Our solar system is much like a trail of microcosmic breadcrumbs: Follow the molecular bits as far back as they go, and you'll learn a thing or two about where many of our planets and other celestial ...

A surprising chemical difference between Pluto and Sedna, another dwarf planet in the distant Kuiper Belt, is helping scientists nail down their respective masses, a new study reports. "Kuiper Belt ...

Ammonite was discovered using the Subaru Telescope in Hawaii, with follow-up confirmation from the Canada-France-Hawaii Telescope. Its orbit and size officially qualify it as a distant dwarf planet.

Astronomers have found an exoplanet that could serve as a benchmark in future studies. It's a rocky planet orbiting an M-type ...

Astronomy has a way of defying labels. Just when researchers think they've drawn a clean line between two cosmic categories, nature tosses in something unexpected. Take stars and planets. A star is a ...

WASHINGTON >> Scientists have identified an object about 435 miles wide inhabiting the frigid outer reaches of our solar system that might qualify as a dwarf planet, spotting it as it travels on a ...

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Scientists may have discovered a dwarf planet far beyond Neptune — an unearthing that may disprove a longstanding theory about the possibility of a giant ninth planet. The dwarf planet's existence ...

A planet circling at a sharp 90-degree angle to the orbits of its two host stars has now been confirmed. This discovery challenges long-standing ideas about how planets form and orbit in the cosmos.