noticed, because we know past, but don’t know future. So, visible for us part of the Universe should have parities between the past and the future, concordant with existing on the Earth as business concerns light radiation. The fact that we see a star means that its thermodynamics is similar to our thermodynamics.



Very interesting mental experience – let’s imagine the reasonable being time for which flows in the opposite direction in relation to our time. For such beings no communication with us would be possible. The signal which it would send us, would reach us in a logic stream of consequences – from its point of view – and the reasons – from our point of view. These reasons already contained in our experience and would serve us as a natural explanation of his signal without the assumption that the reasonable being has sent a signal. If it has drawn to us a square, the square residues would be presented for as kind of harbingers of the square, and the square would seem for us curious crystallization of these residues, always quite explainable. Its value would seem to us so casual, as faces which we see when we are looking on mountains and rocks. Square drawing would seem to us catastrophic destruction of square – sudden, but explainable natural laws. This being would have the same representations about us. We can communicate only with worlds having the same direction of time».

Reminds something, isn't it so?

So, black holes are those heavenly objects which we do not see, thus, we don’t have any possibility to assert that fact that the thermodynamics of black holes is similar to our thermodynamics.

Moreover, according to calculations of General theory of relativity, black holes cannot radiate anything, then according to usual thermodynamic representations black holes as thermodynamic objects which temperature which is not equal to zero and should radiate.

A number of scientists, for example Stephen Hawking, for the conflict resolution even have assumed that radiation of black holes exists. God plays dice, Stephen Hawking declares, in one of the articles specifying that radiation of black holes contradicts the general theory of a relativity of Einstein. Only as we understand, this phenomenon (radiation of black holes) does not have any experimental acknowledgment; moreover, it is not absolutely clear how such acknowledgments can be received.

In connection to this, to tell the truth, it would be desirable not to consider such hypotheses. Especially, there are some more obvious acknowledgments that the thermodynamics of black holes does not correspond to our thermodynamics. One of them, transformation of weight, energy. As it was already specified, thermonuclear (nuclear) reactions connected with transformation of particles having weight of rest in the particles which do not have weights of rest, have a wide circulation in the Universe (the most obvious example - the thermonuclear reaction occurring on the sun). Whereas, the reactions connected with formation of particles having weight of rest from radiation, meet in the Universe much less often, are reversible and are connected with entropy reduction. For example, the most known reaction of formation of particles with weight of rest from radiation - pair formation, occurs in the Universe less often, than return reaction corresponding to it, annihilation of electron and positron and this parity, obviously, will worsen in course of Universe expansion. We don’t know was Feiman serious when he suggested to consider positron, as electron in the opposite direction time.

Thus, everywhere in visible part of the Universe occurs global transformation of particles having weight of rest in particles that don’t have, telling simply transformation of weight to energy.

On the contrary black holes transform radiation to weight – their cumulative weight of rest becomes greater. Such process has no analogues in the visible Universe and quite possible, it occurs contrary to thermodynamic laws known to us. The impossibility of reception of energy (information) from a black hole, does not allow even to use hypothetically a black hole as a perpetual mobile, thus, for us thermodynamics laws remain fair in any case.

The reader can have a question if transfer of information from a black hole to the observer with terrestrial thermodynamics is impossible then why we have the information on existence of a black hole. The answer is very simple, gravitational laws, are symmetric concerning time as Nobert Wiener has remarkably shown (look the first chapter or the book Cybernetics) and even if the thermodynamics of a black hole is distinct from our thermodynamics or even time in a black hole goes in an opposite direction gravitational influence of weight (energy) localized in a black hole can be estimated by the observer from the visible part of the Universe.

If thermodynamic laws in black holes are distinct from what we observe in the visible Universe a picture of expanding Universe becomes not as pessimistic as was specified in the second law of thermodynamics.

And if we will make perfect, fantastic assumption that time in a black hole moves in an opposite direction, then many contradictions seemed insoluble connected with thermodynamics of black hole are solved.

The observer being in a black hole (the dark observer) will then see, only other black holes, and objects of the visible Universe, will be black holes for him (as that light which for us will be absorbed by a black hole, the observer in a black hole will consider it leaving black hole under the name of Solar system). We do not see light leaving from us; the observer in a black hole will similarly consider that the photons coming from the sun are on the contrary radiated by his system. The assumption that time in a black hole moves in an opposite direction than in the visible Universe, surprisingly flexibly solves a problem of that the black hole system inaccessible to us from the point of view of the general theory of relativity should not be closed from the point of view of thermodynamics. Stephen Hawking, at construction of mathematical model of a black hole has shown that it should radiate particles, but it directly contradicts the theory of a relativity of Einstein as for overcoming the gravity of black hole speed of radiation should exceed a velocity of light C. In case if we assume that time direction in black holes is opposite to ours, the general relativity theory is not broken, as laws of the theory of a relativity are dissymmetric concerning time, also as Newton's laws and for the observer being in a black hole the relativity theory will be completely valid. But such observer cannot transfer this information to us that Nobert Wiener has remarkably shown in his great book, thus, the relativity theory will be true and for us. In addition such position is completely co-ordinate with concepts of dark weight (energy), so fashionable now.

