exoplanets habitable zone nearby exoplanets Kepler potentially habitable exoplanets NASA super telescopes universe rare exoplanets super Earth JWST stars Tess space missions earth-like planet Hubble more tags Trappist-1 Earth-sized exoplanets planet exoplanet life super-Earth planetary formation extraterrestrial life VLT exoplanet atmosphere space projects Proxima Centauri red dwarfs James Webb Space Telescope hot Jupiter K2 mission cosmic mysteries protoplanetary disc rogue planets HARPS alpha centauri