What's the latest research on time travel?

I’m doing a bit of research on it now, and basically what I’m finding is:

  1. String theory, Hypertime theory, and multiple universe theory support it.
  2. Einstein’s relativity theory doesn’t.
  3. Viewing the future/past is supported.
  4. Chaos theory says it’s impossible.
  5. Paradoxes also don’t support it.
  6. The two main theories: timeline is subject to change vs timeline cannot be changed both have strong arguments for and against it.

Overall, I’m biased towards the “timeline cannot be changed” argument. But, I am unfamiliar with current research in quantum theory that might support it.

Well, it works. At least for periods of less than five minutes.

Okay. let me try something and I’ll get right back to you with a report.

DrFidelius is funny!!

Proof it will never happen: we’d have heard about it by now, unless it only happens in the future. Think about it.

I don’t know if you really want an honest answer, but the bottom line is that there’s no currently accepted physical theory that includes (backwards) time travel.

There are some situations (for instance, inside black holes) where currently accepted physical theories are known to be incomplete. Various proposals for extending our theories to cover those situations have, in some cases, had mathematical solutions to certain exotic cases that could be sort-of described as being time travel. But none of these proposals have any evidence to support them yet, and aren’t much more than idle speculation. In any case, even in the unlikely event that one of these various proposals pans out, the situations that allow ‘time travel’ are not going to be useful: even if the inside of a black hole does somehow exotically connect to a different point with a time-like separation, any person or object is going to be reduced to featureless mush before reaching the inside of the hole.

You do realize that string theory and hyper-time theory are proposals and are not supported at all (or poorly) by experiment? Especially when considered against relativity.

Secondly chaos theory is better described as non-linear dynamics and is a mathematical tool used to describe systems that exhibit non-linear characteristics. It’s not a theory but a tool.

What is hypertime? The only references I’ve been able to find to it are as a clever way of explaining contradictions in comics (and possibly other media). That’s not a scientific theory or hypothesis at all, so in a scientific discussion it’s irrelevant. I’ve never seen any claims that string theory has any relevance to time travel. Do you know of such a claim? I’m not sure what you mean by multiple universe theory. Are you talking about Wheeler’s multiple universe explanation for quantum theory? That doesn’t have anything to do with time travel. Chaos theory doesn’t make claims about physics at all, so it doesn’t make claims about time travel.

We have no evidence for time travel.
It’s true that we can see supernovas that took place in remote galaxies in the past - but then you could argue that detecting anything is effectively seeing the past, no matter how infinitesimal the time interval.

Apparently an astronaut who travels pretty fast on a ronud trip will find Earth has aged more than he has when he returns.
But I assume that’s also not what you mean by time-travel.

These are highly, highly theoretical. Heck, there’s really no such things as string theory, just a bunch of string theories that crop up and get knocked down every so often. Im not sure what hypertime is and am certain that quantum interpretation of a multiple universe has nothing to do with time travel.

I cant imagine any real reason for time travel. Its illogical on its face. For instance, the mass you are made of cannot be duplicated (cannot create matter) so going back or forward in time is a violation of that law. Even then, the mechanics of time travel is all speculation.

Time travel is a fun thought experiment and a sci-fi stereotype. It really has nothing to do with reality. Your question reminds me of the cabbie from the book “A Demon Haunted World.” Sagan gets in this cab and the guy keeps asking him questions about pseudoscience. Sagan realizes that to this guy time travel, aliens, pyramid power, etc is science. The cabbie doesnt understand the different between pseudoscience/scifi fiction and real science.

Time Travel leaves 3 possibilities:

  1. Its impossible. There is no evidence of it.
    or
  2. Its rigidly enforced by a flawless police force that prevents evidence of it prior to it’s discovery. (the potential for a flawless police force makes this one doubtful)
    or
  3. We never discover it.

There are probably an infinite number of reasons why we don’t see evidence of it. Maybe it’s possible but takes an ungodly amount of energy, making it obscenely rare. Who knows. All we know for sure is that we don’t know.

Einstein’s theory doesn’t forbid the possibility, it just makes it very very difficult.

Isn’t there some “wormhole” hypothesis that postulates a limited effect? The idea is, you invent it today, and switch it on – and you’ve now got the stable tail end of a portal, even as time marches on otherwise. So you can, in days to come, travel back to “today” from next week or next year or whatever, but you can never go back past the moment when that device was switched on.

So if people discover that in the future – well, they can’t use it to visit us; they can never go back past that rainy day in 2035 when Ayo Sotinwa unveiled the world’s first working time machine, or whatever.

I can envision a scenario where a technique can be developed for time travel–forward and backward–but you can only travel back as far as the time when the technique was developed.

A fun xkcd on time travel.

Thanks to special relativity, anything you can use to travel faster than light you can use to travel through time – so if you can actually build an Alcubierre drive, well that’s your time machine right there!

FTL is prohibited by relativity.

No, its not.

That’s a common misconception though.

In relativity FTL = time travel. The impossibility lies in the energy requirements - which are infinite

It’s real allright. I’ve been hunting time travellers for most of my adult life. It’s not even that hard to find them if you think about it logically. Where would a time traveller go? What would they want? What would they be doing?

Time travellers have lierally all the time in the world to fix their mistakes. They can just keep coming back. This means that while it’s not hard to gather enough evidence to prove their existance, you can’t show it.

If you try to prove it to other people, and succeed, the time travellers in the future get wind of it and change things so it never happened.

It’s a real bitch.

Four, actually.

  1. It has been discovered, but only by socks and ballpoint pens.

Of course there are time travelers. Did you notice how it was quite common to use race and nationality to slur people, now people don’t do that. Why? 'Cause time travelers came back and fixed it so it’s not right. And then they rewrite history books into what time travelers call “PC”

So we think “oh the history books were re-written to be politically correct,” but no they weren’t. Time travelers fixed the books and the plausable explination is PC

Also I saw a Calvin and Hobbes cartoon about this and Calvin proved time travel so that’s good enough for me :smiley: