How do stationary space satellite stay in place, and not go around the earth with out falling?



How do stationary space satellite stay in place, and not go around the earth with out falling?

In: Physics

They *are* going around the earth, but they’re doing it at a speed that matches the earth’s rotation.

How long it takes for a satellite to complete one orbit depends on how far away it is. At a certain distance, it takes 24 hours to complete one orbit.

Geostationary satellites are still orbiting, which means they’re moving sideways fast enough that the curve as they fall follows the Earth’s surface and so they maintain the same altitude. What keeps them “stationary” is that their orbital speed is the same as the rotation speed of the planet beneath (e.g. it takes them 24 hours to make a complete circuit), so they stay in the same place in the sky.

They are actually orbiting around the earth if you look at it from outer space. The satellite does get attracted by Earth’s gravity but since it’s also orbiting, it doesn’t fall. For example, if you tie a string to a ball and you make it orbit around your hand, the ball is pulled by the string but it doesn fall into your hand

Orbiting *is* falling. Its just falling and missing. The satellite is falling to the earth, but it is moving so fast horizontally that the “down” just keeps it going in a circle. Eventually it will crash into the earth, and satellites have little boosters that they fire occasionally to make sure that doesnt happen.

They are going around the Earth, only the orbit period is the same as the Earth rotation period. So relative to you it looks stationary

Orbits are basically going round the Earth by falling, in the case of geostationary satellites their falling and missing the Earth perfectly matches their orbital position so even as they move they stay above the same spot

One – The earth’s gravitational force that a body experiences reduces as the body move away from earth. So if you go further and further away from earth – at some particular distance (very large distance) you will be “almost free from earths gravitational attraction”.

Two – If you tie a ball to a string and whirl it you will notice that the ball will fly outwards (away from the center of rotation / your hand). So this means that when you rotate something about a centre point – there is an “radially outward force” that the revolving body will experience (which is directed radially outwards from the centre).

Now satellites stay in their designated locations (stationary orbits) by using both the above concepts. They are so far up – away from the earth that the gravitational force they experience is counterbalanced by the “radially outward force” created by virtue of their revolution (i.e. speed of revolution around earth). The speed of revolution around the earth, of the satellites, is matched to the rotational speed of earth around its own axis (which makes the satellite seem stationary with reference to earth).

“Stationary” satellites are not literally stationary. They are orbiting the earth the same way as all the others. It just so happens that the farthest away from earth you are, the longer it takes for you to complete an orbit around the earth. Low altitude satellites take less than 24 hours to orbit the earth while higher altitude satellites take more than 24 hours to orbit the earth. There is a sweet spot where satellites take exactly 24h to orbit the earth so they look to you as if they were always on the same spot in the sky. Ergo stationary