Time may be disappearing

[mtelya]

Hello everyone,
I just read an article saying that time may be disappearing. This hypothesis is based on string theory, and according to a series of papers published by Jose Senovilla and Mike Mars, our Lorentzian brane signature (with 3 space and 1 time dimension) may be turning into a Euclidean one (with 4 space dimensions), which means that time is slowly disappearing.

Now, all this sounds bizzare to anyone with a rational brain, but say I were a scientist and I wanted to test this hypothesis i.e. time is slowly disappearing, which experiments should I carry out or what types of data can I collect to confirm it ? How can I definitively prove or disprove this hypothesis ?

And please, give me some serious answers. No "just look at your watch" or "just build a time machine" type comments. I'm really curious about this, and I admit that I can't even understand 1 % of the theory behind it, but I still want to know what we, as humans, can do to prove such a hypothesis.

One of Mars' papers says that light cones will stop existing if we only had 4 space dimensions. Would the narrowing of light cones prove that time is slowly disappearing ?

Looking forward to your answers. The more, the better.

Cheers

[tusenfem]

Dear mtelya, welcome to BAUT! (be sure to look through the rules of the board, shown in my sig)

If you want to ask a question like this, it is always VERY useful to give the source where you have read such a thing. Otherwise everyone will have to start searching for themselves. I did a quick look and on arxiv I found the original paper (for those not daunted by higher math).

Have fun here.

[Cougar]

say I were a scientist and I wanted to test this hypothesis i.e. time is slowly disappearing, which experiments should I carry out or what types of data can I collect to confirm it ? How can I definitively prove or disprove this hypothesis ? And please, give me some serious answers.

If you were a scientist, I would seriously suggest you look for a different research project and buck the trend of many recent investigations into areas that have no way to observationally confirm their findings.

[Peter B]

Hello everyone,

G'day mtelya, and welcome to the BAUT Forum.

I just read an article saying that time may be disappearing. This hypothesis is based on string theory, and according to a series of papers published by Jose Senovilla and Mike Mars, our Lorentzian brane signature (with 3 space and 1 time dimension) may be turning into a Euclidean one (with 4 space dimensions), which means that time is slowly disappearing.

Now, all this sounds bizzare to anyone with a rational brain, but say I were a scientist and I wanted to test this hypothesis i.e. time is slowly disappearing, which experiments should I carry out or what types of data can I collect to confirm it ? How can I definitively prove or disprove this hypothesis ?

And please, give me some serious answers. No "just look at your watch" or "just build a time machine" type comments. I'm really curious about this, and I admit that I can't even understand 1 % of the theory behind it, but I still want to know what we, as humans, can do to prove such a hypothesis.

One of Mars' papers says that light cones will stop existing if we only had 4 space dimensions. Would the narrowing of light cones prove that time is slowly disappearing ?

Looking forward to your answers. The more, the better.

Cheers

My first question is this: What do you mean by 'time disappearing'?

[Ken G]

One of Mars' papers says that light cones will stop existing if we only had 4 space dimensions. Would the narrowing of light cones prove that time is slowly disappearing ?

That seems like a logical conclusion. The problem is, I can make a light cone appear to be narrowing just be redefining my units of time and distance such that c decreases with time. There's a way to do that which is actually just the same physics as leaving c alone-- a kind of "sleight of hand" that might have the appearance of time disappearing that really has no such implication at all. But I presume those authors have been careful about that and have found some objective way of talking about what it means for c to be dropping (which would relate to the dimensionless constants you can generate by combining c with the other parameters like G and h), and how physics would be affected. Sometimes people can be pretty clever at tricking themselves though, so you have to watch out-- and you certainly can't trust the journalists not to jump on an idea and make more of it than is really there. So I just get very cautious about this sort of thing-- it's actually pretty hard to make fundamental changes in things like time without messing up the physics that has worked pretty well for us thus far.

Incidentally, you can see how having some fundamentally physical version of c dropping with time would be a lot like time "disappearing", because c is the speed limit for what things can affect other things. As c drops, fewer things are in causal connection with other things, and ultimately, if c was zero, nothing would affect anything else-- everything would be its own "mini universe", and there'd be no concept of elapsed time because nothing can change if there are no interactions of any kind. If that is what they are talking about, it wouldn't matter that the universe would have a 4D spatially Euclidean structure, because there'd be no connections between those different places, so who cares what we want to call its geometry.

