Big bang

[Teralek]

Sorry. An infinite universe makes no sense and in any event contradicts the evidence. I can prove this quite easily, albeit not briefly, so I won't attempt to do so here.

I'm with you... I just thought that this is still an open subject in science. Unresolved question.

How do you decide "backwards" and "forwards"?

Too easy. Forwards is when effects are preceded by their causes. Backwards is the temporally reversed image. This is what the models of physics are modelling.

You did not understand my question I think... because I still feel my question was not answered. You said "What Superman will see is the universe sucking itself back in to a point, the exact temporal opposite of what actually happened. Whichever way we decide to define the big bang the observer can only see it happening backwards because the observer observes a hologram. QED." Can you explain this please? why we see the exact opposite of what happened?! what does this has to do with the Universe being a hologram?! I don't get it...

Not at all. You're late to the conversation so you've missed a fair bit. I'm agreeing with Einstein completely and Einstein is one of my greatest heroes in science. He said from the outset that spacetime should NEVER be regarded as physically real but only as a model of the physically real. He stressed this throughout his life and I simply took him at his word. Niels Bohr said almost exactly the same thing, as did John Wheeler. I'm not a physicist so who am I to argue?

I don't think you understood. you said time and space are mutually exclusive. "Two events are mutually exclusive if they cannot occur at the same time. An example is tossing a coin once, which can result in either heads or tails, but not both." That means you are saying that if space exists time cannot exist, and vice versa. But I think that Einstein said excatly the opposite, no? space/time is the same thing, cannot be separated.

I better qualify this because it's poorly phrased. The universe cannot be infinite in the sense that it cannot contain an infinite quantity of mass/energy. In this paradigm it is in fact temporally infinite in the sense that it is eternal. The less about spatial infinity the better.

Regards Leo

Do you believe the Universe is closed upon itself? Like if you could use your superman again and travel "straight" at incredible speed, will he eventually end up on the place it started? If so how do you explain that the Universe is flat (according to last measurements)?

[Obvious Leo]

I'm with you... I just thought that this is still an open subject in science. Unresolved question.

It's not so much unresolved as ill-defined. Infinity is an an entirely mathematical idea and not a physical one. As such it is an abstraction. For instance we can say that there are an infinite number of whole numbers and we can also say that there are an infinite number of even whole numbers or an infinite number of prime whole numbers and so on. This never stops and these constructs are all infinite but they're not all equivalently infinite. Thus in mathematics and in mathematical physics infinity is only used to describe the way a system tends and is not meant to represent an actual physical state. They think of infinity as a set of infinities and just use them as a mathematical convenience and not as a quantity. Zero is regarded in the same way. In physics infinity is just a polite way of saying "wrong" and mathematical constants are devised to eliminate different infinities from equations. Physicists are perfectly comfortable with doing this because modern physics is just a branch of mathematics. They understand the limitations of what they're doing but it can be rather challenging for the layman.

Infinity can have a metaphysically real meaning, however, even if it can't have a physical one. We can apply it to time and say that time is eternal. Eternity is not an easy notion for a mortal mind to grasp and yet it is self-evident because existence cannot spring from non-existence. The theist has an easy out but the physicist doesn't have this option. However the physicist does have the first law of thermodynamics and that's plenty.

You did not understand my question I think... because I still feel my question was not answered. You said "What Superman will see is the universe sucking itself back in to a point, the exact temporal opposite of what actually happened. Whichever way we decide to define the big bang the observer can only see it happening backwards because the observer observes a hologram. QED." Can you explain this please? why we see the exact opposite of what happened?! what does this has to do with the Universe being a hologram?! I don't get it...

I'm not sure what it is you're not getting. We can imagine the universe "beginning" at the big bang and evolving to its current state over a period of 13.8 billion years. We can say that this is the correct order in which reality has been made so our minds are not deceiving us. However our observation is, even though our minds can easily flip things the right way round. When we observe it we observe it ending at the big bang because we can observe no further into the past. This is literally true and what I said about Superman's observation is perfectly correct. He doesn't see the universe beginning, he sees it ending, so he's looking into time's mirror. If this is still troubling you sing out and I'll see if I can get at it from a different angle.

But I think that Einstein said excatly the opposite, no? space/time is the same thing, cannot be separated.

Indeed he did but he intended this only in a mathematical sense, not in a physical sense. Einstein was not mathematically fluent at the time he published Special Relativity and it was actually his maths teacher, Hermann Minkowski, who invented the four-dimensional continuum known as spacetime. Spacetime is solely a mathematical idea, and a very useful one at that, but after the publication of Einstein's second major relativity theory, General Relativity, he made it publicly and explicitly clear that spacetime should NEVER be regarded as physically real, a stance he maintained throughout his life and repeated often. The history of this is very interesting and also quite instructive as to how physical theories take hold in the mind of physicists. Neurons that fire together wire together and in the early days they all knew they were just playing with equations but gradually they all started to believe their own ********. All except for Einstein, that is, who only went along with Minkowski because his model had such a predictive power. Obviously it would, because it is specifically designed to predict what the observer will observe. We should then hardly feign surprise that the observer duly goes ahead and observes it. This is the spacetime flaw. Einstein was only an average physicist, and a downright mediocre mathematician, but he was a genius of lofty calibre whose genius lay in his piercing insights. He could see this flaw immediately. Not many people can nowadays, so they all just generically call it "the observer problem" without knowing what they mean by it. This is the problem that my philosophy seeks to redress. The observer problem is the worm in the spacetime apple.

Do you believe the Universe is closed upon itself? Like if you could use your superman again and travel "straight" at incredible speed, will he eventually end up on the place it started? If so how do you explain that the Universe is flat (according to last measurements)?

This is the sort of question which I started out asking forty years ago and set me on the path to my philosophy in the first place. It is unanswerable, either by me or any conventional physicist because it makes no sense, either to me or to them. I Intend no insult but it's not a physical question and certainly it's not a metaphysical question. I can make no real comment about this because this is an entirely space-related question and in my paradigm space exists solely in the mind of the observer and as a mathematical idea. It isn't real. Even Superman can't travel faster than time so any thought experiment involving superluminal travel is valueless. The future doesn't exist because it hasn't been made yet and therefore we can make no meaningful statements about it, even in principle.

Regards Leo

[Felix]

"Even Superman can't travel faster than time so any thought experiment involving superluminal travel is valueless."

He did in Superman I (with Chris Reeves) to resurrect Lois Lane after the earthquake... nice little trick.

[Obvious Leo]

what does this has to do with the Universe being a hologram?

I didn't notice this in your post earlier and this may account for the misunderstanding. I didn't say that the universe is a hologram. I said that the observer observes a hologram. This is what the physics part of my philosophy is all about because this is what the observer problem is. This is what has given physics all its angst for all these years and this is why their models make no sense. These models are modelling the hologram, the back-to-front reality.

Interestingly, for a bit more history, both Stephen Hawking and Gerard t'Hooft proposed models in the nineties which became known as the holographic universe models. They got a lot of attention in the scientific media because both these guys have won Nobels, and t' Hooft, in particular, was held in the highest esteem amongst his peers. Neither of them could make their models stick and the idea died a natural death. I didn't like the models either but it planted a germ of an idea in my head all the same. They were also suggesting that the universe actually is a hologram, but it took me a bloody long time to ask myself the question: What if the universe just appears to be a hologram? I thought it was an original line of thinking and I'd already been over the observer problem from every other possible angle I could think of so why not?

Regards Leo