This article is part of a series called Big Ideas, in which the book answers one question: What is reality? You can read more by visiting The Big Ideas Series page.
When I was eight years old, a revelation changed my life forever.
The year was 1955, and the headlines announced the death of a famous scientist. An image attached to an article shows his desk filled with papers and books. As I recall, the photo caption indicated that among the piles of material there was an unfinished manuscript.
This discovery captivated me. What could be so difficult that this man, often lauded as one of the greatest scientists of all time, was unable to complete this work? I had to find out, and over the years I’ve visited bookshops to learn more about it.
His name was Albert Einstein. His unfinished work explored what might be known as the theory of everything, an equation, perhaps no more than an inch long, that would allow us to unify all the laws of physics. Einstein also hoped it would give us a glimpse into the mind of God. “I want to know his thoughts,” said Mashhour. I was hooked.
Today, many of the world’s leading physicists are embarking on this cosmic search, whose far-reaching reverberations extend to our understanding of reality and the meaning of existence. It would be the culmination of the achievement of thousands of years of scientific research, as ancient civilizations also wondered how and what the universe was made of. The ultimate goal of the theory of everything is Combine Einstein’s theory of relativity With the strange world of quantum theory.
In essence, the theory of relativity delves into the universe’s most massive phenomena: things like black holes and the birth of the universe. The field of relativity is no less than the entire universe. On the other hand, quantum theory explores the behavior of matter at the smallest level. Its field includes the smallest particles of nature, those hidden in the depths of the atom.
Uniting these two areas of thought into one coherent theory is an ambitious task, which builds on and adds to the work begun by Einstein. But to do so, scientists must first identify an important fact: where the universe came from.
This is where our two areas of thought clearly diverge.
If we subscribe to Einstein’s theory of relativity, the universe is some kind of expanding bubble. We live on the skin of this bubble, and it exploded 13.8 billion years ago, giving us the Big Bang. This unique universe as we know it was born.
Quantum theory is Based on a radically different picture One of the many. Subatomic particles, you see, can exist simultaneously in multiple states. Take the electron, which is a subatomic particle that carries a negative charge. The wondrous devices of our lives, such as transistors, computers, and lasers, are all possible because an electron, in a sense, can be in several places at the same time. Her behavior challenges our traditional understanding of reality.
Here is the key: in the same way that quantum theory forces us to introduce multiple electrons simultaneously, applying this theory to the entire universe makes us compelled to introduce a multiverse – a multiverse. By this logic, the single bubble Einstein entered is now a bubble bath of parallel universes, constantly splitting into two bubbles or colliding with other bubbles. In this scenario, the Big Bang could occur permanently in distant regions, representing the collision or merging of these bubble universes.
In physics, the concept of the multiverse is an essential component of a leading field of study based on the theory of everything. It’s called string theory, and it’s the focus of my research. In this image, subatomic particles are just different notes on a small vibrating chord, which explains why there are so many of them. Each string vibration, or resonance, corresponds to a distinct particle. String harmonies comply with the laws of physics. Chord melodies explain chemistry.
With this thinking, the universe is a symphony of strings. String theory, in turn, It assumes an infinite number of parallel universesWe are just one of them.
This illustrates a conversation I once had with Nobel Prize-winning theoretical physicist Stephen Weinberg. He told me, “Imagine you are sitting in your living room listening to the radio.” In the room there are waves from hundreds of different radio stations, but your radio is tuned to only one frequency. You can only hear the station that is compatible with your radio; In other words, it vibrates in unison with your transistors.
Now, imagine that your living room is filled with waves of all the electrons and atoms vibrating in that space. These waves may indicate alternate realities—those that contain dinosaurs or aliens, for example—right there in your living room. But it’s hard to interact with them, because you don’t vibrate with them coherently. We have freed ourselves of these alternative realities.
There is an exercise that my colleagues and I sometimes present to their Ph.D. Students of theoretical physics. We ask them to solve a problem by calculating the probability that one will wake up on Mars tomorrow. Quantum theory is based on what is known as Heisenberg’s Uncertainty Principle, allowing for a small possibility that we can exist even as far away as Mars. So there is a small but calculable possibility that a quantum wave will make its way through spacetime and end there.
But when you do the math, you find that for this to happen you have to wait longer than the age of the universe. That is, you will most likely wake up in your bed tomorrow, not on Mars. To paraphrase the saying of the great British geneticist JBS Haldane, reality is not only stranger than we suppose, but even stranger than we are. Can I assume.
It’s been more than six decades since Einstein’s death, and yet I keep going back to that picture of his desk I saw at the age of 8, the work it left unfinished and its deep traces. In the quest to merge two opposing perspectives of the universe, we are left with a set of deeply troubling questions. Is it possible that we are also present in multiple countries? What would we do if we chose a different profession? Married to someone else? What if we could somehow change important episodes in our past? As Einstein once wrote, “The distinction between past, present, and future is an irresistible illusion.”
Perhaps there are versions of us who live completely different lives. If this theory of everything is correct, perhaps there is a parallel world where we billionaires plan our next adventure, or where we live as homeless in a desperate search for our next meal. Who do you know? A simple quantum fork in the road could have made all the difference.
Michio Kaku is Professor of Physics at City University of New York and author of God’s Equation.