Rosie O'Donnell was seen in the tower and is believed to have placed the explosives hidden in Taco Bell Chalupas. Charly Sheen is fully aware of these new developments.

Dust, being light, floats in air. The pics you posted in the OP shows the dust lingering in the air after the steel has collapsed. I'm sure video recording that event would've demonstrated that much les ambiguously.

In the third frame of the larger series of pics you can clearly see the piece of steel is falling.

Thanks, Coughy, that's what I thought.

One good turn deserves another: here's a video showing the outer columns of the South Tower bending inward before and during the initial collapse. I know this thread is for the North tower, but this shows how explosives definitely weren't involved in the initial building failure.

http://video.google.com/videoplay?docid=-5405555553528290546

If you can believe that heat from the fires weakened the exterior columns, why is it such a stretch for you to accept that the inner columns were weakened in the same way, when they were likely exposed to higher temperatures?

If you can believe that heat from the fires weakened the exterior columns, why is it such a stretch for you to accept that the inner columns were weakened in the same way, when they were likely exposed to higher temperatures?

NIST developed a method to characterize maximum temperatures experienced by steel members using
observations of paint cracking due to thermal expansion. The method can only probe the temperature
reached; it cannot distinguish between pre- and post-collapse exposure. More than 170 areas were
examined on the perimeter column panels; however, these columns represented only 3 percent of the
perimeter columns on the floors involved in fire and cannot be considered representative of other columns
on these floors. Only three locations had evidence that the steel reached temperatures above 250 °C.
These areas were:
• WTC 1, east face, floor 98, column 210, inner web,
• WTC 1, east face, floor 92, column 236, inner web,
• WTC 1, north face, floor 98, column 143, floor truss connector
Other forensic evidence indicates that the last example probably occurred in the debris pile after collapse.
Annealing studies on recovered steels established the set of time and temperature conditions necessary to
alter the steel microstructure. Based on the pre-collapse photographic evidence, the microstructures of
steels known to have been exposed to fire were characterized. These microstructures show no evidence
of exposure to temperatures above 600 °C for any significant time
wtc.nist.gov/pubs/NCSTAR1-3ExecutiveSummary.pdf

The modeling suggests a peak total rate of fire energy output on the order of 3-5 trillion Btu/hr, around 1-1.5 gigawatts (GW), for each of the two towers. From one third to one half of this energy flowed out of the structures. This vented energy was the force that drove the external smoke plume. The vented energy and accompanying smoke from both towers combined into a single plume. The energy output from each of the two buildings is similar to the power output of a commercial power generating station. The modeling also suggests ceiling gas temperatures of 1,000 degrees Centigrade (1,800 degrees Fahrenheit), with an estimated confidence of plus or minus 100 degrees Centigrade (200 degrees Fahrenheit) or about 900-1,100 degrees Centigrade (1,600-2,000 degrees Fahrenheit).

ASSERTION #5
"An explosive other than conventional dynamite or RDX was used...a non-detonating compound such as thermite (aka thermate), which gets very hot upon initiation and can basically 'melt' steel. This can be proven by photographs of molten steel taken at Ground Zero, the temperature and duration of underground fires, and comments made by rescue workers."

PROTEC COMMENT: We have come across no evidence to support this claim.

This claim is actually a loose connection of unrelated individual assertions, therefore we must address them as such.

1. The vast majority of comments made by rescue workers, city officials or various others not involved in the actual demolition process at Ground Zero regarding the heat of underground fires or "molten anything" (steel, aluminum, tin, composites, etc.) are conjecture and have no practical value in determining what types of materials were actually burning and at what temperature. Most were simply never in a position to know, and those that were have acknowledged that they don't know for sure.

2. Photographs that we have examined purporting to show demolition equipment extracting "molten steel" from the debris at Ground Zero are inconclusive at best, and most are inaccurate as described. Extracting various hot metallic compounds or debris is one thing, but "molten steel beams" is quite another. As a fundamental point, if an excavator or grapple ever dug into a pile of molten steel heated to excess of 2000 degrees Fahrenheit it would completely lose its ability to function. At a minimum the hydraulics would immediately fail and its moving parts would bond together or seize up. The heat would then quickly transfer through the steel components of the excavator and there would be concern for its operator. The photos we have reviewed on various websites do not show any of this, and if anything, indicate that the underground fires - while very hot - were not hot enough to melt steel.

