Dear sandyRoe,
Can it do a sand dance? If not, it's a fake!
Possible explanations:
(1) Heat (from crowds, sunlight, central heating). Why? Depends on it's composition cos' different materials expand or contract differently e.g. the bi-metallic strip which acts as a thermostat in your electric iron. Note, little or no such heat sources at night.
(2) Sympathetic vibration due to rhythmic movement. That is why when soldiers are crossing a bridge, alternate ranks change step. The viewers may be passing in rhythm. What happens if they all stop?
(3) Solar or battery powered electric motor. Very unlikely as these miraculous statues are not so blatantly fiddled but have a subtle scientific explanations. The classic ones being wooden with all but the eyes painted over so that they weep resin, sometimes bood red of course. I doubt if they weep on cold nights.
I thought you were being sarcastically funny at first but believe you are curious and so am I now!
Unfortunately the jealous christian god killed off all previous gods inc. egyptian so we can rule out that selfish sod.
Nice one sandy,
SIQ.