Some of the earliest pictures we have observed of celestial bodies should be that they are floating in the universe. So surely many people will ask, why are these celestial bodies floating in the universe instead of falling?
After all, these photos are only processed by art rather than taken in real life. In fact, if we simply observe on the earth and do not contact with any modern science, we will have such doubts.
For example, the ancient Greeks wanted to know that everything they saw on the earth fell on the ground, but the picture no longer existed in the sky. So people at that time put forward a theory that the world below the moon, including the earth, was composed of several simple elements. Then some heavy elements will droop, while the lighter elements will stay away from the ground and get higher and higher.
In fact, we can see that the earlier relatively simple materialism was also the law of gravity.
And then came the Copernican Revolution. At this time, we can finally put the physics of the earth and the unified law of celestial body movement together, and this set of theory at that time can solve some questions about celestial bodies for the vast majority of people.
Now we can be sure that when people are on the earth, they always feel like falling down because of gravity. Then the earth is subject to gravity, and the biggest gravity comes from the sun, and then other celestial bodies. For the parts outside the earth, they are not subject to the sun’s excessive gravity, so they will not fall without the force.
So when we see celestial bodies, it seems that they are floating in the universe. In fact, the essence is due to the illusion of the brain, which is caused by human living on the earth. In Newton’s mechanical system, he said that handstand is a certain reason that can change the state of objects. As he said just now, the earth has a great attraction for objects on its surface, so it’s very difficult to understand We’ll all stay on the ground.
If we explain it from Einstein’s theory of relativity, then heaven and earth must move close to space-time, so everything is actually the cause of gravity.