On January 5, 2005, astronomers at NASA discovered Eris, the second-largest dwarf planet in the solar system. Eris is just ...

PHOENIX – The Pluto Discovery Telescope at Lowell Observatory has reopened for the first time in a year after undergoing renovations. The telescope in Flagstaff was made famous on Feb. 18, 1930 when ...

Pluto was the little planet that could — until it couldn’t. Discovered in 1930 at Lowell Observatory in Flagstaff, Arizona, ...

Billions of years ago, in the frozen edges of the solar system, a violent impact shaped one of space’s oddest pairs. Instead of a typical planet-moon setup, Pluto and Charon became a binary system.

Pluto was reclassified as a dwarf planet in 2006 when the IAU redefined what it means to be a planet, declaring that a planet must be a celestial body that orbits the sun, is round or nearly round and ...

Pluto might be small and distant, but it keeps surprising scientists. After the New Horizons spacecraft zipped past it in 2015, we got our first real look at its icy landscape and unexpectedly active ...

The science community may be ecstatic over the discovery of a ninth planet, but the former planet "Pluto" had a totally different reaction. Hours after scientists announced there's solid evidence of ...