Even though time is purely theoretical, I’m posting these questions here and not in Great Debates because I’m asking for the answers that are currently the most widely held belief.
Does the future already exist, or is it being constantly created?
There is no answer to this, no consensus belief, just whatever happens to strike your personal philosophical fantasy.
For that matter, you could say that the future doesn’t exist at all, because we are in a perpetual now.
Say whatever you like. If anyone objects ask for concrete proof. That’ll fix 'em.
Now off to GD.
No concessus huh?
Oh, I guess I never posted how this ties into time travel. I was going to ask if, time travel ever became possible, if you could travel into the future or not (I.E. If the future doesn’t already exist, then the answer would be no).
But since there’s no concessus on if the future exists or not, then there would be no concessus on if it forward time travel would be possible either.
It is possble to travel into the future. I do it all the time. So does everyone else. I travel at a rate of one second per second. But, relatively to other things in the universe, I’m travelling at a different speed.
Yeaaaaa!!! A smart ass. This message board just isn’t complete without one.
My point was just that travelling into the future is easy. It’s going the other way that’s tough.
My point is, if ever became possible to ARTIFICIALLY travel in time, could move ahead of everybody else, or, would you run into a barrier, that barrier being that the future doesn’t exist yet and is constantly being created.
Yes, you can move ahead of everybody else. Look up “twin paradox”.
In the twin paradox one twin (the one who leaves earth) travels about for a bit at close to the speed of light and then returns to Earth. By moving so fast in space time begins to slow down for him compared to the Earth. When I returns to earth he is only, say, 5Years older and his twin (and the earth in general) will have aged 50 years. So he would have effectively travelled into the future. In time we always move into the future, so doing so at a different rate is less of a challange than actually moving the opposite direction. Therefore the biggiest challange ought to be moving backwards in time.
The argument that the future “isnt there yet” is specious, the whole point of traveling in time means it is there… just in the future. To say the universe is being constantly created is in no way contradictory with travelling forward in time. I think the probalems of backward time travel are more paradoxical (back to the future, teminator, a conneticut yankee in king arthor’s court, and many other stories deal with these paradoxes (what would happen “in the present” when changing the past. Its a doozy of a question.
Panopticon
Stephen Hawking covers time travel quite a bit in his book “The Universe in a Nutshell”. He concentrates on going back in time, but it might be a useful resource for your question. I don’t have it handy and wouldn’t dare paraphrase…
There are more than one way to look at what time travel may be possible. For instance, I may be able to travel back in time and the forward again but only back to when I left. Or, in other words, I can’t travel forward to a future that hasn’t happened yet but if I go backwards I can go forward again back to my own time.
There are other theories that hold you could only time travel backwards in time to the point the time machine was invented but not before then. I’m not quite sure of the reasoning behind that one but I’ve seen it bandied about.
Go live on the International Spacestation for six months and I think you’ll be on the order of three seconds younger than everyone else when you left. Of course, you still occupy the same ‘now’ as everyone else but they just aged quicker.
Anyway, there are lots of ways to look at it and as of now many guesses are as good as the next. FWIW time travel IS currently possible given what we know today. Kip Thorne tried to disprove time travel back in the 90’s because he was tired of all the time travel questions he received. To his dismay he found nothing in the science that is accepted today that forbids time travel. Of course, actually doing so is a different matter entirely. Even if it is actually possible the technical challenges are such as to make it practically impossible.
Welcome to Straight Dope, Panopticon.
How about this?
Suppose you start in our universe and go back in time five years. When you get there (or then), you’ve arrived in a universe where everything is exactly as it was five years ago. You can, in the five-years-ago universe, affect the future so that five years later the world would look totally different from how it looked when you began your journey.
However, to those of us who remain in this universe, nothing has changed - except for the fact that you’re no longer there. You have left the universe, and everything continues as if you had just disappeared. We never know about the changes you made to the world in the other universe, and we never see the effects of your changes to the other universe in our own universe.
I haven’t yet worked out whether you’ll be able to come back to us or not. If you go back and change nothing, then the universe five years from then will look much like the universe at the time you left, but it will be a parallel universe. In other words, you’ll see us - or parallel usses with whom you’ll interact with as if they were us - but we won’t ever see you, unless you find a way to travel back to our universe.
What do you think?
Back to the OP, the very language of the question is somewhat paradoxical, since the phrase “already exists” cannot, by definition, apply to the future. However, there is a mode of thinking that the present, past and future are simply artifacts of the way our minds work, that the passage of time is an illusion. In this sense, the future “already exists” and the past “still exists.” There is a concept known as the World Line. This is a conceptual graph of an object’s position in three-dimensional space at all times throughout its existence. One can think of the World Line as being a static description of the object, if you can free yourself from the notion that time flows.
There was a very good article on this topic in the September Scientific American but unfortunately the article
is available only for a fee on their web site.
However, the idea is not yet to the point of being consensus.
First off let me say IANAP.
cuauhtemoc, I agree with you.
Bear with me on this, this will be worded unusually. Ive always thought that every thing that has “happened” or will “happen” has already happened, and cannot be changed. If you go “back” in “time” and change something, you will only be switching to a parralel time line. What I mean is all of space time as viewed from a creature that is not limited in the “time” axis would see all possible futures and all possible pasts at once. If they see you go back in time and change something they would see you go down a “time rail” so to speak, then change direction and head up another “time rail”.
In this way of thinking, time travel would be more like the show “Sliders”. If you want to go to a timeline where Hitler died at birth, you merely jump the rails and get on one where he did just that. This way of thinking also does away with Hawking’s Time Protection Law.
Once again, IANAP.