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Scientists reconstruct still-horrifying 9-11 images

Computer images designed to help study damage done to North Tower include no casualties but are chilling nonetheless.

A computer simulation of the attack on the World Trade Center is now showing at YouTube. While the images are designed to help engineers and scientists study how a large structure behaves when smashed into by an airliner, they are still horrifying.

Flight 11 crashed into the WTC's North Tower on Sept. 11, 2001. A team of researchers from Purdue University used scientific principles, state-of-the-art simulation code and animation computer system to recreate the three-quarters of a second following impact.

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Over and over again, wreckage from the Boeing 767 careens towards the viewer. Sometimes the simulation includes only the body of the aircraft. Other times, the plane is removed from the image so fuel or debris can be tracked.

At one point, the crash is played back and the focus is exclusively on the damage done to the tower's core beams, which are left sliced and twisted in the plane's wake.

The recreation culminates when all the elements: fire, fuel, debris and plane metal are added and the tragedy is depicted with bloodcurdling accuracy.

The simulation is no doubt a scientific marvel. But can anyone watch the scenes without their imaginations adding people to the pictures?