Time Travel - is it possible?
Discussion
Niven's Law: "If the universe of discourse permits the possibility of time travel and of changing the past, then no time machine will be invented in that universe."
No its not possible.
'Time' is something that mankind has invented.
Imagine a book, its starts with you being born and ends with you being born, you are currently on a page in the middle of a book, you can flip back to the beginning or the end because the pages are there.
Now imagine the book is being written as you age, the pages ahead of you do not yet exist, the pages behind you are disappearing as they no longer exist. therefore you cannot go forward or backwards.
That is the best way i can describe my theory, everyone is in the same moment of time together, past events no longer exist, future events do not yet exist.
'Time' is something that mankind has invented.
Imagine a book, its starts with you being born and ends with you being born, you are currently on a page in the middle of a book, you can flip back to the beginning or the end because the pages are there.
Now imagine the book is being written as you age, the pages ahead of you do not yet exist, the pages behind you are disappearing as they no longer exist. therefore you cannot go forward or backwards.
That is the best way i can describe my theory, everyone is in the same moment of time together, past events no longer exist, future events do not yet exist.
Hmmmm, I saw this in the film Interstellar, and didnt quite grasp it. but i think i understand it.
I wouldn't really call it time travel, Its like me walking in a straight line, and you running in an arc, We could arrive at the same point at the same moment, but you would have covered more distance. if we both had a stop watch, mine would sat for example 1 minute, yours would also say 1 minute, but if we both measured our distance travelled, we would get opposing results,
Neither of us has reached a point further than the other.
I wouldn't really call it time travel, Its like me walking in a straight line, and you running in an arc, We could arrive at the same point at the same moment, but you would have covered more distance. if we both had a stop watch, mine would sat for example 1 minute, yours would also say 1 minute, but if we both measured our distance travelled, we would get opposing results,
Neither of us has reached a point further than the other.
ash73 said:
My favourite problem with time travel is, even if you jumped forward or backward just a day, the Earth wouldn't be there anymore; so pack a spacesuit.
I think the major problem is that if you did move forward or back one day, 'you' would still be there. Years ago I thought of a science fiction story where a chap, for reasons which are explained in the book's first hundred pages, goes forward in time and kills his future self. He then returns to the present and, when 'he' appears in his future, kills his time travelling self 'again', although for the first time. He is arrested later but there are all sorts of legal problems. He claims to be himself, if you see what I mean.
callmedave said:
No its not possible.
'Time' is something that mankind has invented.
Imagine a book, its starts with you being born and ends with you being born, you are currently on a page in the middle of a book, you can flip back to the beginning or the end because the pages are there.
Now imagine the book is being written as you age, the pages ahead of you do not yet exist, the pages behind you are disappearing as they no longer exist. therefore you cannot go forward or backwards.
That is the best way i can describe my theory, everyone is in the same moment of time together, past events no longer exist, future events do not yet exist.
Mankind didn't "invent" time - it's been there since the dawn of the universe. All we've done is given it a name, units of measurement and devices to measure it with. Animals can sense the passage of time, so clearly humans aren't the only ones who are aware of it.'Time' is something that mankind has invented.
Imagine a book, its starts with you being born and ends with you being born, you are currently on a page in the middle of a book, you can flip back to the beginning or the end because the pages are there.
Now imagine the book is being written as you age, the pages ahead of you do not yet exist, the pages behind you are disappearing as they no longer exist. therefore you cannot go forward or backwards.
That is the best way i can describe my theory, everyone is in the same moment of time together, past events no longer exist, future events do not yet exist.
ash73 said:
My favourite problem with time travel is, even if you jumped forward or backward just a day, the Earth wouldn't be there anymore; so pack a spacesuit.
If you didnt change your physical location yes you would be quite a distance from earth even for one day shift. Earth travels rather fast, so does the sun/entire system, and the galaxy.but..
ash73 said:
Time is an integral part of the geometry of spacetime
If you can travel in time then distance is literally not an issue. RobDickinson said:
Up until 40ish years ago science thought everything was one big newtonian machine that yes if you could figure out the equations you could calculate everything.
Its not though. The rules can be quite simple but these end up with chaos and structure both from the same simple start! We can never know the starting point of these things with anywhere near enough accuracy to predict ( heisenberg uncertainty principle).
Science has learned to embrace chaos and work with it.
No argument with what you have said there at all from a physics point of view but it is interesting to also think that on the larger scale we can and do predict things with a high degree of accuracy albeit with outcomes based on probabilities rather than certainties.Its not though. The rules can be quite simple but these end up with chaos and structure both from the same simple start! We can never know the starting point of these things with anywhere near enough accuracy to predict ( heisenberg uncertainty principle).
Science has learned to embrace chaos and work with it.
We predict where a comet will be at some point in the future and mostly it tends to work out although we cannot mathematically prove that it will. We have models that predict the stock market, sporting results and the behaviour of structures. We can make informed predictions on social behaviour, political trends and chess games. To go back to the example given you could probably model the behaviour of the roulette ball quite well given some starting behaviour. With enough data and I could probably write a model that predicts divorce (and estimated date) to a reasonable accuracy for a large enough sample set.
None of these are perfect calculations but they can certainly be useful predictions. Didn't Authur C Clarke write some books around these ideas many years ago?
callmedave said:
Hmmmm, I saw this in the film Interstellar, and didnt quite grasp it. but i think i understand it.
I wouldn't really call it time travel, Its like me walking in a straight line, and you running in an arc, We could arrive at the same point at the same moment, but you would have covered more distance. if we both had a stop watch, mine would sat for example 1 minute, yours would also say 1 minute, but if we both measured our distance travelled, we would get opposing results,
Neither of us has reached a point further than the other.
