It’s easy to assume that astronauts float in space because they are far away from the Earth’s gravitational force. But look at the moon. It is much further away than the International Space Station, yet it orbits around the Earth because it is perpetually attracted by its gravitational pull. So if the Earth’s gravity can affect the moon, the astronauts cannot be floating because there is no gravity where they are.
Gravity is an attractive force, which is always present between two objects that have a mass. It’s such a weedy force, however, that we need huge objects such as planets or moons to realize it’s there at all. We usually describe the acceleration of an object with mass towards the center of the Earth by Earth’s gravitational “pull” with the constant “g”—it is just less than 10 meters per second squared. This pull decreases as the distance between the objects increases. But to get rid of it entirely we would have to go an infinite distance away from anything with any mass.
However, we can create environments in which we don’t experience the effects of gravity. Usually people refer to such “microgravity” environments as “zero-g,” because they make objects appear weightless. But what does it actually mean to be “weightless”? The thing about forces is that you only notice them when there is another force counteracting them. Since you have a mass, the Earth’s gravitational pull is always accelerating you towards its center. Luckily, the ground is in the way. But if there was nothing to stop you from falling, you wouldn’t feel the ground “push back” and you would feel weightless.
Revealed: microgravity.
This is the first way to “get rid” of gravity: free fall! Some people think of skydiving, but in fact a skydiver is never really in free fall—air drag can slow objects down. For scientific experiments, however, researchers can overcome the air resistance issue by pumping out air from a huge tower, some 150 meters high. Then they shoot experiments up to the top of the tower—and drop them—yep it’s called a “drop tower.“ The experiment, and everything inside it, is in ”microgravity” as it falls—for about four seconds—until BANG, it hits the ground. That violent end means the type of experiments scientists do in drop towers need to survive regular crashes, which is not always ideal.
