NASA’s Transiting Exoplanets Survey Satellite (TESS) has discovered its first Earth-sized planet — HD 21749c. An artist’s conception of HD 21749c, the first Earth-sized planet found by NASA’s Transiting Exoplanets Survey Satellite (TESS), as well as its sibling, HD 21749b, a warm sub-Neptune-sized world. Image credit: Robin Dienel / Carnegie Institution for Science. The newly-discovered planet orbits HD 21749, a K4.5 dwarf star located...