What is Escape Velocity?

Image: Rhett Allain. Created with Glowscript / VPython

Sure, you can look up the equation for escape velocity, but what does it really mean?

Let’s start with the most conceptual idea possible. Suppose you have a ball and you toss it straight up into the air. As the ball rises, it decreases in speed until it reaches its highest point. After that, it starts moving back down and increasing in speed. That’s something we have all probably experienced (throwing a ball).