Time travel

[Impressionist]

Recently I’ve watched an episode of “Into the Universe with Stephen Hawking” about time. Hawking tried to find out whether traveling in the fourth dimension – time – was possible.

At first he wanted to check if we could go back to the past. It turns out that there are plenty of microscopic quantum tunnels all around us. But even if the scientists succeeded to enlarge one of such tunnels, going back to the past would be rather impossible, mainly because of paradox. Hawking showed an example of a crazy scientist who created a tunnel which could transport him 1 minute back in time. Using this tunnel he shot himself (in other words the “present scientist” shot the “past scientist”). So, if the “past scientist” has been killed, who shot him? And this is paradox.

Next Hawking wanted to figure out whether going into the future was possible. Again, it turns out that very heavy objects make time slow down. So for people who are standing next to a pyramid in Egypt the time passes slower than for people on the desert. The difference is incredibly small. But if humans managed to build a spacecraft which could move around a black hole (which is incredibly heavy), the difference would be much bigger. So if the crew of that spacecraft spent 10 years moving around the black hole, people on Earth would be 20 years older.

Another possibility: we could build a train which would move around Earth (on its surface) almost with the speed of light. Time inside that train would pass much slower. Like: 1 year for the people on Earth and 1 week for the passengers of the train.

I know, sometimes I fail at explaining, but I tried to do it the easiest way. It’s hard to understand this, but I’d like to know your opinions. What do you think of Hawking’s theories? If traveling into the future was possible, would you like to go there? And why?

Thanks for reading this. Here’s the link to the video, if someone would like to watch it. YouTube - Pt 1 of 4 Stephen Hawking's Time Travel

If you notice any grammatical errors here, please let me know.

[Layzie]

That is really interesting, I'm glad you made this thread. I can use some of the info I just read in future arguments about time travel.

I can't watch the video(s) now though, I will in the morning though.

[tm20]

I'm no genius, but Hawkings is and I've seen his "Into The Universe" series (well I missed that part about time travel) so I would believe anything he says XD

[Banefull]

Before watching this I had a deep understanding of what "deep" physics dictated (not the actual mathematics but a good summary). I was already under the impression that time travel to the past was impossible (at least in theory but who knows); however, if you did manage to go back in time and shoot yourself, the timeline in a parallel universe would change rather than the universe you were currently inhabiting so no paradox would exist. I find Hawking's explanation for feedback as the reason for no time travel to the past odd because could you not send something back in time (something a few nanometers long) through a tiny microscopic wormhole (accumulating feedback at a slower rate by virtue of its size) before it collapsed (Unless of course a smaller wormhole requires less radiation to destroy in which case it would still be infeasible but I would still imagine the difference rate that a wormhole accumulates feedback would not increase in a one to one ratio to the level or radiation required to collapse it).

[The Man in Black]

Originally Posted by Banefull

however, if you did manage to go back in time and shoot yourself, the timeline in a parallel universe would change rather than the universe you were currently inhabiting so no paradox would exist.

This is correct, because if you overcame near impossible odds to time travel into the past (which I still believe is impossible), you would be doing so in a mirror universe where your actions would have no consequences in the present universe.

However, time travel into the future, so to speak, is easy. Travelling at high speeds causes time dilation: someone travelling at near the speed of light for extended periods of time would have time go "slower" for them compared to an observer on Earth. That said, you could leave Earth at near the speed of light and age some years and return to Earth finding everyone you knew long dead. This has been experimentally proven using highly accurate atomic clocks. So by driving a car or flying in planes for your whole life, you have traveled into the future by a zillionth of a nanosecond compared to someone who did not.

[LOVEavatar]

This leaves me wondering, a lot... as with all scientific TV-programs Still though, I don't really see what we would gain out of this into the future time travel if the travelers would still exists in the same universe as -all others-

I mean, the way I view time travel as is a journey minded in helping people... not just travel away for some time and then come back and like WHOAH, look! Everything is so different!... but how will we be able to travel back and tell everyone about this? <:O *great shock* Well you can't! Because there are no such thing as time travel to the past!

Meh, I've never really been comfortable with the way scientists make impossible odds hypothesis's just so they have something to ponder over :/

Hawkings is damn smart though. Even though his theories might be wrong (as some above claim) If he's wrong it will just help other to get it right
You can't be right without someone else being wrong.

