When astronomers found a large world farther out than Pluto, it became one of the final nails in the coffin of our ninth ...

In this video, I set out on an extraordinary mission to discover a new planet. With the odds stacked against me, I rented a ...

The number of planets that orbit the sun depends on what you mean by “planet,” and that’s not so easy to define ...

So when we found Eris, all of a sudden, astronomers started thinking, “If this thing is bigger than Pluto, then it’s got to be a planet, too, right?” You know, “What exactly is our ...

Although Seeing in the Dark doesn't directly discuss Pluto, it does celebrate the joy of observing planets. Viewers who watch the show may wonder what happened to Pluto in 2006 and whether any of ...

And I just think it's the coolest world out there, that we know of. Brown discovered the dwarf planet Eris, a breakthrough that helped prompt a new definition of planethood. Eris is my favorite ...

is a disc-shaped region beyond the orbit of Neptune’s in the outer solar system—50 Earth-sun distances—that’s home to dwarf planets like Pluto, Makemake and Eris. It’s also thought to be ...