The Pentagon
At 9:37 am on 9/11, 51 minutes after the first plane hit the World Trade Center, the Pentagon was similarly attacked. Though dozens of witnesses saw a Boeing 757 hit the building, conspiracy advocates insist there is evidence that a missile or a different type of plane smashed into the Pentagon.
Big Plane, Small Holes
Claim: Two holes were visible in the Pentagon immediately after the attack: a 75-ft.-wide entry hole in the building's exterior wall, and a 16-ft.-wide hole in Ring C, the Pentagon's middle ring. Conspiracy theorists claim both holes are far too small to have been made by a Boeing 757. "How does a plane 125 ft. wide and 155 ft. long fit into a hole which is only 16 ft. across?" asks reopen911.org, a Web site "dedicated to discovering the bottom line truth to what really occurred on September 11, 2001."
The truth is of even less importance to French author Thierry Meyssan, whose baseless assertions are fodder for even mainstream European and Middle Eastern media. In his book The Big Lie, Meyssan concludes that the Pentagon was struck by a satellite-guided missile—part of an elaborate U.S. military coup. "This attack," he writes, "could only be committed by United States military personnel against other U.S. military personnel."
FACT: When American Airlines Flight 77 hit the Pentagon's exterior wall, Ring E, it created a hole approximately 75 ft. wide, according to the ASCE Pentagon Building Performance Report. The exterior facade collapsed about 20 minutes after impact, but ASCE based its measurements of the original hole on the number of first-floor support columns that were destroyed or damaged. Computer simulations confirmed the findings.
Why wasn't the hole as wide as a 757's 124-ft.-10-in. wingspan? A crashing jet doesn't punch a cartoon-like outline of itself into a reinforced concrete building, says ASCE team member Mete Sozen, a professor of structural engineering at Purdue University. In this case, one wing hit the ground; the other was sheared off by the force of the impact with the Pentagon's load-bearing columns, explains Sozen, who specializes in the behavior of concrete buildings. What was left of the plane flowed into the structure in a state closer to a liquid than a solid mass. "If you expected the entire wing to cut into the building," Sozen tells PM, "it didn't happen."
The tidy hole in Ring C was 12 ft. wide—not 16 ft. ASCE concludes it was made by the jet's landing gear, not by the fuselage.
Read more: 9/11 Conspiracy Theories - Debunking the Myths - Pentagon - Popular Mechanics