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.
Imagine a world where the Sun never rises and never sets! It feels like that here in the UK sometimes with what feels like a never-ending cover of cloud. On one side of a world like this, a permanent blazing day whilst on the other, an endless frozen night. No seasons, no dawn, no dusk just an eternal, pitiless divide. For more than three quarters of the stars in our Galaxy, this is the reality facing their planets. And now, for the first time, astronomers have mapped the climate of two such worlds in extraordinary detail.
