Physics seems to be fine-tuned for life, but the confusing part for many physicists is the strength of dark energy that appears to accelerate the universe’s expansion. If this acceleration were a bit stronger, there would be no life. A similar would happen if it were slower. This fine-tuning caused many scientists to believe that we live in a multiverse despite not being able to find the proof.
Much of scientific knowledge is theoretical
Swedish-American physicist and cosmologist Max Tegmark presented a theory of the Type 4 multiverse. He also shared that much of scientific knowledge is purely theoretical.
Alongside Brian Greene, an American theoretical physicist and mathematician, Tegmark proposed different classification schemes for multiverses. Greene suggested there were nine types of multiverses. At the same time, Tegmark pointed out that Level I is an extension of our universe, Level II represents universes with different physical constants, Level III contains many-worlds interpretation of quantum mechanics, and Level IV is the ultimate ensemble.
The concept is as old as time
The idea there is more than one universe dates back to ancient Greeks. Philosopher and psychologist William James used multiverse” in the late XIX century, though in a different context. Multiverse was also discussed during the Middle Ages.
Nobel prize winner Erwin Schrödinger presented “superposition” in the 1950s, a fundamental principle of quantum mechanics. Before that, Churchill wrote in his biography, “Certainly nothing could be more repulsive to both our minds and feelings than the spectacle of thousands of millions of universes – for that is what they say it comes to now – all knocking about together forever without any rational or good purpose behind them.”
The existence of a multiverse is still puzzling. In 2015, Dr. Ranga-Ram Chary analyzed the cosmic radiation spectrum and discovered “a signal 4,500 times brighter than it should have been, based on the number of protons and electrons” previously believed to exist in the early universe. But, to this day, it remains a hypothesis.
The most popular explanation for the fine-tuning of physics
In a recent study by Dr Norbert Lange, published in The Conversation, he talked about his book “Why? The Purpose of the Universe” and gave some interesting examples.
Lange wrote, “Suppose Betty is the only person playing in her local bingo hall one night, and in an incredible run of luck, all of her numbers come up in the first minute. Betty thinks to herself: ‘Wow, there must be lots of people playing bingo in other bingo halls tonight!’ Her reasoning is: if there are lots of people playing throughout the country, then it’s not so improbable that somebody would get all their numbers called out in the first minute.”
However, Dr. Lange argued, “probability theory says it is no more likely that Betty herself would have such a run of luck.” Then he pointed out, “Multiverse theorists commit the same fallacy.”
The struggle is real
Lange added how Multiverse theorists think, “Wow, how improbable that our universe has the right numbers for life; there must be many other universes out there with the wrong numbers!” However, he said this was just like Betty believing she could explain running out of luck.
The author also noted that there is a difference between thinking that a universe is fine-tuned and believing that THIS universe is fine-tuned. But how did we end up with such a fine-tuned universe? Lange writes, “Either it’s an incredible fluke that our universe happened to have the right numbers.”
There have been several theories by the brightest minds that promote the existence of the multiverse. However, with every such theory comes just as many respected scientists who argue against it.
Philosophers, physicists, and mathematicians will continue looking for clues, but unlike the Big Bang, which left clues, the multiverse might forever remain a mystery.