Goddard–Thorn theorem

The Goddard-Thorn theorem is a fancy rule that helps us understand how physics works in space. Imagine throwing a ball while standing on the ground - the ball will eventually come back down because of something called gravity. But in space, there isn't any gravity pulling objects back down. Instead, objects move in circles around bigger objects, like planets orbiting around a sun.

Now, the Goddard-Thorn theorem is saying that if you want to send something from one planet to another, you need to aim your spaceship in a specific direction and at a certain speed. This way, the spaceship can follow a path that gets it to where it needs to go without wasting any energy or getting lost in space.

It's kind of like playing a game of pool. If you want to hit a specific ball into a specific pocket, you need to aim your cue stick at just the right angle and hit the ball at just the right speed. Otherwise, the ball will go in a completely different direction, or miss the pocket altogether.

So, the Goddard-Thorn theorem helps scientists plan out space missions and figure out the best way to get spaceships from one planet to another. It's like giving them a map and a set of instructions, so they can make sure they get to where they need to go.