The first law of thermodynamics, also is symmetric concerning the time and the first position of Freedman will be fair even for the dark observer and he should see Universe equally, so

If astronomical supervision will suddenly show that black holes settle down in space also uniformly,then assumption that time in black holes moves in the opposite direction, is not a FANTASY.

The determinacy of the Universe is one more consequence of that in other parts of the Universe time moves in opposite direction in relation to us, it only remains to agree with the great physicist - "God does not play dice".

 

[eherrtelle59]

Let's consider the 1st Law of BH thermodynamics, which relates change of mass/energy to change of horizon area, angular momentum and charge:

[itex] dM=\frac{\kappa}{8*pi} dA + \Omega dJ + \Phi dQ [\itex]


Now

Case 1) In the Reissner Nordstrom J=0 and m>Q (but only slightly larger---it's a "near" extremal solution), we consider a small amount of charge dQ. In considering amount of work to be done to bring this charge dQ in from infinity to the BH horizon, is the extremal solution m=Q possible?

Or, would [itex]\Phi[\itex] blow up, and therefore M would explode?

Case 2) Now consider the full Kerr Newman above

Here, this seems like such a scenario is possible.

Try adding a small bit of charge from infinity, and J and A could go to zero.
Try adding a small bit of rotation dJ, and Q and A could go to zero.

Apparently there is a theorem by R. Wald which addresses this, but I'm not completely sure I understand it.

Does this make sense to anyone?

 

[Gerard1]

Hey folks, I could use a little help with something. This might take more than a few minutes, so I am prepared to pay a consulting fee (say $100/hr). I don't think it will take more than an hour, so nobody gets rich.

I don't have a strong background in physics, but I am preparing a paper that makes passing mention of mass accretion by stellar-sized black holes. I have the book by Frolov and Novikov (Black Hole Physics), which I think is probably the primary text on the topic. I find the relevant equations in Chapter 9, but I have a little bit of confusion as to some of the parameters. Anyone interested in a little pocket change?

 

[Orion78]

Thanks 94JZA80 for your help.
About my question, I agree with you that the answer is yes, but if we exclude the fact that a part of the orbit of the gas is traveling away from us and another part of the orbit of the gas is traveling towards us, I mean, let pretend we don't have this specific information. If we only know that the the supermassive black hole that form the active core of M87 is a strong source of radiation made from at many wavelengths and emits a jet of energetic plasma extending at least 5000 light years and that astronomers have measured the velocity of gas which surrounds and orbits the central black hole of galaxy M87 using the emission lines of various atoms, how the orbital motion of gas about the central black hole in M87 affect its spectrum when observed from the Earth? How therefore could we see an oscillation of the emission/absorption lines in the gas' spectrum between lower frequencies (longer wavelengths) and higher frequencies (shorter wavelengths)? Might have something to do with the fact that the gas are not still but are rotating around the black hole?
Is there another observations we could make or consider in order to answer yes to the question? Thanks!

 

[Greg Bernhardt]

Definition/Summary

Mass-equivalent radius: $M$, a mathematically useful distance.

Inner Ergosphere: $R_{e-}$, the boundary where time-like intervals return to the azimuthal plane for a rotating black hole.

Inner Event Horizon: $R_-$, the radius inside which there is "normal" space-time.

Outer Event Horizon: $R_+$, the radius from which no orbit may escape the black hole.

Outer Ergosphere: $R_{e+}$, the boundary where space begins to rotate faster than the speed of light for a rotating black hole. Objects within the ergoregion cannot remain static in relation to the rest of the universe.

Radius of Photon Sphere: $R_{ph}$, the radius where a photon may be in circular orbit around the black hole. The orbit is unstable and the photon either falls into the black hole or escapes.

Radius of Marginally Bound Orbit: Apparently the radius, $R_{\text{mb}}$ where a test particle starts (as viewed from infinity) to be gravitationally bound by the black hole.

Radius of Marginally Stable Orbit: $R_{\text{ms}}$, radius of smallest circular orbit for material, usually the radius of the inner edge of the accretion disk.

