Deep in the outer solar system, billions of miles from Earth, lurks a realm of small, icy worlds called dwarf planets. Astronomers know relatively little about these dim and distant objects, but in ...

Pluto hasn't been a planet for almost 20 years. In the early 2000s, scientists discovered several objects of a similar size to Pluto. So, during the summer of 2006, members of the International ...

Pluto was reclassified as a dwarf planet in 2006. Our solar system may have a ninth planet after all, researchers say. The possibility that an additional planet may be hidden far into the solar system ...

Does our Solar System have 9 planets or only 8? Astronomers have gone back and forth on that a lot, with Pluto now being classified as a dwarf planet. However, out beyond Neptune there could be ...

An artist's rendition of the eight planets in our solar system. The planets are depicted closer together than they really are. NASA / JPL Nearly two decades after Pluto got kicked out of the planet ...

David Rothery is co-leader of the European Space Agency's Mercury Surface and Composition Working Group, and a Co-Investigator on MIXS (Mercury Imaging X-ray Spectrometer) that is now on its way to ...

Researchers estimate that the number of captured free-floating planets in the outer solar system with mass strictly greater than that of Mars is ∼1.2 and that the number of such planets with a strict ...

NASA's New Horizons spacecraft captured this high-resolution enhanced color view of Pluto that is inserted beneath the Short Wave logo. The image combines blue, red and infrared images taken by the ...

Though Pluto has formally been considered a dwarf planet for almost two decades, it still has many lessons left for planetary scientists —... Pluto isn’t a planet — but it gives us clues for how the ...