What is Time and Space

This is not on topic here. Please leave religious conjecture out of this forum.

You mentioned a few posts back that you are a fan of Penrose. I googled around a bit and found that he is heavily into sorting out the mysteries of consciousness.I'm not at all sure that I got this right but is he suggesting that "time" is just something that is perceived by our consciousness?Certainly our perception of time appears to change. We all know how much faster our perception of time is as we age. I think most of us have experienced time slowing down immensely in a time of crisis.Just curious as I spent a lot of time researching Penrose and found him to be a bit of an enigma.

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Everybody is entitled to my opinion.

Penrose is the greatest mathematician alive (in my eyes).
His perspectives on Quantum Physics in "The Road to Reality" really opened my eyes.Especially the perspective of approaching Quantum Gravity from a relativists point of view, instead of a QFT point of view.(Not to say that a relativistic approach is better, just that I've never seen it before).cavediver, what is part III like in Cambridge?
I've always been tempted to do it.

It's a long time since Part III for me. At the time it was incredible. I would still describe it as possibly the best year of my life; I have never worked so hard, nor achieved so much. My Part III notes take up more room than my degree! I came to Part III as a physicist and expected to fail... I left as a mathematician. If it's anything like it was, then I would certainly recommend it. There are probably good (and cheaper!) alternatives now, but that wasn't really the case then. The lecturing was fairly poor, as with most of the maths Tripos at the time. But then it sometimes made up for it with the excellent quality of the tutors

Cavediver, you mentioned the projection idea or something related to it with the suggestion what we study and observe is not the real world per se. To be honest, I am not sure I understand the claim, but my question is, and maybe it will help me understand it better:Is math then just dealing with the projection or whatever, or of the reality of which the observed world is derived from?

Cavediver: "No, the opposite. It points us to a lower dimensional reality!"Yikes! What does this say for hidden variables? I thought they were to reside in higher dimensions if they were to be found, or am I confusing two separate issues?

Both, but the mathematics that will lead us to more fundemental understanding will be that of the projecting world. One way of thinking about this (for the computer literate) is the difference between raster and vector graphics. We usually imagine the universe as a raster graphic bit-map... there is a background (space-time) and at certain locations, there are particles (bits set to be on) and at other places there are no particles (bits off). This idea of a projection is more like vector graphics. There is a particle at one particular "location", and a 2nd at another "location". There is no concept of anything being between the particles, although a "distance" can be defined based upon the two "locations". Hmmm, this is a bit fuzzy at the moment... I need to work on this analogy, but I think it has merit.

Yes, you are There are no hidden variables as such. If you are thinking of Hilbert space (infinite dimensional) then this is very different to the dimensions of space-time>And I'm not saying that there aren't higher dimensiosn - I'm fairly convinced that there are - just that all of these dimensions are possibly just a projection or an emergent concept from a low (2?) dimensional (nehind the scenes) reality.

I realize this is all theory, but what do you think might be some of the characteristics of a 2d projector.

Well, at the moment it is just background independent string theory... a 2d geometry in the form of a network of interconnecting tubes. It is the surface of the tubes that is reality. There is no inside or outside of the tubes, other than that used by us to picture what's going on.

"Hmmm, I'm not so sure. Greene will talk about loops of string, he's a particle physicist"Indeed he does and makes the distinction that string theory has as an advantage the idea that the smallest constituents of everything are not infinitely small and pointlike, but spread out in a string.

I asked this elsewhere, but maybe someone on this thread could answer. If we were to measure the universe from the perspective of the photon, there would be no time due to special relativity and no space due to length contraction, right?If that's true, then can it not be said that time and space do not always exist in the universem or from every vantage point in the universe?That suggests to me that the universe consists of something more fundamental than space and time.This message has been edited by randman, 08-26-2005 01:41 AM

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