Billions of years ago, it rained on Mars. The water collected in valleys and rivers, filled and spilled over the rims of craters, and was funneled into canyons, perhaps even making its way to a large ...

Ask someone on Earth for the time and they can give you an exact answer, thanks to our planet's intricate timekeeping system, ...

Mars has long been framed as a cold, dry desert, but new research is revealing a planet laced with hidden ice and glacial ...