There are many unsolved mysteries in the world, and I believe many of them, because I have some assumptions about the generation of these mysteries.
1. Conjecture of human time travel in the future
Science and technology is constantly improving, especially in some opportunities, science and technology will be explosive progress. So I believe that in the future, mankind will invent the time machine, which may be a long time later, but I believe in the possibility of this.
So people in the future will want to go back to the past through the time machine.
As for the paradox of time crossing, if I go through the past and change the events that will affect the future, so that I will not choose to cross, or even affect the invention of the time machine, then how can I cross time? If there is no crossing, and there is no event that will affect the future, then I will cross. This kind of contradiction will not be discussed this time.
There’s a question here, if I’m a future person who can use the time machine, what time in the past would I want to cross.
Let’s suppose that human will invent the time machine in 3000 A.D., then I think that people at that time will prefer to travel to the future, or to a time close to themselves, such as when they were young, or to change some things that they care about, and will travel to a past that was not very far away from him. Therefore, most of them will not travel to the time near or before my age. If I could take the initiative to choose the time of crossing, I would not choose to travel to ancient times, such as 200 BC, because even if I have some modern high-tech knowledge and skills, that era is too boring for me.Moreover, it also involves the question of whether the energy supply needs to be re supplied after the time machine passes through. If the time machine passes through the time machine too far, it will be so difficult to obtain the energy for the time machine to go back.
Of course, the above is my guess of most future people. The difference between people is very large. There must be a small number of future people who choose to travel to a very long time in the past. Maybe this is the reason why some unsolved mysteries in the world are produced. Created by humans from the future…
2. Extraterrestrial conjecture
There are three kinds of conjectures about the unsolved mysteries caused by aliens here:
（1）Aliens visited the earth in ancient times. They left behind a lot of things belonging to extraterrestrial, produced a lot of unsolved puzzles. Even human beings are created by them.
（2）Aliens are now constantly interacting with earth. There are unsolved mysteries produced during interactions.
（3）Aliens visited the earth in ancient times, and have been continuously interacting with the earth, resulting in many unsolved mysteries。
In my personal opinion, the existence of aliens is inevitable, because the universe is too vast. As for whether or not aliens have made contact with us, I can only say that it is possible.
Even I have a conjecture that aliens are always around us. What if these aliens were only 1/10000 of our size, so we don’t see them? Maybe it’s just that we don’t have an opportunity to communicate with them.
