Why Astronauts Float Above Earth

An astronaut, a person who works in space, lets go of a pen. It stays nearby instead of dropping to the floor. Earth is still pulling on both of them. They float because they are falling together.

On Earth, the ground stops you from falling. It pushes up against your feet. This helps you feel your weight.

A space station, a place where people live and work in space, is different. The station, the people and their things are all falling around Earth together. The floor does not have to hold them up.

Why does the station not hit Earth? It moves sideways very fast. Earth pulls it down, but Earth is round. As the station falls, the ground curves away below it. So it keeps falling around Earth without reaching the ground.

Earth's pull at the International Space Station is only a little weaker than on the ground. People do not float just because they are high above Earth. When someone lets go of a pen without pushing it, both keep moving along almost the same path.

Large, heavy things are still hard to start or stop moving. People must move them carefully.

The Moon also moves around Earth this way. Earth's pull makes its path curve.