Proofs of Demolition

Demolition of the Twin Towers is Provable Through Simple Analysis
Despite the destruction of the most significant evidence of the Twin Tower collapses -- the structural steel -- it is relatively easy to prove the towers were demolished. Determining how they were demolished without the benefit of the steel may be difficult or impossible, but proving that a gravity-driven collapse is insufficient to explain the characteristics of the collapses documented by photographic and seismic evidence is not.
There are numerous pieces of evidence that strongly indicate demolition, including the fact that authorities destroyed and suppressed evidence, the more than 100 years of engineering experience with steel-frame buildings, the misleading representation of the towers' design by truss theory proponents and the implausible sequence of events proposed by that theory, and the many collapse features that seem irreconcilable with gravity-driven collapses.
Proving demolition requires more than enumerating evidence. It requires making logical inferences about events using the evidence. Three fairly strong proofs are as follows. These are presented as qualitative arguments only. Each suggests an approach for developing a rigorous quantitative proof.

* The towers fell faster than they could have if they were crushing themselves.
* The volume of dust was too great to have been the product of a gravity-driven collapse.
* The South Tower's top shattered before falling, and so its breakup was not a result of gravity-driven crushing.

Speed of Fall
Twin Towers' Rates of Fall Proves Demolition
The towers collapsed completely in intervals of time similar to that taken for a block of wood dropped from a tower's roof to reach the ground. A block of wood has about the same average density as the main components of the towers near their tops.
In a vacuum, a block of wood (or lead) would take 9.2 seconds to fall from the tower's roof. In the air a block of wood, say ten inches on a side, might take 50 percent longer than in a vacuum. Fifteen seconds, a good estimate for the total time of collapse of the North Tower, is about the time it would take our block to fall from the roof. The rubble from the Tower probably had similar average density to our block of wood, since the floor slabs consisted of corrugated sheet metal and lightweight concrete, and the perimeter steel columns were hollow with walls only 1/4th inch thick at the Towers' tops. Air resistance alone could account for the slowing of the falls to the point where each Tower took about 15 seconds to completely come down.
The official story requires that more than air resistance was slowing the descents. The falling rubble would be having to crush every story below the crash zone -- ripping apart the steel grids of the outer walls and obliterating the steel lattice of the core structure. The resistance of the intact building itself would be thousands of times greater than air resistance.
If air resistance is able to increase total collapse times by even 20 percent, then shouldn't the addition of the resistance of the buildings themselves increase the time several thousand percent, to at least tens of minutes?
Of course the idea of a collapse lasting minutes is absurd. So is the idea of a steel frame building crushing itself.

Breakup of WTC 2's Top
Shattering of South Tower's Top Proves Demolition
There are several pieces of evidence that show the structure of the 30 stories of the South Tower above the impact zone was shattered before it started its precipitous plunge. How could the steel frame of many stories above the impact zone have broken up even before it started to fall? The proponents of gravity-driven collapse maintain that the tops of the towers crushed the floors below the impact zones as they fell. The tops functioned as pistons, according to Bazant and Zhou, crushing the stories one by one. What one actually sees in the case of the South Tower is that their piston disintegrated even before it started to fall. A gravity-driven collapse cannot account for that disintegration, nor for how a cloud of rubble could crush the intact structure below the impact zone.


These frames from a South Tower collapse video are separated by equal time intervals. Examining the middle edge of the falling portion of the tower shows that its angle of tilt from vertical remains about the same between the second and third frames, and therefore the top has stopped rotating. But unless the top had already been shattered, it should have continued to rotate in accordance with the law of conservation of angular momentum.