A Time experiment

[Dan O.]

The knowledge of how to construct a time machine has bee around for many decades for those that have been following scientific advancements. I learned about it from reading an article in the November issue of Scientific American in the 80's. In that era, the only entangled forms we could easily deal with we're photons. A time machine using quantum entangled photons needs an isolated light path 300,000km long to get a time shift of just 1 second. But that didn't keep MIT from trying (time machines are easy to spot if you know what you are looking for).

 

[Verklagekasper]

Problem with #1 is that so much stuff is d0one elctronically now. Even lottery in some country. So
1) put a PC with WIFI connected to your home in your garage, close the garage shortly before lottery to avoid time paradox
...

Well, then you would not even have to travel back in person. You would only have to transmit the numbers back in time to the PC. The rest could be done by the PC on its own.
If this worked, however, there would be the contradiction that, if you change your own past this way, you are no longer the same person. Particularly, you are not - and have never been - the person who found it necessary to send back a message to win the lottery. Because you would have been a lottery winner all along. So you would not send the message back in time. Therefore, it cannot be you but at best an alternate version of yourself in a parallel universe who get the cash.

 

[AvalonXQ]

Well, then you would not even have to travel back in person. You would only have to transmit the numbers back in time to the PC. The rest could be done by the PC on its own.
If this worked, however, there would be the contradiction that, if you change your own past this way, you are no longer the same person. Particularly, you are not - and have never been - the person who found it necessary to send back a message to win the lottery. Because you would have been a lottery winner all along. So you would not send the message back in time. Therefore, it cannot be you but at best an alternate version of yourself in a parallel universe who get the cash.

That's easy to fix.

On Monday, I set up the PC to, on Tuesday morning, receive the signal and buy the lottery ticket for the Tuesday night lotto, and on Wednesday morning, transmit the winning numbers back to Tuesday. I close the door Monday night and go about my business.
On Wednesday night I access the PC and get my winnings.

 

[marplots]

[I have been sharpening my claws in another thread about time and SR... here we go:]

Only the present moment exists, and future moments will soon exist. The past does not exist. Therefore going back in time is not possible, because where you want to go does not exist. (next part snipped)

Ah, but since the past you go to is in your future, the picture isn't quite as simple as that. For example, there is nothing in your framing that prevents me from recreating the past in my future.

In fact, I do this every other day when I reboot my computer (not totally, there is some information that is preserved). I am recreating a past state in some subset of the entire universe where this past state interacts with my future state -- which is what we want in time travel, isn't it?

The difficulties come in when you extend the amount of past you want to visit and the fidelity you wish to obtain. For winning the lottery, you'd only need to recreate this one planet with enough accuracy that the same numbers are drawn.

(Here I will once again request an independent, privately-funded grant.)

 

[JJM 777]

I do this every other day when I reboot my computer (...) I am recreating a past state (...) which is what we want in time travel, isn't it?

Your scenario doesn´t involve any time travel, what you do there is done in present time. Creating now something similar to what has existed also before. All materials involved get older and more worn-out at each loop, including you who operate the experiment.

For winning the lottery, you'd only need to recreate this one planet with enough accuracy that the same numbers are drawn.

Just break into the office where the lottery machine is stored, and tweak it in such a way that you can know which numbers will be drawn next. This doesn´t involve any time travel either.

 

[marplots]

Your scenario doesn´t involve any time travel, what you do there is done in present time. Creating now something similar to what has existed also before. All materials involved get older and more worn-out at each loop, including you who operate the experiment.

But that's exactly the point. Time travel happens in the traveler's present. In no scenario is the entire past recreated, otherwise, the traveler wouldn't be there (or not as a traveler, but as they were then).

I was keying off of, and agreeing with, your premise that the past doesn't exist. As far as "older" goes, you could address that as well. As I mentioned, it is a matter of fidelity.

On the gross scale, you can put someone in a room that never changes. Tomorrow would be the same for them as today and yesterday -- except, of course, while the room (from the interior) wasn't traveling through time, the occupant would be. They are, after all, the "traveler" in this scenario.

