Mercury

A solid metallic core nearly as large as Earth's might be lurking deep within the solar system's smallest planet.

Mercury shares its orbit with a ring of wandering dust, and a cloud of as-yet-undiscovered asteroids likely gave rise to a similar ring in Venus' neighborhood, recent research suggests.

Once again, it is time to seek out what has often been called the most difficult of the five brightest naked-eye planets to see: Mercury.

Astronomers just found an asteroid that zips around the sun every 165 Earth days — the shortest year for any known asteroid.

The year 2018 saw a wide range of milestones in spaceflight, stretching all the way from the sun to the edge of interstellar space. Here are some of the highlights.

The BepiColombo mission to Mercury that left Earth on Oct. 19 has a long journey ahead of it, but the spacecraft just ticked off an important milestone.

Whether Mercury formed from a single collision or multiple impacts, the iron-rich planet is probably a rare breed.

The historic capsule that carried the second American to fly into space is set to land in the second most populous city in Kansas.

A joint European-Japanese mission to the tiniest planet, Mercury, blasted off from French Guiana on its long journey tonight (Oct. 19, Oct. 20 GMT).

Tiny Mercury is a strange planet that may hide secrets to how our solar system formed — and that's why the European and Japanese space agencies decided to build a pair of spacecraft to study it.

It's been more than 14 years since a spacecraft launched toward Mercury, so don't miss your chance to watch a rocket do just that.

The Saturn V rocket and its predecessors soar toward open space in the first of three new posters by Space.com celebrating landmark anniversaries in space history.

Mercury has been devoid of human-built companions since April 2015, and while the next spacecraft bound for the innermost planet launches in October, it won't arrive until 2025.