How Strong is the Gravity?

On Earth, we experience a force that pulls us to the ground. That force is called gravity. It is probably not something that you think about too much. Yet without gravity, we would all float away into the atmosphere. Everything from walking, riding a bike, driving a car, or sleeping in a bed is possible because of gravity. Our strong skeletons support our bodies against the pull of Earth’s gravity.

In space, the force of gravity is so weak that a feeling of weightlessness results. Astronauts use the word microgravity to describe this lack of gravity in space. Here’s how one NASA astronaut recounts the experience.

From the Journal of Ed Lu

Many different things happen to the human body while in space because of microgravity. Blood shifts from the lower body up to the top. Because of this, astronauts may appear to have puffy heads! Fortunately, their heads go back to normal size upon returning to Earth. Astronauts also get a little bit taller during long stays in space. The absence of gravity allows the spine to stretch slightly.