For example, on a fundamental level, get a photon to bounce back and forth and watch as states loop through to previous states. Is it meaningful to then say that the last time the photon was here it was younger?

I understand that the first instinctual reaction is to feel cheated, but it is arguably a way to "travel to the past." Especially since there is, as yet, no past to travel to. Creating it solves several intractable problems. I'd also point out that with enough detail, for the traveler it wouldn't be detectable as other than authentic.

The unstated supposition in time travel as usually presented is that the entire universe is in a previous state -- I think that's a bit unreasonable, since the traveler isn't. And as soon as you accept the traveler as moving forward in time (the rest of the universe is past, but that past is in his future before he leaves) then you might as well take a smaller, doable slice and say that that piece is in a past state, even though the whole universe isn't.

 

[Skeptic believer]

[I have been sharpening my claws in another thread about time and SR... here we go:]


Only the present moment exists, and future moments will soon exist. The past does not exist. Therefore going back in time is not possible, because where you want to go does not exist.

I would question your assumption that the past does not exist.
You cannot see the past, as you exist only in one point in the time dimension - called your 'present'.
However, behind you is the past - it is called the past because time has 'passed' - and like other things which we have passed, they still exist.

You cannot see the past simply because we exist only in three dimensions - A theoretical four dimensional being would see the whole of time at once.

Indeed, for light, the past, present and future exist as one, and cannot be seperated -
which indisputably illustrates and proves that it is possible for the past, present and future to all exist simultaneously

 

[Roboramma]

The knowledge of how to construct a time machine has bee around for many decades for those that have been following scientific advancements. I learned about it from reading an article in the November issue of Scientific American in the 80's. In that era, the only entangled forms we could easily deal with we're photons. A time machine using quantum entangled photons needs an isolated light path 300,000km long to get a time shift of just 1 second. But that didn't keep MIT from trying (time machines are easy to spot if you know what you are looking for).

Since you can't use entanglement to transfer information faster than the speed of light, I don't really know what you're talking about.

 

[Roboramma]

Other times exist in exactly the same way as other places exist.

Of particular note is that, because of the relativity of simultaneity, there is no absolute way to differentiate between "past", "present", and "future". They are mixed up as different reference frames put different events into each of those categories. And even in one particular reference frame some events cannot be categorized into any of those categories, but instead exist in the "absolute elsewhere". (hope I got my terminology right on that last bit).

 

[AvalonXQ]

Since you can't use entanglement to transfer information faster than the speed of light, I don't really know what you're talking about.

Let me illustrate this point with an analogy.

You have a magic box. If you put two coins in the box together, and then take them out and flip them, one will flip heads and the other will flip tails. It's random which is which, but once one coin has flipped heads, no matter how far away the other coin is, flipping it will produce tails, and vice versa.
After each coin is flipped the first time, it becomes a normal coin until you put it back in the box.

Assuming you have this magic box and a bunch of coins, explain how you can use the coins to communicate any faster than you could have without the coins.

 

[aleCcowaN]

Only the present moment exists, and future moments will soon exist. The past does not exist. Therefore going back in time is not possible, because where you want to go does not exist.

Well said. People think they might travel to a past time just because they remember it and because they also reason that present consequences have old causes and hence the past "lives" through its actual consequences, so it's somewhat reachable. They're mixing up causality and record of past times with existence.

Not strangely this thread starts with ideas come in dreams about winning the lottery. Each human being has events in his life when he chose in a way that he would do differently if given the chance; also the ability to see possible exploits of travelling to a past time. Once quenched greed and power, the ultimate goal is obtaining redemption by going back and avoiding the sin -a basic and primitive human desire related with our remembered past-, so a time machine would be a useful gadget for those that haven't learnt how to apologize for their mistakes -or even admit they made them-.

Don't even allow us imagine that the sole existence of entropy may explode our speculations on the subject, and let's find in paradoxes and other ruminations the amusement we are entitled in this hedonistic era. Don't feel discouraged for any technical challenge like the elemental particles that constitutes our actual body existing in the remote past we aspire to visit, or the problem of appearing in the right place when our homes move at tens or hundreds or thousands of kilometres per second. Such minor details must be pushed into the background when we are in a wild epistemologically hedonistic moment.

