A Poltergiest or Physics?

About 11pm  Sunday evening, July 24th. I'm sound asleep, and Marla is down in the family room, and suddenly there is a very loud "BANG"!!  I did not hear it, but I certainly heard Marla call out my name.

She had discovered, that the glass in our very large Anderson sliding door to our deck had completely shattered. The outside sheet of glass only. The inside sheet still intact. We'd never seen anything like it before. No evidence of anything striking it. The screen on the sliding screen door which is on the outside, is as tight as the head of a banjo.  We stood there in the quiet of the house, after 11pm, and you could still hear the glass fracturing.  Hundreds of long fractures radiating out from a somewhat central point, and even hundreds more small fractures appearing at 90 degrees to the long ones, connecting them all together......WTF????