With the "walking in a straight line vs. curve" thing you haven't considered that the two people are both walking at the same speed - the speed of light. The person who walked around the curve would arrive after the person who walked in a straight line, even though they had both travelled at the same speed.I wouldn't really call it time travel, Its like me walking in a straight line, and you running in an arc, We could arrive at the same point at the same moment, but you would have covered more distance. if we both had a stop watch, mine would sat for example 1 minute, yours would also say 1 minute, but if we both measured our distance travelled, we would get opposing results,
Neither of us has reached a point further than the other.
Whilst at uni I wrote an essay on this but it Related to Einstein's Theory of Relativity, according to that, no it isn't possible. I also used the example of a being made up from tachyons (faster than light particles) coming over and b
h slapping you. Or course he hasn't traveled through time, but you still didn't see it happen because he was faster than light. I believe these guys can exist on nights out.
h slapping you. Or course he hasn't traveled through time, but you still didn't see it happen because he was faster than light. I believe these guys can exist on nights out.Oh you can certainly predict things with enough accuracy.
We went to the Moon on newtonian maths, even though we know the moons distance form earth varies its only by a very small amount.
Likewise with a comet there are few new inputs/variables so its quite predictable.
But for a roulette ball there are far far too many.
You would need to know its surface down to an atomic level as well as the wheels, its momentum/direction/spin etc. Even then only a tiny error in its first bounce and you have lost it all.
We went to the Moon on newtonian maths, even though we know the moons distance form earth varies its only by a very small amount.
Likewise with a comet there are few new inputs/variables so its quite predictable.
But for a roulette ball there are far far too many.
You would need to know its surface down to an atomic level as well as the wheels, its momentum/direction/spin etc. Even then only a tiny error in its first bounce and you have lost it all.
RobDickinson said:
Oh you can certainly predict things with enough accuracy.
We went to the Moon on newtonian maths, even though we know the moons distance form earth varies its only by a very small amount.
Likewise with a comet there are few new inputs/variables so its quite predictable.
But for a roulette ball there are far far too many.
You would need to know its surface down to an atomic level as well as the wheels, its momentum/direction/spin etc. Even then only a tiny error in its first bounce and you have lost it all.
The same is true for the moon. We just used equations that said "most of this stuff probably isn't relevant'We went to the Moon on newtonian maths, even though we know the moons distance form earth varies its only by a very small amount.
Likewise with a comet there are few new inputs/variables so its quite predictable.
But for a roulette ball there are far far too many.
You would need to know its surface down to an atomic level as well as the wheels, its momentum/direction/spin etc. Even then only a tiny error in its first bounce and you have lost it all.
I'm not certain about the roulette example. I suspect that if you very accurately knew the release parameters of the ball, the mechanical arrangement of the wheel and its rotation etc, you could make a pretty accurate prediction of the outcome to a high accuracy. It would never be 1 though.
On the question of time travel:
No you can't go back and interact with the past. Physics and logic start to fall apart if you do. Nature always dodges such problems. You might be able to go back and not interact, after all what are memories, films photos etc.
Forward time travel is certainly on, provided it is not relative to yourself. You cannot end up with two of you. As others have said, time dilation will do it. Another method would be suspended animation. It is forward time travel in effect.
I'm not certain now exists though. Everything is in the future, or in the past. If 'now' is simply the border between the past and the future then it doesn't exist. In which case when does anything actually happen? It can't happen in the future or the past.
The question boils down to; is time quantized. Is there a minimum length of time allowable?
Not surprisingly I'm far from the first to think of this, but science doesn't actually know yet.
http://www.scientificamerican.com/article/is-time-...
On the question of time travel:
No you can't go back and interact with the past. Physics and logic start to fall apart if you do. Nature always dodges such problems. You might be able to go back and not interact, after all what are memories, films photos etc.
Forward time travel is certainly on, provided it is not relative to yourself. You cannot end up with two of you. As others have said, time dilation will do it. Another method would be suspended animation. It is forward time travel in effect.
I'm not certain now exists though. Everything is in the future, or in the past. If 'now' is simply the border between the past and the future then it doesn't exist. In which case when does anything actually happen? It can't happen in the future or the past.
The question boils down to; is time quantized. Is there a minimum length of time allowable?
Not surprisingly I'm far from the first to think of this, but science doesn't actually know yet.
http://www.scientificamerican.com/article/is-time-...
mebe said:
None of these are perfect calculations but they can certainly be useful predictions. Didn't Authur C Clarke write some books around these ideas many years ago?
Isaac Asimov's Foundation series is possibly what you are thinking of. It is also a key part of the Lensman series by EE Doc Smith. Toltec said:
mebe said:
None of these are perfect calculations but they can certainly be useful predictions. Didn't Authur C Clarke write some books around these ideas many years ago?
Isaac Asimov's Foundation series is possibly what you are thinking of. It is also a key part of the Lensman series by EE Doc Smith. 'Ever heard of the Butterfly Effect and wondered why everyone decided butterflies were the theory’s key insect? It’s because, in the 50s. Ray Bradbury decided it would be so in A Sound of Thunder. A butterfly plays a key role in changing history in this time travel tale about a T-Rex safari.'
If it's the story I recall, a group of tourists goes back to the time of the dinosaurs and is warned not to step off the path. One of them does, and squashes a butterfly. When they return to modern day, the spelling on the company's sign is different.
Toltec said:
Isaac Asimov's Foundation series is possibly what you are thinking of. It is also a key part of the Lensman series by EE Doc Smith.
Foundation! exactly, brain was on holiday. Not sure I remember the same concepts in the Lensman books as much, will have to re-read a few, have about 5 kicking around somewhere from a misspent youth in WH Smith.Gassing Station | Science! | Top of Page | What's New | My Stuff