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echolocator

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echolocator

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echolocator

Cheers

echolocator

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Originally posted by echolocator

Cheers

echolocator

Well, you have to remember that dimensions of time (and space, for that matter) are not added for fun or because it might look neat, they are added out of mathematical necessity (or mathematical convenience).

Anyway, if there is more than one Universe (as you indicate by saying "a given universe"), then there must be space between it and the next Universe, meaning that there is an ultimate Multiverse, and spacetime would be a property of the Multiverse, not of the individual Universes (or so it seems to me).

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Demystifier said:

Interesting. Any references on that?

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Actually Itzhak Bars [USC] does have such a theory.

Two-Time Physics (2T-physics)

http://physics.usc.edu/~bars/research.html

One might also argue that Steven Hawking in ‘A Brief History of Time’ introduced a similar concept with “Imaginary Time” which is complex time with both real and imaginary components.

https://www.amazon.com/dp/0553103741/?tag=pfamazon01-20

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However, in reading Lisa Randall's book "Warped Passages", the claim is made that 26-d theory has but one time dimension. Is she correct and/or are both possibilities?

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yanniru said:

However, in reading Lisa Randall's book "Warped Passages", the claim is made that 26-d theory has but one time dimension. Is she correct and/or are both possibilities?

By "original" string theory, I presume that you mean bosonic string theory. Bosonic string theory was proposed as a string theory in a D-dimensional Minkowski background and was found to be even semi-consistent only if D=26. While it does indeed predict negative mass states (tachyons), there was only ever one time direction.

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josh1

Demystifier said:

You can change the signature of the spacetime metric without losing hyperbolicity. But what you can`t have are equations of motion with more than two derivatives of time.

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CarlB

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William M. Pezzaglia Jr., John J. Adams

http://arxiv.org/abs/gr-qc/9704048

My work is (-+++) or (-++++) signature, or, when I let my real feelings out, (++++) newtonian.

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arivero

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It seems that arivero is contradicting coalquay404 who in answer to my question said that 26-d string theory has only had one time dimension.arivero said:

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CarlB

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yanniru said:It seems that arivero is contradicting coalquay404 who in answer to my question said that 26-d string theory has only had one time dimension.

26 = 25+1

25-1 = 24.

No contradiction, only one time dimension in 26-d string theory.

Doesn't mean string theory makes sense.

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arivero

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CarlB is right. It is a nice trick in Clifford algebras and also of selfdual lattices.

I have a far fetched conjecture related to this: count the alphabet keys in your keyboard. There are also around 24. It could be that the neural recognisers in the brain are optimum for Leech lattices, thus 24 dimensions. In English sound recognision seems to pivot aroun 24 + 24 for vowels and consonants either. In other languages is more as 8 + 24.

So it is not a coincidence that the numbers of keys in your keyboard is about the same as the bosonic string: both facts would came from the same mathematical object, the Leech lattice. As you may know from theoretical computation lectures, this lattice is also reponsible for the format of self-correcting codes.

I have a far fetched conjecture related to this: count the alphabet keys in your keyboard. There are also around 24. It could be that the neural recognisers in the brain are optimum for Leech lattices, thus 24 dimensions. In English sound recognision seems to pivot aroun 24 + 24 for vowels and consonants either. In other languages is more as 8 + 24.

So it is not a coincidence that the numbers of keys in your keyboard is about the same as the bosonic string: both facts would came from the same mathematical object, the Leech lattice. As you may know from theoretical computation lectures, this lattice is also reponsible for the format of self-correcting codes.

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Consider acceleration. We use time square in the denominator. So it is quite evident that the idea of time having more than one dimension is not only acceptable, it is necessary to explain ordinary phenomena.

R

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Consider acceleration. We use time square in the denominator. So it is quite evident that the idea of time having more than one dimension is not only acceptable, it is necessary to explain ordinary phenomena.

R

Time squared arises because acceleration is the second derivative of position wrt time not because of multiple temporal dimensions.

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