Scientists confirm the closest known Earth-sized world, LTT 1445 Ac, orbiting a red dwarf star just 22 light-years away. Despite being too hot for life, its similarity to Earth makes it an excellent candidate to study planet evolution. Using the Hubble Space Telescope, researchers obtained high-resolution measurements of LTT 1445 Ac, suggesting it is a rocky exoplanet similar in size and composition to Earth.