# Why the satelites do not fall to earth

Look at the two pictures given to make this clear. The first is when someone throws a stone. The velocity of the stone is shown as two elements, vertical and horizontal. Since there is no force in the opposite direction to the coastal component, the stone travels away until it falls to the ground.

As gravity acts in the opposite direction to the steep element, it (the steep component of velocity) first decreases and then comes in the direction of gravity and the stone falls to the ground. Depending on the speed at which the stone is thrown, it will travel farther before it falls to the ground.

The second image shows five bullets being fired from a cannon at the top of an imaginary tower 250 km above the Earth’s surface, with the first two slower bullets falling at A and B. The speed of the third bullet is very high. It also falls as a result of gravity, but is unable to reach the Earth’s surface due to the Earth’s curvature. So it keeps going through the path of C. The same thing happens with moons. They are also falling to the ground but never reach the earth due to the curvature of the earth. This is the secret of the moons’ orbit around the earth without falling to the ground.

This fall, which is subject only to the Earth’s gravity, is called a free fall.

The speed of the fourth bullet is greater than the critical speed of the 250 km high orbit, so it travels in an elliptical orbit. The speed of the fifth bullet is the speed of the Earth’s escape, so it leaves the Earth in a parabolic path. If it accelerates further, it will leave the Earth in a hyperbolic path.

The fourth and fifth cases of the above are somewhat troublesome. The satellites need powerful rockets to accelerate their escape from the Earth. Some of Russia’s early Luna missions and China’s Chang’e missions have traveled this way.