Absence of gravity is known as weightlessness. It is like floating, the feeling you get when a roller coaster suddenly goes down. Astronauts on the International Space Station are in free fall all the time.

What does anti gravity do to your body?

In the absence of gravity there is no weight load on the back and leg muscles, so they begin to weaken and shrink. In some muscles degeneration is rapid, and without regular exercise astronauts may lose up to 20 percent of their muscle mass within 5-11 days.

Does zero gravity make you feel sick?

NASA astronauts acclimating themselves to space adaptation syndrome in a KC-135 airplane that flies parabolic arcs to create short periods of weightlessness. In about two thirds of the passengers, these flights produce nausea, giving the plane its nickname "vomit comet".