<< Yes i saw it.. very informative as NOVA always is.. I do have to say however that it could be a little rough on those who were involved.. endless replays of the impacts and collapse of the towers... I have to say the whole event still gets to me, knowing people who were in the towers on that day. >>
I agree. As everyone already knows, the towers collapsed due to fire-induced failures or additional structural steel elements (on top of those damaged by the actual collisions). The interesting explanation was that the jet fuel itself burned up very quickly (doh!) but started everything else already in the building on fire (i.e. office furniture, paper, etc.). The continuing fire of the internal material led to the failures. The other major finding was that the material blown through the floors by the collision removed much of the critical foam insulation on the structural members, leaving them much more exposed to the heat of the subsequent fires. It was also interesting to learn that the towers collapsed in two different ways due to the way that each was hit by the airliner.