Is there really another universe?

The Mysterious Multiverse

1. Traditional Universe

The first sentence in the classic Chinese elementary school article "The Thousand-Character Classic" is "The sky and the earth are black and yellow, and the universe is primitive." , the word "universe" here comes from "Huainanzi", "The four directions above and below are called Yu, and throughout the ages they have been called Zhou." Therefore, "Yu" is the concept of space, and "Universe" is the continuation of history and the concept of time. Therefore, the universe referred to in ancient my country represents the concept of "time and space" in modern science. The word universe we use today is just a physical space, which is equivalent to what the ancients called "universe". There is no concept of universe.

From ancient times to the present, human beings have never given up on the exploration of the universe. From Chang'e's flight to the moon to today's Shenzhou 11, human beings have already had a very in-depth understanding of the universe. The ancient Greeks were the first to begin scientific exploration of the universe, and the creation of the Hubble microscope enabled humans to see more distant places in the depths of the universe. Scientists have generally believed that the universe we live in is single, but with the development of science, a group of professional scholars have proposed the theory of multiverses. The emergence of the multiverse theory has completely subverted people's traditional understanding of the universe in the past.

2. The concept of multiverse

The concept of multiverse was proposed thanks to the scientific discovery of modern quantum mechanics. In quantum mechanics, particles have no definite position. We can determine There is only the probability of each particle appearing at each location. From this point of view, the world is a completely uncertain existence from its origin. Since all matter in the universe is composed of quanta, scientists speculate that since each quantum has a different state, the universe may not be just one, but may be composed of multiple similar universes, called parallel universes. Or the multiverse.

Before the concept of the multiverse was proposed, the "universe" was defined as a container of space and time, which included all the stars we can see (about 500*1021) and the approximately 80 billion galaxies they formed. . However, with the discoveries of astronomical telescopes and particle colliders, as well as the emergence of new mathematical insights, we have to abandon this traditional old "small universe" and instead believe in a larger universe. Compared with the new universe, the old universe is like a small insect and an elephant. The complexity of this new universe is far beyond human comprehension.

3. Theories related to the multiverse

Brian Greene, a professor of physics and mathematics at Columbia University in New York, elaborates on various related theories in his new book "The Hidden Reality" The multiverse theory, he believes that the universe we live in is just one of countless parallel universes. The pictures of these parallel universes are even more incredible, including: quilted multiverse, inflationary multiverse, string multiverse, quantum multiverse, holographic multiverse, virtual multiverse and ultimate multiverse.

(1) The quilted multiverse is the simplest version. The Quilted Multiverse is a parallel universe, which refers to other universes that are similar but different from a certain universe and exist parallel to the original universe. The concept of the beginning and infinite extension of space-time means that such an existence is mathematically bound to repeat itself at some point, a concept sometimes referred to as the "quilted multiverse." This creates an interesting phenomenon. If you look far enough, you may find another version of you. In fact, there are infinite versions of you. Some of your twins may wear the same or different clothes, do the same or different jobs, and live the same or different lives as you.

The observable universe is the Hubble volume. The space-time beyond the observation range (Hubble volume) is another independent universe (Hubble volume). A large number of universes exist apart from each other, forming an infinite universe. Megaverse. The infinite extension of space and time leads to the repetition of space and time at certain nodes, forming a giant universe made up of infinite different universes.

(2) The inflationary multiverse was proposed by Russian-American physicist Andrei Linde in Los Angeles in 1999. He invited a group of reporters to watch a strange computer simulation. The idea of ????the "inflationary multiverse" was demonstrated on the spot. In this version, the rapid expansion that followed the Big Bang never stopped once it occurred, creating a vast network of bubble universes, one of which we inhabit. Different bubble universes have different physical constants and physical laws. Each bubble universe is limited from the outside, but the residents inside the bubble believe that the bubble universes in eternal inflation are infinite.

(3) The multiverse of strings is the most eye-catching multiverse theory, and this is so because it is likely to become the ultimate theory. At present, quantum mechanics, which describes the microscopic world, and general relativity, which describes macroscopic gravity, are fundamentally in conflict. The smooth space-time of general relativity contradicts the violent quantum fluctuations of space-time at the microscopic level. This means that both cannot be correct, and neither of them can String theory is the latest attempt to combine quantum physics with gravity to completely describe the world, and it perfectly solves this problem. Brian Greene is one of the leading figures in the cutting-edge theory of theoretical physics, "String Theory." He has a detailed and vivid description of string theory in his book "Hidden Reality."

String theory will realize Einstein’s dream. It believes that the universe we live in is a mixture of reality and science fiction. This is an 11-dimensional universe, and parallel worlds are within reach. The basic idea of ??string theory is surprisingly simple. It believes that everything in the world, from tiny particles to the most distant planets, is composed of the same element - an unimaginably small filament that vibrates with energy, also known as string. Just like the strings on a cello can play a large number of different notes, in string theory these tiny strings vibrate in a large number of different ways, thus making up everything in nature. In other words, the whole world is like a vast and infinite world. A cosmic symphony resounds loudly in the various notes emitted by the vibrations of all these tiny energy filaments.

