what about a florescent strip light that went on late at night with no one in the house no break in ? what could have caused this ?   ?

It might be a light that was turned on earlier and the person who turned it on forgot to turn it off. The tube could be burning out so it went dark for a while but then turned on again.

Spooks................

the thing was turned on earlier but failed to ignite and the user didn't shut it off.  most common -- needs new bulb.  second most common -- needs new ballast.  handyman can do the second task if new bulb doesn't solve it

i would ask an electrician about it

A faulty ballast. Fluorescent lights use a ballast to turn on. It's common for a ballast to go bad, so when you hit the light switch, the light doesn't come on. Sometime later, though, it often will come on seemingly by itself, not because it actually does come on by itself but because the faulty ballast has warmed up enough to spark the gas inside the tube and get it to light up and glow white.