Planitia structure on its surface. Ever since NASA's New Horizons sent back the first-ever photos of Pluto in 2015, the dwarf planet's mysterious heart-shaped region has puzzled scientists.

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 ...

When the International Astronomical Union (IAU) demoted Pluto from a planet to a dwarf planet in 2006, it surprised a lot of ...

Pluto has had a tough couple of decades. Formerly the ninth planet in our solar system, Pluto was demoted in 2006 to a “dwarf planet.” Only 1,400 miles wide, about half the width of the lower ...

Viewed in this longer context, the previously modern idea of having nine planets, which came about in the 1960s and lasted only until 2006, was a blip on the screen. And if you are still a Pluto ...