Earth is the home of humanity and the planet we first learned about.
Everything about the Earth has not yet been fully studied, but it has advanced a lot compared to the past.
For example, we already know the diameter and weight of the Earth, as well as the structure of its interior, and we continue to improve our understanding of the Earth as science advances.
The Earth is a rocky planet, and its overall weight is also very impressive, reaching 60 trillion billion tons.
On Earth, heavy objects will automatically fall downward, but the Earth is floating in space, so why does the Earth not fall downward?
The key to this problem lies in the concept of "gravity", as long as we understand this point will not be confused.
1. Why does the Earth not fall?
If you have learned the theorem of gravity, you will know that the reason we can stand on the ground, the reason why the object will fall, is because of the Earth's gravity in action.
The center of the earth is the core of the earth, everything on the earth is attracted to the core, so we can stand firmly on the earth.
But in space, after we will be "weightless", can float.
For example, space station astronauts can float and move, because we have been removed from the Earth's gravity.
The Earth is a planet revolving around the Sun, and the Earth is subject to the gravitational pull of the Sun, just as the Moon revolves around the Earth.
2. So why aren't we falling directly toward the sun?
Our Earth is rotating while being attracted by the Sun, and the resulting centrifugal force keeps the Earth from being completely captured by the Sun's gravity.
Therefore, the Earth can maintain its rotation around the Sun for a long time, and one revolution around the Sun is a year.
3. Is there a center of gravity in the universe?
If we strictly follow the theory of gravity, there should be a gravitational center in the universe.
But just like us and the Sun, we are not completely captured, even though we are rotating around the center.
The sun is a star, but it is not completely stationary, it is also rotating around the center of the galaxy at an extremely slow speed, only we can hardly feel it during our lifetime, so it feels like the sun is constant.
Both humans and the Earth have a very small presence in the entire universe, and our current understanding of the universe is still too limited.
But this does not stop the pace of human research, and in the future people will continue to explore and understand more about our material world.
