Whether Mercury formed from a single collision or multiple impacts, the iron-rich planet is probably a rare breed.
Learn more about NASA's New Horizons mission, which performed history's first flyby of the Pluto system on July 14, 2015.
Evidence of a big, unseen world in the extreme outer solar system continues to mount, giving astronomers more and more confidence that "Planet Nine" is real.
Moons could possess moons of their own. Kepler-1625b-i, a newfound candidate to be a giant alien moon, may even possess one or more moons that once had habitable surfaces, a new study finds.
When skywatchers acquire their first telescope, I suspect there are two objects at the top of their observing list: the moon and the ringed planet Saturn.
NASA's New Horizons spacecraft successfully completed a brief engine burn on Oct. 3, the first maneuver in which it was able to rely on actual photographs it had already taken of its eventual target.
Scientists have discovered another marker on the trail toward the putative Planet Nine — an extremely distant dwarf planet called 2015 TG387, and nicknamed 'The Goblin.'
NASA's New Horizons team has passed its 'final exam' ahead of the probe's Jan. 1 flyby of the distant object dubbed Ultima Thule.
The sharpest-ever photo of the big asteroid Ryugu shows a complex surface strewn with rocks and rubble.
A new paper published Monday (Sept. 24) reveals that Titan may be the third rock in the solar system with dust storms.
Scientists have struggled for decades to explain how the two tiny moons of Mars came to be, but a new study relying on old data bolsters one of the two major hypotheses.
As Parker Solar Probe prepares for an unprecedented close-up of the sun, the new spacecraft sent data home showing that all is well in the mission.