Will time travel be ever possible?

[Roses]

Are any scientists looking into the possibility of time travel?  If anyone had suggested, say 200 years ago, that humans would land on the moon one day, they would have been told it would never happen. Human ingenuity being what it is, maybe in the future we will be able to go forwards and backwards in time. However, supposing it is possible one day, would it be a good or bad thing, I am not sure about that?

[BeRational]

I watched a programme recently by Steven Hawking who strongly suspected that time travel to the past will not be possible.

Time travel to the future is what we do all the time, but I assume you mean further into the future than a normal human lifetime.
The answer to this is yes, and we already know how it can possibly be done, but it is not technically possible at the moment.

The two way he postulated where:-
1. Position yourself in orbit around something very massive like a black hole where time could pass at about half speed relative to someone not in orbit around the black hole.

2. Travel extremely fast up to some portion of the speed of light, where relativity again slows down the passing of time for the travellers.

As you can see, the known laws of physics has no problem with time travel to the future, but at the moment we do not have to ability to do it.

[Roses]

I have just been looking on-line about the possibility of travelling forward and back in time and apparently some scientists are researching it.

[SteveH]

If time travel to the past was possible, we'd've met future time-travellers by now. It also involves obvious anomalies, such as killing your parents, and preventing your own birth. It would also mean that the atoms which compose your body would exist twice over, which may also be anomalous.
I have also read that if travel to the past were possible, one could alter the past, but only if one already has done. For example, a time-traveller could not prevent the assassination of President Kennedy, but could prevent the assassination of Pope John-Paul II, because his would-be assassin missed, and only wounded him - maybe because a time-traveller managed to jog his elbow.

[Samuel]

The paradoxes only occur if the changes you make in the past contiue on the same timeline as the one you come from. I'm no expert, but my understanding is that the multiple earth / parralell universe theory means that any and all events have taken place, with each divergence creating parralell realities. So, you can't change your own past, only do things that make you move into a different timelines where, for example, you were there to save Kennedy's life. Your own past would always be the reality where Kennedy died though...

I think...

Hoenestly, I don't really understand any of it

[Walter]

to travel forward in time would require enough energy to create a new universe for an event to take place in (and that's a lot of energy)

To travel back in time would require the same thing because all possible events in a (persons) 'timeline' have already occurred . The universe would have to be reset with every sub atomic particle put back in the same place as it was at the time you wanted to go back to (that is impossible).

Nobody knows if time actually exists .What we experience is a series of events which our brains puts one after another in order to make sense of what we see and feel .All we really know about time is that we can measure its passing with a type of clock and input that measurement into our theories which we have developed to explain and predict how the universe works

To be honest there is no scientific reason why the universe might simply not exist at all in the next 'second'.

[SteveH]

to travel forward in time would require enough energy to create a new universe for an event to take place in (and that's a lot of energy)

To travel back in time would require the same thing because all possible events in a (persons) 'timeline' have already occurred . The universe would have to be reset with every sub atomic particle put back in the same place as it was at the time you wanted to go back to (that is impossible).

Nobody knows if time actually exists .What we experience is a series of events which our brains puts one after another in order to make sense of what we see and feel .All we really know about time is that we can measure its passing with a type of clock and input that measurement into our theories which we have developed to explain and predict how the universe works

To be honest there is no scientific reason why the universe might simply not exist at all in the next 'second'.

St Augustine of Hippo suggested that al the exists is the present moment. The past only exists as present memories, and the future only as present expectations.

[Walter]

St Augustine of Hippo suggested that al the exists is the present moment. The past only exists as present memories, and the future only as present expectations.

did he say anything about physics though ?