The idea of space elevator was first put forward by tsiolkovsky, the father of space navigation and a famous Russian space scientist. You may not be familiar with this man, but you must know his famous saying: the earth is the cradle of mankind, but mankind will not stay in the cradle forever. Tsiolkovsky was deaf from childhood, never went to school, and all his knowledge was taught by himself. Later, he became a math and physics teacher. In his spare time, he studied many physics subjects. The famous Tsiolkovsky formula in the field of rocket design is named after him. He first proposed to use thrust to make rockets, calculated the speed of the first universe, and designed the model of jet rockets. When he visited the Eiffel Tower in France on 1895, he came up with the concept of cosmic elevator.
How to build a space elevator? Is it too difficult to build a towering tower on the surface of the earth and then install an elevator? No, actually, you don't have to go to so much trouble. Let's start with the geosynchronous orbit. There is a geosynchronous orbit over the equator. After the satellite is launched here, it can move synchronously with the earth. Seen from the ground, it looks motionless. Why is it still? Due to the gravity of the earth and the centrifugal force of the object thrown out when the earth rotates, when the satellite flies to a certain height above the earth, it is pulled back to the ground by gravity and thrown into space by centrifugal force. When these two forces are equal, the satellite can neither fly out nor fall to the ground. This is geosynchronous orbit, 36,000 kilometers above the ground.
Similarly, if a rope is long enough to extend from the ground into space, when its height is lower than the synchronous orbit, the rope will fall back to the ground under the action of the earth's gravity. If it continues to extend upward, it will be pulled up by centrifugal force after exceeding the height of synchronous track. When gravity and centrifugal force are equal, the rope will stand upright without support, because two forces hold it tightly at both ends. At this time, we can rely on this rope to install the space elevator.
At present, its structure, space elevator can only be built on the equator of the earth, because only on the equator is its centrifugal force and gravity in the opposite direction. If the space elevator is erected on the equator, its height must be higher than the synchronous orbit, because only above the synchronous orbit can gravity and centrifugal force reach a balance. The elevator can set up a station at the synchronous track, that is, 36 thousand kilometers, where you can experience the feeling of weightlessness and build a base on the ground to fix it. At the same time, add a counterweight at the upper end of the elevator.