1a. Free fall
In all videos available, I make the collapses at closer to about 15 seconds. Video based observations have a large error. The seismic observations tend to agree with the 13-15 second estimate (
http://911research.wtc7.net/wtc/analysi ... efall.html). In any case, all available videos show material falling faster than the overall collapse. That is, some material is ahead of the collapse, and at the level of intact floors. By definition then, the buildings did not collapse at free fall speed. But the question remains, how much more slowly should they have fallen in the absence of cutting charges? I don't think there is a clear answer to this question
1b. Design for aircraft impact
I don't think any of the designers were bold enough to claim that the towers could "easily" withstand an aircraft impact. They did claim that the WTC was designed to resist an impact by a Boeing 707 (116 570 kg max take-off weight). While the designers don't mention speed in the interviews and quotes I have seen, they might have been thinking in terms of normal cruising speed (900 km/h).
By contrast, the 767 has a max take-off weight of 179 170 kg, and with a max level speed of 1000 km/h, can be expected to have been flying faster when they hit the towers. They could have been flying as fast as 1200 km/h, just under Mach. The difference in energy between the 707 and 767 impacts is important.
2) See 1a.
3) Falling too fast
This is a much more important problem than that of the free-fall. I think it is fairly well established that the towers did not in fact collapse at free-fall speed. But did they collapse too fast? And if so why? All the work of which I am aware in this area studies the towers as designed, rather than as built, or even as they existed in 2001. First, given that the problems of
corruption in the construction industry in NY/NJ in the 60's and 70's are so well known, it is suprising that we don't immediately suspect the towers collapsed too far because they were built below specs. Second, the towers may not have been as strong in 2001 as they were when built. Any complex system generates unintended consequences, and the towers may have been weakened over time in ways that we still don't (and probably never will) understand.
At the moment, there seems to be too much information missing to decide whether the towers fell to fast, or how much faster than could have been expected.
4) How did tons of concrete and all the building contents, including many human bodies, get turned into particulate matter?
This is far from convincingly established. First, there are obviously non-particulate elements seen in the collapse videos. Second, post-collapse pictures and video of the debris show many large chunks of metal and concrete. But lets not forget the awesome amount of potential energy that was suddenly turned into kinetic energy by the collapses. How much energy was required to produce the amount of concrete dust produced? Since we have no clear idea of what proportion of the concrete was ground into particles, and since we don't know how much energy was released, any statements about particulate matter can't be treated as strong evidence. Not to mention the problem of design vs building.
5) How did tons of this debris complete with tons of steel beams get projected horizontally hundreds of feet to form a 1200 foot-wide concentric debris field?
This is where we start hitting some contradictions. If the towers collapsed at free fall speed, and the path of greatest resistance was cleared by cutting charges, why was material being projected horizontally? We would expect material to be projected out horizontally precisely if the vertical path was blocked, at least partially. Some of the energy of the towers was clearly being expended in the horizontal ejection of material, before it overwhelmed the vertical resistance. This argues against the presence of cutting charges or other forms of CD.
A second important contradiction: The towers cannot simultaneously have been collapsed into their own footprint by CD
and have created a 1200 foot wide concentric debris field.
6) Why do photographs and videos of the destruction of the Twin Towers show this rapid high-energy ejection of tons of debris quite clearly, not from "fuzzy" or "doctored" sources?
See 5.
7a impossible temperatures
Burning is one of those complex processes. Prehistoric furnaces with natural induction allowed the smelting of iron, which requires at least 1535 C. It isn't hard to imagine a natural furnace effect taking place in the WTC pre-collapse.
7b aluminium
The intriguing footage of flowing metal, as far as I have seen, shows flows that originate not far below the impact points. I don't see how aircraft aluminium can absolutely be ruled out. Significant quantities of other metals with low melting points could easily have been kept in the WTC offices for various reasons: Gold (1064 C), copper (1084 C). I also wonder whether some executive washrooms didn't have significant quantities of brass (Cu/Zn alloy). Most brasses, depending on the proportion of zinc, have a comparatively low melting point.
8. pools of molten metal
That is a mystery, no doubt. But coal fires have been known to burn for decades at very hot temperatures after mine explosions, so this is not unprecedented.
9) Why was the exact chemical signature of thermite found in the WTC dust spead over NYCity?
I need to look into this more.
10) Why was the exact chemical signature of thermite found in cooled molten material in debris attached to steel beams sent off as memorials and also on areas of the steel beams that were not cut by acetlyne torch?
see 9
11) Why were there massive steel beams curved without fractures as can only happen under thousands of degrees of heat like the 4500 f. that thermite burns at?
Comustion is not the only source of heat. Pressure also generates heat. I think we can agree that very high pressures were generated by the collapses.
12) Why were iron-rich spheroids found in the WTC dust? These can only be created by molten metal turned into a spray of micro-droplets with massive energy.
"Can only be created by" is a bad start for a scientific argument. One can't rule out that there exists alternative mechanisms for the production of an outcome. "Cannot be the result of" is a much better start. I'd be more impressed with this claim if a range of alternatives were also examined and ruled out.
13) Why did hundreds of first responders report that they heard and felt bombs in the WTC before it came down and just before and during its destruction?
They certainly heard explosions. That is, they heard sudden releases of energy. That isn't surprising, given that massive towers were in the early stages of collapse. Literally, something had to pop for those towers to come down. Whether those sudden energy releases were caused by bombs is quite a different question, and the witnesses were probably not in a position to answer it. If you've ever spent a very cold night near a large lake, you know exactly what I mean.
) but there could have been NO room for this on the 911 operation.
