The closest potentially habitable worlds: Proxima Centauri b at 4.2 light-years, Barnard's Star b, Ross 128b, Wolf 1061c, Tau Ceti, and the Breakthrough Starshot plan.
Reaching Proxima Centauri with today's fastest spacecraft would take 73,000 years — inside Breakthrough Starshot, light sails, nuclear propulsion, and generation ships.