[SaphirJD]

Well, if i could go into the future, i want to go to that time where the universe ends, Must be a brilliant spectacular scene

[Banefull]

Originally Posted by SaphirJD

Well, if i could go into the future, i want to go to that time where the universe ends, Must be a brilliant spectacular scene

Wouldn't that mean you would end too (if you were actually present inside that universe)?

[LOVEavatar]

Originally Posted by Banefull

Wouldn't that mean you would end too (if you were actually present inside that universe)?

lol self ownage

Edit:

Hmm... seems like I missread "Into the future"... well.... I dunno really... maybe to 2014 to see "avatar 2"

not really though :/ would ruin the experience to watch it right away.

[SaphirJD]

Originally Posted by Banefull

Wouldn't that mean you would end too (if you were actually present inside that universe)?

This is a very very late response i know Well, nothing beats a spectacular showdown, and it would be a perfect scene to leave the universe with a bang

[GP-5]

I think you all have heard this one before...."If timetravel will be possible in the future, where are all the timetravelers?"

[LOVEavatar]

Originally Posted by GP-5

I think you've all have heard this one before...."If timetravel will be possible in the future, where are all the timetravelers?"

lmao

Good quote

(PS: Haven't heard it before )

[Impressionist]

Hmm, quite interesting opinions here

Originally Posted by GP-5

I think you all have heard this one before...."If timetravel will be possible in the future, where are all the timetravelers?"

Yeah, exactly. This explains why traveling into the past is impossible.
But generally, I think that there are no timetravelers, because the future is still in front of us. The timetravelers have nowhere to come from.
Meh, it's confusing.

[LOVEavatar]

Originally Posted by Impressionist

Hmm, quite interesting opinions here



Yeah, exactly. This explains why traveling into the past is impossible.
But generally, I think that there are no timetravelers, because the future is still in front of us. The timetravelers have nowhere to come from.
Meh, it's confusing.

Do we really know that? What if we are in the past without knowing it?

There are multiple theories about dimensions as we know them in the universe, one specific I heard about a while ago (can't really remember) but it built on that it was all divided into 11 different dimension. And instead of describing 3rd and 4th dimension as <- that, they had name as "Feelings/Emotion" and "Thoughts". And I remember the higher ones as "Magnetic Energy", "Matter Energy" etc. And the ones on the top were something like "The all God" and "Servant to the all God".

That last part might sound silly, but that's how I recalled it of being. And it might just be more than that, what if both are probable?

Ah, seems like I finally found something of what I was referring to:

"Multiple Dimensions

For years, Einstein hoped to unite the contemporary ideas of relativity and quantum mechanics. Yet, he could not unite these theories because he limited his parameters for a unifying equation to the four dimensions that humans consciously experience. The first physicists to truly pursue the theory of additional dimensions were Kaluza and Klein. They noticed that if a fifth dimension were to exist in the universe, there would be fields of angles between all of the existing dimensions. By applying this to Einstein’s geometric model of gravity, Kaluza and Klein noticed that gravity, the force that relativity is concerned with, and electromagnetism, one of the forces that quantum mechanics deals with, showed similar properties. Therefore, by adding a fifth dimension to the universe, the same equations that apply to electromagnetism could also apply to gravity. It was later shown that not only is one additional dimension required for this link to be solidified, but six more dimensions. Even further down the road, it was discovered that the formulas used to determine this number (which are actually mathematical methods of approximation, since the actual formulas are unknown) we slightly off, resulting in yet another necessary dimension. Therefore, our three physical dimensions plus one time dimension plus seven additional dimensions results in there being eleven dimensions!"

Maybe this also have some valuable points:
Multiple time dimensions - Wikipedia, the free encyclopedia
Have in mind though that that^ is almost as much physics as philosophy.

I don't usually (like... never?) get myself involved into discussions, even less scientific ones, but now I felt like i wanted to share my two cents

[Human No More]

Knew most of that before. You can also experience time more slowly by travelling close to the speed of light (the reason the ISV trip takes ~5.75years on it and ~6years from the perspectives of Earth and Pandora), with the rate of time dilation increasing the faster you go.

The way I see it, paradoxes have three possible solutions: Time is nonlinear, in which case it would be easy to travel back and kill your past self and you would change the future while the now-alternate you would still be in that time, time is linear so that would not be possible because if you did, you would have been unable to travel back from the future, or time self-corrects in which case if you killed your past self, you would disappear too (unlikely, but occurs in some fiction).