Gravity is the most common force in nature, called universal gravitation. Any two objects, regardless of their size, will have a pulling effect. Modern physics believes that this pulling effect is caused by the bending of the object caused by the disturbance of time and space.
In theory, the gravity of any object acts on the entire universe, so there is no question of how many meters above the earth there is no gravity. It can only be said that the extent of the Earth’s gravity is not obvious.
It can be said that the gravitational range of all the data is unfounded. The range of gravity can reach infinity. But here is a point, the strength of the gravitational effect is inversely proportional to the distance. The closer the distance, the stronger the gravitation, the farther the distance, the weaker the gravitation. Just like a magnet, I don’t know how to play it. But gravity is proportional to quality. The greater the mass of the celestial body, the stronger the gravitation.
Speaking of this, perhaps the rebuttal is coming. It is like an astronaut who can float in space and not fall on the earth. If gravity is infinite, how can it float by the gravity of the earth.
In fact, the astronaut is not static in space, it is a process of high-speed movement around the earth, but there is no reference object, it seems that there is no movement at all. During this high-speed movement, a centripetal force (centrifugal force) is generated with the earth. This force can counteract the gravity of the Earth and keep it in balance. It is weightlessness. But it cannot be said that it is not affected by the gravity of the earth.
Friends who don’t understand the centrifugal force can think about the swivel chair of the amusement park. When you sit on it and spin it up, you will feel like you have a feeling of flying outwards, but it is bound by the chain. The moon is far more distant from the Earth than the astronauts, and is still captured by the Earth as a satellite. The reason why it does not crash into the earth, but also the centripetal force during the revolution is to resist gravity.
When the speed reaches a certain level, gravity is also no way. Therefore, the first, second, third and other cosmic escape speeds were born.
The speed of the first universe is 7.9 kilometers per second. This is the speed of the surround, that is, to maintain this speed, it can orbit the earth in orbit, and it will not be able to pull off the gravity of the earth, nor will it be pulled down by the gravity of the earth;
The second cosmic speed is 11.2 kilometers per second, and you can break away from the gravity of the earth and fly to deeper deep space;
The third cosmic speed is 16.7 kilometers per second. It is the relationship between the position of the earth and the sun’s gravity, and the speed of the sun’s gravitation.
So how far is the gravity of the earth? There is no way to answer this question. If the universe has only one planet on the earth, how far away the earth’s gravity still exists, but the farther it is, the smaller the influence will be.
After a million kilometers, the gravitational force of the earth on a 100 kilogram object is only 0.036 cattle, which is 3.6 grams of force. With a little force, it can break away from the gravitational constraint of the earth.
The use of gravitation and distance is inversely proportional to the quality of the knowledge point, which explains why the sun can capture the eight planets, but the moon is revolving around the earth.
Capturing the eight planets is where people’s quality is placed. As for the moon, it is better to explain around the earth instead of the sun. Because the moon is too far from the sun relative to the sun, the gravitational effect is weak. The gravitational pull of the Earth that is not close to the sun is strong.
So gravitation, even if you are far away, you can’t feel its existence at all. You can only say that gravity is far from being far away because of the distance, but you can’t say no.
Oktay added: The world is big, no wonder. There are some magical places on the earth. The person can be suspended in midair, and interested friends can like and comment.