My refutation of the WTC big nuclear demolition hypothesis

I prefer not to go to the actual mechanism how the WTC buildings came down. For me it is enough to start from the official story and show that using official figures one can already prove that the official story is false. So, with the Holocaust I use official figures, not because they necessarily are correct, but because they are accepted. My baseline demolition theory for WTC, given in another post, is of this type. It is not necessarily correct (I do not think it is correct), but it is a small modification of the official story and demonstrates that a demolition theory can explain the collapse exactly as well as the official theory. Not as well – it explains it better: it can explain the symmetric collapse and observed very high temperatures.

            This time however my friend Iris sent me some links of the big nuke theory of demolition, or she presented it and I asked her for links. I read those links and evaluated the big nuclear device demolition theory again. Among the three links was a paper from Francois Roby:

https://hal.archives-ouvertes.fr/hal-02004696v3/document

            This is a good paper by a physicist and worthy of reading. Roby got an estimate for the total energy released by three collapsed WTC buildings as

7*10^14 J

            I looked at his derivation and this estimate is justified and I consider it correct. Roby concludes from this very high energy value that the buildings could have collapsed only through nuclear demolition: three large nuclear devices were needed. The rest of the paper describes nuclear demolition.

            However, at the end of the paper Roby mentions some problems in this hypothesis. There were two that caught my attention. The observed seismic signals were too small for large nuclear explosions and the necessary cavities were missing. The last is because Roby discards the cavities that there are: according to Roby they are in wrong places and too close to the surface. I fully agree. Roby suspects that the real cavities are deep down and filled with rubble. I do not think so. The ground was cleaned to the bedrock and the cavity we should find is not any small hole, it would be about the size of the building footprint. So, it is not there and I discard the big nuke theory.  

            How can we then explain the very high value of total energy?

            There were fires. Firemen were putting down fires. Thus, something was burning. Some of the stuff that burned was certainly combustible material in the buildings.

            Let us estimate how much of the total energy can be from combustible material in the three buildings. The floor area in WTC1 and 2 was about 350,000 m2 and WTC7 had about 200,000 m2. Thus the three towers together had the floor area 900,000 m2.

            NIST in WTC7 report uses 20 kg/m2 on floors 7 to 9 and 32 kg/m2 on floors 11 to 13 estimates for combustible material

http://www.911facts.dk/resources/NIST/NCSTAR_1-9_Vol_2_Chapters_9_-_Appendix_E.pdf

Is this estimate reasonable? It is quite reasonable. When I moved from 150 m2 house all went to a car not bigger than 2*3*10=60 m3. That gives 0.04m3 per square meter, that is 40 liters per square meter. It is about 20-30 kg/m2.

Using this NIST estimate of 20-32 kg/m2 for the amount of combustible material and Roby’s estimate 7*10^14 J of total energy, we get the energy content of office material as 24 MJ/kg to 39 MJ/kg, assuming that there is nothing else burning, only this office material.

           Kerosene gives about 43 MJ/kg, but office material must be less than that. I think the range 24 MJ/kg to 39 MJ/kg may be a bit high, I would prefer 15-20 MJ/kg, but Roby’s estimate is approximate. My conclusion is that combustible material in the buildings can explain Roby’s total energy. It explains it better than the nuclear demolition hypothesis because of two things Roby noted: the seismic signals were too weak for nuclear explosions and there was no visible cavity since he discarded the cavities that there were.

Admittedly, the seismic data can be questioned. It seems to record times when the planes hit the buildings but not the time when WTC7 fell. This is unreasonable, I must look at it. But the cavity should be there. Roby suggests that the big nuke was placed to the depth of 100 m and that the cavity formed by the nuclear explosion was larger than the diagonal of the building. The diagonal of WTC1 and 2 was about 90 m. Thus, the cavity should have the radius of about 50 m. Undamaged bedrock should be at the depth of 150 m and the cavity should not be a small hole that you can miss, it should be about 50 m radius circle. It may have been filled with rubble, but when the rubble was cleaned to the bedrock, there should be this mighty hole in the ground. It is not there, so I discard the big nuke theory. Notice that I do not discard a smaller nuke theory. Roby’s paper has a good calculation of the total energy, and it has a good ending of nuclear demolition, but there is a small error in the middle: all of the total energy do not need to be from any explosion. Some, or the major part of it, can be from combustible material. Thus, we do not know how large the explosive was. It could have been a nuke of any size based on the total energy and the lack of cavity shows it was not a large nuke. But it may have been a smaller nuke.

As for the lack of radiation, I do not accept this counter argument as such because there are new weapons of the nuclear family. We do not know what their fallout level is and cannot conclude that they had similar fallout as the Sedan hydrogen-atomic bomb test. It is a long time since Sedan and reducing fallout must have been a goal.

            Thus, we are back to the original demolition theory. There certainly was something burning with very high temperatures, such that office material and jet fuel should not give, but it does not need to be big nukes. It can be thermite or a small nuclear bomb, or both.