I don't buy the conspiracy theories, but I've heard a lot about the main point of this article. I do think that a real investigation should be held if for no other reason to clarify the day and help prevent the same mistakes from being made again.
http://www.informationclearinghouse.info/article14566.htm
What we know and don’t know about 9/11
Paul Craig Roberts
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I will begin by stating what we know to be a solid incontrovertible scientific fact.
We know that it is strictly impossible for any building, much less steel columned buildings, to “pancake” at free fall speed. Therefore, it is a non-controversial fact that the official explanation of the collapse of the WTC buildings is false.
We also know for a fact that the Air Force somehow inexplicably failed to intercept the alleged hijacked airliners despite the fact that the Air Force can launch jet fighters to 29,000 feet in 2.5 minutes. We also know that the two co-chairmen of the 9/11 Commission have just written a book that reveals that the US military lied to the Commission about its failure to intercept the hijacked airliners.
There are various explanations for this second fact. The military could have lied to cover up complicity or to cover-up its incompetence. However, no investigation has been made to ascertain the true explanation for the failure.
This leaves us with the incontrovertible fact that buildings cannot “pancake” at free fall speeds.
The only explanation known to science for the free fall collapse of a building, especially into its own footprint, is engineered demolition, which removes the supports for each floor of the building at split second intervals so that the debris from above meets no resistance on its fall. To call this explanation a “conspiracy theory” is to display the utmost total ignorance. Any physicist or engineer who maintains that buildings can “pancake” at free fall speed has obviously been bought and paid for or is a total incompetent fool.
The WTC buildings are known to have collapsed at free fall speed into their own footprints.
This fact does not tell us who is responsible or what purpose was served.
Since the damning incontrovertible fact has not been investigated, speculation and “conspiracy theories” have filled the void. Some of the speculation is based on circumstantial evidence and is plausible. Other of the speculation is untenable, and it is used to protect the official explanation by branding all skeptics “conspiracy theorists.” I would not be surprised if some of the most far-out “conspiracy theories” consist, in fact, of disinformation put out by elements in the government to discredit all skeptics. But I do not know this to be the case.
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