http://georgewashington2.blogspot.com/2008/08/nist-discovers-fire.html

NIST has solved the mystery of WTC 7, explaining that a brand "new phenomenon" was discovered, namely, that "thermal expansion" of the thick structural steel of WTC 7 led to its weakening.

In the process of discovering this new phenomenon, NIST also discovered another new phenomenon it calls "fire". (NIST explained that fire is hot). It was this new thing - fire - which led to the "thermal expansion".

In addition, NIST has discovered a third new phenomenon called "gravity". Gravity, NIST explains for the rapt press, makes things "fall down and go boom" really fast.

In related news, NIST - the government agency responsible for advancing measurement science, standards, and technology - has announced that nuclear reactors can be powered with play-doh and that our nation's fighter jets can be powered by gummy bears.