Astronomer Dean Regas maps out how kids can teach grown-ups the truth about Pluto and out solar system.

Curious Kids is a series for children of all ages. Have a question you’d like an expert to answer? Send it to . “Comet,” “star” and “planet” are category names that immediately tell ...

Pluto hasn't been a planet for almost 20 years. In the early 2000s, scientists discovered several objects of a similar size to Pluto. So, during the summer of 2006, members of the International ...

On Aug. 24, 2006, the International Astronomical Union (IAU) decided that Pluto wasn't a planet anymore. Instead, Pluto is now officially classified as a dwarf planet along with four other confirmed ...

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.

Pluto's status has been a heated debate for decades with arguing over a dwarf planet classification. Here's what international standards say in 2023.

In 2005, a new object was discovered in the outer solar system, Eris, that is even heavier than Pluto. This led astronomers to consider if both Eris and Pluto are planets or not.