"Though our Mars orbiters continue to make impressive contributions to Mars science, it's always extra exciting to see them ...

Thirty years ago, on a crisp October day in 1995, two Swiss astronomers changed the course of cosmic history. Michel Mayor ...

Earth is getting darker. A subtle drop in reflectivity, driven by melting ice and cleaner air, is amplifying global climate ...

The retired system, in use since the 1980s, included a World War II-era Howitzer, an M60 tank and a recoilless rifle.