Gravity

Have you ever jumped as high as you can and felt a little tug bringing you back down to the ground. That’s me. Have you ever dropped a toy and watched it fall right to the floor instead of floating away. That’s me, too. I am like a giant, invisible hug for the entire world, always keeping your feet on the warm grass and the water in your cup. I make sure that when you throw a ball to your friend, it always comes back down for them to catch. I am everywhere, all the time, but you can never, ever see me. You can only feel me, working my magic to keep everything in its proper place. My name is Gravity, and I am one of the most powerful secret forces in the whole universe.

For thousands of years, people felt me but didn't quite understand what I was. They just knew that things fell down, not up. Then, a long time ago, around the year 1687, a very curious man named Isaac Newton was thinking in his garden. The story goes that he saw an apple fall from a tree, and it made him wonder. He didn't just wonder why the apple fell down, but he wondered if the same pull reached all the way up to the sky. He had a brilliant idea. He realized that I am the same invisible hug that pulls an apple to the ground and also keeps the Moon circling the Earth. I was the secret glue holding our solar system together. Many years later, in 1915, another brilliant person named Albert Einstein imagined me in a new way. He thought of the universe as a giant, stretchy trampoline. He said that big things like the Sun make a deep dip in the trampoline, and smaller things like Earth roll around inside that dip. It was another wonderful way to picture how I work.

So you see, I have a very important job. It’s my job to pull bits of dust together over millions of years to build brand new stars and planets. But I also have smaller jobs, like helping you have fun when you zoom down a slide at the playground. I keep the oceans from floating away and hold the air you breathe close to the Earth. When brave astronauts travel into space, they can float around because they are far away from my strong hug. But when they are ready to come home, I am always here to gently pull their spaceship safely back to the ground. I am a reliable and steady force that holds everything, big and small, together. So next time you drop a spoon or jump in the air, remember me, the invisible hug that keeps our amazing universe in order.