Tiny device only needs the Sun to lift off

A device takes advantage of the properties of two layers of material to levitate using only the power of sunlight. The top layer is transparent, allowing sunlight to shine through it, and the bottom layer absorbs that sunlight. Gas molecules moving from the cold transparent layer to the hot bottom layer creates a lift that is similar to that created by a helicopter’s whirring rotor, says engineer Igor Bargatin, who has pioneered work on similar devices.