Equations

Mass-equivalent radius for body of mass m:

$$M\ =\ \frac{Gm}{c^2}$$

Non-rotating uncharged spherically symmetric body (Schwarzschild solution):

$$R_-\ =\ R_+\ =\ \frac{2Gm}{c^2}\ =\ 2M$$

$$R_{ph}\ =\ \frac{3Gm}{c^2}\ =\ 3M$$

$$R_{mb}\ =\ \frac{4Gm}{c^2}\ =\ 4M$$

$$R_{ms}\ =\ \frac{6Gm}{c^2}\ =\ 6M$$

Rotating uncharged spherically symmetric body with angular momentum $aMc$ (Kerr solution):

$$R_\pm\ =\ M\ \pm\ \sqrt{M^2\ -\ a^2}$$

$$R_{e\pm}\ =\ M\ \pm\ \sqrt{M^2\ -\ a^2\ cos^2\ \theta}$$

$R_{ph}$, $R_{mb}$ & $R_{ms}$ have prograde and retrograde orbits around a rotating black hole. The upper sign characterizes the prograde orbit (corotating with the black hole) and the lower sign holds for the retrograde orbit (counterrotating against the black hole)

$$R_{ph}\ =\ 2M\left[1\ +\ cos\left(\frac{2}{3}cos^{-1}\mp \frac{a}{M}\right)\right]$$

$$R_{mb}\ =\ \left(\sqrt{M}\ +\ \sqrt{M \mp a}\right)^2\ =\ 2M\ \mp \ a\ +\ 2\sqrt{M(M \mp a)}$$

$$R_{ms}\ =\ M\left(3+Z_2 \mp \sqrt{(3-Z_1)(3+Z_1+2Z_2)}\right)$$

where

$$Z_1=1+\left(1-\frac{a^2}{M^2}\right)^{1/3}\left(\left(1+\frac{a}{M}\right)^{1/3}+\left(1-\frac{a}{M}\right)^{1/3}\right)$$

$$Z_2=\sqrt{3\frac{a^2}{M^2}+Z_1^2}$$

Extended explanation

Fast rotating black hole:

For a "fast rotating black hole", with angular momentum $aMc$ greater than $M^2c$, $R_-$ $R_+$ and $R_{ms}$ do not exist, and so there is no event horizon, and no minimum circular orbit, and the black hole has a "naked" singularity.

* This entry is from our old Library feature. If you know who wrote it, please let us know so we can attribute a writer. Thanks!

 

[Greg Bernhardt]

Definition/Summary
The four laws of black hole thermodynamics are as follows…

The Zeroth Law
Surface gravity $(\kappa)$ is constant over a black holes event horizon.
The First Law
‘This law deals with the mass (energy) change, dM when a black hole switches from one stationary state to another.’ The following (in natural units) applies-
$$dM=\frac{\kappa}{8\pi}\,dA\,+\,\Omega\,dJ\,+\,\Phi\,dQ$$
where the first term is relative to irreducible mass- $M_{ir}=\sqrt(A/16\pi)$, the second to rotation- J and the third to charge- Q.
In accordance with Cosmic censorship: $Q\leq M,\ a\leq M,\ J=aM\leq M^2$ and $Q^2+a^2\leq M^2$ where $M=Gm/c^2$.
[tex]\begin{align*}& A=4\pi\left( 2M^2-Q^2+2M\sqrt{M^2-Q^2-a^2}\right)\\& \kappa=\frac{4\pi \sqrt{M^2-Q^2-a^2}}{A}\\& \Omega=\frac{4\pi\ ,a}{A}\\& \Phi=\frac{4\pi\, Q\...

Continue reading...

 

[Tendex]

HST unveils a compact mildly relativistic broad-line region in the candidate true type 2 NGC 3147
Stefano Bianchi, Robert Antonucci, Alessandro Capetti, Marco Chiaberge, Ari Laor, Loredana Bassani, Francisco J Carrera, Fabio La Franca, Andrea Marinucci, Giorgio Matt ... Show more
Monthly Notices of the Royal Astronomical Society: Letters, Volume 488, Issue 1, September 2019, Pages L1–L5, https://doi.org/10.1093/mnrasl/slz080
Published: 11 July 2019

https://academic.oup.com/mnrasl/article/488/1/L1/5522653

 

[mfb]

Found August 14. LIGO/Virgo estimate 99.8% chance that it is such a collision and only 0.2% chance that one of the objects is in the "mass gap": Between 3 and 5 solar masses, heavier than known neutron stars but lighter than known black holes. The chance for every other type of event is negligible. This is certainly something new and will keep astronomers busy for months.
The small mass means the signal is notable for a while, that is good for localizing the source. They could narrow down the origin to 23 square degrees in the sky (most events have hundreds of square degrees). So far no electromagnetic signal has been found, despite this good localization.

If the neutron star was deformed significantly or ripped apart before it fell in, the signal might tell us more about the interior of them.

News articles: Science, Scientific American

List of detected events by type:
Binary black holes: 10 published, ~15 more strong candidates in the analysis pipeline
Binary neutron stars: 1 published, in addition 1 strong and 1 weak candidate* being studied
NS/BH: This event (being studied)
Mass gap: -

* this one is very unclear. 49% binary neutron star, 13% neutron star/black hole, 24% mass gap, 14% random noise