3. In an effort to further research this assertion, we spoke directly with equipment operators and site foremen who personally extracted beams and debris from Ground Zero (several of whom have requested anonymity to prevent harassment). These men worked for independent companies in separate quadrants of the site, and many were chosen due to their extensive experience with debris removal following explosive demolition events. To a man, they do not recall seeing any evidence of pre-cutting or explosive severance of beams at any point during debris removal activities.

4. The assertion that thermite played a role in the towers' collapse has been put forth by Steven Jones, a Professor at Brigham Young University. This author spoke with Professor Jones at length in February 2006, and we have corresponded via email a few times since. As he has explained it, metallurgic tests were conducted on two sections of steel beams that were saved for 9/11 memorials in the New york area. These beams apparently tested positive for "trace amounts of thermite", which led Jones to conclude that thermite was used on 9/11 by unknown parties to compromise support beams in WTC 1, 2 and 7. Professor Jones acknowledges that his investigation is still in the research phase and that questions regarding the viability of his theory remain unanswered. For example, it is unknown how thermite's destructive process could have been applied and initiated simultaneously on so many beams - in several buildings - undetected and/or under such extreme conditions. It is also unusual that no demolition personnel at any level noticed telltale signs of thermite's degenerative "fingerprint" on any beams during the eight months of debris removal. And a verifiable chain of possession needs to be established for the tested beams. Could they have been cut away from the debris pile with acetylene torches, shears, or other potentially contaminated equipment while on site? Could they have been exposed to trace amounts of thermite or other compounds while being handled, or in storage, or during the transfer processes from Ground Zero to the memorial sites? We do not know the answers, but these and may related questions should be addressed if this assertion continues to be pursued.
Source

I'm searching for the NIST report section that stated the temperatures reached 1,000°C; I'll edit this post when I find it.

I found this from the FEMA study:
Still searching for a link.

ETA: Found it:http://www.fema.gov/pdf/library/fema403_ch2.pdf

What point are you making here?

danemburke asked why I thought the fires in the WTC buildings reached temperatures high enough to weaken steel. If you look at the post directly above the one you quoted it'll become obvious.

ETA: Indeed, the several posts we exchanged make quite clear the point I was making.

In watching the video, I noticed that the part of the tower that you are referring to is actually fallen and left small particles of debris that were left there from the main collapse of the tower. The pictures you posted are misleading. I suggest that everyone watch the video at :57 seconds.

danemburke asked why I thought the fires in the WTC buildings reached temperatures high enough to weaken steel.

If you can believe that heat from the fires weakened the exterior columns, why is it such a stretch for you to accept that the inner columns were weakened in the same way, when they were likely exposed to higher temperatures?

Why do you believe they [the inner columns] were likely exposed to higher temperatures?

You'll notice that I actually posted the video in post #10 and have already accepted this explanation.

Looks like you misunderstood my question. I'm still interested in an answer...because like I said, it seems to me that fires should have been at their weakest in the core.

When the jet crashed into the building, it went into the center, and the fire was concentrated on the jet. I'm not sure if this was you, but didn't you say that because of the flammable office materials you think the sides were exposed to higher temperatures? If so then there are many flammable things on planes also. If you didn't say that, then I apologize, I just remember reading it and I think it was you.

No, actually:
Looks like you misunderstood my question. I'm still interested in an answer...because like I said, it seems to me that fires should have been at their weakest in the core.

That still doesn't account for why the temperatures in the core would have been higher. The area outside the core seems to have had much more fuel and oxygen.

All I'm able to think of right now other than the fuel on the plane is upholstery and plastics. It seems they would have been smashed to small peices as scattered randomly, if not instantly consumed in the initial fireball. It took approximately 50-100 minutes for the towers to collapse after the plane impact, and I really don't think the flammables from the plane would have lasted anywhere near that long, unless they were burning so slow as to affect the steel temperature by very, very little.

