Artist’s impression of the newly-discovered rocky exoplanet, LHS 1140b. (European Southern Observatory), CC BYThis summer, exoplanet science — the study of planets orbiting stars beyond our sun — took a big step forwards. Reports of helium gas escaping from the atmosphere of LHS 1140b propelled this exoplanet from the pages of scientific journals into the mainstream media. LHS 1140b orbits a faint, red star within the constellation of Cetus — na…