Time at the Event Horizon

"Einstein famously taught us that time is relative, and there are no absolute clocks, quantum mechanics is built on the notion that time is absolute. So before going any further, the physicists had to get a handle on what makes time tick.

So, just what is time? It's essentially being able to tell the change in one observable quantity with respect to changes in another--making up a clock tick. In classical physics, the clock is external to the system being studied. But if you're considering situations near the origin of the universe, or close to black holes, you are not going to have any handy clocks nearby. You won't even find objects or variables that could behave like classical clocks and rulers, says Pullin. Instead, you'll be forced to use some of the variables of the system you are studying, to measure the rest of the system."

Time is not the process of moving from one event to the next, but one event replacing the previous. The earth doesn't travel the fourth dimension from yesterday to tomorrow. Tomorrow becomes yesterday because the earth rotates. Time is an effect of the motion, not the basis for it. There is no external clock. It has more in common with temperature than space.

Finally! I will be teaching these ideas to my future students.

In the universe observer observes material change in space. Time as a part of space cannot be observed. According to Gödel time is not part of space. Fourth coordinate of space-time is spatial too.

Quantum gravity describes space as granular. Space is made out of quanta of space QS volume of Planck. Prevalent idea in physics is that space has three spatial dimensions and one temporal dimension. It is difficult to imagine that quanta of space QS have three spatial dimensions and one temporal dimension. Experimental data confirms that with clocks we measure a frequency , velocity and numerical order of material changes that occur in a quantum space. Physical time that is run of clocks ("tick" of clocks) is not a part of quantum space in which change occurs. With clocks we do not measure time as a fourth dimension of space. Quantum space itself is timeless. Fourth dimension of quanta of space QS is spatial too. Space-time is mathematical model merely were fourth coordinate X4 is a product of imaginary number i, light speed and number t that represents "tick" of clock: X4 = i x c t.

In stronger gravity speed of clocks and of all material changes slows down.

You can read more on the subject of time and gravity in my essay "Awakening of the Observer in Physics"

PS Few days ago I had discussion with one of the members here. He is convinced that "time dilatation" as slower velocity of clocks is a result of 4th coordinate of space-time shrinking.

Even if space-time would exists as a physical reality would not be possible to explainj how shrinking of space is related with slower speed of clocks. There is no mechanism known and described how shrinking of space-time slows clocks speed.

It is quite amazing how we are attached to some fix ideas in physics that have no correspondence to physical reality.

yours amrit

I think these models are in trouble. The Fermi spacecraft has demonstrated that very different frequencies of light travel at the same light speed. I kept saying these ideas of frequency dependencies, such as from LQG, on the speed of light were wrong. Well read 'em and weep

http://www.nasa.gov/home/hqnews/2009/oct/HQ_09-254_Fermi_anniversary.html

On May 10, 2009, Fermi and other satellites detected a so-called short gamma ray burst, designated GRB 090510. Astronomers think this type of explosion happens when neutron stars collide. Ground-based studies show the event took place in a galaxy 7.3 billion light-years away. Of the many gamma ray photons Fermi's LAT detected from the 2.1-second burst, two possessed energies differing by a million times. Yet after traveling some seven billion years, the pair arrived just nine-tenths of a second apart. The speed of light for the two photons is the same to one part in a million billion.

This causes troubles for these "slice and dice," to use a phrase from the above article, ideas about spacetime near the Planck scale. The problem is this results in the breaking of Lorentz symmetry, which should show up as a small difference in light speed for photons with different wavelengths.

String theory makes a nice prediction that the quantum foam which produces this effect is valanced or renormalized out from observable physics. I don't think gravitation is quantized directly. At most I think general relativity exhibits quantization at the tree or one-loop level. I think general relativity is transformed into another form. In a general setting gravitation is transformed in a way which reduces the gravitational multiplet to an abelian Skyrme theory. In this way one does not have to directly quantize gravity. Spacetime and gravitation is essentially a smooth, classical field that emerges from an underlying substratum.

Cheers LC

LC plese explain what is "underlying substratum". Do we have any evidence of it or it is one more hypothetical idea ?

yours amrit

amrit,

On a philosophical point, thought is a function of making distinctions, but reality is a consequence of connections.

On a more practical note, logically space is an equilibrium state and motion is relative to that equilibrium, not other motion. That's why the speed of light is constant.

