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 ...

(This is an expanded version of an earlier post, taking into account escape velocity as well as surface gravity.) Earth-sized exoplanets have been very much in the news lately. In early November ...

Earth’s magnetic field has long been framed as a planetary force field, a protective bubble that keeps the worst of the Sun’s radiation at bay. Increasingly, though, scientists are finding that this ...

Terminal velocity is the maximum speed gravity can pull an object toward Earth. Escape velocity is the speed necessary to break out of Earth’s gravitational pull. Which of these is most important ...

Hypervelocity stars have, since the 1920s, been an important tool that allows astronomers to study the properties of the ...

The very minimum requirement for a space elevator is, obviously, a cable strong enough to support its own weight when hanging from geostationary orbit down to earth, 36000 km below. That is a very ...

Well, dangit. I screwed up. This happens sometimes. What makes this one frustrating is that it’s one of those mistakes where I should’ve known what I wrote was wrong, but somehow got it in my head ...