Is anyone interested in Science Fiction as I am, some egg heads now think it is possible to travel back in time, but I cannot get my head round this one. How can a person go back to the past? surely that has gone for ever and if it has, then there is nothing to go back to.

I am not a brainy man but this sounds to me like some ramblings of a scatty Professor and in the realms of a comic book. Will you give me your thoughts on this theory as I am fascinated by the subject.
If you would like to look it up.

here is the address. vega@vega.org.uk

As i understand it to achieve time travel you have to reach the speed of light which is impossible as a craft would need infinite mass to do this, didn't Einstein work this out in his theory of relativity? It is a long time since i read it.

Stephen Hawkins said that if time travel were possible how come no-one has come back from the future to visit us.( or something like that, you get the idea)

8) Watch Donnie Darko

Donnie Darko is sooooo cool. Explains some wonderful theories from the occult too!!

Moon

Originally posted by Jon
8) Watch Donnie Darko
i'm with him^^ :)

8) him has a name lol :lol:

Originally posted by Jon
8) him has a name lol :lol:
sorry jon lol :lol:

Originally posted by halevan
Is anyone interested in Science Fiction as I am, some egg heads now think it is possible to travel back in time, but I cannot get my head round this one. How can a person go back to the past? surely that has gone for ever and if it has, then there is nothing to go back to.

I am not a brainy man but this sounds to me like some ramblings of a scatty Professor and in the realms of a comic book. Will you give me your thoughts on this theory as I am fascinated by the subject.
If you would like to look it up.

here is the address. vega@vega.org.uk

Time travel opens up all sorts of paradoxes that seem insoluble, but in essence there is nothing to prevent it.

I frequently travel into the future - simply by lighting up a phattie, slumping in my favourite armchair, and suddenly I'm 3 hours into the future.

The trick, the impossible thing, is to travel in time and then return to the point in time at which you departed.

The main arguments against this form of time travel rely on showing the consequences of it being true as being absurd.

You could meet yourself.
You could kill your parents
You could accidentally kill a microorganism millions of years ago and the entire human race never happens.

These are the paradoxes that tell us that time travel, in any meaningful or useful sense, is impossible.

Whether time travel is scientifically impossible seems unlikely, but for the moment, they are talking about sending individual quanta fowards and backwards in time, not even a whole atom.

But time is a peculiar concept, non-existent outside of the human mind except as another dimension of spacetime.

As has been pointed out above, if you could attain lightspeed and remain in video comms with the earth, you would see everything speed up incredibly, whilst everyone on earth would look at your frozen face, wondering if you were dead, or whether someone had just clicked 'pause' on the video feed.

I was watching the Discovery Channel one time on the subject of time travel. A scientist used beams of light in a swirling rectangular shape to illustrate how time travel 'could' work.

What he said is, as soon as the machine turns on it becomes a gate way to the future. You could use it to send message to the past as it only works from the time it was switched on. You can't send back people, just messages (i.e. on paper, in CD formatt etc). What worried him is that when the machine is switched on (which is yet to be finished) that all these messages start dropping through which he may have sent himself. Should one know the future? What if something terrible has happened? What if by knowing this information a paradox occures... etc.

I'll see if I can find a link!

the best evidence against the existence of time travel, now or in the future, is that no-one from the past has made it back here (in the open, of course they've secretly being doing it for years).

If a time machine existed then, now or in the futire is irrelevant, because to a chrononaut all things are in the same place.

For an absolutely dlightful romp through the world of Time Travel, beyond HG Well's classic, ought to look no further than 'Dancers at the end of time" by Michael Moorcock (none of your Elric stuff this).

Originally posted by Jon
8) Watch Donnie Darko

Watched it last night and really enjoyed it, very good film.

However, I did feel that the ending was a bit of as cop out as he travels back in time and dies in an accident thus avoiding all the major questions relating to time travel once it has been achieved.

As posted above;
You could meet yourself.
You could kill your parents.

Being now dead what happens to all the events from the time he is killed to the time he decides to go back in time.(If you know what I mean). Doesn't everyones life change that he came into contact with and wouldn't they know that something weird was happening?

Need a lie down.:o

Fascinating stuff, physics. In a way, we already time travel. The fact that we move through time (as a dimension), and also the fact that We only ever see the past - we don't even see the present, unless we are recieving light from exactly the same point in space as the original source of the photons.

If, for example, you are sitting talking to someone, 1 metre away from you, you're not actually seeing them as they are now, but as they were approximately 3.33 x 10^-9 seconds ago - the time it takes for light to reflect off the object (person) and reach us (we see because of light) 1 metre away:

speed(s) = distance(d)/time(t)

Therefore, t = d/s

distance = 1 metre
speed (of light) = 3x10^8 m/s

t = 1/3x10^8

t = 3.33x10^-9 seconds

In the same principle that we only see the Sun as it was approximately 8 minutes ago, and stars millions, or billions of years ago, and so on.

This, for me, throws up dozens of other equally fascinating questions - especially with regards to our universe, and what/where/when we can see. It's generally thought that the Big Bang occured between 12 and 15 billion years ago, and that the universe has possibly been expanding at almost the speed of light. So, theoretically, if we have a telescope powerful enough to 'collect' light from a distance of 12 - 15 billion light years, we may be able to see the Big Bang, and since the universe has been expanding in all directions, we may therefore theoretically be encased in a "shell" of the Big Bang - i.e. whichever direction we look in, at that distance, all we will see is the Big Bang. Further, it may be so that we cannot see any distance greater than 12 - 15 billion light years, since we are i) possibly encased in this "shell", and ii) nothing, it is thought, existed before the Big Bang, so there is nothing to look at even if we could see past the barrier.

But... nothing is infinite - quite literally - you can't have no nothing (a vacuum, if you like), so to speak, so the only infinite thing in the universe is nothing.

What if this universe is not the only one too? What if there were dozens, thousands, billions, centillions of Big Bangs accross the expanse of infinite nothing?

The mind boggles.

:roll:

:help:

Just kidding, I envy your knowledge:D