Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: NTHstars on 28/05/2018 21:03:35
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If faster-than-light travel (or wormhole tunneling or some other exotic means) was found to be able to communicate information from the future to the present, what would that indicate about the structure of time? Some might argue that would indicate a block-type of time structure, since from the perspective of the present the future doesn’t exist yet. But if the information literally “goes backward” ONLY at a moment in the future when the information is available, is a necessity for a block universe just an illusion?
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I had not heard of a "block universe" before.
Here is a brief introduction: https://plus.maths.org/content/what-block-time
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Yep, that is the general view of a block time universe. What I'm getting at is...if anything from a future can go backward in time (info, people, whatever) what does that imply about the structure of time? How would that information plug into current established physics, the view of time, etc.? So I'm only interested in what the consensus would likely say it means, so I'm not trying to throw the baby (mainstream science) out with the bathwater.
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if anything from a future can go backward in time (info, people, whatever) what does that imply about the structure of time?
It would probably say that the time structure was such that rational beings could not survive it it!
The fact that rational beings do inhabit in our Universe, with its existing time structure, may well militate against the realisation of past-directed time travel of any sort.
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Alicia lives in a timeless space. And when she looks back at the block universe she sees all of our past and all of our future simultaneously.
If Alicia is in a timeless space, she can do nothing. Doing something is effecting change; change needs time. Fairytale cosmology rules, OK?
I’m not arguing against the “block universe”, there are some aspects of it that undoubtedly have merit, but playing fast and loose with change and time is not conducive to making a convincing case.
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I think you are right, that at a glance it seems any kind of backward travel of information (and certainly people) could create incredible havoc, and since we don't see havoc, logic dictates such chaos is not at work. I believe people cannot and will not ever be able to travel backward in time for the most obvious reasons (thermodynamics, causality, and that thing called death), but information is another subject. Plus, if they can...where are they? Of course, where is anybody off Earth, but that's another subject.
I realized today I could have gotten to the root of my question far easier, perhaps without having to elicit the polarizing idea of faster-than-light exchange, by simply asking: "if we ever developed a methodology that generated evidence that the future exists from the standpoint of the present, what would that imply about the framework of time and perhaps the correct interpretation of quantum theory?"
Of course that's not shorter, so not sure that helps ;0
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I had not heard of a "block universe" before.
Here is a brief introduction: https://plus.maths.org/content/what-block-time
That website is wrong. Whoever wrote it doesn't understand spacetime completely or what Einstein said about spacetime.
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Can you explain how it is wrong, or point to a more accurate explanation? Thanks!
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well, the notion been around for quite some time. It's what I would call a 'static universe', in where everything 'exist'. From that notion doesn't follow that everything will be realizable in 'time'. And why that is is because of 'free will' and HUP ( Heisenberg's Uncertainty Principle ) existing. Those guarantee that only some/one of those possibilities can fall out at any given time or if you like, 'instant of time'.
It's nothing new actually
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you can think of it as a endless labyrinth in where your choice defines your path
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From that viewpoint, the "brick" as some call it would really consist of superpositions always resolving into now---the present---based on apparent randomness as well as specific choices. Interesting enough, one could argue that isn't much different than Many Worlds. A potential key difference would be whether paths not taken are actually realized "elsewhere."
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Alternatively, one could reason that the cosmos is eternal and unchanging. Within the cosmos, everything simply “is”. The perception of time and change is an illusion, peculiar to our Universe, which make it possible for us to exist within, and make sense of the Universe.
Barbour’s “Platonia” is a slightly more extravagant version of this.
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Can you explain how it is wrong, or point to a more accurate explanation? Thanks!
The author of that page wrote
A consequence of Einstein's unifying space and time is that there are no preferred dimensions; there's nothing special about time. Just as all of space exists in the block, so does all of time. "The importance of this is not so much that there is an extra dimension," says Cortês. "The outrage is more that time is confined in our four-dimensional block." So Alicia lives in a timeless space. And when she looks back at the block universe she sees all of our past and all of our future simultaneously.
This is wrong. Space and time are treated in a similar maner mathematically but they are very different kinds of things physically. The great physicist Richard Tolman once said that you can rotate one spatial axis into another (i.e. you can rotate a rod into a rod) but you cannot rotate a clock into a rod. Any first rate relativist will you this.
In fact I'm going to ask Alan Guth to do some more videos for me for the common misconceptions part of my website. We'll do it on this point.
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Nothing confuses people more than time, perhaps. That alone is fascinating, because our everyday experience of it is so straightforward, rigid and...boring. Yet Einstein saw through that.
Taking a left turn...The fact time-like curves emerge from some of the relativistic equations, and that nature tends to utilize whatever "assets" it has...should make us suspect the phenomenon could be at work somehow, likely not violating self-consistency (as has been suggested should be the case, IF they exist). So, if there was "communication from the future" as I speculated, it's content would have to reflect some rather specific constraints that GUARANTEED consistency was maintained.
And I can't not notice you mentioned you make videos with Alan Guth...that is quite important work. Thanks for your insight.
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Why I personally like a static universe is because I don't like 'many wolds scenarios' in where everything bifurcates into different 'Dimensions/universes/time lines/ etc etc'. As each universe created by by a bifurcation in its turn also should bifurcate it gives me a logic headache. It seems also a waste of 'energy' to me and it's not 'simple'. A static universe is like a 'block' of 'energy', it should have a defined magnitude of whatever it needs to 'transform' into 'paths taken'. And I agree with Pete, 'time' is a very special thing, pointing only one way, the 'arrow of time', whereas any other dimension we measure do point two ways.
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A very good argument against infinite creations of new universes is that question from where this 'energy' to do so would come? Contained where?