It may sound like an idea from a sci-fi movie, but the small town of Rjukan in Norway has built a sun mirror to extend the days in winter.

Thousands of people travel to Norway every summer to witness the midnight sun. In winter this is reversed and many people up north experience the polar night. However, this effect also extends further south, especially in the small town of Rjukan in Norway, located in a narrow valley. Due to the tall mountains on both sides the sun is blocked and they stay in the dark for weeks at the time in winter.

In 1913 it was proposed to make a sun mirror to reflect the sun from the hillsides down into the valley below. At the time this was not technologically feasible and in 1928 a mitigation was introduced: A cable car taking people to the top of the mountain. Still, this took the people to the sun, not the sun to the people.

As tehnology improved the original idea became more realistic. In 2013, 100 years after it was originally proposed the sun mirror of Rjukan was built and operational.

The final scale did not go full death star. The mirror lights up the town square rather than the entire city. Still, the solution is rather fancy. The mirror is actually three mirrors with a total size of 51 square meters. They are automatically programmed to track the sun to keep the light focused on the town square throughout the day. Power is naturally generated from solar panels (and a small windmill) and the whole system can be remotely controlled from the town.

The sun mirror is located 450 meters above the town and can be reached by a relatively short, but very steep hike. Check out the video below where Jørn makes the way up to  the mirror: