Now here's a question i'd definately love to have answered.
Imagine you recorded the results from a double slit experiment and you seperated the results taken at the back plate from the results taken at the slits counting and observing the Photons. No one has seen the results so far. The data from the slits ends up at one side of our Galaxy and the data from the back plate ends up at the other side million and millions of light years away. Someone opens the data taken from the slits and observes it. This should collapse the wave function when the other set of results is opened at the other side of the Galaxy. Lets say the results were opened within a couple of minutes of each other. Will the results be instant? If the results are instant, how much faster than the speed of light has the information passed across the Galaxy? Will the results be the same as the data taken from the spinning pairs of Photons experiment when it was discovered that if you change the spin direction of one Photon the counter spin of the other photon changed instantly proving that Photons communicate faster than light speed at Quantum levels?
The double slit experiment remains one of the most confusing aspects of Quantum. Basically it was found that the wave function of a Photon or an Electron can collapse when such particles have been observed by Humans.
The experiment involved firing Photons through two slits in a screen onto a plate behind which could show patterns where they were striking.
When the Photons were observed on the plate they showed interferance patterns much like water. It was observed that the Photons were peeking on the rear plate where interferance patterns overlapped. The Photons had an observable wave function.
To avoid these patterns the experiment was changed so that one Photon at a time was fired through the slits. Then there was no way the Photons could interfere with one another. Strange thing was the same interferance patterns emerged on the back plate. So they changed the experiment again and put a sensor on both the slits counting and observing which slit the Photons went through.
Very strange thing happened, the wave function of the Photons collapsed and they began to show properties of a particle, striking the wall in a linear fashion like firing bullets would appear through the two slits. The fact that they were observing the Photon before it hit the rear plate collapsed the wave function.
See here:- http://www.youtube.com/watch?v=wEzRdZGYNvA
The strangest part of this experiment is this:-
If they didn't observe the Photons going through the slits then the Photons struck the rear plate as a wave function. If they observed the Photons going through the slits then they appear as a particle bahaving in a convensional manner.
This is the absolute crazy part:- They recorded the observational data at the slits without looking at it and didn't observe the data from the back plate, both sets of data were recorded and never seen by anyone for a while. They found out that when they went to the back plate data first and observed it, the wave function collapsed because the slit data was still viewable. If they destroyed the recordings of the Photons being captured going through the slits before anyone saw it before they observed the back plate then the wave function appeared on the back plate. The Photons went through the slits days ago yet there were still two possibilities of where they could strike the back plate depending on whether you read the data or destroy it
Either way you look at this, if you observe a Photon then you change its future and it becomes a particle rather than a wave function. The waves have become known as 'waves of possibility' and have all their options 'open' until someone observes them and changes their future. That possible future can be in two different places at the same time and remain there for millions of years until someone views the data. Totally bizaar.