So, was the great blackout of '03 a sign that Osama is about to shut down the power grid?

Phil Anderson, a homeland security guru at the Center for Strategic and International Studies, doesn't think so.

Last fall, Anderson helped put together a high-level simulation, "Silent Vector." In it, the bad guys unleashed multiple attacks on America's "energy infrastructure."

"We looked at a hit on the power grid for Silent Vector," Anderson tells Defense Tech. But the strike was ruled out, "because it was well within the realm of the too hard to do."

"It would require dozens of substations being blown up to shut all of the power down," he adds.

If that's the case, how did last week's blackout happen so easily, so suddenly?

"It's a complete mystery to me," Anderson says. "It doesn't jive with any of the research we've done."

THERE'S MORE: Slate's Fred Kaplan doesn't think Al-Qaeda could cause another power grid shutdown, either. He cites a Gartner simulated attack on the lights, done for the Naval War College. Like Anderson, those wonks thought it would take "the physical destruction of key transmission bottlenecks" in order to turn the power off, Kaplan says. They also believed that such strikes would have to be accompanied by cyber-attacks.

That's becoming less and less possible, Kaplan notes, relying on a ZDNet article for evidence.

"Invading key nodes of the electrical network, whether by hacking or whacking, is very difficult and getting harder."

AND MORE: A Qaeda-linked group is taking responsibility for the blackouts, according to WorldTribune.com.

AND MORE: "I'm scratching my head over this group of stories," says one Defense Tech reader. "In June 1997 the NSA did a No-Notice Interoperability Exercise known as Eligible Receiver. While the report is still classifed, what little has come to light is that the 30+ members of the red team using open source tools found off the Internet had the capability to shut off the power in nine major cities, not to mention taking over several U.S. Commands around the globe and at the Pentagon."

Many people, however, have dissed Eligibile Receiver as a boogeyman, used to hype up the "cyber-terror" threat.