Low earth orbit is generally defined as orbiting the Earth at between 200 and 2,000 kilometers (124 to 1240 miles) above the Earth's surface.
Below 200km, the gravity of the Earth causes the orbit...
Low Earth orbits decay into lower Earth orbits and then re-entry into the atmosphere happens and the orbiting thing either burns up in the air or crashes into the Earth somewhere.
The further away from the planet a satellite is, the longer the orbit. So satellites in low earth orbit - from about 120 to about 600 miles up - orbit the Earth in about 90 to 100 minutes, doing...
Gravity pulls the moon toward the Earth but the moon does not crash into it because it is already moving sideways compared to that gravity. By the time the gravity has pulled the moon down a mile or...
The moon orbits the Earth, but technically, the moon and Earth orbit each other, around a center of gravity. And due to the moon's size, the moon-earth system is sometimes called a "binary planet"...