The official number of exoplanets—planets outside our solar system—tracked by NASA has reached 6,000. Confirmed planets are added to the count on a rolling basis by scientists from around the world, ...

NASA Administrator Jared Isaacman has reiterated his support for Pluto to be reclassified as a planet. Pluto was downgraded to a dwarf planet in 2006 because it has not cleared its orbital path of ...

Pluto's 2006 status change from planet to dwarf planet is still a sore subject for many, including a fourth grader in Tampa, Florida. Credit: NASA / Johns Hopkins University Applied Physics Laboratory ...

Many of us are old enough to have grown up with the idea of nine planets orbiting the Sun. In 2006, however, a controversial decision in the astronomy community resulted in the official list being cut ...