New Horizons spent only hours gathering its best observations of Pluto, yet those close-ups may define the dwarf planet for ...

On August 24, 2006, in Prague, members of the International Astronomical Union gathered for the final day of their General ...

Twenty years after Pluto became a dwarf planet, people are still fighting over its status. Experts explain why the debate feels so personal.

For decades, scientists and the general public have argued over the astronomical status of beloved dwarf planet Pluto. In the latest salvo, NASA Administrator Jared Isaacman said that he was “very ...

Add Yahoo as a preferred source to see more of our stories on Google. Guests visting the Lowell Observatory in Flagstaff, Arizona during the I Heart Pluto Festival gaze at celestial objects from the ...

Explore Pluto's reclassification as a dwarf planet and how Eris's size advantage challenges old beliefs about planetary status. Images taken in December 2005 by Brown and others with the Hubble Space ...

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

Pluto’s atmosphere may finally be thinning as it moves farther from the sun, with observations suggesting atmospheric pressure has fallen by as much as 16%.

In 2006, a vote by the International Astronomical Union determined that Pluto was no longer a planet. The decision sparked a heated public debate, and many planetary scientists disagreed with kicking ...

Since it was stripped of planetary status, Pluto’s defenders have been fighting the decision – and they’re only getting more passionate Twenty years ago, Pluto got demoted. After a vote by the ...

Using the James Webb Space Telescope, scientists have detected gas on the distant dwarf planet, Makemake. Credit: NASA / ESA / Southwest Research Institute / A. Parker illustration Scientists have ...

Learn how Pluto nearly kept its planet status in a proposed 12-planet Solar System as its demotion marks its 20th anniversary. Eight days before Pluto lost its planetary status, it appeared ready to ...