What are the functions of natural satellites

Speed ​​in space

Objects orbiting a planet are called satellites. Each complete orbit of a planet by a satellite is called an orbit.

Our earth has a natural satellite - the moon. However, since October 1957, many thousands of artificial (man-made) satellites have been carried in orbits around our earth.

In order to be able to maintain their orbit, satellites have to reach a very high speed, which depends on the height of the orbit. For example, a circular orbit 300 km above the earth's surface requires a speed of 7.8 km / s (28,000 km / h). At this speed, a satellite orbits the earth once every 90 minutes.

Satellites have to move so fast to counterbalance the gravitational pull of the earth. This can be compared to throwing a ball. The harder the ball is thrown, the further it flies before falling back to the ground.

If you could throw it hard enough to reach the required speed, the ball would go into orbit. He would never fall back to earth. If you threw it harder so that it could reach a speed of 11.2 km / s (40,300 km / h, the so-called escape speed), it would leave the earth completely. Our ball would then become a satellite of the sun.

Last modified October 12, 2011

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