Since the 1990s, astronomers have found a handful of other dwarf planets in the belt, such as Eris and Sedna, along with ...

Mercury is the smallest planet in our solar system. Explore its size, extreme temperatures, core structure, and comparison with Pluto.

As next-generation telescopes map this outer frontier, astronomers are bracing for discoveries that could reveal hidden planets, strange structures, and clues to the solar system’s chaotic youth.

Discover the Kuiper Belt: a frozen ring of dwarf planets and trillions of icy bodies, currently being explored by NASA's New Horizons mission.

By Will Dunham WASHINGTON, Feb 14 (Reuters) - Astronomers have observed a planetary system that challenges current planet formation theories, with a rocky planet that formed beyond the orbits of its ...

One of the longest stellar dimming events ever observed was likely caused by the gigantic saucer-like rings of either an unseen brown dwarf or "super-Jupiter" blocking its host star's light, ...

Astronomers have uncovered a distant planetary system that flips a long-standing rule of planet formation on its head. Around the small red dwarf star LHS 1903, scientists expected to find rocky ...

Gas giants are large planets mostly composed of helium and/or hydrogen. Although these planets have dense cores, they don't ...

A mysterious object has caused a long-lasting and extreme dimming of a distant star, but is this object a 'failed star' brown dwarf, or an exceptionally massive super-Jupiter exoplanet?

Typically, from what astronomers have gathered thus far, star systems follow a tidy logic: small, rocky worlds huddle close to the warmth of their star, while massive gas giants bloat up in the colder ...

A planetary system 116 light-years from Earth has a peculiar pattern. It could flip the script on how planets form, scientists say.

A newly identified planet candidate, HD 137010 b, looks strikingly Earth-like in size and orbit — but it may be colder than Mars due to its dimmer star. If it has a thick enough atmosphere, though, ...