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A Practical Time Machine

Posted: Tue Jun 24, 2008 3:12 pm
by GeorgeC
Produce a pair of entangled photons, A and B, and let them move off in opposite directions. If after a few nanoseconds you interact with photon A, then the corresponding effect occurs with photon B instantaneously. This is now well known and demonstrable science.
One explanation for this is that when you interact with photon A, it sends a propagating signal to photon B (some other sort of photon). When photon B gets the signal it sends a reverse wave signal back to A, which travels backwards in time. The reverse signal gets there at the instant the forward signal takes off, hence the instantaneous transfer of information. This is also theory put forward by reputable quantum physicists.
Now introduce a mini black hole into one side of the apparatus. The effect of this will be to slow down time for the forward and reverse signals. The side you place the black hole in will determine whether the reverse signal event will arrive late or early.
If it arrives early then the effect on B will be observed before you interact with A.

So if you arrange that the interaction on A is initiated by the press of a switch (or not), and the result on B is to make a light come on (or not), you will now observe the light come on before you press the switch. You are therefore sending a binary bit of information back in time. The apparatus will be of finite size, so the shift backwards in time will be nanoseconds, but put a feedback loop into the system so that the switch is pressed automatically when the light comes on, and a sequence of flashes will propagate backwards in time.

So it would be quite easy to send a signal back for an hour to let you know what the lottery numbers are…

Re: A Practical Time Machine

Posted: Tue Jun 24, 2008 3:52 pm
by RL Astro
GeorgeC wrote:So it would be quite easy to send a signal back for an hour to let you know what the lottery numbers are…
If you can harvest this peculiarity you could make a fortune. Be it for working out how to use it or by not telling anyone and constantly winning the lottery! :lol:

Posted: Tue Jun 24, 2008 5:09 pm
by Eclipse
So post the maths then.

Re: A Practical Time Machine

Posted: Tue Jun 24, 2008 5:34 pm
by GeorgeC
RL Astro wrote: Be it for working out how to use it or by not telling anyone and constantly winning the lottery! :lol:
Keep an eye open for if anyone ever wins it two weeks in a row!

Posted: Tue Jun 24, 2008 6:40 pm
by GeorgeC
It seems that some people are even getting money donated to try experiments with this sort of thing.
http://cosmiclog.msnbc.msn.com/archive/ ... 74531.aspx

We will have to wait until CERN switches on the LHC to see if we can get a supply of mini black holes...

Posted: Wed Jun 25, 2008 12:30 pm
by Quasar
That is a very interesting concept. How can you be sure the black hole will be of influence on the two 'instantaneous signals'?
This I have heard before where some physicists argue about Photons in empty space. The theories suggest that a photon doesn't exist until it is observed or has impacted an object. When it impacts an object it sends a instantaneous signal back to the source and vice versa with data. This is problomatic in several ways:- If a star ten million light years away gets sucked into a black hole then the transfer of 'instantaneous information' is short of a partie. So when we see the light and the instantanious signal is sent back there is no scource electron. The Physicists have argued that this is natures way of telling you the scource does not exist anymore and you will in fact never see the light at all if this instantaneous signal process doesn't take place. It's an amazing theory, but not terribly difficult to understand. It does have, as George suggests - alsorts of complications with time, but I would like to see a mathematic model for this Quantum exercise.

Posted: Wed Jun 25, 2008 11:52 pm
by Cliff
Dear al(L)
The topic is titled "A Practical Time Machine".
Personally I am not interested much in the theory or the maths, I would just like to see a real practical working time machine.
I'm afraid, indeed I feel confident it will never happen.
In my opinion at best human time travel will only be practicable in a very limited fashion eg as experienced travelling in fast long distance space craft. I doubt that humans will ever travel to any distant stars (other than the odd manned spacecraft possibly banging into our own Sun.
Just imagine travelling to the nearest night sky star in a pretty fast space ship. Unless there were a bunch of very attractive ladies on board the space craft, I think I would rather watch paint dry.
Then youve got to travel back home again, having found that exoplanet orbitting your lovely star is not quite the utopia that the astronomical observers who discovered it thought it would be.
Best of luck from Cliff

Posted: Thu Jun 26, 2008 7:29 am
by Earthshine
Cliff wrote:Unless there were a bunch of very attractive ladies on board the space craft, I think I would rather watch paint dry.
The ladies of 'SHADO' were very nice (UFO from the 1970's), and those uniforms..... :shock: 8)

Posted: Thu Jun 26, 2008 2:52 pm
by Quasar
Cliff wrote:Dear al(L)
The topic is titled "A Practical Time Machine".
Personally I am not interested much in the theory or the maths, I would just like to see a real practical working time machine.
I'm afraid, indeed I feel confident it will never happen.
In my opinion at best human time travel will only be practicable in a very limited fashion eg as experienced travelling in fast long distance space craft. I doubt that humans will ever travel to any distant stars (other than the odd manned spacecraft possibly banging into our own Sun.
Just imagine travelling to the nearest night sky star in a pretty fast space ship. Unless there were a bunch of very attractive ladies on board the space craft, I think I would rather watch paint dry.
Then youve got to travel back home again, having found that exoplanet orbitting your lovely star is not quite the utopia that the astronomical observers who discovered it thought it would be.
Best of luck from Cliff
I agree.

