How could we tell if something was traveling back in time. Lets take a time traveling car for example. Not a car that jumps from one time frame to another but one that is travaling back in time at the same speed as we are traveling forward. Would it be right to assume that if I hit the car with a hammer a dent would return to normal. In a way would the car get newer as time went on. Or on the other hand would me putting a dent in the car being in my timeline going forward for example I hit it with a hammer and put a dent in it but the car still gets newer. Would the car seem any diffrent to us at all. Would it seem to be getting older but really its reaching its orignal state and perhaps we are all heading back in time.
To make it less confussing because I can’t write my ideas down well.
We are not “travelling forward”. (How fast are we going: one second per second?!) Events exist in time just as points exist in space - the flow of time is an illusion.
I found your diagram even more confusing than the text, but there would be no way for your two domains to interact with each other. On the other hand, it is easy to imagine a life lived backwards (f. Time’s Arrow by Martin Amis) - just imagine a rewound film.
One problem is that you wouldn’t really see the person/item that is traveling backwards through time as you are traveling forward. You’d only be in the same time frame for a brief instant.
It’s like driving down the highway. If you stare directly out the side window (in theory, don’t do this while actually driving), you’d clearly see the people and cars traveling at the same speed and direction as you. But, if someone was traveling in the opposite direction, or standing still, or even moving significantly faster or slower than you, you’d only see that person for a brief instant.
As for seeing dents in a car undent themselves, it wouldn’t happen. That dented car would have to be moving forward in time, along with you, for you to see it change. But, you’ve defined that it is moving backwards.
Beg pardon? Think about how you’re defining your terms, and you’ll realize that you’re saying that you’d only be at the same time at the same time once. The car would get “younger” while you get “older”, but you’d still both exist at all times. And at any given time, you’re both at that time simultaneously.
Well, I was speaking in loose terms, to match the OP.
Perhaps we do need some definition of terms, however. When I speak of traveling backward in time, the object simply moves from now to a point in the past. It does not grow younger in the process. So, the mad scientist would still be 35 years ago if he traveled back to 1776.
Perhaps what you and the OP are talkng of is a sort of regression, where an item remains in the current time, but simply grows younger. I have no idea whether a dented car will lose the dents as it grows younger.
Most science fiction stories tend to use the former definition of time travel. I suppose it’s easier to hire one actor to play the character in all points in time rather than hire a dozen different actors.
i think the word causing the problem is “travel”. travelling in time, as we all are, doesn’t mean that we have to necessarily move from one spot. if i stand next to a car that is travelling back in time whilst i am travelling forwards, though neither of us moves, maybe this is what the OP is questioning.
as for that, how would shadows work, as my sun is travelling in the opposite direction of that shining down on the car. we’d have to be talking two completely different… somethings.
Let me consider a simplified universe. A plane. x-axis is space. y-axis is time. Draw a diagonal line. This might as well represent a particle moving forward in time; that is, at a later time the particle has moved a distance proportional to the time passed from the original position. But now draw a curve in an ‘n’ shape. One leg can represent a particle ‘moving forward’ but the other leg must represent it ‘moving back’. Another view is that there’s a particle and an antiparticle moving forward and they obliterate at the top of the curve. This has been proposed as way of viewing antiparticles, though I don’t know if it’s still valid.
But the laws of physics work backwards as well as forwards. A particle moving backwards wouldn’t be obvious or even necessarily possible to be told as such .
Without giving away too much, the VSTM shows up in a lab and observation reveals its occupant to be moving backwards in time. The scientists watch him grow younger, he uneats food, his hair and beard shorten etc.
If I understand the OP correctly, the answer is if you dented the car at 8:00 it would be undented at 8:01, but dented at 7:59, 7:58 and so forth.
Regression, such as you describe, seems the least likely possibility for time travel. It just seems to be completely impractical. So, you have a glass booth and a car inside it, growing younger – unburning gasoline, undenting itself, and so on. To me, it’s a problem of physical existance.
To unburn the gas, lots of CO2 will have to be sucked into the exhaust. Where will this CO2 come from? To undent a door panel, energy will be released into the environment. What creates that energy? Suppose there’s blood on the carpet in the trunk (from a murder?). When the car grows younger, what happens to the blood? Can it go back into the victims body? Where is the victim? Does the victim suddenly appear and begin to grow younger? What about all the spare parts that have been added to the car over the years? Are they replaced by the original factory parts?
And then what happens when the car regresses past its “born on” date? Does the car become a pile of coal, oil, leather, and iron ore? That’s probably more raw material than can fit in the glass booth.
Nah, I’ll take time travel in the most common, science fiction sense – the traveler stays the same age, but simply moves to different points in history.
