So just a question about the jet fuel theory?
First of all, you have the burning temperature of jet fuel wrong, it is physically impossible for it to burn that cooly, because of the first law of thermodynamics, to illustrate lets take the maximum burning temperature of carbon- 3200 degrees celcius and Hydrogen- 2750 degrees celcius, Even with breaking the bonds you could never get down to 1400 degrees celcius. But disgregarding that you guys do realize that Steel loses half its strength at about 650 degrees celcius right? The 1975 fire in the WTC burned at about 700 degrees Celcius (without an accelerante that rapidly spread the fire over multiple floors, which were approximately 43,000 square feet a floor), so even assuming a 50 degree loss, about 122 degrees farenheit, over 5 floors, you would have major heat damage. about 50% loss, not including the thermal expansion of steel which warped the supports and led to even more support loss. Compound this by the colums damaged by the plane impact and the loss of several floors of floor joists on one side that connected the inner core with the perimeter of the building, and you have major catastrophic failure. The weak point was not the inner core that was so highlighted, but instead theses floorjoists, that were only rated to 1,300 tons over their current load without halving, that failed, and with it 45000(19.8 million kilograms) tons that was falling with an acceleration of 9.8m/(s^2) for a total of 1,940,400,000 Newtons. But, alas this begs the question why didnt it topple over, well there is a fairly easy explanation to this as well, because the floor joists on the upper floors were able to aide in the distribution of the load to hold themselves up, so long as they had aide from the lower floor joists. As soon as those failed the building plummeted straight down all at once, and the smoke leaving the building is generally called the pancake effect caused by the ceiling crashing into the floor and ejecting all the debris outwards.

If anything the way it collapsed was a testament to its design, and how well built it was. to be able to withstand heat plus the force of a plane collision.

Yes the first law of thermodynamics states that energy cant be destroyed or created, just changed. But you also have to look at the 2nd law of thermodynamics. In order to keep a constant temperature, it has to somehow be contained, because the 2nd law of thermodynamics states that heat energy flows from hot to cool areas, and if you take the first law of thermodynamics into account, the heat (energy) isnt being destroyed, it's flowing.