Does Time ever run backwards: Perhaps.

New law implies thermodynamic time runs backwards inside black holes
September 3, 2015 by Lisa Zyga feature

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The new area law states that the area of a future holographic screen (the solid blue line in [a]) is always increasing in one direction, while the area of a past holographic screen (the solid blue line in [b.]) is always increasing in a different direction. Credit: Bousso and Engelhardt. ©2015 American Physical Society
(Phys.org)—Black holes are known to have many strange properties, such as that they allow nothing—not even light—to escape after falling in. A lesser known but equally bizarre property is that black holes appear to "know" what happens in the future in order to form in the first place. However, this strange property arises from the way in which black holes are defined, which has motivated some physicists to explore alternative definitions.



Read more at: http://phys.org/news/2015-09-law-implies-thermodynamic-black-holes.html#jCp

 

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http://www.sciforums.com/threads/does-time-ever-run-backwards-perhaps.152557/

New Area Law in General Relativity
Raphael Bousso and Netta Engelhardt
Phys. Rev. Lett. 115, 081301 – Published 18 August 2015


ABSTRACT
We report a new area law in general relativity. A future holographic screen is a hypersurface foliated by marginally trapped surfaces. We show that their area increases monotonically along the foliation. Future holographic screens can easily be found in collapsing stars and near a big crunch. Past holographic screens exist in any expanding universe and obey a similar theorem, yielding the first rigorous area law in big bang cosmology. Unlike event horizons, these objects can be identified at finite time and without reference to an asymptotic boundary. The Bousso bound is not used, but it naturally suggests a thermodynamic interpretation of our result.

 

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What does that mean for entropy and the 2nd Law?

 

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Good question Daecon, I'm not sure how to answer it.

http://superstringtheory.com/blackh/blackh3a.html

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If the Four Laws of Black Hole Physics looked familiar, it's because they sound just like the Four Laws of Thermodynamics, which are:

The Four Laws of Thermodynamics
0The temperature T of a system in thermal equilibrium has the same value everywhere in the system.
1The change in energy of a system is proportional to the temperature times the change in entropy.
dE = T dS
2The total entropy of a system can only increase, never decrease.
3It is impossible to lower the temperature T of a system to zero through any physical process.
There seems to be a direct correspondence between the properties of a classical thermodynamic system, and the properties of a black hole, shown in the table below

Thermodynamic systemBlack hole
temperaturesurface gravity at horizon
energyblack hole mass
entropyarea of horizon
A black hole spacetime seems to behave like a thermodynamic system. How could this be true? This is spacetime geometry, after all, not a cylinder of gas or a pot of liquid. The importance of this apparent thermodynamic behavior of black holes was made undeniable when black hole radiation was discovered by Hawking.
Black hole radiation, known as Hawking radiation, comes about because relativistic quantum field theory is invariant under Lorentz transformations, but not under general coordinate transformations. In flat spacetime, two observers moving at a constant velocity relative to one another will agree on what constitutes a vacuum state, but if one observer is accelerating relative to the other, then the vacuum states defined by the two observers will differ. This idea, when extended to the spacetime of a black hole, leads to the conclusion that to an observer who stays at a fixed distance from a black hole event horizon, the black hole appears to radiate particles with a thermal spectrum with temperature (in units with GN=c=1)T=1/8pMkB, where kB is Boltzmann's constant and M is the black hole mass.
Since plane waves and Fourier transforms are at the heart of relativistic quantum field theory, this effect can be illustrated using a classical plane wave, without even appealing to quantum operators. Consider a simple monochromatic plane wave in two spacetime dimensions with the form

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An observer traveling in the x-direction with constant velocity bperceives this plane wave as being monochromatic but the frequency w is Doppler-shifted:

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An observer traveling in the x-direction with constant acceleration a does not perceive this plane wave as being monochromatic. The accelerated observer sees a complicated waveform:

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This wave as perceived by the accelerated observer is a superposition of monochromatic waves of frequency n with a distribution function f(v) that, as shown below

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appears to be a thermal distribution with temperature T=a/2pkB. The result from this simple example matches Hawking's black hole result if the acceleration is related to the black hole mass by a=1/4M. And indeed, the acceleration at the event horizon of a black hole of mass M does satisfy a=1/4M. Why does this work so well? Because an observer held at a fixed distance from the event horizon of a black hole sees a coordinate system that is almost identical to that of an observer undergoing constant acceleration in flat spacetime.
But don't be misled by this to think that the full black hole radiation calculation is as simple. We've neglected to mention the details because they are very complicated and involve the global causal structure of a black hole spacetime.
Conservation of energy still applies to this system as a whole, so if an observer at a fixed distance sees a hot bath of particles being radiated by the black hole, then the black hole must be losing mass by an appropriate amount. Hence a black hole can decrease in area, through Hawking radiation, through quantum processes.
But if area is like entropy, and the area can decrease, doesn't that mean that the entropy of a black hole can therefore decrease, in violation of the Second Law of thermodynamics? No -- because the radiated particles also carry entropy, and the total entropy of the black hole and radiation always increases.

