1, light speed obstacle
The upper limit of speed in the universe is the speed of light. Although this theory has been recognized by countless scientists, many people don't seem to believe this statement, but until now, human beings have not been able to make any aircraft or find (in a vacuum) that can exceed the speed of light. So on the road of exploration, there are still many unsolved mysteries waiting for us to discover.
Supernova explosion is the most feared thing for human beings. Because the gamma rays during the supernova explosion will have a negative impact on the earth. Of course, the merger of neutron stars will also cause gamma ray bursts. These rays will destroy the earth's ozone layer, reach the earth's surface, and cause biological DNA breakage, which is extremely harmful, but their speed is the speed of light.
So we can't receive any warning before the gamma rays reach the earth!
In short, it's like walking blindfolded on a road full of traps. People will find out only when they step on the trap and fall into it. This situation cannot be avoided in advance. Therefore, at least in geological history, gamma-ray bursts did not make us completely extinct, and it is not easy for human beings to go to the present.
2. Fermi paradox
What does Fermi Paradox cover? Since there are aliens everywhere in the universe, where are they? Fermi paradox has two explanations, which are both interesting and terrible.
There is a theory in Star Trek that there will be no discovery of life in the universe until we can make space navigation equipment with faster than light speed, because no one will contact us actively. Now the earth is still in the "developing life reserve" in the Milky Way. It's a bit like Sino-US relations now. Once a developing civilization is found to have surpassed it, it will start the suppression mode.
Another dimension theory explains that our world is actually a multidimensional space, but human beings can only recognize three dimensions at present. High-dimensional civilization and the earth exist in the same universe. But they can control everything, such as appearing, disappearing, taking people away and so on. But we can't see them at all. Even if there is, we will only think that we are deceiving ourselves, because the time from appearance to disappearance is only a blink of an eye.
Either way, human beings exist as observed forms, and we have no privacy. Just like aquatic creatures in an aquarium, they think they exist in their own space, and the so-called personal space does not exist. Therefore, the so-called obstacles we think in three-dimensional space are not unsolvable for high-dimensional observers.
3. Parallel worlds
Not long ago, the news that a high school student in Tianjin was suspected of entering parallel space caused heated discussion. In his memory, there was a boy who grew up playing and disappeared out of thin air, as if he had never appeared. Although the high school student's voice is just an impulsive post, only those who know the truth know what is right and wrong.
The theory of parallel space comes from quantum theory, Big Bang and time travel. Of course, parallel space in quantum theory and time travel is even more terrible. Among them, parallel space is the space-time formed by two different choices of an event in modern space-time.
At first, the pace of the two is the same, but the longer it takes at any time, there will be many crossroads, which will split different time and space.
Then came the terrible events. If you have been in a project, you have two choices, one is the last stop and the other is to stop the loss in time. You chose the last stop in your space, the project was successful, and you also had your own successful career. Then, suddenly, at the peak of your life, you become an idle person. Are you afraid at this time?
Just like dreaming, I was still very moved after waking up for a long time, so moved that I became rich in my dream.
In the movie Flying High, something happened in parallel space. A mother fell asleep during the flight after boarding the plane with her child, and then woke up to find that the child was gone, even without any trace of her existence. If it were you, what would you do? Think of yourself as having a real dream?
4. The antimatter world
Antimatter is an extension of the concept of antiparticle in particle physics. For example, antiprotons and positrons can form antihydrogen atoms. Theoretically speaking, they will be annihilated when they meet matter, which is called energy. Because it is the annihilation of positive and negative matter, the efficiency of mutual conversion between mass energy and energy is 100%!
According to the theory that the universe originated from the Big Bang, positive and negative matter should be equal. In other words, there is an antimatter world in the universe. In that world, everything is the same as the physical universe. Antimatter can also form stars, planets and galaxies, and even life can appear. What's more, it may have reached the advanced civilization of space navigation!
So, if this advanced civilization visits the earth one day, what good time do you think will happen? Or if one day the Milky Way leads the solar system into the Ju Yuan at a speed of more than 600 km/s, what should human beings do, or what kind of identity will human beings exist?
5, vacuum decay
1980, physicists sidney coleman and Frank Delucia published a paper on "Gravitational Effect and Vacuum Attenuation" in Physical Review.
They think that vacuum is not only an empty existence, but also an empty vacuum state in quantum theory. In fact, during this period, there are some instantaneous active quantum activities in a high-energy state, and particles appear and then disappear. Most areas of our universe are in such a vacuum state.
The high energy state will decay to the low energy state. A real low-energy vacuum is a real vacuum. Is the universe in the lowest energy state now? Or like the nucleus of uranium -238, we can't find it because its half-life is 4.7 billion years?
Or is our universe in this pseudo-vacuum state with a long half-life? Always maintain a stable state, and then it is actually a cover-up. In fact, it exists as a temporary metastable state. Maybe one day, it will be triggered somewhere in the universe and the speed of light will spread to the outside world!
Liu's Wen Chao Dao describes such a scene. The equatorial accelerator of human beings has accumulated a certain initial energy, which can make the pseudo-vacuum state of the universe decay into a real vacuum state. In other words, when the event happened, it was the moment when the cosmic vacuum began to decay, so the "civilization of the troubleshooter" prevented the accelerator from opening.
Once the vacuum decays, even its propagation speed will reach the speed of light, and the energy level of the whole universe will be transformed into a real vacuum state. And there is no way to stop this change. Even if you want to take any measures, you can't implement them because of the speed of light. So we won't know until the event happens before our eyes.
Therefore, as long as we don't have the super-light-speed information transmission technology imagined in the legend, we will always be the last person to know the truth! The light speed barrier covers our eyes like an eye patch, and vacuum attenuation is the biggest trap. Once you fall, you can never turn over and become a landlord.