What people forget about time travel

Originally posted by FabianFnas
"H G Wells' machine does not transport you instantaneously, but rather takes you along a line through spacetime."

His machine wouldn't work in reality. It's fiction.

Gosh, what a revolutionary insight.

"Scientist prove time travel impossible - news flash yesterday at eleven."

Originally posted by Shallow Blue
Gosh, what a revolutionary insight.

"Scientist prove time travel impossible - news flash yesterday at eleven."

Yes, of course, in our current technology, time travel isn't possible.

So this is a hypothetical discussion, isn't it?

So, what time traveling method did the author Wells use in his time machine, in your opinion?

What people forget about time travel to the past is that they don't remember time traveling because it they haven't done it yet.

Originally posted by Shallow Blue
Gosh, what a revolutionary insight.

"Scientist prove time travel impossible - news flash yesterday at eleven."

It's an interesting question whether time travel is possible. Going forwards in time isn't a problem, unless you have access to a rotating black hole then backward in time travel appears to be a problem. It's not clear that there is any particularly good reason why it should not be possible. The normal argument is something along the lines that it would violate causality, summed up by the grandfather paradox. But why should causality be a fundamental rule of nature? It's empirically justified, but so was Newtonian Physics up until the late nineteenth century.

In Feynmann's interpretation of the negative energy solutions to the Dirac and Klein-Gordon equations (relativistic versions of Schrodinger's equation) the particles propagate backwards in time, a negative energy electron propagating backwards in time appears to us as a positive energy positron propagating forwards in time. So at the elementary particle level going backwards in time is not that unusual. That we live in a universe which is matter dominated means that these backwards in time propagating states are suppressed somehow (this is linked with CP violation and can partially be explained in the standard model).

The other observation is that the reason we remember the past and don't know the future is connected with the rate of increase of entropy being positive semi-definite. So travelling back in time might do me no good, unless I'd made a mistake I wanted to forget about...

Time travels is impossible. That I've been told next year.

Originally posted by vivify
Think it through:

http://media.biggestproblemintheuniverse.com/wp-content/uploads/2015/02/time_machine_earth.jpg?1ce589

That's what the flux capacitors are for, stupied.

I think time travel must be impossible. If it were possible then we would have already met time travellers from the future. To travel back in time and not interact is pointless exercise.

Originally posted by divegeester
I think time travel must be impossible. If it were possible then we would have already met time travellers from the future. To travel back in time and not interact is pointless exercise.

How do you know you haven't met a time traveller?

Originally posted by divegeester
I think time travel must be impossible. If it were possible then we would have already met time travellers from the future. To travel back in time and not interact is pointless exercise.

Its not impossible, its simply self eliminating. The moment you do interact, you change the future and eliminate yourself.

Originally posted by twhitehead
Its not impossible, its simply self eliminating. The moment you do interact, you change the future and eliminate yourself.

Maybe not if the multiverse theory is correct, the many worlds interpretation. Where you go back in time but start a new string in the time flow so you can't go back to the original universe you just left and so cannot eliminate yourself by killing your grandpa or some such. You CAN go into the new universe that you started by your time travel trick and you CAN kill your grandpa there but you are from another universe so you don't just die yourself but exist out of time from that time frame. So in the old universe you just disappear and in the new one you just appear.

Originally posted by sonhouse
Maybe not if the multiverse theory is correct, the many worlds interpretation. Where you go back in time but start a new string in the time flow so you can't go back to the original universe you just left and so cannot eliminate yourself by killing your grandpa or some such. You CAN go into the new universe that you started by your time travel trick and you ...[text shortened]... m that time frame. So in the old universe you just disappear and in the new one you just appear.

I'm not so sure about this.

Every interacting changes the future. Especially in the universe you do the interacting with.

So if you really go back in time, one click to the next universe and kill your grandfather there, you will certainly not be born in that specific universe.

In the very moment you bring up the multiverse theory, you are speculating, but that you know already.

Originally posted by FabianFnas
I'm not so sure about this.

Every interacting changes the future. Especially in the universe you do the interacting with.

So if you really go back in time, one click to the next universe and kill your grandfather there, you will certainly not be born in that specific universe.

In the very moment you bring up the multiverse theory, you are speculating, but that you know already.

Of course I knew I was speculating but so is this entire thread. Time travel is speculation at this point in time in spite of the hypotheses about time loops and such and black holes connecting black holes and such and travel around a specific path of craft skirting a black hole.

All speculation.

Of course if time travel does turn out to be possible we'll have to abolish the future perfect as it'll just be too confusing.

Originally posted by DeepThought
Of course if time travel does turn out to be possible we'll have to abolish the future perfect as it'll just be too confusing.

Being a time traveler myself, I can affirm that that is indeed what happened. What will have had happened, I mean... Well anyway the Germans sort it out by deferring all verbs to the end of the next day.