The Norwegian town of Rjukan sits in an unfortunate spot. During the winter, the nearby Gaustatoppen mountains block the sun entirely, leaving the town’s 3,500 people in a frigid shadow for five months.

Rather than wait for the Earth’s tilt to change, which might take a few million years, the town has a more immediate plan. It’s called the Solspeil, which means sun reflector in Norwegian. Starting in late October, three large mirrors will sit at the top of the mountains and follow the sun across the sky. They’ll reflect a single beam of light about 2,100 square feet (200 square meters) into the Rjukan’s town square. Collectively, the mirrors will act as an artificial sun. People who are deficient in