Even many years later, some astronomers want to revise the definition of a planet to clarify the parameters that set planets apart from other celestial objects. But why isn't Pluto considered a ...

Today, when tens of thousands of minor planets have been discovered (most residing in an "asteroid belt" between Mars and Pluto), not even the meanest of teachers would require students to learn ...

According to a recent YouGov poll, 35% of Americans think Pluto is not a planet. But they are all wrong—kind of. To get to ...

"Get over it. It's done. Just get over it." The StarTalk Radio host explains why it makes perfect sense to classify Pluto as a dwarf planet. Produced by Kamelia Angelova, Will Wei, & Alana ...

In fact, Charon and Pluto are so similar in size that they are considered a double dwarf planet system, not a planet and moon. Charon is smaller than Earth's moon. In fact, Pluto is smaller than ...

Not every talk at ... 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-is-a-planet holdout ...

Narrator: OK, so basically Stern says it depends on context. But why? Back in the early '90s, Pluto was a planet, period. No context needed. So what changed? By the late '90s, it was becoming ...