Have the Iranians just tested a nuclear device? Maybe. Check out In From the Cold's post on Thursday. Spook is relying on some reports from the Israeli press that haven't been picked up on much here. There are probably half-a-dozen intelligence agencies who could make educated guesses as to whether the Iranians just had an earthquake, or whether something more sinister was going on.
The Iranians are going to test a device sooner rather than later, but I find the idea of a test just now to be rather unlikely, and without more, I'm not buying it. Still, the tale is interesting.
Of more immediate concern are Iranian naval activities along their Persian Gulf coast, in particular the constuction of new naval bases; and their sabre-rattling in the general direction of US aircraft carriers. It's hard to know what to make of the talk about the ships; the Iranians aren't stupid, and the ability to destroy an aircraft carrier would be positively counterproductive from their point of view. Surely the Iranians know that a good way for them to learn much too much about nuclear weapons would be by causing harm to a US aircraft carrier.