Discovered in 1930 at the Lowell Observatory, Pluto was demoted as a planet in 2006. Some want President Trump to take action ...

A simple comparison of Pluto’s size with other planets, explaining why its small scale influenced its reclassification.

NASA chief Jared Issacman appears to be among those who support Pluto being reclassified as a planet. Could President Trump ...

Add Yahoo as a preferred source to see more of our stories on Google. Guests visting the Lowell Observatory in Flagstaff, Arizona during the I Heart Pluto Festival gaze at celestial objects from the ...

President Donald Trump and his NASA administrator are reviving the Pluto debate again — apparently at the urging of “Star ...

For decades, Pluto was our solar system's ninth planet. This video explains the scientific journey that led to its controversial reclassification in 2006. We break down the International Astronomical ...

Flagstaff, Arizona (CNN) — For no explainable practical reason, humans are enamored with – and even empathetic toward – specific inanimate objects. Our first car. A choice coffee mug. And for a ...

Hundreds of people who love the little planet that was dissed, gather every year in the Arizona town where Pluto was discovered. They celebrate scientific discovery, history and our solar system’s ...