Orbital plane

Imagine you are standing on a flat surface and you want to throw a ball. You throw the ball and it goes up in the air and then falls back down to the ground. Now imagine that instead of a ball, it is a spaceship that you throw.

This spaceship is going to travel around a big object, like a planet or a star. But when it is thrown, it doesn't just go straight up and down like the ball did. Instead, it travels in a path that is like a big circle around the object it is orbiting. This path is called an orbit.

Now imagine that you can look at the spaceship from above, like looking down on a map. You can see the circle that it is traveling in, and you can also see the direction that it is traveling in. This direction is like an imaginary line that points from the front of the spaceship to the back.

The plane of the orbit is like a big flat sheet of paper that the circle of the orbit sits on. If you were to cut the circle out of the imaginary sheet of paper, it would look like a round disc.

The imaginary line that points from the front of the spaceship to the back is called the axis of the orbit, and it is important because it helps us figure out where the orbit is going to be in the sky.

So when we talk about the orbital plane, we mean the imaginary sheet of paper that the orbit sits on, and the direction that the spaceship is traveling in while it is in orbit.