However, they do not feel their weight because nothing is pushing back on them. In this sense, they still have weight, even though Earth’s gravitational force is smaller in orbit than it is on Earth’s surface (Box 1). So what does this mean for orbiting astronauts? In space, astronauts and their spaceship still have mass and are still acted upon by Earth’s gravity. However, since the astronaut is also moving forward super fast, he/she continuously falls around the Earth rather than crashing into the Earth. (B) An astronaut orbiting the Earth does feel weightless because there is no ground or normal force to counteract the force of gravity. (A) An astronaut standing on Earth does not feel weightless because the ground creates a normal force that opposes the force of gravity. Astronauts feel weightless when there is nothing opposing the force of gravity. This inability to feel gravity would make us feel weightless (at least for a moment Box 1). If the ground beneath our feet were to disappear, gravity would nonetheless be acting upon us, but we would be unable to sense it. It is through this contact (or normal) force on our feet that we are able to perceive the force of gravity as weight. However, because our feet are in physical contact with the ground, there is also a normal force pushing upwards on our feet (Figure 1A). This opposing force is termed normal force, which in contrast to gravity, is a contact force that acts upon objects that are physically associated with one another.įor example, when we are standing on the ground, the force of Earth’s gravity pulls our body towards the ground. In fact, we do not feel the force of gravity unless there is some opposing contact force to counteract it. As the name implies, a non-contact force is one that acts between two objects that are not in physical contact with one another, meaning that we need not be touching Earth for gravity to be acting upon us. This attractive force, more commonly known as gravity, is a non-contact force that acts on us from a distance.

Our weight on Earth depends on our mass, which is how much matter we are made of, as well as the force of attraction between our mass and the mass of planet Earth.

To prepare for our journey, we must first understand what the heck weightlessness actually is. Our dreams of floating in space are closer to becoming reality than ever before.

Weightlessness may only be for astronauts, but with the help of private companies like SpaceX, Blue Origin, and Virgin Galactic, becoming astronauts may not be so far-fetched. So, is dreaming really as close as we’ll ever get to floating in space? Is the magical experience of weightlessness really limited to the tiny proportion of human beings who get to call themselves something-nauts (you know, astronauts, cosmonauts, taikonauts, spationauts)? Not so fast. The weight of our rear ends pressed firmly into our seats brings us crashing back to planet Earth, back to reality. We have seen footage of astronauts floating around the International Space Station playing Ping-Pong with balls of water and Pac-Man with strings of M&Ms.įor a moment, as we watch these astronauts thriving in an environment completely alien to us, we are able to imagine ourselves floating around with them. Weightlessness is something many of us have dreamed about since we were kids.

No gravity experience