A black hole is an object so massive that even light cannot escape from it.This requires the idea of a gravitational mass for a photon, which then allows the calculation of an escape energy for an object of that mass. When the escape energy is equal to the photon energy, the implication is that the object is a "black hole".

A lot of us understand I think that the cosmological world we had been lead through by Einstein, has geometrical principals embued with this organizational ascent. So too alongside of this equative understanding, the geometry must be understood as well, as the role we have in develoing to non euclidean geometry.

The basic principals have direct physics results as we learn to explore these potentials.

If we are taken to understand this progression, how did we get here? Are there higher dimensions without the geometry?

**Measuring the depth of ideas**

**Lubos saids**:Instead, let us ask: is quantum mechanics deep? Yes, I think that quantum mechanics is perhaps the deepest idea we know. It is once again a deformation of a conceptually simpler picture of classical physics. Much like the speed of light is finite in relativity and it unifies space and time, the Planck constant is finite in quantum mechanics which allows us to identify the energy with the frequency, among many other things - quantities that would otherwise remain as independent as space and time without relativity.

Lubos Motl talk about the depth of ideas, for me, leads to this progression of geometry. Talked about it in a way I saw leading and consenting ideas to this progression, by developing these deeper qualities of "quantum mechanics".

We had to understand then that such a physics progression would follow hand in hand, with the ideas of geometrical expression? So how were we lead into the non-eucldean world?

So too then, how would it be, if we use a different method to extoll the holographical understanding in how we percieve the natural abilties of information related to this geometrical form? Bekenstein Bound holds important clues about this fifth dimensional attribute?

Holography encodes the information in a region of space onto a surface one dimension lower. It sees to be the property of gravity, as is shown by the fact that the area of th event horizon measures the number of internal states of a blackhole, holography would be a one-to-one correspondance between states in our four dimensional world and states in higher dimensions. From a positivist viewpoint, one cannot distinquish which discription is more fundamental.

Pg 198,

**The Universe in Nutshell**,

*by Stephen Hawking*

How would then would we reduce Higher dimensions to relativity?

Superstring theory rules in the 5-D spacetime, but a so-called conformal field theory of point particles operates on the 4-D hologram. A black hole in the 5-D spacetime is equivalent to hot radiation on the hologram--for example, the hole and the radiation have the same entropy even though the physical origin of the entropy is completely different for each case. Although these two descriptions of the universe seem utterly unalike, no experiment could distinguish between them, even in principle.

## 4 comments:

So a photon needs gravitational mass in order to be affected by gravity? The statement 'a photon has no rest mass' which is widely held to be so deep, is meaningless. Who cares about the 'rest mass' of a particle that's never at rest? What information does the statement deliver? None.

What matters is whether the photon has mass at its natural velocity, c. To deliver momentum it must have effective mass.

If you could trap a photon into a blackhole but utilising its own gravitational mass, it would spin around endlessly. In classical electromagnetism, a photon is pictured as a pair of sine waves, one representing electric and the other magnetic field. Half of the photon is negatively charged, and half positive. Although pair-production is normally thought of as being an abstract process, it can be considered crudely in classical terms. You need a gamma ray of at least twice the rest mass energy of the electron. It interacts with a string field near a nucleus, and there emerges a positron and electron. Somehow the energy of the photon has been converted into matter and antimatter. If the classical analogy is of any use, the photon has broken into two loops, two black holes, each spinning at light speed. When you look at the electric and magnetic fields which result for this electron, it gives the radial electric field, magnetic dipole, spin, and mass.

The usual barrier between classical and quantum theory can be broken down.

Hi Nigel,

I needed to refamiliarize myself with the points you are making.

Does light have massLight is composed of photons so we could ask if the photon has mass. The answer is then definitely "no": The photon is a massless particle. According to theory it has energy and momentum but no mass and this is confirmed by experiment to within strict limits. Even before it was known that light is composed of photons it was known that light carries momentum and will exert a pressure on a surface. This is not evidence that it has mass since momentum can exist without mass. [ For details see the Physics FAQ article What is the mass of the photon?].Nigel said:Somehow the energy of the photon has been converted into matter and antimatter. If the classical analogy is of any use, the photon has broken into two loops,I was interested in seeing the map process that you are speaking too in pair production.

Like X-ray detectors,gamma-ray detectors depend on a photon's interaction with a medium. One new form of interaction with detector material which comes into play for gamma rays (at least those with energies larger than 30 MeV) is pair production (defined below). Pair production telescopes are just one type of gamma-ray detectors; these, along with a few others, are described below.Here is what Smolin saids.

Smolin:And there are published predictions for observable Planck scale deviations from energy momentum relations[22, 23] that imply predictions for experiments in progress such as AUGER and GLAST. [B]For those whose interest is more towards formal speculations concerning supersymmetry and higher dimensions than experiment, there are also results that show how the methods of loop quantum gravity may be extended to give background independent descriptions of quantum gravity in the higher and super realms[31]-[35][/B]. It thus seems like a good time for an introduction to the whole approach that may help tomake the basic ideas, results and methods accessible to a wider range of physicists.Hi Plato:

The evidence for a photon having no mass while in transit is that at light velocity it would have infinite mass, as determined by Lorentz (who put the classical electron mass-versus-radius into the contraction formula to obtain the variation of mass with velocity of a material body) and Einstein's work.

However, electromagnetic energy has gravitational mass! If you have a given amount of energy, it has gravitational mass, which by Einstein's equivalence principle is the same as inertial mass.

The usual statement in my my textbooks is 'a photon has no rest mass', which simply means that if you have zero velocity (at rest) you have zero mass because there is no photon radiation.

Put this another way: Einstein's thought experiment at age 18 was that if he rode on the back of a light wave, he would see no electromagnetic energy (and by E=mc2, no mass either).

This is the point I was trying to make.

Best wishes,

Nigel

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