A surprisingly gentle merger between two small primordial bodies formed the distant object Ultima Thule, a new study suggests.
Learn more about NASA's New Horizons mission, which performed history's first flyby of the Pluto system on July 14, 2015.
Learn about the physical characteristics of Saturn and its famous rings, what we know about Saturn’s moons and Saturn’s roots in Greek mythology.
Beyond Neptune, the Kuiper Belt is a vast region of icy objects called Kupier Belt Objects (KBOs), including dwarf planets Pluto, Eris, Maumea and Makemake — and possibly a true ninth planet.
An ethereal track by Queen lead guitarist Brian May accompanies the awe-inspiring time-lapse view from NASA's New Horizons flyby of a distant solar system object.
The New Horizons spacecraft is speeding away from its recent flyby target, a distant icy space rock nicknamed Ultima Thule, but the view from Earth is only getting better.
The best-ever photos of Ultima Thule have made it down to Earth, and they heighten the intrigue about the frigid and faraway world.
The final photos that NASA's New Horizons spacecraft snapped of Ultima Thule during the probe's epic Jan. 1 flyby reveal the distant object to be much flatter than scientists had thought.
Astronomers just found an asteroid that zips around the sun every 165 Earth days — the shortest year for any known asteroid.
If you don't like your local weather, perhaps you would prefer the atmosphere on Uranus or Neptune — and the Hubble Space Telescope has an update on each planet's current conditions.
Learn about planet Mars’ atmosphere, water supply and the possibility to support life, plus, findings from the Mars exploration rover mission.
'Oumuamua is long gone, but it's still leaving scientists guessing. A new explanation proposes that the strange object was a "monstrous fluffy dust aggregate" produced by a busted-up comet.
Pioneers 10 and 11, Voyagers 1 and 2, and New Horizons are the only spacecraft currently capable of leaving the solar system. Which one will be the next to go?
NASA's Parker Solar Probe has completed its first loop around the sun and entered the second of 24 planned orbits.
The far outer solar system is teeming with mountain-size space rocks left over from the long-ago planet-formation period, a new study suggests.
See amazing images of the night sky and cosmos in Space.com's gallery of cosmic images posted in December 2018.