posted by jmog
A day late, but here goes...
The famous physics experiment known as the double slit experiment was originally done with water waves to show how waves interfere with each other and create amplifying and cancelling wave frequencies.
Later on, in 1801, it was done for the first time with light. At the time scientists weren't sure if light was particles or waves. The double slit experiment, when done with light showed the same interference patterns that a water wave does.
This led them to conclude that light was a wave...not a particle.
Fast forward to 1927 and it was done for the first time specifically with subatomic particles, this time electrons. Electrons, and protons for that matter, were assumed to be particles, and therefore the double slit experiment should not show interference patterns, but simply two "exit" markers on the "reading" filament (think if you threw baseballs repeatedly through 2 different slits and marked where they hit the backstop). That's what they assumed electrons, and later protons) would do. However, it showed interference patterns like waves?
So how can something that we can measure its mass (at this time we knew how much electrons and protons weighed) be a wave?
This led to the understanding that subatomic particles sometimes behaved as particles and sometimes as waves, which also made them reconsider light from the 1801 experiment. Light also shows wave and particle characteristics (hense a photon was discovered as the subatomic particle of light).
So, what in the world does this have to do with alternate dimensions/multiverse? Ok, before we jump that far ahead we need to simplify subatomic physics a little bit, because it gets really SCREWY when we get down that small...
Ok, first the Heisenberg Uncertainty Principle says that the more precisely we measure the position of a subatomic particle the less precisely its speed can be known/predicted and vice versa. In the subatomic world, specifically for an electron to make sense, you can not possibly know where the electron is located at a given time AND its velocity at that time. It's impossible. For this reason all subatomic physics (mostly called molecular dynamics) is expressed in statistical probabilities.
For instance, the simplest atom, a hydrogen atom does not REALLY look like what we learned in high school chemistry:
No, it looks more like this...
Where all the black dots are probable electron locations, and it is more like an electron "probability cloud". And it only gets crazier (the electron clouds) from there as we get to larger and larger atoms.
So, now that we understand that in subatomic particles we can only talk about probabilities lets talk about the next step in the electron double slit experiment...
They then decided to slow down the electron beam flow to the point where only a SINGLE electron was shooting out at a time and therefore only one electron was going through the 2 slits at a time. the electron would have to either go through the left or right slit. They just had to run this experiment a LOT longer to see how the pattern would develop on the collector filament.
They FULLY expected it to show its "particle" behaviour at this point (like if it were baseballs) and just have 2 spots where the electrons hit on the other side. 1 behind the left slit, and 1 behind the right slit.
The results utterly floored them, so much that they didn't believe it and ran the experiment over and over again....the same exact interference pattern showed up on the filament as if they were shooting millions of electrons at a time.
How in the WORLD is this possible? There was no other electron going through the slits for the electron to "interfere" with!
There are two prevailing theories to this day, and both are equally weird/unbelievable....
The first one uses the probability nature of an electron listed above to explain that the electron actually goes through BOTH slits and interferes WITH ITSELF!
Ok, if that doesn't flip your mind...the next one will...
The other prevailing theory is that the electron actually interferes with electrons FROM ANOTHER UNIVERSE. Yes, look up quantum foam, its an "out there" idea that on the quantum levels alternate universes can not only interact with each other, but subatomic particles can travel back and forth between universes.
So, that's how a water wave double slit experiment eventually leads to a multiverse/alternate universe theory being REAL in physics, and not just in Marvel movies/comic books.
For an AMAZING science fiction book that covers this exact theory of the double slit experiment and multi-verse, read Michael Crichton's (yes, same guy that wrote Jurassic Park) book Timeline.
The movie truly sucked, they butchered the book, but the book was truly Crichton's best in my opinion, even better than Jurassic Park.
Hope I didn't bore you too much...
I understand your lack of empathy.