Twin Towers attackWhy the Twin Towers collapsed: new theory

Just before the two New York skyscrapers collapsed on 11 September 2001, powerful explosions within the building could be heard, leading many people to believe that overheated steel beams in the building were not the cause of the collapse.

The explosions fed the conspiracy theories that someone had placed explosives inside the towers.

At an international materials technology conference in San Diego, senior scientist Christian Simensen of SINTEF Materials and Chemistry present an alternative theory, based on the physics of materials, of what happened in the towers when they were attacked by the aircraft. Siemensen believes that his theory is much more likely to reflect the actual situation than the official explanation of the collapse.

In the wake of the conference Simensen had an article published in the journal Aluminum International Today, describing his theory.

A SINTEF release reports that Simensen believes that it is overwhelmingly likely that the two aircraft were trapped inside an insulating layer of building debris within the skyscrapers. This leads him to believe that it was the aircraft hulls rather than the buildings themselves that absorbed most of the heat from the burning aircraft fuel.

Siemensen says that the heat melted the aluminum of the aircraft hulls, and the core of his theory is that molten aluminum then found its way downward within the buildings through staircases and gaps in the floor — and that the flowing aluminum underwent a chemical reaction with water from the sprinklers in the floors below.

“Both scientific experiments and 250 reported disasters suffered by the aluminum industry have shown that the combination of molten aluminum and water releases enormous explosions,” says Simensen.

“I regard it as extremely likely that it was these explosions that made the skyscrapers collapse by tearing out part of the internal structure, and that this caused the uppermost floors of the buildings to fall and crush the lower parts. In other words, I believe that these were the explosions that were heard by people in the vicinity and that have since given life to the conspiracy theories that explosives had been placed in the skyscrapers.”

The official report on the causes of the collapse of the three buildings (WTC1, WTC2, and WTC7) was drawn up by a commission appointed by the U.S. government and has since been supported by other publications. The report came to the conclusion that the collapse was caused by heating and failure of structural steel beams in the centre of the buildings.

Simensen disagrees. “I believe that it is overwhelmingly probable that the theories regarding the cause of the collapse of WTC1 and WTC2 are wrong, but that the report very likely came to the correct conclusion as regards WTC7,” he says.

The reason for the investigative commission’s mistaken conclusions? “The [U.S.] federal government commission did not take sufficiently into account the fact that the aircraft brought 30 tons of aluminum into each of the two towers.”