Rubble Falling Through Towers Encountered No More Resistance than Air

Given the mushrooming of the tops, most of the mass fell outside the footprint of the building.

• An object in a vacuum would take 9.2 seconds to fall from the towers' height.
• It took the rubble from the towers' tops about 13-16 seconds to reach the ground, both inside and outside of the tower's footprint.
• Air resistance was the only thing slowing the descent of the rubble outside the footprint.
• 1000 vertical feet of intact vertical structure would have been slowing the rubble inside the footprint, barring demolition.

Since a steel structure should have provided hundreds, if not thousands, of times the resistance of air, it must have been demolished ahead of the falling mass.