Thread: Using resources obtained from the future.

In a hypothetical future in which forward and backward time travel are possible, imagine there is a corporation that travels to a future time, say the end of the universe, in order to mine resources from dead planets or asteroids or what-have-you to bring back to use in their present time. Would this violate the law of conservation of energy? I tend to think not, since the energy isn't actually leaving the universe, just the time. But, I'm not a physicist, so any opinions would be appreciated.

The immense amounts of energy required to actually travel through time would make this completely impractical.

It doesn't violate the conservation of energy because if we use a relativistic forward time traveling machine the energy of the object traveling at relativistic speeds stays within the universe. If you go back in time well who knows, I have often thought of backwards time travel as an object going faster than light:

If you imagine an object 10 astronomical units away is traveling towards earth you will see this object from earth at a point where it is right in front of you, as it passes you will see it apparently moving backwards in time as the light from when it bounced off it is reaching you after each increment of light bounced off of it until you see it again from where it started. This idea however implies that the object going faster than light - if it could, would still remain in a forward moving universe. We can only speculate what the FTL object sees. But if both still stay in a progressive universe forwards and backwards I can't imagine that this violates conservation of energy.

I figured that there wouldn't be a violation of the law of conservation since they would remain in their own universe. Mining resources from other universes would most likely cause some serious problems though I think.

"The immense amounts of energy required to actually travel through time would make this completely impractical."

Good point but since energy/matter cannot be created or destroyed it doesn't really matter how much energy you use to get to the future because anything you bring back would add to the energy/matter of your current time in the universe. Right? Hmm, it's a thinker.

i asked a similar question on another forum and was told that Noether's theorem had something to do with it. as i don't fully understand this i can't help ant further but put it here as an avenue for anyone to maybe elaborate on.

I can't see how ol' Emmy has any input since the OP implies that changes will be made by external agencies (e.g. humans going in and taking resources), but I'll have another look and see if anything jogs my memory. It's too many years since I did any of this for real.

I don't really see the use of this concept. First of all, time travel is impossible.
Second Mining from the past, will not increase our total amount in the present, and is hence completely useless.
And Mining in the future, Is just like a loan, in the end, we cannot 'mine' faster then we have the ability to. And hence there is no added benefit from mining the future any more then just mining somewhere else. Probably even less.

One problem is that, if we go into the future to get at those materials, that's indicating that we've run out of all sources now.
And that indicates that those sources won't be there because they've already been used.
Likewise if we mine from the past we're removing materials "before" we need them so they'll be gone in the present day - exacerbating the shortage.

I never said anything about going to the past to mine. I was talking about going to the end of the universe where nobody is left to use the resources. And if we go to the future to mine resources then that would ensure we still have some around in the present. Also, the universe is very big, I don't see any way we could use all of the resources in the present anyway. The point of the whole thought was that at the end of the universe is a whole universe of resources that nobody is using.

Also, time travel is impossible? Only in practice, not in theory. It was once thought impossible for humans to fly too. Or break the sound barrier. Or go to space. If your only argument is time travel is impossible then you are just narrow sighted.

Originally Posted by drwelch

And if we go to the future to mine resources then that would ensure we still have some around in the present.

How much would it cost to do that? As compared with the normal cost of obtaining what we're after?

Also, the universe is very big, I don't see any way we could use all of the resources in the present anyway.

Then why, exactly, would we need to go to the future? I don't see the point at all.

Also, time travel is impossible? Only in practice, not in theory.

Yeah? We have no theories that would allow us to do so. That seems like a small problem.

It was once thought impossible for humans to fly too. Or break the sound barrier. Or go to space. If your only argument is time travel is impossible then you are just narrow sighted.

Er no. There was never, at any time, any theory or science that said any of those were "impossible".

This was a hypothetical question about the law of conservation of energy. Since I am not living in the HYPOTHETICAL future, I can't say how much it would cost. As for why we would need to go to the future for resources, I don't know. It's hypothetical. Maybe some alien super race has control of the resources in this future. Again, not the point. A theory on backwards time travel has been presented, here it is Real Time Travel by professor Ronald L. Mallett and forward time travel has been theoretically possible for almost 100 years now. And finally, if we look back say 500 years, things such as human flight and space travel were definitely considered impossible. You don't have to try to make others look stupid so you look smart, you know?

Originally Posted by drwelch

This was a hypothetical question about the law of conservation of energy.

Uh, okay.

