On the 95th anniversary of its discovery, Pluto remains one of the most beloved and enigmatic worlds in our solar system, ...

“New Horizons shattered a major paradigm of planetary science,” says Alan Stern, the mission’s principal investigator. “Pluto ...

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.

The number of planets that orbit the sun depends on what you mean by “planet,” and that’s not so easy to define ...

Eris is three times more distant than Pluto. And its relationship to Pluto — a world demoted since 2006 from the solar system’s ninth planet to a lowly dwarf planet, in large part due to the ...

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 ...

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

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute With Pluto's "demotion" to dwarf planet status ... along with bodies like Eris, Ceres and Pallas.

For all of this promise, Pluto struggles for respect, with the “dwarf planet” label continuing ... you would have to confer the same honor on Eris, a Kuiper Belt object of about the same ...