After studying thousands of computer simulations of the solar system, researchers at Rice University and the Planetary Science Institute think there’s a 40% chance an elusive “Planet Nine” or “Planet ...

Growing up, I was taught that there were nine planets in the solar system. That all changed in 2006, when the International Astronomical Union voted to demote Pluto’s status to that of dwarf planet.

A possible new dwarf planet has been discovered at the edge of our solar system, so far-flung that it takes around 25,000 years to complete one orbit around the sun. Subscribe to read this story ...

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Prefer Newsweek on Google to see more of our trusted coverage when you search. Good news for those with a Pluto-shaped hole in their life, as astronomers may be on the verge of finding a new ninth ...

Using two infrared space telescopes and a 23-year gap, scientists may have spotted a mysterious, slow-moving object beyond Neptune. Reading time 3 minutes A team of astronomers says it has identified ...