The double slit experiment –

Picture three playing cards standing up like dominoes. The first card has one hole in it. The second card has two holes in it. The third card has no holes in it. As the light comes out of the 2 holes they interact with each other in a process called “diffraction”. Imagine throwing stones into the water. Some of the waves that form will cancel each other out (the dark patches), while other waves will combine to form bigger waves (bright patches). These patches of light and dark land on the last card and is called “interference”.

This interference obviously indicates that light is acting like a wave and not a particle. If light acted like a particle, you’d expect big blobs of light behind the two holes. Imagine throwing darts through the holes.

Electrons shot out will form an interference pattern, but each individual one creates a point like a particle. So, electrons travel like waves, but land as particles. Light, electrons, and all other quantum particles thus act as both waves and particles.

Here’s where the things get crazy: If you shoot out electrons one at a time, the interference pattern still forms. That means 2 things. 1) Each electron must be passing through both holes at the same time AND 2) a single electron is then interacting with itself to create the wave (and interference). Remember, the patches are based on waves interacting with each other. But how can a single electron interact with itself?

Furthermore, shooting them out one at a time still creates the same overall pattern. That means that they “know” where their fellow particles have landed and continue the pattern accordingly. Shooting a million out at the same time will create the exact same pattern as shooting a million separate shots. But how do they “Know”???

Now, when you set up a detector at card 2 to see which hole a particle of light (or electron) is going through, everything changes. Instead of going through both holes and interacting with itself to form an interference pattern, all of a sudden they start acting like particles (darts) and 1) go through only one hole and 2) thus just form 2 blobs of light on card 3. They know they are being watched! Their behavior changes based on being observed.

The second you turn the detector off, they go back to acting “weird”.

So, they then created a “delayed choice” experiment. Instead of detecting the light at the holes in card two, they wanted to look at it half way between card 2 and card 3. Obviously, by this point, the light has passed through card 2 (either through one hole {particle/blob}, or both holes {wave/interference}).

When the detector is on (in mid flight mind you), the light lands as blobs (indicating that they passed as particles. But, if the detector is turned off, they form an interference pattern. So, the decision of whether or not to look at the light at this moment somehow affects how the light acted BEFORE it got to this moment. Past, present, time, causation??? Throw it all out of the window, it no longer exists.

We are only talking about billionths of a second here, but in theory, this should work for anything. There’s something called gravitational lensing. In short, as light travels through galaxies it can be bent by extreme gravitational forces. It’s similar to having the two cards out there in space, galaxies apart. If we decide to observe the light now, it should change to acting like a particle. Not just change now, but go back into time (before our solar system was even formed) and change then. How can what we do now affect a decision that was made billions of years ago?