This Computer Simulation Explains How the Twin Towers Fell

Recent questions

• Why did the US government commission an investigation after the 9/11 attacks?

  The US government commissioned a $16 million investigation by the National Institute of Standards and Technology to explain the structural failures of the World Trade Center towers after the 9/11 attacks. The investigation involved examining debris, running computer simulations, and conducting lab tests to understand the collapse mechanics.

• How did Dr. Frank Greening determine the Twin Towers' collapse?

  Nuclear chemist Dr. Frank Greening conducted research to determine if the Twin Towers could collapse under their own weight without explosives. Using a momentum transfer program, he calculated that the weight of the buildings above the impact floors would cause each floor below to give way, leading to the collapse. The North Tower fell in 13 seconds, while the South Tower, with more floors above the impact site, collapsed in 11 seconds, resembling a controlled demolition.

• What was the key factor in the collapse of the Twin Towers?

  The key factor in the collapse of the Twin Towers was the weight of the buildings above the impact floors. Dr. Frank Greening's research showed that this weight caused each floor below to give way, ultimately leading to the collapse of the towers.

• How did the collapse of the North Tower differ from the South Tower?

  The collapse of the North Tower took 13 seconds, while the South Tower, with more floors above the impact site, collapsed in 11 seconds. This difference in collapse times was due to the varying number of floors above the impact site, with the South Tower resembling a controlled demolition.

• What methods were used in the investigation of the World Trade Center towers' collapse?

  The investigation of the World Trade Center towers' collapse involved examining debris, running computer simulations, and conducting lab tests. These methods were employed by the National Institute of Standards and Technology to understand the structural failures of the towers after the 9/11 attacks.