In 1974, on a survey in Hadar in the remote badlands of Ethiopia, U.S. paleoanthropologist Donald Johanson^[1] and graduate student Tom Gray found a piece of an elbow joint jutting from the dirt in a gully^[2]. It proved to be the first of 47 bones of a single individual – an early human ancestor whom Johanson nicknamed “Lucy.” Her...

For about 15 minutes on July 21, 1961, American astronaut Gus Grissom^[1] felt at the top of the world – and indeed he was.

Grissom crewed the Liberty Bell 7 mission^[2], a ballistic test flight that launched him through the atmosphere from a rocket. During the test, he sat inside a small capsule and reached a peak of over 100 miles up...

Curious Kids^[1] is a series for children of all ages. If you have a question you’d like an expert to answer, send it to This email address is being protected from spambots. You need JavaScript enabled to view it.^[2]. Why do some planets have moons and some don’t? – Siddharth, age 6, Texas On Earth, you can look up at night and see the Moon shining bright from hundreds of thousands of