A tiny object far beyond Pluto, newly discovered by the Subaru Telescope, could reshape our understanding of the early Solar ...

As Voyager 1 pushes beyond Pluto, it reveals a shocking truth,the solar system is far vaster and more mysterious than we ever ...

The celestial body's unusual orbit “implies that something extraordinary occurred" in the early days of the solar system—and ...

"It is possible that a planet once existed in the solar system but was later ejected, causing the unusual orbits we see today ...

NASA's New Horizons spacecraft made history by flying past Pluto, sending back groundbreaking data that would change our ...

But long before the Pluto “controversy,” other objects moved on and off the official list of solar system planets. Indeed, a kindergartener in the early 1800s would have learned that Ceres was ...

So on Pluto’s day of demotion, we celebrate how the lonely dwarf planet has forever changed our view of our solar system. The “killing” of the planet was actually more of an involuntary ...

Pluto has taken a special place in planetary scientist Alan Stern's mind since 1988. That's when he first began pushing NASA to send a spacecraft to what was then the ninth planet in our solar system.

Since 1930, we’ve discovered that Pluto is one of the solar system’s most fascinating worlds. It features blue skies, red snow, glaciers made of frozen nitrogen, and dunes made of frozen ...

On February14, 1990, NASA's Voyager 1 probe pointed back toward the sun and took a seriesof pictures of the sun and the planets, making the first ever"portrait" of our solar system as seen from ...

Though Pluto has formally been considered a dwarf planet for almost two decades, it still has many lessons left for planetary scientists — including hints about how the solar system formed.