This is very close to what I am thinking. I’ll take another crack at making myself clear. If the car was traveling back in time and you were heading forward but you were in the same place. You are traveling through time as you are now and the car is doing the same but backwards.
Now a light just went off in my head. If you dent the car, in an unblemished area that dent would travel into the future. however if you make a dent that travells back into the past when you hit the car in that spot that you made the dent at the time you made the dent you will undent the car. Make sense? I was never any good at explaining. Basically you can hit the car and the dent will travell forward or backward depending of course on its original or final shape.
Everyone except DocCathode seems to view this time machine as one which works instantaneously, such that I turn it on at 3 PM Tuesday, and suddenly it becomes 3 PM Monday. But let’s consider one which (like in H.G. Wells’ original novel) takes some time to work.
Let’s say that our machine takes one hour to move 2 hours backwards in time. Let’s also say that when I begin the journey, both my wristwatch and the wall clock say 3:00. A half-hour later from my prespective, my wristwatch will read 3:30, and the wall clock with say 2:00. (At this point, I’ll tear a piece of paper.) When the journey is complete, my wristwatch will say 4:00, but the wall clock will have regressed to 1:00 (two hours prior to the beginning of the trip).
From the perspective of someone outside the machine, but looking in through its window, at 1:00 they’ll see my watch reading 4:00, and a torn piece of paper. They’ll also notice that my watch it running backwards at a rate of 30 seconds per minute. An hour later, at 2:00, they’ll see that my backwards-running watch has reached 3:30, and the torn paper will amazingly become whole. Another hour later, at 3:00, the wristwatch will also read 3:00.
I don’t think it really makes sense to talk about this at all unless you’re defining exactly how the method of time travel is working. Are we talking about two people somehow going in different directions in time? It just seems like the biggest problem being had in trying to discuss this is that none of us are exactly sure of the logistics of the situation.
Also, it seems kinda funny to me that Chronos posted in here, but maybe that’s just me.
One thing I read in Brian Greene’s The Elegant Universe was that we are moving through time at the speed of light. All objects move at the speed of light through spacetime proportionally; as we move faster through space, our speed through time slows down, and vice versa. One of Einstein’s ideas, probably more of a conceptual thingy, though.
Many people have said that when you look at einsteins theories the unusual property of time travel is mathamaticaly possible. Has Quantum Physics changed that point of view. Also what are the workings of the equation that shows time travel as mathamaticaly possible.
The reason I want to know this is because if Einsteins theories show that time travel is mathamatically possible is it possible that there is a missing part of the equation that would make time travel impossible.
That would be the {Ya knew this was coming} Flux capacitor.
On a more serious note, my previous post was simply an attempt to restate the OPs question, and answer based on the assumptions given.
Not to express my personal views or theories on nonstandard chronal movement or displacement.
Frankly, I was stumped on a workable method of time travel until a bizzare elderly getnleman I met in the library gave me a report he’d apparently printed out on his home pc. I only met him once, but he must’ve been watching me- he was wearing several rings that were identical to ones I own. Considering I got mine over many years of flea marketing, I don’t know how he managed to find copies. I still don’t know anything about the man. There was a chocolate fingerprint on one of the pages, but closer examinatio revealed it to be mine. Though, I could’ve sworn I hadn’t eaten anything while reading it. There were several white beard hairs stuck between pages. But when I had a friend analyze them (he works in a university biology lab and owes me quite a bit due to his ineptitude at playing poker), they were also mine. I hadn’t known my beard was going white, and have yet to spot a single white hair. In anv event, it’s a fascinating report.
I’m sure another Doper with a better knowledge of physics will come along and give you an in depth reply.
OTTOMH, and IIRC time travel, like wormholes, and a few other things may be possible due to a quirk in relativity. But it would require things like magnetic monopoles, infinite energy, and objects with negative mass. Ie It might be possible, but the things you’d need to accomplish it are not.
No, it’s not just you. It’s just me. As most regular Dopers know, I’m obsessed with time. Therefore, I chose Chronos as my username, and also therefore, I usually take a look at threads on things like time travel.
DocCathode, wormholes are time travel. Or more broadly, anything that lets you get from point A to point B before light would get there (warp drive, hyperspace, magic portals, whatever) can also be used for time travel. And I’ve never seen any proposal for such where infinite energy or magnetic monopoles would be necessary. For the various models I’ve seen, negative mass is necessary and sufficient to produce a time machine. Now, whether negative mass can exist is probably a question outside the scope of general relativity. It may be within the scope of quantum mechanics, but unfortunately QM has not yet given us a definitive answer. Since we’ve never seen any evidence for the existance of negative matter, though, most folks accept that it doesn’t exist.