Just a thought; What would space as an equilibrium state do for the need for a Higgs?

John I would like to put more light in the subject here: What is with time near and in black holes: Imagine you are in spaceship traveling into direction of a black hole. With your friend that has remained in a spaceship far away you will communicate that your clocks run slower by coming closer the black hole. At the certain distance from the centre your spaceship will be smashed. What will remain is observer. Let's imagine observer travels beyond Schwarzschild radius. Here he sees that mass transforms in quanta of space that build up cosmic space. In black holes are mass transforms into space. Hawking predict that black holes emit elementary particles. In that way black holes are rejuvenators of the universe. Astronomical observations show that AGN sucks in old stars and throw out fresh gas.

My idea is that in intergalactic space density of quantum space is extremely high and elementary particles are continuously created out of quanta of space. In black holes and AGN density of mass is high; density of quanta of space is extremely low. In black holes and AGN mass is transformed back into quanta of space. This transformation is in a permanent, universe has no beginning and no end. It is a system in dynamic equilibrium.

Quantum space is timeless; physical time is merely run of clocks. There is no physical time behind run of clocks. Clocks are fundamental measuring instruments of physics. Barbour idea that time does not exists is not pragmatic. Time does not exist as a fourth dimension of space as Gödel already explained. Physical time definitely exists as a run (thick) of clocks in a timeless quantum space.

PS regarding light speed:

You take light as a phenomenon A in a medium B that is cosmic space. If A has same speed for different moving systems in medium B this means that A is vibration of medium B.

Light needs 8 minutes to arrive from the sun to the earth. So light propagate in space with a light speed. But once light is arriving to the earth than it can be seen as a vibration of space itself.

Packets of energy named "photons" are emitted from the sun and they "jump" from one to other quanta of space in a Planck time. First photons need 8 minutes to arrive to the earth.

So signal of light moves with light speed through cosmic space but also light is a vibration of cosmic space.

Amrit,

There might be possible evidence, or something which could in principle be searched for. If you read my essay paper

http://www.fqxi.org/community/forum/topic/494

which is really half a sketch of sorts, I talk about the D5-D2 brane duality. This involves aspects of black hole complementarity. It we could produce quantum black holes in the laboratory then in principle this physics could be observed. The M2 or D2 brane has the signatures of the Chern-Simons Lagrangian that is involved with the underlying Skyrmion structure I advance. This emerges from the automorphisms of the Jordan exceptional matrix, which indicates that underneath things, physics is reduced to a simple abelian structure with fermionic content.

Some signatures for black hole-like amplitudes have been dectected in the RHIC, so there might be more data with the LHC. So we might get some signatures of this, say a hundred bytes of data out of 10^{15} per second, which is the LHC data stream rate. Rather astounding to think this is the magnitude of the information LHC detectors will log in.

This underlying structure involves the cosmological constant as well. That it one main thrust of my paper, where by observing the vacuum structure of the universe we are "looking inside" a black hole. The fermionic content exhibits quantum phase transitions, similar to the behavior of Landau electron fluids.

Cheers LC

Carrying further, the net impact is that gravitation or general relativity is not fully quantized. It emerges as a semi-classical theory from an underlying substratum that is quantized. The structure (underlying structure) here is abelian and nicely linear. That can be quantized well enough. What emerges at lower energy is gravitation (and other gauge fields), and where gravitation is highly nonlinear and not quantizable directly. Gravitation at this lower energy is only semi-classical, or quantized on the tree level or one loop quantum correction level.

Cheers LC

Lavrence

I read your article. You see black holes more as a mathematical objects, I see them more as a physical objects. Black hole exists in a medium we call cosmic space. If space has a granular structure must also have density. In black holes density of space is extremely low in intergalactic space density of space is extremely high. In centre of black holes mass transforms in quanta of space, in intergalactic space quanta of space transforms in elementary particles. This transformation is permanent, universe is in dynamic equilibrium.

yours amrit

amrit,

I also see it as a cycle of what is falling into gravitational black holes as emerging as the cosmological constant/vacuum fluctuation/dark energy which causes intergalactic space to expand and the process starts over again. About a decade ago, in a conversation on this topic, it was pointed out to me that light and other forms of radiation would be the logical medium by which this energy/space is redistributed, or at least a significant percentage of it.

