"Why does season 3 begin with Adama launching nukes at Earth?"

No the new season hasn't begun just yet.

So I'm introducing my upstairs neighbor (we live in a duplex of sorts) to the fun that is the new Battlestar Galactica series as she's got access to my wireless network and last night she called me and asked:

Why does season 3 begin with Adama launching nukes at Earth?

to which I replied:

Just bringing peace to the middle east.

As it turned out... she started with the wrong episode and instead of starting with Occupation (3x01) she accidentally started with Rapture (3x12).