ERROR: 'The Towers Collapsed in 10 Seconds'

Each of the Twin Towers totally collapsed in intervals of approximately 14 to 16 seconds. A temporal record of the entire North Tower collapse is provided by the real-time CNN broadcast feed aired during the attack. (This table shows frames from that video at half-second intervals.) It allows reasonably accurate measurement of gross collapse features such as the growth and descent rate of the rubble and dust cloud. However, this and other video evidence does not allow the determination of a precise time of total collapse because each tower's destruction remains hidden behind an expanding dust cloud which, because of its size, reaches the ground over a span of several seconds.

Despite the availability of video evidence establishing lower bounds of total collapse times of over 13 seconds for each of the towers, assertions that they collapsed in under ten seconds are widespread. Collapse times of eight to ten seconds are common not only in literature of the skeptics, but also in publications promoting the official explanation. A Scientific American article about a 2001 public meeting of engineers on the MIT campus in Cambridge, MA gives a figure of nine seconds.

The 9/11 Commission also endorses the 10-second figure.

The book Painful Deceptions, the first book to provide a detailed exposition on the World Trade Center demolition, labels an illustration of the South Tower destroyed down to its 30th floor "4 1/2 seconds" (page 77), a moment that was actually more than ten seconds into the collapse.