Where does the entropy come from?
One of the great achievements of quantum mechanics in the 20th century was explaining the microscopic basis of the thermodynamic behavior of macroscopic systems that were understood in the 19th century. The quantum revolution began when Planck tried to explain the thermal behavior of light, and came up with the concept of a quantum of light. The thermodynamic properties of gases are now well understood in terms of the quantized energy states of their constituent atoms and molecules.
So what is the microscopic physics that underlies the thermodynamic properties of black holes? String theory suggests an answer that we will explain in the next section.
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Not sure if that helps.

 

Didnt Feynman say that an electron is a positron moving backwards through time? Is this a similar concept?

 

Isn't that just because it spins in the opposite direction, so it's mathematically equivalent, or something along those lines? Of course I could be misremembering...

 

Since areas of both future and past screens are finite, it suggests a finite past and also a finite future, but the finite future appears to be incomprehensible.

This increase in future holographic screen area suggets expansion faster than the speed of light, that means universe is expanding, and non asymptotic aspect says infinite future, almost contradicting with the above observation.

This questions the prevalent definition of Event Horizon, Does it not ? And moreover existence of multiple Black Holes is like having multiple data (past information) storage devices, with an additional feature of having future information available as well.

Its a long travel for BH, from complete information destruction to having complete information of past and future mapped inside. The pertinent issue is how (and what) Black Hole maps the past, does it simply transfers the data from future Hologram available with it to its past Hologram, or it collects the entire past data in one sweep shot from the Universe or it is just the past and future (if anything left) of accreted material.

Quite interesting.

 

The paper itself is http://arxiv.org/abs/1504.07627 And what I read there is not that interesting at all.

Roughly speaking, we have a local theory, GR. Then it appeared that for some solutions, some interesting surfaces - horizons - exist. Unfortunately, the very definition of these surfaces was problematic, because it requires knowledge of the future - light can never escape the horizon. This is problematic for some approaches. I would reject the approaches which depend on such notions as nonsensical. Of course, the proponents of such approaches will disagree, and try to find some replacements for the unreasonable horizon definitions. This is one attempt to reach this.

Behind this is another pseudoscientific idea - that of black hole thermodynamics. It is an example of mathematical mysticism: There is some formal similarity between the mathematics of thermodynamics and the mathematics of black holes. Such similarities of the mathematical apparatus applicable to certain things means nothing at all. The obvious example is the wide domain where we can use the mathematical apparatus of natural numbers. We apply them to count everything, from atoms, water drops, and children, to stars and galaxy clusters. To guess that there is some deep connection between children and galaxy clusters simply because we can count them would be rejected as completely nonsensical, but the use of similar mathematics in thermodynamics and gravitational physics is nothing conceptually different.

But this pseudoscientific mysticism about the deep connection between black holes and the cooling of hot water depends on horizons, because it is the horizon surface which defines the "temperature" of the black hole.

 

http://www.cnn.com/2015/09/03/opinions/lincoln-hawking-black-holes/index.html

According to Hawking's latest, information (energy) from things falling into an event horizon, once formed, are stored there indefinitely until the black hole completely evaporates. This process has been likened to a holographic memory.

Now according to the OP of this thread, time may possibly reverse direction in the interior of a black hole. This means, among other things, that energy propagates backwards, and that unbound energy events (like its initial collapse) would likewise reverse in the sense that the original collapse would "bounce", directing all energy and matter from the initial collapse back toward the event horizon, from the inside, where, just like any matter falling into it from the side that is our universe, would have all of its information stored there, just like the information that has already been holographically stored there.

No changes in gravitation as seen from the outside of the BH EH would result because of matter-energy equivalence, combined with conservation of energy. Does gravity ever reverse direction with time? Perhaps that is what happened with inflation before the Big Bang. For all we know, we could all be inside of a black hole, right now. How could you even tell if time was not running in the "right" direction, if all the time you ever experienced was running the wrong way? Maybe things are supposed to fall in the direction of "up".

Even if this works, things on the other side of the event horizon of a black hole, or in the EH itself will not be released until it completely evaporates. This is a grand experiment and also a practical one. All we need to do is wait long enough for one to completely evaporate. It will need to be one that is on the smallish side, but at least now we know what it is we will be looking for. Anyone trapped inside of a BH at least have gravitational time dilation working for them, which is nice.

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However, time reversal would mean Bill would lose his caddy gigs. Don't be so cruel to Mr. Bill!