(4) The quantum multiverse was proposed by Hugh Everett III in 1957. Quantum mechanics is a description of atomic particles in the microscopic world, using probabilities rather than definite results. Quantum mechanics mathematically states that all possibilities for an event will occur in all independent universes. Just like Schr?dinger's cat theory, Brian Greene wrote in the book: In each universe, there is a different you who is witnessing different results of the same thing, and you all think that the world you live in is the only one in which you exist. is the only reality.

(5) The holographic multiverse theory was proposed by the contemporary American quantum physicist and scientific thinker David Bohm. He believes that objective reality does not exist, although the universe looks concrete. And solid, but in fact it is just an illusion, a huge and detailed holographic photo! Our universe is not material, but information. The universe we feel is actually information from the outside world. The core idea of ??holography is that the universe is an indivisible whole with closely related parts, and every part contains information about the whole. It sounds more like pure mysticism.

(6) The virtual multiverse theory believes that we live in a false multiverse. Nick Bostrom, a philosophy professor at Oxford University, first proposed such a view in 2001: What we, our world, and even the vast expansion of spacetime seen in the first multiverse scenario were largely nothing more than a giant computer simulation. The so-called simulation argument has the same characteristics as many levels in traditional Buddhist thought. On the other hand, the concept of fictional universes also appears in novels and movies, but Nick Bostrom's theory provides a series of seemingly reasonable assumptions and statistical calculations.

If we can use computers to simulate even part of a universe of self-aware entities, then someone will surely do it. As Nick Bostrom explains, computers can even simulate weather or nuclear explosions. And this simulation is run not just once, but thousands or even billions of times. Once someone masters the ability to simulate the universe, virtual universes will spring up like mushrooms after rain, and will soon exceed the number of real universes. Nick Bostrom asserts that if an intelligent creature is randomly selected as the subject of investigation, it is more likely to live in virtual reality than in real reality. For example, if there are many computers in a certain universe creating many virtual realities, then it is very likely that our existence is actually a life simulated by a more advanced civilization.

(7) Brian Green also mentioned the concept of an ultimate multiverse. The idea of ??an ultimate multiverse is that anything that is logically possible (mathematically defined, not physically realistic) is real. You don't necessarily need material things to become the embodiment of this reality. Max Tegmark, a professor of physics at MIT, proposed the Mathematical Universe Hypothesis. The mathematical universe hypothesis states that mathematics not only describes the world we live in, it constitutes the world itself. He believes that the universe and everything are mathematical, and the core of everything is numbers.

4. The impact of multiverse theory on human beings

If we are very likely to live in a virtual reality and we are just virtual creatures in it, then what should we do? Okay? Robin Hanson, an economist at George Mason University, wrote several comments on Nick Bostrom's simulation paper. He believes that all we can do is try to create opportunities to extend our survival time in this simulation, or seek to be simulated again in the future. His conclusion is rather depressing: If our descendants prefer interesting simulations, then you should want both you and the events around you to be interesting, otherwise the "operator" running the simulation is likely to make everything Back to the beginning, leaving us with no trace. In a simulated universe, morality no longer matters, instead Hitler, Jesus or Princess Diana are retained because of their fun entertainment.

Scientists once proposed the concept of "fine-tuning", that is, a small change leads to amazing results. For example, if we swap the masses of protons and neutrons, the protons will decay into neutrons and other particles in about 15 minutes. It was originally expected that protons would combine with electrons to form hydrogen gas 380,000 years after the birth of the universe. As a result, no more hydrogen gas would be produced due to the decay of protons.

As a result, gravity still attracts the neutrons to hold them together, but the star never burns as it does now. Without hydrogen, the chemistry would certainly be very different. Simply swap the masses of protons and neutrons, and the entire universe would be completely different. Of course, humans would not exist. Astronomer Royal Martin Rees believes that our universe appears to have been suspiciously fine-tuned to allow the existence of life, the so-called "anthropic principle." Change any fundamental parameter, even slightly, the strong nuclear force or the gravitational constant, and you end up with an uninteresting universe. We live in a universe that can contain life because there are many universes to choose from.

This fact seems to tell us that the existence of the universe seems to be carefully designed and arranged, and we seem to see the hand of God invisibly controlling all this.

From Nicolaus Copernicus to Edwin Hubble, our understanding of the universe is constantly deepening and expanding. But we still doubt that the universe is so big that it is difficult for us to even understand the parameters that describe it. The road to understanding the universe in the future is long and far away.

In the multiverse, anything that can happen will happen, all possibilities are inevitable, and morality is even more elusive than in the old-fashioned universe. If there are one or more of your twins in some corner of the world, then what’s the point of your existence? The development of science has been reducing the centrality and uniqueness of human beings, and the multiverse theory is almost gone in this regard. At the top.