What could make a window shatter?

Question

Ok, we pulled up the shade on a window today that we havent looked at in a couple months and noticed the thing is completely shattered, and I'm guessing we have tempered safety glass because it is still holding together. and I think both panes are broken (double paned window) but I'm not sure.

So I was wondering if lighting or ice or any weather related things could cause this, because my mom is convinced the maids did it but I'm not so sure considering the most likely point of break is in the upper corner (about 8 feet up) and there arnt any holes in it like you would usually see with broken glass just a point on the window where all the lines seem to originate from.

This is what the entire window looks like:

http://img233.imageshack.us/img233/2151/p4260003np5.jpg

Answer 1

Ok well what could have happened is since you've got saftey glass is a rock carried by wind or a ball hit it and something else is if it was cold one day and hot the next it could causs different stress levels and put cracks in the glass or even an insect hope it helps! oh additional details well: If it was a storm it could have been struck by lighting and then hit by heavy rain increasing the crack

Answer 2

looks like something got thrown at your window wether it be wind or human

Answer 3

If that was not caused by a person, it could have been caused by large hail.  Golf ball size hail can start causing damage to windows.  Hail was the most likely weather cause that made the window shatter.  Lightning could have done it like if it would have struck the house or close to it but you prob would have noticed more damage if it was lightning.  If it was not human made it was hail.