Still think that something other than a mere plane crash brought down the World Trade Center towers? According to a Norwegian materials expert, you may be right. Just … you know … not in the way most Truthers probably expect.

Christian Simensen thinks the Twin Towers were ultimately felled by a thermite reaction.

"If my theory is correct, tonnes of aluminium ran down through the towers, where the smelt came into contact with a few hundred litres of water," Christian Simensen, a scientist at SINTEF, an independent technology research institute based in Norway, said in a statement released Wednesday. "From other disasters and experiments carried out by the aluminium industry, we know that reactions of this sort lead to violent explosions." Given the quantities of the molten metal involved, the blasts would have been powerful enough to blow out an entire section of each building, he said.

This, in turn, would lead to the top section of each tower to fall down on the sections below. The sheer weight of the top floors would be enough to crush the lower part of the building like a house of card, he said.

I honestly don't know how plausible an idea this is. It sounds reasonable to a layperson, but I'm curious what those of you with more engineering expertise think.

The AFP has a write-up about the theory. There's also a more-detailed explanation on the website of SINTEF, the Norwegian research lab where Simensen works. Finally, this appeared in the trade journal Aluminum International Today, and they've got an email address where you can request a copy of the story.