Gravity is a force, or power, that attracts objects to the center of the Earth. It is also one of the main forces that keeps the moon in orbit around the Earth and the Earth in orbit around the sun.
Gravity makes rivers run to the ocean and fruits fall from trees. Gravity also allows you to walk, because it acts against the energy of your steps and holds you to the planet. Without gravity, everything on Earth would float away into space. In fact, the Earth itself would fall apart and float away. Gravity is one of the most mysterious and least understood forces of Nature.
In this section, you will discover the power of gravity. You will learn how tree branches defy gravity, how tightrope walkers balance, and even why the moon revolves around the Earth.