What makes a planet friendly to life? That question generated a lot of social media debate last week when researchers announced they found water vapor in the atmosphere of a largeish planet called K2-18b that is classified, depending on who you speak with, either as a "super-Earth" (a little larger than Earth) or a "mini-Neptune" (a little smaller than Neptune). Reporters also struggled with the demands of figuring out sometimes conflicting interpretations from competing teams and outside researchers, as this Twitter thread from the Atlantic's Marina Koren shows. But the find also raises a larger question: What is "potentially habitable"? Does it mean a planet has life?
What Do We Think Is 'Habitable'?
Why It's So Hard to Define
Written by Elizabeth Howell September 16, 2019
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