Re: Physics of the 9/11 building collapses?

On the topic of Bayesian priors, here's some food for thought. Since
1970, NIST has found 6 incidients of a steel reinforced structure
collapsing due to fire. Four of them happened on September 11, and the
other two were partial collapses of a few floors (
http://www.haifire.com/presentations/Historical_Collapse_Survey.pdf,
check the table near the bottom for the exact details, but the rest is
a good read if you have time), and this is in spite of the fact that
most highrise buildings suffer at least one major fire in their
lifetimes. Thus, any model that points to fire as the primary
contributing factor for a total collapse must invariably have a low
prior because it presents a scenario that has never happened before;
now, hypothesizing that such an event occurs not once, but four times
in a single day... well, you get the idea.

Honestly, I think the problem really comes down to the planes:

If the plot was completely orchestrated by a foreign agency
(terrorists), who were able to place explosives in the buildings, why
bother with planes at all? In that case, hitting the buildings with the
planes only allowed more people to escape. Had they simply detonated
the three buildings (1, 2 & 7) simultaneously, the effect would have
been far more dramatic, and the loss of life *significantly* higher.

If the plot was completely orchestrated by a government agency, why
bother with both the explosives and the planes? If they felt that
hitting the buildings with planes was sufficient to fulfill their
agenda, then the explosives are redundant; if they felt that the
explosives were necessary to fulfill the agenda, why bother with the
planes?

Neither scenario really makes sense. That leaves us trying to devise a
more complicated scenario that could explain the necessity for both
events.

A.

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