Hugh Everett proposed the strange theory of parallel universes. He proposed a multitude of universes, each a home to an alternate reality, including alternate versions of you and me. It may sound crazy but the theory of parallel universes is now considered serious science.
Hugh Everett’s theory was so bold that it set him on a collision course with the most brilliant minds of the Physics world. Taken to the extreme, parallel universe would mean that with every event that could happen in more ways than one, universes branch off in different directions. That means that we also divide into multiple versions of ourselves.
In one universe I could be having tea and getting ready for bed while in this universe, I’m boring you to death!
Atoms are the building blocks of the Universe – tiny particles that make up everything we see around us, from apples to bloggers. If you could somehow look inside one of these atoms you would see a concentrated middle, the nucleus, formed of protons and neutrons. Around the nucleus are tiny particles called electrons which spin super quick around the nucleus.
Now for the weird part…
The classical laws of Physics seem to work perfectly fine for everything bigger than an atom. Sir Newton said that gravity makes apples go down rather than up. And for us, normal, regular people these classical, Newtonian laws make perfect sense.
But when it comes to really tiny stuff like atoms, the classical laws no longer work. The electrons don’t fly around the nucleus in nice regular orbits like the planets around the sun, but instead they’re smeared out, taking a cloud-like form. AND… they’re everywhere at once.
In the late 1920s Niels Bohr proposed that everything can be divided into two categories: big stuff like apples, houses, bloggers and readers which obey the classical or Newtonian laws of Physics. Small stuff however, of the size of atoms, obeys the crazy laws of Quantum Mechanics.
Bohr also describes what happens when you look at something very tiny: when you try to measure the particle aspect part the wave part disappears from your perspective, and vice versa. In other words, when you observe the tiny particle, it stops behaving so weirdly. Instead of being a smeared out wave and in many places at once, when observed, it’s just in one place. A well-behaved tiny particle!
This was the Copenhagen Interpretation, named after Bohr’s birthplace, in case you were wondering.
But how could just measuring something change its behavior?
In the 1930s Erwin Schrodinger wrote a paper in which he pointed out that something’s afoot with this Copenhagen Interpretation: we are made of atoms, and if an atom can be in two places at once, so can we!
And with this in mind he came up with a thought experiment which gave birth to the most famous feline in science: Schrodinger’s cat.
A cat is penned up in a steel chamber, along with a radioactive substance such as Uranium, a Geiger counter attached to a quick-release hammer and a flask of poison gas. At the heart of it all is a quantum event: every now and then, completely randomly, there’s a chance of a uranium atom decaying and emitting radiation. This radiation is enough to trigger the counter that sets off the hammer, that breaks the vial, that poisons the cat. But if none of the uranium atoms decay during the experiment, the cat will live.
At the end of the experiment we ask: is the cat alive or dead? The answer according to Quantum Mechanics is 50% alive, 50% dead.
Schrodinger found it quite disturbing that the fate of a single atom dictates the fate of a cat. According to the Copenhagen Interpretation, until we open the box and observe what has happened, the entire contents of the box exists in two states: each atom both has and has not decayed, and further, the cat is both dead and alive!
This is what troubled Schrodinger and also what helped Hugh Everett come up with the theory of Parallel Universes. He said that everything in this world, big or small obeys the laws of Quantum Mechanics, and instead of the observer, he introduced the notion of splitting. Splitting occurs each time an event can have more than one outcome. This is how parallel universes are created.
This also solves the Schrodinger paradox: there is not one cat that is both dead and alive. There are instead two cats, existing in two separate worlds, one dead and one alive!
How is this for fascinating stuff?
I wonder what the other versions of me are doing in the other universes. Sleeping, I bet!
Where do you think you’d be in a parallel universe?