On February 18, 1930, Clyde W. Tombaugh, an assistant at the Lowell Observatory in Flagstaff, Arizona, discovered Pluto. For over seven decades, Pluto was considered the ninth planet of our solar system.

Did you know that Pluto was named after Percival Lowell, an astronomer who spent years studying the Planet Mars? But, perhaps his greatest contribution

Lowell Observatory, founded by Percival Lowell in 1894, is a living piece of Arizona history. It’s located on top of Mars Hill about one mile from downtown Flagstaff, Arizona

January 17th marks the passing of two people, William Pickering and Clyde Tombaugh, who were important to the discovery of the dwarf planet, Pluto. William

On January 23, 1930, Clyde Tombaugh photographed Pluto. Formerly the ninth planet from the sun (usually), Pluto was named for the Roman equivalent of the

1733 - Joseph Priestley was born. Priestley is credited with the discovery of the element oxygen. 1781 - William Herschel discovers the planet Uranus.

Lowell Observatory visitor guide includes when to go, directions

A biographical profile of Amy Lowell, who was born into a prominent New England family, essentially educated herself and became a truly independent woman, Imagist poet, critic and biographer of Keats.

Come with us as we tour Flagstaff, Arizona on foot. See the Northern Arizona University campus, stop by a coffee shop or shop 'til you drop at the outdoors stores and boutiques of Flagstaff.

Learn about the history of science by reading about the significant scientific events that took place on this day in history.