 

[AvalonXQ]

Be careful in endorsing JJM's ideas of the past, as he advocates an "absolute time" and eschews relativistic time dilation.

When it is understood that time is linked to, and a property of, space, we start to recognize viable methods by which the manipulation of space may also cause some manipulation of time.

Time travel isn't likely, but it's certainly possible.

 

[pilsan]

The interpretation I favor is that two timelines are created. And thus two Bobs and two Amys.

If two timelines are created doesn't this imply that there are now two universes where once there was one. If so, where does all the extra energy come from?

 

[quarky]

It is odd that winning the lottery has become an icon of paranormal proof.
Most people who win are fairly miserable and broke in a short time.

Whenever I travel to the past, I focus on not getting mud on my new pants.

 

[Brian-M]

1. You can change the past.
Then it is unlikely that you will get the same lottery numbers once you travelled back. For example, when you travelled back and want to go get a lottery ticket, you will encounter some people. By your presence, you will change their behavior at least slightly, like they wait 0.5 seconds to let you pass by, or they look at you for 0.1 seconds. Since they changed their behavior, the people encountering them will change their behavior in just the same way that you changed the behavoir of your first encounters, and so forth. You have caused a chain reaction of changes that first spreads at the speed of pedestrians, then at the speed of cars (as car drivers will be affected as well), and finally at the speed of planes. In the end, the person preparing the lottery machine will have been affected by this wave of changes as well, so the lottery machine will be prepared in a slightly different way, resulting in different numbers to be picked.

You're not being very creative with this.

For example, if you wanted to play Wednesday's lotto, you might pick up a lotto form on the previous Friday, and fill in a bunch of games with randomly selected numbers in pencil. Possibly go through it a second time with an eraser, and change some of the numbers at random.

Then you leave it the form in your lab next to your time machine for the next five days until Wednesday morning (by this time you've forgotten which numbers you've put on there) then go out and buy a lottery ticket with it, without paying any attention to which numbers are on it.

Wednesday night you write down the winning lotto numbers, pop back in time a few days, and change one of the games on the lotto form so that it now has the winning numbers, and return to your own time.

Then you check the lotto ticket you bought to see if it really did work.

If you do it this way, traveling to the past would have no effect except to change what numbers are on the ticket. Maybe not even that, because you might even have picked the winning numbers by accident.

 

[Dan O.]

Since you can't use entanglement to transfer information faster than the speed of light, I don't really know what you're talking about.

Wouldn't that argument be circular reasoning?

I based my time machine around an actual experiment where it was shown that the entanglement propagated both ways along a photon's timeline. Interfeering with a photon's path along one leg of the experiment was detectable along the other leg of the experiment.

Granted, spooky action at a distance is indeed spooky. But you can't just wish it away. Is there an actual experiment that proves it is impossible? And if action at a distance is impossible, what explains the results of the experiment I referenced?

 

[WhatRoughBeast]

If this worked, however, there would be the contradiction that, if you change your own past this way, you are no longer the same person. Particularly, you are not - and have never been - the person who found it necessary to send back a message to win the lottery. Because you would have been a lottery winner all along. So you would not send the message back in time. Therefore, it cannot be you but at best an alternate version of yourself in a parallel universe who get the cash.

Folks, you all need to read a lot more science fiction.

Verklagekasper, what you are describing is the Grandfather Paradox, except that you go back in time to win a lottery, rather than kill your grandfather.

Because it's more dramatic, let's use the classic formulation, where you invent a time machine, travel back to the past, kill your own grandfather, and thus were never born and never went back to kill him, etc.

