Why is Pluto no longer a planet? Discover the real reason behind Pluto’s reclassification as a dwarf planet and the science that led to this change.

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 the bottom of whether Pluto is a planet, I tracked down planetary scientist ...

Filmmaker Adam Nemoy helps celebrate the 90th anniversary of Pluto's discovery this month at the 6th annual 'I Heart Pluto' ...

In August 2006, the International Astronomical Union made the controversial, but correct, decision to demote Pluto from its ...

Scientists at NASA for the first time have been able to observe the make up of Pluto and other small and icy celestial bodies ...

Pluto isn't alone—it's part of the Kuiper Belt with possibly hundreds of other planet-sized objects. Because Pluto hasn't ...

Trans-Neptunian objects (TNOs) are icy bodies that vary widely in size, from large dwarf planets like Pluto and Eris—each ...

Take advantage of a special 6-7 planet alignment from Earth's perspective. Planets 'line up' in the skies over California in ...

If planets had social media accounts, the solar system would showcase a frenzy of unique personalities. Mercury tweets at ...

These popular astronomy questions, answered by Astronomy magazine, will help you better understand our universe - and share ...

How to pack for Pluto? With girded loins, gritted teeth and a brave heart, folks. Pluto’s orbit is arduously long, with the planet changing signs once every twelve to thirty years. Pluto’s ...