The long-standing debate over Pluto's planethood recently got a public boost from NASA Administrator Jim Bridenstine, who said the world should definitely be a planet.
Pluto, once considered the ninth and most distant planet from the sun, is now the largest known dwarf planet in the solar system. It is also one of the largest known members of the Kuiper Belt, a shadowy zone beyond the orbit of Neptune thought to be populated by hundreds of thousands of rocky, icy bodies each larger than 62 miles (100 kilometers) across, along with 1 trillion or more comets.
New Horizons made an epic flyby of a Kuiper Belt object to ring in the New Year — but scientists need brand-new observations to truly understand that data.
Pluto lost its "official" planet status over a decade ago, but fans of the solar system's underdog are still rooting for it. And NASA Administrator Jim Bridenstine is one of them.
Buried oceans like the one sloshing beneath the icy surface of the Jupiter moon Europa may be far more common across the cosmos than scientists had imagined.
A surprisingly gentle merger between two small primordial bodies formed the distant object Ultima Thule, a new study suggests.
Eleven-year-old Venetia Burney was eating breakfast at her home in Oxford, England, on the morning of March 14, 1930, when her grandfather delivered some exciting news.
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.
A friendly debate about Pluto's planethood yesterday (April 29) ended in an informal vote that came down in favor of reinstating the dwarf planet's status.
Ever since Pluto was demoted to dwarf planet in 2006, the debate over its planethood has raged on. Tonight, April 26, you can watch that debate online.
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.
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.
The weirdly clustered orbits of some far-flung bodies in our solar system can be explained without invoking a big, undiscovered "Planet Nine," a new study suggests.
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