Astronomers using the Hubble Space Telescope have conducted the first spectroscopic survey of the Earth-sized planets within the habitable zone around the nearby star TRAPPIST-1. Hubble reveals that at least three of the exoplanets (d, e, and f) do not seem to contain puffy, hydrogen-rich atmospheres similar to gaseous planets such as Neptune. The results, instead, favor more compact atmospheres like those of Earth, Venus, and Mars.