Even before the appearance of Everett and his idea of multiple universes, physicists were at an impasse. They had to use one set of rules for a subatomic world that is subject to quantum mechanics, and another set of rules for a large-scale everyday world that we can see and touch. The complexity of the transition from one scale to another twists the brains of scientists into bizarre forms.
For example, in quantum mechanics, particles do not have certain properties, as long as no one looks at them. Their nature is described by the so-called wave function, which includes all the possible properties that a particle can have. But in a single universe, all these properties cannot exist simultaneously, so when you look at a particle, it takes one state. This idea is metaphorically portrayed in a paradox with the Schrodinger cat – when the cat sitting in the box is both alive and dead until you open the box for verification. Your action turns a cat into a warm and lively or into a scarecrow. However, scientists can not agree with this either.
In the multiverse, you do not need to worry that you can kill a cat with your curiosity. Instead, whenever you open a window, the reality falls into two versions. Unclear? I agree. But somewhere there may be another version of the event that just happened in your presence. Somewhere there it did not happen.
It remains to find out what causes scientists have found to tie this incredible theory to the facts.
Thus, the reality can be infinite
In an interview 2011, Columbia University physicist Brian Green, who wrote the book “Hidden Reality: Parallel Universes and Deep Cosmic Laws,” explained that we are not quite sure how large the universe is. It can be very, very large, but finite. Or, if you leave Earth in any direction, the cosmos can last forever. Approximately so, most of us represent it.
But if the cosmos is infinite, it must be multiple universes with infinite parallel realities, according to Green. Imagine that the universe and all matter in it are equivalent to a deck of cards. Just like in the deck of 52 cards, there will be exactly as many different forms of the substance. If you mix the deck long enough, eventually the order of the cards will repeat the original one. Similarly, in an infinite universe, the matter will eventually be repeated and organized in a similar way. A multiple universes, the so-called multiverse, with an infinite number of parallel realities contains similar but slightly different versions of everything that exists and thus provides a simple and convenient way to explain repetition.
So you can explain how the universe begins and ends
People have a special passion – and it is connected with the ability of the brain to form schemes – we want to know the beginning and the end of each story. Including the history of the universe itself. But if the Big Bang was the beginning of the universe, what caused it and what existed before it? Does the universe wait for the end and what will happen after it? These questions were asked each of us once.
The multiverse can explain all these things. Some physicists have assumed that infinite regions of the multiverse can be called world-branes. These branes exist in multiple dimensions, but we can not find them because they are able to perceive only three dimensions of space and one – time in our own braneworld.
Some physicists believe that these branes are stacked like slabs together, like bread in a bag. Most of the time they are separated. But sometimes they collide. Theoretically, these collisions are catastrophic enough to cause repeated “big explosions” – so that the parallel universes begin anew, again and again.
Observations suggest that multiple universes can exist
The Planetary Orbital Observatory of the European Space Agency collects data on the cosmic microwave background, or CMB, – the background radiation, which is still shining since the first and hot stages of the existence of the universe.
Her research also led to possible evidence of the existence of a multiverse. In 2010, a team of scientists from the United Kingdom, Canada and the United States discovered four unusual and unlikely circular patterns in the CMB. Scientists have suggested that these labels can be “bruises” that remained on the body of our universe after a collision with others.
In 2015, ESA researcher Rang-Ram Hari made a similar discovery. Hari took the CMB model from a celestial picture of the observatory, and then removed everything else that we know about it – stars, gas, interstellar dust and so on. At this point, the sky was supposed to become mostly empty, not counting the background noise.
But it did not. Instead, in a certain frequency range, Hari was able to detect scattered spots on the map of space, areas that were about 4500 times brighter than they should have been. Scientists came up with another possible explanation: these areas are the imprints of clashes between our universe and the parallel.
Hari believes that if we do not find another way to explain these marks, “we will have to conclude that Nature can eventually play dice, and we are only one random universe among many others.”
The universe is too large to exclude the possibility of the existence of parallel realities
There are chances that multiple universes exist, although we have not seen parallel realities because we cannot refute its existence.
At first, it may seem that this is a clever rhetorical trick but think about the following: even in our world we found many things that were not previously suspected of existence, and these things happened – the global crisis of 2008 is a good example. Before him, no one thought that it was possible at all. David Hume called this kind of event “black swans”: people will assume that all swans are white until they see black swans.
The scale of the universe allows us to think about the possibility of the existence of multiple universes. We know that the universe is very, very large, possibly infinite in its size. This means that we will not be able to discover everything that exists in the universe. And since scientists have determined that the universe is about 13.8 billion years old, we can only detect the light that has come to us during this time. If the parallel reality is further than 13.8 light years from us, we can never know about its existence, even if it exists in the dimensions that we can see.
