Apparently in the Manchester museum, an Egyptian statue turns around while in a sealed display case. There is time-lapse footage of the statue, and in the article, Brian Cox is quoted as saying that:
Brian thinks it's differential friction, where two surfaces - the serpentine stone of the statuette and glass shelf it is on - cause a subtle vibration which is making the statuette turn.
Is that possible? Watching the video it seems that the statue doesn't have a constant rate of turning; it seems to turn only during the day, and it stops turning once it has completed a half-turn.
The only references to differential friction I could find were in the context of a moving vehicle braking when the left and right tyres were on different road surfaces, resulting in differential friction which could cause the car to swerve to one side. How can it function on a stationary object?