How big would a telescope have to be to see Kepler 452b?

A square kilometre telescope could see an Earth-sized planet orbiting 1 AU from a star that was 100 LY away with a resolution of 1 pixel. To see a planet, directly and optically, that is 1400 LY away will obviously need an optical interferometer... read more

A square kilometre telescope could see an Earth-sized planet orbiting 1 AU from a star that was 100 LY away with a resolution of 1 pixel. To see a planet, directly and optically, that is 1,400 LY away will obviously need an optical interferometer that is far, far larger still. read more