THAT’s NO MOON - Earth doesn’t just have one moon; sometimes, it has a companion satellite or “mini-moon.” Discovered on ...

SEATTLE – NASA has discovered the smallest planet ever seen beyond our solar system – a rocky world just 1.4 times larger than Earth – using its planet-hunting Kepler observatory. The planet, called ...

A spacecraft operated by the European Space Agency and the Japan Aerospace Exploration Agency has made its final flyby of Mercury, as scientists now work to guide BepiColombo into the planet’s orbit.

American astronomers say they have discovered the two smallest planets yet orbiting nearby stars, trumping a small planet discovery by European scientists five days ago and capping the latest round in ...

Some countries are so tiny they could disappear into the suburbs of a big city — yet they’re rich in culture, history, and ...

Please enable JavaScript to read this content. Detailed maps of Mercury's cliffs and ditches show the solar system's innermost and smallest planet Mercury has lost ...

(Correction: An earlier version of this story misstated how far Pluto is from the sun. The correct number is 3.7 billion miles.) What was discovered in Flagstaff, Arizona, and killed off in Prague? If ...

CAPE CANAVERAL, Florida (Reuters) - Detailed maps of Mercury's cliffs and ditches show the solar system's innermost and smallest planet Mercury has lost much more real estate due to cooling over four ...