Research editor for Popular Mechanics magazine, Ben Chertoff, discussed some of the most prevalent claims made by conspiratorial theorists regarding 9/11 and how the staff of Popular Mechanics debunked them.
According to Chertoff, one such conspiracy alleges that no fighter jets were scrambled during the 9/11 terrorist attacks because the U.S. Air Force had been ordered to stand-down. He pointed out that on 9/11 there were only 14 fighter jets on alert in the U.S., and just five within range of the hijacked flights. Chertoff said this was "standard operating procedure" for the military, which until the 9/11 attacks did not expect threats from domestic air travel. He reported that several jets were eventually launched, but were kept in a holding pattern over the Atlantic Ocean because nobody knew the exact location of the hijacked flights.
Chertoff also shed light on the role jet fuel played in the collapse of the World Trade Center. Conspiratorial theorists believe that since jet fuel does not burn hot enough to melt steel, planted explosives must have been used to bring down the buildings. While Chertoff admitted that jet fuel could not have melted the steel, he also stated that "steel doesn't need to melt to have a collapse like we saw on September 11th." Chertoff's research showed that the plane crashes knocked spray-on fireproofing off of the steel beams. After the jet fuel ignited fires throughout the WTC, exposed areas on the steel beams heated. The heat was transferred to the entire beam, causing them to expand and soften. This combination of events, he concluded, is what eventually caused the WTC buildings to collapse.
Conspiracy theorists claim a photo taken by Rob Howard and published in New York magazine shows an 'extra' object underneath the fuselage at the base of the right wing. They speculate that this object is a bomb or a missile, and point to it as evidence that the 9/11 attacks were a U.S. military operation. Photography expert Ronald Greeley has examined the photo and thinks it's merely a play of sunlight against the plane's undercarriage. Read more at popularmechanics.com.