Astronomers have observed a planetary system that challenges current planet formation theories, with a rocky planet that formed beyond the orbits of its gaseous neighbors, possibly after much of the ...

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 ...

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.

Key takeawaysIf a gas giant planet is big enough to ignite deuterium fusion, it becomes a brown dwarf instead of a planet.

If a gas giant planet is big enough to ignite deuterium fusion, it becomes a brown dwarf instead of a planet. But this definition is incomplete and does not tell us how gas giants form or what ...

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, ...

Liquid water might not need a perfect location to exist, and neither might alien life. Researchers now believe that planets ...

Astronomers using the Subaru Telescope in Hawaiʻi have discovered a massive planet and a brown dwarf orbiting distant stars. The discoveries are the first results from OASIS (Observing Accelerators ...

Pluto did in fact both bend and accelerate the trajectory of New Horizons when the spacecraft reconnoitered the dwarf planet in 2015, but only very slightly. There are three reasons the trajectory ...

In an ancient star system expected to be stable and dormant, scientists found a 3 billion-year-old white dwarf star still tearing apart massive quantities of rock. “The rate we’ve seen rock consumed ...

The end of this entry's definition reads: "The largest known dwarf planets are: Eris, Pluto, Ceres, Makemake, and 2015 RR245." Why is 2015 RR245 listed as one of the largest dwarf planets? For ...