For three winter months of the year, Rattenberg, a mountain village near Innsbruck, is permanently in the shadow of the Stadtberg Mountain. Inhabitants can see sunshine across the valley, but for three months they get nothing and feel depressed.
To bring some light to the village, engineers at the Bartenbach Light Laboratory in Aldrans, Austria, plan to install up to 30 mirrors on an opposite hillside. Computer-controlled motors will tilt the mirrors so they continuously track the sun’s position. Light will be bounced onto a second bank of mirrors, which in turn will illuminate the streets below.
It would take a mirror 10 times the size of the village to illuminate all of it, but an array of mirrors, each up to 2m across, will be able to pick out individual streets, squares and building facades, says Zangerl.