Making contact with ET? Aliens may already know we're here
Earth is dotted with many humongous, human-made structures.
To an alien eye, they may be tell-tale signs of intelligent goings-on, betraying our existence and hinting at our capabilities.
Earth is dotted with many humongous, human-made structures.
To an alien eye, they may be tell-tale signs of intelligent goings-on, betraying our existence and hinting at our capabilities.