A theory on backwards time travel has been presented

That's backwards - the opposite of what you wanted.
And it's been discredited.

forward time travel has been theoretically possible for almost 100 years now.

Um no. It's not been ruled out which not to say that we actually have any theories on how it could be done (beyond the use of handwavium at least).

And finally, if we look back say 500 years, things such as human flight and space travel were definitely considered impossible.

Let's try again: There was never, at any time, any theory or science that said any of those were "impossible". There may well have been technological difficulties, people claiming that we'd never be able to build X, Y or Z to enable us to do that - but there haven't been any scientific theories saying those things were impossible.

Well you just can't be reasoned with. Your nit-pickiness of the details of my original post has exhauted my patience for trying to explain what I'm talking about. Go ahead and get your last word after this post and give yourself a hug for still being the king of everything in your world. I'm finished arguing. +10 cool points for you.

Hey....Dy is just being thorough. The OP is a kind of mix between real science and science fiction. Don't take offense.

Originally Posted by drwelch

Well you just can't be reasoned with.

Have you tried? Beyond making unsupported claims that is?

Your nit-pickiness of the details of my original post has exhauted my patience for trying to explain what I'm talking about.

Yeah, maybe you missed post #7?

Edit: you'll find that I'm not "nit-picking" because details are what are important. If you don't have the details then all you're doing is hand-waving.

I don't think you could really predict what would happen with a known scientific principle like Conservation of Energy with a completely unknown principle like time travel....since we don't know what happens if we were able to travel in time. For instance, what happens to this timeline when you leave this time and travel to the future? Does the entire timeline "reset" as if you never existed, and all of the events that you influenced are changed? or would it just stay the same? What happens when you bring back the resources? There would be a slight difference in the mass of the earth with the new material just appearing. Would the timeline "reset" to accomidate the change?

You just say "time travel is impossible" and dismiss everything. All I'm saying is it might only seem impossible right now. Maybe some theory has come forward disproving time travel that I haven't heard of yet, if so, where can I find it?
I'm not trying to prove anything here, I just had a thought pop in my head and thought, "Hey, maybe someone else might find this interesting". I'm not a physicist and I don't have a whole lot of opportunity to speak to physicists so I post on here. Jeez, I didn't realize I needed a PhD to be on this forum

Originally Posted by MacGyver1968

I don't think you could really predict what would happen with a known scientific principle like Conservation of Energy with a completely unknown principle like time travel....since we don't know what happens if we were able to travel in time. For instance, what happens to this timeline when you leave this time and travel to the future? Does the entire timeline "reset" as if you never existed, and all of the events that you influenced are changed? or would it just stay the same? What happens when you bring back the resources? There would be a slight difference in the mass of the earth with the new material just appearing. Would the timeline "reset" to accomidate the change?

I know we can't really predict what would happen for sure, so speculation is the best we can do. But isn't speculation fun?

You don't need a Phd to be on this forum....I'm sure not. But it is a science forum, so you should expect to get a scientific answer. Your OP asks us to speculate on the completely unknown. There's no way to know if COE would come into play with time travel...since we don't know what effect time travel would have on the universe. If all of time-space changes when you time travel, we have no way of knowing if COE would be effected.

Originally Posted by drwelch

You just say "time travel is impossible"

Ah I get it. You can't read. What I actually said was "we have no workable theories on how it could be done".

All I'm saying is it might only seem impossible right now.

And all I've done is point out that your "counter examples" are false.

I'm not trying to prove anything here, I just had a thought pop in my head and thought, "Hey, maybe someone else might find this interesting".

And it is - in a completely illogical and hypothetical way.

I'm not a physicist and I don't have a whole lot of opportunity to speak to physicists so I post on here. Jeez, I didn't realize I needed a PhD to be on this forum

But you need a PhD (or equivalent thereof) to provide a workable answer... It's a physics problem - that requires a physics answer.
Unless you just want to settle for a hand-waved answer.

Now that I think about it...I think mass/energy would be conserved. From what I understand, all of the mass/energy in the universe was created during the big bang. That mass/energy would exist in some form or another no matter what happened to the time line. If I just "blipped" out of existance in this timeline when my father traveled to the future...all of the minerals and elements that made up me would just revert back to where they came from. Nothing would be created or destroyed. In your time travel scenario...you would just be moving the mass/energy to another place and another time. It would just take different forms...but the total mass/energy of the entire universe would still be the same.

I think....

