The Best American Science and Nature Writing 2020 edited by Michio Kaku

 

"But finally, in the spring of 2015, they both agreed, the only other explanation for this clustering of Kuiper Belt objects was indeed a planet--a big one. On January 20, 2016, they made the announcement proposing that our solar system has a giant planet orbiting far away from everything else. They told all astronomers with access to the most powerful telescopes to go and find it. They wanted to find it too."