This morning, I heard a "boom!" Startled me. I came downstairs and asked the husband if he knew what it was. No. He had looked outside to see "if anything fell."
So I come into the family room and pop on the TV, vaguely hoping it would tell me what that boom was. And it did! As soon as the picture came on, I saw the shuttle coming down for the landing. What we had heard was the sonic boom.
I've only heard the sonic boom from the shuttle once before (it has to return from the south of us for us to hear it,) and that was a double boom. This might well have done it twice, but I wasn't fully awake.