Anyone who grew up learning that our solar system has nine planets probably remembers the moment Pluto got demoted. That ...

In 2006, Pluto was famously demoted from a planet to a dwarf planet. It remains the most famous dwarf planet today, but there are others in our solar system, including potentially hundreds that ...

Twenty years after Pluto lost its planetary status, the debate continues as scientists still disagree over what defines a planet.

The small world was found during a search for the hypothetical Planet Nine, and astronomers say the next time it will reach its closest point to the sun is in the year 26186. By Kenneth Chang Kenneth ...