What is a parallel universe? In fact, parallel universes are easier to understand. For example, your present occupation is a salesman, maybe in another time and space, your present occupation may be a teacher. Moreover, in different parallel universes, identities may be different and there is a subtle connection. It's just that in our lives, we don't feel ourselves in parallel universes. And in the parallel universe, you can't feel your existence.
Some people don't believe in parallel universes, but in 2007, some scientists found that there is a big hole in the universe, and there is no other matter in this hole. At that time, scientists said that the hole was probably a channel connecting parallel universes, so it is certain that the universe is very diverse and there is not only one universe.
After so many years of exploration, the existence of black holes has been discovered, which has also confirmed the existence of other celestial bodies in the universe. But now human beings have limited ability to explore the universe and there is no way to find out the secrets of the universe. Therefore, mankind still needs continuous development, and maybe an accurate answer will be found in the future.
Conclusion:
The universe is so big, there are many things that we can't find the answer now, so there is no accurate answer whether there is a parallel universe or not. Maybe you think there is, but there is. If you don't think so, then there isn't .. In short, I think that when our technology is strong enough, maybe the answer will surface.