You Wouldn't Want to Live Without Gravity!

Gravity is an ever-present force in our lives. It does lots of useful things-like keeping us on Earth and holding the entire universe together! Read about the scientific quest to understand the mysteries of gravity, such as how it affects the movements of the planets and helps us make power from waterfalls. Excerpts from Experts: Astronauts don't lie down to sleep, because in space there is no difference between lying down and standing up! If you went to live on a planet with more gravity, you would eventually develop a stronger heart and bones. Protect yourself from gravity's effects by wearing a helmet when biking. Anything that has mass exerts a gravitational pull-including you!