Editor’s note: Welcome to Just4Kids, a new feature with content from The Conversation for Kids, a nonprofit in which scholars answer kids’ questions about science, health and more, that will be ...

Escape velocity is the speed an object needs to break free from a planet or moon’s gravity without further propulsion. It’s a key factor in rocket design, mission planning, and understanding planetary ...

I was idly speculating about the various possible ways in which we can (at least in theory) get stuff from the Earth into space. One method might be to construct some kind of rail and accelerate an ...