 

"Only science affords us such wholesale conjecture with only a trifling investment of fact." --paraphrased quote by Mark Twain

 

Proviso that any photon emitted just this side of the horizon, directly radially away, will appear from that local frame to hover just above that EH forever, never seccumbing to the EH, but never quite getting away either.

http://www.physics.umd.edu/grt/taj/776b/lectures.pdf

Abstract
These notes are based on five lectures given at the University of Utrecht in early 1996. My intention was to introduce the subject of black hole thermodynamics starting at the beginning, at a level suitable for anyone with a passing acquaintance with general relativity and quantum field theory. Although the approach is elementary, several aspects of current research are discussed. The coverage of topics is very uneven. Properties of classical black holes and both classical and quantum black hole thermodynamics are treated. The selection and focus is determined by my idiosyncracies, time limitations, and an effort to illuminate some topics that have not traditionally been emphasized. Vast amounts of interesting and important work on the subject are not mentioned. I am very grateful to the Institute for Theoretical Physics for the hospitality and support they have provided during a very stimulating sabbatical year I spent there.
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https://en.wikipedia.org/wiki/Black_hole_thermodynamics
In physics, black hole thermodynamics is the area of study that seeks to reconcile the laws of thermodynamics with the existence of black holeevent horizons. As the study of the statistical mechanics of black body radiation led to the advent of the theory of quantum mechanics, the effort to understand the statistical mechanics of black holes has had a deep impact upon the understanding of quantum gravity, leading to the formulation of the holographic principle.
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I see these as far more reliable then your own maverick opinion which you so ignorantly put down to pseudoscience, probably more for dramatic effect then anything else and of course to gain some attention to yourself.

 

NOTE :
Spacetime of course is not curtailed by the normal universal speed limit.
"c" applies to anything with mass.

 

http://www.scholarpedia.org/article/Bekenstein-Hawking_entropy

Bekenstein-Hawking entropy:

The Bekenstein-Hawking entropy or black hole entropy is the amount of entropy that must be assigned to a black hole in order for it to comply with the laws of thermodynamics as they are interpreted by observers external to that black hole. This is particularly true for the first and second laws. Black hole entropy is a concept with geometric root but with many physical consequences. It ties together notions from gravitation, thermodynamics and quantum theory, and is thus regarded as a window into the as yet mostly hidden world of quantum gravity.

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Figure 1: The Bekenstein-Hawking entropy is the entropy to be ascribed to any black hole: one quarter of its horizon area expressed in units of the Planck area [see equation (1)].

 

http://www.astro.sunysb.edu/rosalba/astro2030/BHTherm.pdf

http://newt.phys.unsw.edu.au/PHYS2060/readings/Black-hole Thermodynamics - Jacob Bekenstein.pdf


http://arxiv.org/abs/1410.1486

Black Hole Thermodynamics
S. Carlip
(Submitted on 6 Oct 2014 (v1), last revised 26 Aug 2015 (this version, v2))
The discovery in the early 1970s that black holes radiate as black bodies has radically affected our understanding of general relativity, and offered us some early hints about the nature of quantum gravity. In this chapter I will review the discovery of black hole thermodynamics and summarize the many independent ways of obtaining the thermodynamic and (perhaps) statistical mechanical properties of black holes. I will then describe some of the remaining puzzles, including the nature of the quantum microstates, the problem of universality, and the information loss paradox.

 

This is probably off-topic, but why are the Planck units represented by triangles?

 

The triangles are Planck areas; the area is the square of a Planck length.

Start there. I think it's about triangulating the surface, one other clue: the Planck length is the shortest distance between two events so they can be distinguished.
That is, it's the shortest distance in space that makes physical sense; Planck time is likewise the shortest time interval.

I'm not sure myself how this information gets the Bekenstein bound.

 

Of course, you always consider the mainstream opinion as far more reliable. Almost by definition. For you, it is completely sufficient that my position is "maverick" and the other one mainstream. Anyway, you are unable to distinguish which is right by evaluating the content.

 

I thought troika of Asimov, Heinlein and Clarke (and of course their clan) had the IPR of wierd science fiction..

 

Please refer the concurrent discussion on the Hawking radiation which evaporates the BH in finite time. So this hovering forever contradicts hawking radiation.

Morover as the EH decreases due to evaporation, what will happens to this Photon, will it travel down maitaining the gap with the EH or just hover wherever it was produced. On the other hand if accretion takes place at some other place of EH, then EH increase then also will the Photon Hover or get sucked away or move proprtionally outward. So this foreover hovering needs to be improvised.


I fail to understand this past and future mapping in Holographic screen. Hawking said EH is real, so where does this 2D hologram get formed, outer surface of EH or inner surface of EH. I think past gets on the outer surface, but future gets mapped on the inner surface (secretive, hidden on the interior of EH). But I am just wondering what gets mapped, what is past information and what is future information for a BH is a very profound aspect for further understanding of BH.

Quite interesting object this BH, can't put Hawking along with Troika, can we ?

 

I generally most certainly do. That's why in most cases it is mainstream.

I've seen your position on science and politics.
And I have given reputable links supporting theoretical concepts such as the OP, rather than stupidly writing them off as pseudoscientific, considering where and who they originated from.
For a professional as you claim to be, you often surprise me as to the depths you sink.