Multiple universes make sense from the point of view of atheism
As Stanford University physicist Andrew Linde explained in an interview in 2008, if the physical world were subject to several other rules, life would not be able to exist. If protons were 0.2% more massive than now, for example, they would be so unstable that they would decay into simple particles instantaneously without the formation of an atom. And if gravity were a little more powerful, the result would be monstrous. Stars like our sun would be compressed tight enough that they would burn out their fuel for several million years, without giving a chance to form planets like Earth. This is the so-called “problem of fine-tuning.”
Some see in this precise balance of conditions the proof of the participation of the almighty power, the supreme being that created everything, then the atheists strongly angry. But the possibility of the existence of a multiverse, in which this force will simply be in a separate reality with all the factors necessary for life, quite suits them.
As Linde said, “for me, the reality of many universes is logically possible. We can say: perhaps this is some kind of mystical coincidence. Perhaps God created the universe for our good. I do not know anything about God, but the universe itself could reproduce itself an infinite number of times in all possible manifestations. ”
Time travelers can not break history
The popularity of the trilogy “Back to the Future” made many get carried away with the idea of time travel. Since the film was released on the screen, no one has yet developed DeLorean, capable of moving back and forth in time, for decades or centuries. But scientists believe that time travel can be at least theoretically possible.
And if it is possible, we could be in the same position as the protagonist “Back to the Future” Marty McFly – risking unintentionally changing something in the past, thereby changing the future and course of history. McFly accidentally prevented his parents from meeting and falling in love, thereby successfully removing themselves from family photographs.
However, in the article of 2015, it was suggested that the existence of the multiverse does not make such efforts necessary. “The existence of alternative worlds means that there is no single chronology that can be broken,” wrote Georg Dvorsky. On the contrary, if a person goes to the past and changes something, he will simply create a new set of parallel universes.
We could be a simulation of a developed civilization
All these topics about parallel universes, which we discussed at the moment, were extremely interesting. But there is something else interesting.
In 2003, the philosopher Nick Bostrom, director of the Institute of the Future of Humanity at Oxford University, wondered if anything that we perceive as a reality – in particular, our separate parallel universe – could simply be a digital simulation of another universe. According to Bostrom, it will take 10 36 calculations to create a detailed model of the whole human history.
A well-developed extraterrestrial civilization – creatures whose technological level makes us look like cave inhabitants of the Paleolithic – might well have enough computing power for this all. Moreover, the modeling of each separately living person does not require any completely dizzy electronic resources, so the creatures modeled on the computer can be much more real.
All this may mean that we live in the digital world, as from the movie “The Matrix.”
But what happens if this developed civilization itself is a simulation?
People have been thinking about multiple universes since time immemorial
It will be extremely difficult to prove this. But here one cannot help recalling the old statements attributed to Picasso or Susan Sontag: if you can imagine something, it must exist.
And there’s something in it. In the end, long before Hugh Everett sipped his cognac, many people throughout the history of mankind imagined different versions of the multiverse.
Ancient Indian religious texts, for example, are filled with descriptions of a set of parallel universes. And the ancient Greeks had a philosophy of atomism, in which it was asserted that there is an infinite number of worlds scattered in the same infinite emptiness.
In the Middle Ages, the ideas of multiple worlds were also raised. The Parisian bishop in 1277 maintained that the Greek philosopher Aristotle was mistaken in saying that there is only one possible world because this casts doubt on the almighty power of God, capable of creating parallel worlds. This idea was resurrected in the 1600s by Gottfried Wilhelm Leibniz, one of the pillars of the scientific revolution. He argued that there are many possible worlds, each of which is endowed with a separate physics.
All this fits into our knowledge of the universe
However strange the concept of a multiverse may seem, it is in some way consistent with the progress of modern history and in how people see themselves and the universe.
In 2011, physicists Alexander Vilenkin and Max Tegmark noted that the people of Western civilization gradually calmed down as they discovered the nature of reality. They began with thinking that the Earth was the center of everything. It turned out that this is not so, and that our solar system is only a tiny part of the Milky Way.
The multiverse should bring this idea to its logical conclusion. If the multiverse exists, it means that we are not the chosen ones and that there are endless versions of ourselves.
But some believe that we are only at the very beginning of the path to the expansion of consciousness. As the theoretical physicist at Stanford University, Leonard Susskind, wrote, in a couple of centuries, philosophers and scientists will look back at our time as “a golden age in which the narrow provincial concept of the 20th century universe was replaced by a larger and better multiverse staggering proportions.”