Is our 3D universe a shadow of a 4D Universe?

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Is it possible that our 3D universe is just a shadow in 3D space of 4D or higher dimensional reality? And we are limited in our perception of it by our 3-dimensionality. In other words like Flatlanders would just see s square of a cube sitting on the plane or passing through the plane. Actually they would see a line, but they could deduce that this line represents a square by the number and type of corners (angles) they could feel by going around the line? Similarly we deduce a lot of things by studying nature. But all of the results are limited by our 3-dimensionality?
 

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  • #2
phinds
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Sure. It's also possible that unicorns actually exist but I'm not holding my breath since there's no evidence for either one.
 
  • #3
Ibix
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Is this just the block universe, stated rather imprecisely? "The universe now" is a 3d spacelike slice through 4d spacetime. Even viewed like this, though, the universe isn't a shadow of spacetime any more than a slice of ham is a shadow of a pig. So it's possible I'm searching too hard for meaning here.

OP - look up "block universe". If that's what you meant, then yes. If you meant something like Plato's cave then there is nothing like that in modern physics that I'm aware of.
 
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If phinds can not find evidence, it does not mean things do not exist.
 
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Ibix
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If phinds can not find evidence, it does not mean things do not exist.
That is not how science works. You need falsifiable predictions and then experimental tests of them - what phinds sums up as "evidence".

If you meant the block universe then that's a way of conceptualising relativity theory, which has tons of predictions and tests of it, and is science. If you meant something else then it's almost certainly something with no evidence for it, and probably no possibility of evidence. That's not science, and therefore not a valid topic of discussion here (i.e. unless you can provide peer-reviewed papers supporting whatever it is you are getting at the thread will probably get locked).
 
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phinds
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If phinds can not find evidence, it does not mean things do not exist.
I agree. Absence of evidence is not evidence of absence. I still don't believe in unicorns or in what you are suggesting and my statement was NOT that *I* can't find evidence but that (as far as I know) there IS no evidence. I feel confident that if there WERE any evidence it would be a big deal and I would have heard of it.
 
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From what I understand growing block universe theory of time is different in that more and more spacetime is coming into being, Here we are talking about 4 D objects passing through a 3D space. For example if a cube (3D object) is passing through a plane (2 D space), some hypothetical 2 D beings, living on that plane would "see" it as a line that exists in their space for the duration of the passage, and then it is gone. They would not have the ability to comprehend what is the real nature of the object (cube), due to their 2D space limitations.
 
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phinds
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From what I understand growing block universe theory of time is different in that more and more spacetime is coming into being, Here we are talking about 4 D objects passing through a 3D space. For example if a cube (3D object) is passing through a plane (2 D space), some hypothetical 2 D beings, living on that plane would "see" it as a line that exists in their space for the duration of the passage, and then it is gone. They would not have the ability to comprehend what is the real nature of the object (cube), due to their 2D space limitations.
Yes, I've read Flatland and it's a wonderful and very clever book but I think extrapolating it to the real 3D world is a waste of time.
 
  • #9
Ibix
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The block universe asserts that all of spacetime always exists in some sense. No growth is needed. What you call "the universe now" is a 3d slice through that.

If you mean something other than that, I'll repeat: do you have a text book or peer reviewed journal article reference for what you want to discuss? If not, this thread is going to get locked because PF rules require that as a minimum standard for discussions.
 
  • #10
berkeman
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The block universe asserts that all of spacetime always exists in some sense. No growth is needed. What you call "the universe now" is a 3d slice through that.

If you mean something other than that, I'll repeat: do you have a text book or peer reviewed journal article reference for what you want to discuss? If not, this thread is going to get locked because PF rules require that as a minimum standard for discussions.
Thanks @Ibix -- this is a good place to close the thread for a bit.

@Zdravko -- If you have such references, please send them to me via Private Message (click my Avatar and Start a Conversation). Thank you.
 

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