Posted: Fri Jun 27, 2008 10:07 pm
by GeorgeC
Cliff wrote:I'm afraid, indeed I feel confident it will never happen.
I agree that the time machine of science fiction will never be made. The easiest proof of this is that if it could be made, people from the future would have visited us already.
But, if the quantum notion of reverse waves travelling backwards in time turns out to be true (and a lot of people cleverer than me think it is possible) then in theory it could be possible to make a gizmo that could flash a light BEFORE you press the switch to flash the light.
How much before is debatable. It obviously could not flash the light at a time before the device was created, so if it is created in 2030 we cannot know of its existence before then. At best I can see a time machine sending binary digits backwards in time. One that sends a person back to the dinosaurs is the stuff of stories.

Posted: Fri Jun 27, 2008 10:25 pm
by Quasar
One that sends a person back to the dinosaurs is the stuff of stories
If your gonna play with the concept, play with it properly!!! :wink:

Posted: Mon Jun 30, 2008 10:46 pm
by Cliff
Dear GeorgeC and Quasar
George although to be honest I did not follow your argument fully. I would just mention that with regards to your reference to waves, that in some areas of physics (such as the study of light) waves only partly describe its behaviour. In some respects I think it can be said light acts as if it is a series of particles.
Therefore I am trying to suggest that it may be possible to follow one particular line of thought too far.
Quasar, I suggest the same to you and this is where I think your arguments sometime fall down. If I understand your recent post satisfactorily I think you may have a problem.
We can play with a concept and even if the concept is wrong the experience can be a useful one. However, I am inclined to think that there are some very good concepts and some bad ones.
Even pushing (playing with) a good concept too far can sometimes be a mistake. Pushing a bad concept too far might just prove to be just lucky, but I think is more likely to be disastarous.
Conjecture can be a very good thing , but at the end of the day as they say the proof of the pudding is in the eating (not reading the recipe).
Best wishes from Cliff

Re: A Practical Time Machine

Posted: Fri Jul 04, 2008 11:12 pm
by big_kev
GeorgeC wrote:Produce a pair of entangled photons, A and B, and let them move off in opposite directions. If after a few nanoseconds you interact with photon A, then the corresponding effect occurs with photon B instantaneously. This is now well known and demonstrable science.
I have two issues with this.

The first one is that my understanding of entangled photons is different.

I understand that interacting with an entangled photon and measuring the reaction with tell you what the result of the same interaction would be with the other photon should you make that same interaction.
basically if you interacted with photon A and it caused a particular effect then you would know that if you made the same interaction with photon B you would get exactly the same effect....whereas with non-entanglked photons it would be random.
this may have a great use in computing but not I fear in time travel.

Secondly consider the scenario ( if my first response is wrong...which it may be ) where the result of sending a signal back in time has the result of prohibiting the initial reaction with the first photon......the kill your mother scenario.

How would you initiate this " time travel" if the initiation never happened ?

Causality will always prevent "time travel".

Posted: Tue Jul 08, 2008 8:28 pm
by GeorgeC
I agree that causality is a headache. If we imagine that the proposed machine could be built and operates such that when a switch is flipped a light comes on before the switch is flipped, then what happens if we get contrary and observe the light come on and then refuse to flip the switch?

Posted: Tue Jul 08, 2008 9:32 pm
by big_kev
GeorgeC wrote:I agree that causality is a headache. If we imagine that the proposed machine could be built and operates such that when a switch is flipped a light comes on before the switch is flipped, then what happens if we get contrary and observe the light come on and then refuse to flip the switch?

For the light to come on in the past the switch has to be flipped in the future, it can't be avoided.

However as I stated "causality" prevents the future influencing the past.

Time can only flow one way by its very nature.

The direction is independant of the observer.

A period of time is best viewed as two parallel lines one above the other.

All the universe moves from the bottom line at the same vertical rate.
However a person may move perpendicularly and cover the distance in what seems like a very short time to themselves and another may move almost parallel ( but not quite) to the bottom line and take a long time to reach the top line.

However at all times both people would be the same vertical distance above the bottom line. One can never fall behind the other into their "past" or indeed their own.

It might be easier to turn this upside down and have people "falling " through time, although gravity starts to look very similar ?