Drinking glass randomly cracking

No.10888186 ViewReplyOriginalReport
So something weird happened to a drinking glass of mine and I wanted to see if someone here could shed some light on the whole ordeal.
>be in living room
>suddenly hear continuous cracking coming from somewhere in the room
>sounds like ice cracking very slowly
>lasts for maybe 10 seconds then it stops
>meanwhile can’t find the source
>later notice that one of the drinking glasses (which was empty the entire time) had a large crack across it
>not exposed to any significant air currents
>nothing on or touching it
>not close to any source of heat or direct sunlight
>glass looks very close to pic related

What the fuck happened?