History and Sky Lore

On the 40th Anniversary of Apollo 17

Forty years after the last human visitors departed the Moon aboard Apollo 17, space historian Andrew Chaikin talks about why we should return.

Astronomy & Observing News

A Bizarro "Cometoid"

Is it a comet? Is it an asteroid? Astronomers aren't sure what to call 133P/Elst-Pizarro.

Astronomy & Observing News

Radiation Dangers for Mars Astronauts Downgraded

An experiment onboard Mars Odyssey suggests that radiation isn't as big a concern for Mars astronauts as once thought.