How Gravity Works
Gravity is an invisible force that attracts all objects with mass toward each other. Every object in the universe, from tiny grains of sand to enormous planets, has gravity. The bigger an object is, the stronger its gravitational pull. Earth's gravity is strong enough to pull us down and keep everything from floating into space.
Gravity in Everyday Life
You experience gravity every single day without thinking about it. When you jump, gravity pulls you back down. When you throw a ball in the air, gravity brings it back to Earth. Gravity also keeps the moon orbiting Earth and keeps Earth orbiting the sun. Without gravity, everything would float away into space.
How Strong Is Gravity?
Gravity's strength depends on how much mass an object has and how far away other objects are. Earth's gravity is powerful enough to keep objects on the ground and pull them down if they fall. However, gravity is the weakest of all the forces in nature. On the moon, gravity is only one-sixth as strong as on Earth, so astronauts can jump much higher there.
Distance and Gravity
Gravity gets weaker the farther away objects are from each other. If you move twice as far from Earth, gravity's pull on you becomes four times weaker. Even though gravity weakens with distance, it never completely disappears. This is why distant planets and stars still affect each other gravitationally. 
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