Lawrence is right about there being a tidal wave of information coming from the LHC and, I suspect, the rejuvenated Hubble. Some of the old ways of thinking will have a lot to withstand.

The point of the Fermi data is that spacetime does not have the sort of grandular structure people think it has. I don't see black holes as mathematical structures, but mathematics is the language of physics.

Cheers LC

Lawrence,

The problem is there is a natural institutional preference for the order of mathematics over the messiness of reality. So the institution spins off into its own debates over form that have little bearing on reality. I suspect history will not be to kind to the whole Big Bang to multi-worlds modeling currently obsessing the physics community.

"Messiness" would be a misnomer. Complexity and chaos might be more descriptive.

John and Lawrence

Hawking proposes black holes emitts particles:

. I. V. Volovich, V. A. Zagrebnov and V. P. Frolov, Quantum particle creation (Hawking effect) in nonstationary black holes, Theoretical and Mathematical Physics, http://www.springerlink.com/content/k7466h61j25r3164/

I think here more on global cosmic dynamics. Here idea is proposed that in black holes inside Schwarzschild radius where density of mass is extremely high and density of space is extremely low mass is disintegrated in quanta of space. Quanta of space are "fundamental elements" of energy that builds up elementary particles.

In outer space where quantum space is extremely dense quanta of space get formed into cosmic rays.

"Enigmatic for many years, cosmic rays are now known to be not rays at all, but particles, the nuclei of atoms, raining down continually on the earth, where they can be detected throughout the atmosphere and sometimes even thousands of feet underground".

. Michael W. Friedlander, A Thin Cosmic Rain - Particles from Outer Space, Harward University Press (2000) http://www.hup.harvard.edu/catalog/FRITHI.html

Transformation "mass - quanta of space - mass" is permanent. Universe is a system in a permanent dynamic equilibrium without beginning and with no end.

According to the first law of thermodynamics energy of the universe cannot be created and not destroyed, it can only be transformed. The sum of energy in the universe is constant.

Expanding of the universe is the result of high density of quantum space in outer space. High dense space is expanding similar as a high dense gas. With a continuous creation of elementary particles in outer space amount of mass in the universe is increasing and cosmic space is getting less dense. This process is more intensive as a transformation of mass in quanta of space in centre of black holes. Process of continuous creation of particles in outer space increases presence of mass in the universe, ends expansion and starts contraction. Universe shrinks in huge back hole where mass will be transformed into quanta of space. Density of quantum space will extremely increase; this will lead to the new "big bang".

Gravity rules permanent cosmic dynamics of expansion and contraction with transformation of mass in quantum space and vice versa.

The universe is not a system in some eternal equilibrium. This is something which has been thought to be the case, and even Hawking spent considerable effort trying to show the universe came about from a random fluctuation, just one which resulted in an unusually low entropy form. There are serious problems with this idea. In particular it is not hard to argue that an unusually low entropy fluctuation, but one which is not as low in entropy and more probable, could just generate a virtual reality generator (processor) or the Boltzmann brain. Yet these ideas are difficult to support.

The universe has the entropy it currently has because it had lower entropy in the past. So the universe started out with a very low entropy. So the number of microstates it existed in at the very early stage was small, and the number of possible configurations for these microstates into macrolevel configurations (macrostates) very small. It is the case with the setting up of a billiards table. The racked balls represent a very limited number of states (positions on the table) in a configuration which is unique. Then breaking the racked balls puts the system in a scattered configuration, where a whole range of microstate configurations can generically describe the arrangement. Further if we see two balls scatter each other, and take a video of the event we are not able to easily tell which has time forwards and backwards. Yet we can certainly distinguish the time direction for breaking the racked balls. A video where an arrangement of balls spontaneously arranges itself into the racked position is clearly time reversed.

This gets into the issue of multiverse, and while I really dislike that term, it has some merit to it. Just consider a model where quantum fluctuations of the vacuum state in the universe results in some vacuum energy, as determined by the cosmological constant, is quantum tunneled out of the spacetime. This packet is the seed for another spacetime vacuum or universe. In this setting there is no unique time direction imposed on the new cosmology, or for that matter the vast number of other ones. So the net time direction as a sum over all of these is zero and there is ultimately reversibility.

There are aspects of this multiverse approach to the arrow of time which are attractive and which present difficulties. But pondering these things is at least interesting.

Cheers LC