Gravity is just gravity, right? You slip on some stairs, take a tumble to the bottom, and everyone laughs. Hilarious, that’s a given, but that’s also not giving gravity its due. Gravity is all around us, an omnipresent force that keeps our feet on the ground or our bodies falling down the stairs, but there’s actually a whole lot more to this story.
Think about how you feel sitting right now. Kinda heavy, as your arms fall to your side? Great! Earth’s gravity is pulling you onto the planet’s surface, and everything’s in working order. Earth is also pulling on the moon, keeping it in orbit, and the moon is in turn pulling a bit on us, while the Sun is pulling on Earth, keeping us from flinging out into the cosmos.
But maybe a better way to approach gravity is to think not about being stuck on Earth but about being weightless. This is the kind of thinking that helped Einstein revolutionize the field of physics.