[TigersEye]

"My guess is a missile with a leak that had to be launched."

bvw posted this. It is one of the most interesting speculations I have seen. It fits in several ways. It accounts for a very big missile. It accounts for a completely unexpected launch and it very well might be considered too embarrassing to tell the truth about. It would also explain the contradiction between saying no one knows anything about it yet confidently state there is no threat.

[Candor7]

I think thats the best theory so far.