Goldilocks Zone
In February, exoplanet hunters announced the discovery of seven rocky planets orbiting a star called TRAPPIST-1 only forty light-years away. Compared to our sun, TRAPPIST-1 is tiny, and all its planets orbit closer than Mercury orbits Sol. But three of them are still in the Goldilocks zone that could be "just right" for life, and all seven planets could theoretically hold liquid water. While Ethan Siegel introduces the neighboring star system with spectacular illustrations from NASA and ESO, Greg Laden notes that the practice of saying these images are artistic interpretations "has largely…