Gravity is not a push. It's not a wall. It's a pull that reaches across any distance with no contact required, and it never, ever switches off. Right now, you're being pulled toward the center of the Earth, toward the Moon, toward the Sun, toward the Andromeda Galaxy two million light-years away. The forces from far away are tiny, sure. But they're real, and they're constant. Gravity is the universe's most patient force.

Isaac Newton cracked the core of it in the late 1600s. Two objects with mass pull on each other. The bigger the masses, the stronger the pull. The farther apart they are, the weaker it gets — and it weakens fast. Double the distance and the force drops to a quarter. This is the inverse square law, and it's why the Sun can hold planets in orbit from 93 million miles away, but you can jump off the ground without needing a rocket.

An orbit isn't a stable position. It's a controlled fall. When you watch footage of astronauts floating in the ISS, they're not outside gravity's reach. They're in freefall, constantly falling toward Earth, but moving sideways so fast they keep overshooting it. They feel weightless because everything around them is falling at the same rate.

Einstein pushed this even further. He said gravity isn't really a force at all — it's a curve in the fabric of space and time. Massive objects bend spacetime around them, and other objects follow that curve. It sounds like science fiction, but it has real consequences. GPS satellites have to correct for the fact that time runs slightly faster in orbit than on the ground — because they're farther from Earth's mass, spacetime is less curved up there. Without that correction, your GPS would drift by miles every day. Einstein's weird idea about curved spacetime is literally inside your phone.