Pluto and Charon are smaller and colder ... A binary system forms when two celestial bodies orbit around a shared center of ...

In 2006, the International Astronomical Union (IAU) decided that a large celestial object is a planet only if its gravitational orbit around the sun makes it round and if it’s big enough to ...

Even many years later, some astronomers want to revise the definition of a planet to clarify the parameters that set planets apart from other celestial objects. But why isn't Pluto considered a ...

Here is everything to know about the history of Pluto being discovered in an Arizona observatory. For more information on the biggest astronomical events of 2025, check out our celestial calendar.

TIME's World's Greatest Places list includes Celestia (Indonesia), Raffles Jaipur ... The Lowell Observatory—famous as the site of Pluto’s discovery—now features an open-air planetarium ...

Scientists at NASA for the first time have been able to observe the make up of Pluto and other small and icy celestial bodies in the outer solar system. They had expected to find that the surfaces of ...