Geodesics

Okay kiddo, imagine you are walking on a big, round ball. Whenever you walk, you create a path that goes from where you started to where you end up. This path can be straight, curved or even wiggly, right?

Now, geodesics are kind of like those paths you make when you walk on the ball, but they have a special property. They are the shortest possible paths between two points on the ball.

You know how sometimes you take a longer path to get somewhere because it's more fun or because you want to see something else along the way? Well, that's not how geodesics work. They always pick the fastest way to get from point A to point B.

But here's the thing - when we talk about "shortest", we don't just mean the straightest line between two points. On a ball, a straight line looks curved to you and me because we are used to walking on flat surfaces. So the shortest path between two points on a ball might not look straight to us, but it still is shorter than any other path you could take.

Geodesics are not just limited to balls; they exist in all kinds of curved surfaces, like the earth's surface or even the curved spacetime that makes up the universe. Scientists use geodesics to figure out how things move and interact on these surfaces - sort of like the ultimate shortcut-finder!