At this time, we can't help but think: in a distant time and space, there is another self, who has a completely different situation from himself, maybe there, he can have a perfect life.
I have to say that the concept of parallel universes is very fascinating, but at the same time it seems a little confusing, will parallel universes be real?Is it science fiction or science?It is a bit far-fetched to say that a parallel universe is a scientific conjecture, because no matter what form of parallel universe it is, it can be said that it cannot be falsified, and this does not meet the basic requirements of science. But it is by no means a pure science fiction concept, because from the classical theory, it does have the possibility of existence.
How big is the universe?Is the radius 46.5 billion light years?It's just the size of the observable universe.
In our world, there is a limit to the speed of light moving, i.e. 299792458 meters per second, what does it mean?It means that it is impossible for us to see everything in the universe, because the age of the universe is 13.8 billion years old, so the light in the universe has only traveled for 13.8 billion years at most, and theoretically we can only see things 13.8 billion light-years away at the farthest, but because the space of the universe itself is expanding, when the light beyond 13.8 billion light-years reaches our eyes, the things there have run to 46.5 billion light-years away, so the range of the observable universe is 46.5 billion light-years away.
We can call the entire universe the "big universe", and the observable universe we live in is only a small part of the big universe.
We don't know, and we can never know, how big the universe is, the only thing we know is that the big universe is big, big, and contains countless observable universes. Every observable universe is finite in size, and the types of particles in it are finite and identical, which means that there is a finite number of combinations of these particles. Of course, there are many combinations of particles, so our world has a variety of different substances, but no matter how many combinations there are, it is ultimately limited.
The number of observable universes is innumerable, far more than the way particles can be combined.
This means that in the vast number of observable universes, there must be some universes where all or some of the particles are combined in exactly the same way, so the matter in these universes is exactly the same, there is also the sun, there is the earth, there is a you and a me. Of course, just because the "you" there is exactly the same as you in terms of material composition does not mean that he has the same living environment, the same family and friends, and the same way of thinking as you.
The above is only a possibility of parallel universes, which is based on the concept of parallel universes derived from the classical theory of the universe, although this parallel universe is not satisfactory, but it at least shows that the existence of parallel universes has a theoretical possibility, not a simple science fiction concept.
In addition to the possible existence of parallel universes in space, parallel universes may also exist in time. The universe has a beginning, it was born 13.8 billion years ago, and perhaps an end, when the universe expands to a certain limit, it will start to contract, and eventually return to an infinitesimal singularity.
Next is another big **, expanding, contracting, and returning again.
The universe is endless, so in each cycle, exactly the same parallel universe will be born, which is the parallel universe in time. Of course, none of these parallel universes are the parallel universes that everyone wants, most people want the kind of parallel universes proposed by the mathematician Penrose, each parallel universe is isolated from each other but can be connected to each other in some unusual way, such as going to another universe through a wormhole or a black hole, and exchanging identities with the "self" there, and such a parallel universe seems to be more like a science fiction concept.