Originally Posted by MacGyver1968

Now that I think about it...I think mass/energy would be conserved. From what I understand, all of the mass/energy in the universe was created during the big bang. That mass/energy would exist in some form or another no matter what happened to the time line. If I just "blipped" out of existance in this timeline when my father traveled to the future...all of the minerals and elements that made up me would just revert back to where they came from. Nothing would be created or destroyed. In your time travel scenario...you would just be moving the mass/energy to another place and another time. It would just take different forms...but the total mass/energy of the entire universe would still be the same.

I think....

I was thinking the same thing. It would only be a problem if you went to a parallel universe because that would actually add the the mass/energy of your universe.

Originally Posted by drwelch

You just say "time travel is impossible" and dismiss everything. All I'm saying is it might only seem impossible right now. Maybe some theory has come forward disproving time travel that I haven't heard of yet, if so, where can I find it? I'm not trying to prove anything here, I just had a thought pop in my head and thought, "Hey, maybe someone else might find this interesting". I'm not a physicist and I don't have a whole lot of opportunity to speak to physicists so I post on here. Jeez, I didn't realize I needed a PhD to be on this forum

Actually, travelling back in time is theoretically impossible, and it has been confirmed. if it would be possible then the bell inequalities. Wouldn't be violated. The explanation is cumbersome, and requires a lot of quantum theory. But it basically boils down to this. (and for responses, you might want to start a new thread on thephysicsforum) the past has no physical existence in the present. The past only exists documented in the present. And it is not fixed.

Originally Posted by drwelch

This was a hypothetical question about the law of conservation of energy.

I don't think conservation of energy comes into it. It is, as far as I know, only a local thing. So, for existence, photons from distant galaxies are red-shifted and so have apparently lost energy. That enegry hasn't gone anywhere. But they started out in a different frame of reference so there is no meanigful way to compare of conserve energy. I assume the same is true for time travel. (But it might be a reason why time travel is impossible, for all I know.)

[I may be completely wrong about the above; it is based on memories of things I read a long time ago ... (now, if only I had a time machine...)]

Originally Posted by MacGyver1968

Now that I think about it...I think mass/energy would be conserved....

I think....

And that seems to make sense as well.




I think....

Bottom line everyone is that this thread is purely hypothetical and no offering of information or opinion goes anyway moreso in being more or less credible than the next.

SR allows forwards time travel.
GR postulates possible backwards time travel, or at least, closed time like loops.

Thats it, that's all established science can offer on the whole matter. Anything else is hypothetical woo, for the moment!

Originally Posted by Quantime

Thats it, that's all established science can offer on the whole matter.

Well, that's all the "experts" on this thread can offer! Maybe a real expert would be able to say more....
[speaking purely for myself, of course]

Originally Posted by Quantime

Bottom line everyone is that this thread is purely hypothetical and no offering of information or opinion goes anyway moreso in being more or less credible than the next.

SR allows forwards time travel.
GR postulates possible backwards time travel, or at least, closed time like loops.

Thats it, that's all established science can offer on the whole matter. Anything else is hypothetical woo, for the moment!

From a quantum mechanical point of view. (which is also relativistic, so the first one naturally applies)
There is no backwards time travel. For the following simple reasoning:

If you travel back in time, you travel somewhere.
You travel to a moment in time and space, that lies 'before' our time. But even in relativity this poses a problem, a ligthcone travels rather specific forward in time, but backtracking them is less clearly done.

Now in Quantum mechanics, observations are done, which literaly change the present. This is the present. However on observation, done in the present. Is only affected by previous observations. Which needless to say lie in the 'past'. These are determined. But offer an intrinsically and measurable incomplete images of the 'past'. So at any observation there is 'elbow' room, with what the past dictates us.

You can do this experiment (Delayed choice experiment) And see that indeed we can affect things which can chronologically only lie in the past. And there is nothing wrong with this. As not 4-dimensional locality nor 4-dimensional causality are violated. This however makes up an interesting point;
The past, as we know it and mean it in conversation, is not fully written yet. It is full of (expanding) 'Holes'. This is because all of the past that affects the present in a physical manor is recorded in the past. And destroying such records before reading also destroys the affect such observation would have on the present (Quantum Eraser experiment).

In other words, there is no such thing as a set past, or a place to go back to. It is an illusion created because people think that there is a seperate 3D world and a seperate 1D timeline. Whereas this is of course a 4D world which we live in. There is no physical past, and hence no path towards it. Hence travelling to it is also stupid to think of. (denote that however we can put the past to our use, as long as it hasn't been observed before.) And all thanks to experiments

Quantum Physics is awesome