### What Is Weightlessness?

The term "weightless" is usually thought to mean that someone is in a "zero-gravity" zone, aka space or freefall, and therefore has no weight. This can be seen in many space-related movies, like Apollo 13. However, if you actually look at the physics of it, this is false. Weightlessness is actually the absence of a normal force. Most people don't know what this is so let's contextualize. To do this, we'll have to take a look at Newton's three laws. Or at least two of them.

According to Newton's second law, for there to be a net force acting on an object, there has to be some sort of mass and acceleration. But as commonly misconstrued, mass does not equal weight. So where does weight come in? Well, Newton's third law states that for every action, there is an equal an opposite reaction. So when your body is pushing on the Earth due to gravity pulling you down, the Earth is pushing right back with the same amount of force perpendicular to the …

According to Newton's second law, for there to be a net force acting on an object, there has to be some sort of mass and acceleration. But as commonly misconstrued, mass does not equal weight. So where does weight come in? Well, Newton's third law states that for every action, there is an equal an opposite reaction. So when your body is pushing on the Earth due to gravity pulling you down, the Earth is pushing right back with the same amount of force perpendicular to the …