Why do astronauts float in space?

Astronauts float because they and their spacecraft are falling around Earth together, not because gravity has vanished. The station moves sideways so quickly that as gravity pulls it downward, Earth's surface bends away beneath it. Everything inside shares that same fall, so people feel weightless.

At the space station's height, Earth's pull is still strong, which surprises many children. The speed is the trick: one orbit takes about ninety minutes, giving crews sunrise after sunrise while their pencils, socks, and snacks drift along beside them.