Astronomers have observed an object that originated from beyond our solar system, thought to be an interstellar comet, ...

For the dwarf planet candidate, one trip around the sun takes over 24,000 years. Its orbit challenges a proposed path for a hypothetical Planet Nine.

As climate change has led to more severe weather, wildfires, storms and more, many people are thinking about how to save what ...

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

In Flagstaff, Lowell Observatory has proclaimed the “Year of Pluto” and planned a series of celebrations, beginning with a visit Feb. 21 from mission leader Stern, who said in Tucson recently ...

New images of Pluto are broadcast on a globe at Lowell Observatory in Flagstaff, Ariz., on Tuesday, July 14, 2015. American astronomer Clyde Tombaugh discovered Pluto at the observatory in 1930.

The designation is already used in other parts of the world to raise awareness for space science and planetary defense.

As Asteroid Day marks its 10th anniversary, U.S. Senators Kelly and Cornyn introduce a resolution to establish National Asteroid Day.

Exterior of a telescope at Lowell Observatory in Flagstaff, Arizona. Clyde Tombaugh was working at Lowell in 1930 when he ...

Legendary Apollo astronaut Rusty Schweickart, astronomer Scott Manley and acclaimed author Mary Robinette Kowal, known for ...

Highlights in Flagstaff include the Lowell Observatory – where you can learn why Flagstaff is an International Dark Sky City – and Historic Downtown Flagstaff.

U.S. News Insider Tip: Try to plan your evening at the Lowell Observatory around the weather, as clear skies (read: no cloud cover) make all the difference. The observatory recommends checking the ...