In 1929, Clyde William Tombaugh, a farm boy who grew up in Illinois and Kansas, began working at Lowell Observatory in Flagstaff, Arizona. The director of the facility, renowned astronomer Vesto ...

Pluto’s thin, blue haze glows in this image from NASA’s New Horizons spacecraft. Though the dwarf planet is just a faint speck through a telescope, opposition this month offers skywatchers their best ...

Even early humans quickly recognized the difference between the stars and the planets, with the objects now known as planets appearing to travel across the night sky over the course of the year, or ...

Think you can spot Pluto? On July 25, the famously elusive dwarf planet reaches opposition—its best and brightest moment of the year. That makes now the ideal time to try to catch a glimpse of it from ...