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 January 5, 2005, astronomers at NASA discovered Eris, the second-largest dwarf planet in the solar system. Eris is just slightly smaller than Pluto, and it orbits the sun about three times farther ...

In 2006, the International Astronomical Union (IAU) voted on the definition of a planet. Famously, Pluto no longer met the criteria and was demoted to a dwarf planet. Things have been a bit of a mess ...

On January 1, 1801, a Sicilian astronomer named Giuseppe Piazzi discovered the dwarf planet Ceres orbiting the sun between Mars and Jupiter. At the time, Ceres was considered to be a planet. But after ...

Eighteen years ago today, Pluto lost its planetary status in a vote by International Astronomical Union (IAU) members on the final day of their 2006 general assembly meeting. The word "planet" comes ...

Animation made from still images of Ceres taken by Dawn on Feb. 4, 2015. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI New images from NASA's Dawn spacecraft reveal ...

If you woke up Thursday morning and sensed something was different about the world around you, you’re absolutely right. Pluto is no longer a planet. The International Astronomical Union, wrapping up ...

Pluto, once considered the ninth planet, was reclassified as a dwarf planet in 2006 because it shares its orbital path with ...

NASA's New Horizons spacecraft captured this high-resolution enhanced color view of Pluto that is inserted beneath the Short Wave logo. The image combines blue, red and infrared images taken by the ...