[Jeff Root]

This is amazingly closely-connected to tommac's thread,
http://www.bautforum.com/showthread....-we-determine-...

-- Jeff, in Minneapolis

[mtelya]

Hey Cougar,
If I were a scientist, I wouldn't be asking questions such as these ones on this forum. I would just ask my peers. I am only posing a hypothetical here, because I am curious about the notions that time may be disappearing, and I don't have any contacts in the "Scientific community". I already tried asking the authors of the research paper, but no reply.

Cheers.

[mtelya]

Well, the paper said that the time dimension, as we know it, may be morphing into a space dimension, which is why we may be percieving an accelerated expansion of the universe. It is mentioned in one of Mars' and Senovillas paper, titled "ACCELERATING EXPANSION AND CHANGE OF SIGNATURE". There are many other papers by these authors on this topic as well.

[Strange]

Not sure if this is the article the OP was referring to: http://www.scientificamerican.com/ar...could-time-end (whole article not available without a subscription)

The article references: http://arxiv.org/abs/hep-th/0603104 and http://arxiv.org/abs/0710.0820

[mtelya]

Hi Ken,
Thanks for your reply. I re-read Mars' and Senovilla's paper titled "Branes changing signature", and they didn't mention anything about changing the units of time or speed. Their artice just says that light cones degenerate into a single direction as they approach a euclidean signature. There are many other complex calculations and string theory jargon-bombs in there is well, which I am trying to decipher. But it was published in the Journal of Physics, so it must be peer reviewed. It looks trustworthy to me.

But your notion that the disappearing of time may correspond with a reduction in the speed of light makes sense. So if the speed of light is percieved to be slowing down, then Senovilla's propositions could be proven ?

[astromark]

You have got to be more careful... To say a theorem is wrong without providing any science to support it is a little risky.

To say that it must be so because a mathematical solution can be found... Is not a confirmation of facts. Is it ?

To say there is more unknown than known is a ' Hard to argue with concept.'

I will make the assertion that. ' There is something wrong or, at least odd about our view of ever eccelorating expansion from a

singularity concept...' But I have NO idea how I could be scientific about this... I simply do not have the information required.

This enquiringly is a perfect case for. How will we ever know. No. I do not see time diminishing as a dimension of reality.

As a ever increasing volume of the universe unfolds... I can imagine sparsity.

[Ken G]

But your notion that the disappearing of time may correspond with a reduction in the speed of light makes sense. So if the speed of light is percieved to be slowing down, then Senovilla's propositions could be proven ?

It sounds like it is using theories that I don't know, like string theory, but we can certainly see that slowing light would close down the light cone, but it really wouldn't change the qualitative nature of space and time until the speed got all the way to zero, which is a singular limit of a dropping speed. I don't think that is what they are talking about, because there's a big difference between a slow speed, and a zero speed. A very slow light speed is the opposite limit from Galilean relativity, because in the latter, spacetime is divided into past and future by a single plane of absolute simultaneity, like c->infinity. If c->0, the dividing region between past and future would be everything that is outside the world line of any given object, that is, every object would share nothing of the past or future of any other object, and there would be no meaning to motion. That's not a Euclidean signature, it's a signature where space completely dominates the concept of separation between events, just as in Galilean relativity, time does.

A Euclidean signature for spacetime would have rather strange properties, like what one observer perceives entirely as spatial separation, another perceives entirely as temporal separation. Cause and effect could no longer be supported as an objective principle of physics, which is probably what they mean by the "disappearance" of time.

[mtelya]

A Euclidean signature for spacetime would have rather strange properties, like what one observer perceives entirely as spatial separation, another perceives entirely as temporal separation.

How can there be temporal seperation in a Euclidean universe, it there is no timelike dimension ?

[Ken G]

How can there be temporal seperation in a Euclidean universe, it there is no timelike dimension ?

The timelike dimension would be purely by convention, if we are stipulating that we have three dimensions of space and one of time. That's why a simple rotation would turn the timelike dimension completely into a spacelike dimension, ruining the concept of causality. Put differently, we are saying the same thing-- if there's no causality, there's no reason to call one dimension time and another space, so the timelike dimension would "turn into" a spacelike dimension, and time, and causation, would have "disappeared." One way to do that is set c=0, but that only works when c is exactly 0, not in the limit of small c, so I don't think letting c get small is really what they are talking about. Similarly, it cannot just be a narrowing of the "light cone", that really isn't on the way to "disappearing" time, it's just on the way to a slower c.