It's been one Neptunian year—or about 165 Earth years—since astronomers first observed the most distant planet from the sun.

HOUSTON, Texas -- A new National Geographic film about NASA's mission to integrate their space program had a screening in Houston on Tuesday, and it came on the heels of a major announcement about the ...

When you buy through links on our articles, Future and its syndication partners may earn a commission. Credit: National Geographic A new documentary about the life and hidden love of astronaut Sally ...

The National Geographic Encyclopedia of Space offers clear and concise explanations of the planets; telescopes; manned space flight; satellites; the origin of the universe; the contributions of ...