The simplest way to deal with this paradox is to assert alternate time tracks, which has been done on this thread. Let me list a few more possibilities

1- When you change the past, you change the future, but the time traveler continues to exist. From the point of view of the altered time line, the time traveler appeared from nowhere and killed his grandfather amd

a) got back into the time machine and disappeared forever (this is identical to one of the two tracks in a multi-track model)

b) got back into the time machine and reappeared in a "new" present, where history was slightly different, and he had no identity.

c) got back into the time machine and found that the machine no longer works (because it was never invented), so he gets arrested, tried and convicted for murder.

d) got back into the time machine and found that the machine no longer works, so he is stranded in the past. He fell in love with his grandfather's widow and conceived a son who was his father, and the cycle repeated

e) there exists a "time police" who look for the telltale marks of historical revision, and they appeared after the traveler appeared in the past and arrested/killed him before he was able to kill his grandfather

2 - You can travel to the past, but the universe preserves its temporal integrity, so

a) there are regions of the past, such as your grandfather's era, which the time machine simply will not reach. Note that you can go back to the Cretaceous and kill a T. Rex, because nature will "fill in" the effects after a few years, and the long-term effect is nil.

b) when the traveler tries to shoot his grandfather, the gun misfires. When he tries to approach to do it with a knife he steps in a pothole and breaks his ankle. His grandfather never knows there was a problem.

c) when the traveler exits his machine, he is hit by a meteorite and killed.

d) when the traveller decides to build his machine, he is hit by a metorite and killed.

e) when the traveller decides to build his time machine (or when anyone decides to build a time machine) the sun goes nova and destroys the human race.

Finally, of course, there is the non-technological version: the time traveller goes back in time, kills his grandfather, then jumps back into his machine and returns to the present. Nothing has changed. "It is a wise man who knows his own father.", or grandfather in this case.

And for yet another version, I really recommend that you rent the movie "Primer". Then find some websites that have diagrams.

 

[WhatRoughBeast]

If two timelines are created doesn't this imply that there are now two universes where once there was one. If so, where does all the extra energy come from?

Same place the energy for this one came from.

 

[Roboramma]

Wouldn't that argument be circular reasoning?

What circular reasoning? I only pointed out the fact that entanglement doesn't allow for the superluminal transfer of information.
If you have an example in which it does, or can offer some method of using it to do so, please bring it forward.

I based my time machine around an actual experiment where it was shown that the entanglement propagated both ways along a photon's timeline. Interfeering with a photon's path along one leg of the experiment was detectable along the other leg of the experiment.

But you can't transfer information that way.

 

[Dan O.]

Let me illustrate this point with an analogy.

You have a magic box. If you put two coins in the box together, and then take them out and flip them, one will flip heads and the other will flip tails. It's random which is which, but once one coin has flipped heads, no matter how far away the other coin is, flipping it will produce tails, and vice versa.
After each coin is flipped the first time, it becomes a normal coin until you put it back in the box.

Assuming you have this magic box and a bunch of coins, explain how you can use the coins to communicate any faster than you could have without the coins.

I based my time machine around an actual experiment where it was shown that the entanglement propagated both ways along a photon's timeline. Interfeering with a photon's path along one leg of the experiment was detectable along the other leg of the experiment.

But you can't transfer information that way.

Let's see if I can't. I like the coins and the box analogy so I'll use that. Though I have to explain one misconception, there is no such thing as a normal coin. Every coin carries with it the entire history of entanglements every time it is put in a box with another coin. Also, the box is entropy neutral in that in neither produces nor consumes energy ie: the entanglement goes both ways.

I'll start out with a collection of 5 coins. The first thing we will do is pair up 4 of the coins and put each pair in the box so they are entangled as (A, B), (C, D) and E is left alone. Then I will split the pairs and put (A, C) and (B, D) in the box. Now we get tricky. And put C, D, E and the box in a time vault. We will also put in the vault a question about the future that can be answered yes or no. The vault will be left in the care of a trusted agent who at the appointed time will open the vault, read the question and if the answer is yes he will put coins C and D in the box. if the answer is no he will put coins C and E in the box.

After the agent has left with the vault, we flip coins A and B. if they are still entangled they will flip heads and tails. If the entanglement has been broken they will flip heads and tails with a probability of 1/2. We repeat the experiment in parallel with as many sets of 5 coins, boxes, time vaults and agents as we need to give us the desired confidence to act on the result.


PS: I have always realize that if the existence of real time machines were to become public knowledge, the financial markets would be devastated overnight. Thanks to a bunch of greedy bankers, I no longer have any incentive to keep this a secret.