A theory for the collapse of the World Trade Center

Two airplanes of type Boeing 767 flew into the Twin Towers in the morning of September 11th 2001. The crashes caused fuel to ignite, and the airplanes to be cut to pieces and be buried under building fragments. They were subsequently heated to a high temperature. 30 tonnes of aluminium alloys in the airplanes were melted at 660 °C while the surrounding building was only heated to a much lower temperature due to insulation effects. When the temperature reached 750–800 °C, the huge amount of aluminium melt managed to stream down to the lower floors. There it came in contact with water from the automatic sprinkler devices and possibly other sources. This encounter resulted in a series of fierce explosions due to the generation of hydrogen gas and local heating to high temperatures well above 1200 °C. A complete floor of the buildings was blown apart, and the upper part fell onto the bottom part leading to a complete collapse.