The core collapsed first, atleast in the North tower. Also, we're told that the buildings probably could have stood indefinitely if it hadn't been for the fire. So while the plane certainly helped weaken the structure, it was the heat (we're told) that made it collapse. Therefore it would seem that the temperatures in the core should have been at or near their highest at the point of collapse...yet I don't know of any fuel present in the core that would be burning long enough and hot enough for this.

(NOTE: I'm not saying the fires weren't hot enough, I'm saying I can't imagine what fuel would be responsible for such fires in the core)

I really get sick of hearing FIRE did all this to the building, when it simply isnt true.

They're were no raging infernos, at all!

Fact*1: There were metallurgy test done by NIST's own Frank Gayle, the project leader of WTC Investigation;NIST Metallurgist. He was the leader of project 4 out of 8 projects. Basically, he done the analysis of the steel directly from the impact zone and ground zero.
NIST "None of the recovered steel samples showed evidence of exposure to temperatures above 600 degree C for as long as 15 minutes."
Nist Page 180.

Fact*2: Within the investigation of the recovered steel, Frank Gayle's group performed a paint defermation test which showed how paint would curl or change in a certain temperature range. So they took the samples and analized them to see what kind of temperature they were exposed to by looking at the paint. Less than 2 percent of the samples which have been pulled specifically from the fire zones, despite pre-collapse exposure to fire less than 2 percent seen temperatures of 480 degrees F* which is very low relative to the temperatures to "soften or melt" steel.
NIST page 181" Only three of the recovered samples of exterior panels reached temperatures in excess of 250 degrees C* during the fires or after the collapse. This was based on a method devoloped by NIST to characterize maximum temperatures experienced by steel members through observations of paint cracking."
Fact*3:"NIST contracted with Underwriters Laboritories to conduct test to obtain information on the fire endurance of the trusses like those in the WTC towers. NIST P. 142" "All four test speciments sustained the maximum design load for approximately 2 hours without collapsing."NIST p.143 Big Red Flag.

Fact*4: NIST P.143 " The results establish that this type of assembly was capable of sustaining a large gravity load,without collapsing, for substantial periods of time relative to the duration of the fires in any given location on Sept 11th. "

however, these columns represented only 3 percent of the perimeter columns on the floors involved in fire and cannot be considered representative of other columns on these floors.
Source

And you see that core, the core didnt topple over as you would expect, but instead it collapses straight down as if it had been cut. Fire cannot produce this kind of phenomenon. The other alternative is explosives, to get that core to do exactly what it did, they would be needed. Cores dont collapse straight down so neatly as you saw, show me an model where fire can produce that same effect on a core.......something else was taking place for this core to just drop to dust.

Before disappearing from view, the upper part of the South tower was seen to tilt signif-
icantly (and of the North tower mildly). Some wondered why the tilting (Fig. 1d) did not
continue, so that the upper part would pivot about its base like a falling tree (see Fig. 4 of
Ba·zant and Zhou 2002). However, such toppling to the side was impossible because the hori-
zontal reaction to the rate of angular momentum of the upper part would have exceeded the
elasto-plastic shear resistance of the story at least 10.3x (Bazant and Zhou 2002).
Source

Do you know what is fuelling those fires, HL?

HeyLeroy:

A consequence of the 2nd law of thermodynamics is that heat always transfers from an object with a higher temperature to one with a lower temperature, and never in the opposite direction.

You say that the core reached higher temperatures than the perimeter, and this is only possible if the source of high temperatures is coming from the core itself. The perimeter fires could not make the core hotter than the perimeter itself, that violates a law of thermodynamics.

So while the perimeter fires could have "insulated" the core and slowed the rate of cooling, they could not have contributed to the high temperatures in the core unless those temperatures were, in fact, less than those of the perimeter.

But this does not appear to be the case. W'ere told the collapse was due to the heat weakening the already damaged structure, and the location of critical weakening was in the core.

So the question remains: what fuel was making these high temperatures in the core? (and what evidence is there for the existence of higher core temperatures?)

There's one possible "out" I can think of: while the critical weakening was in the core that critical weakening was not due to it having a higher temperature, but due to too much load being transferred to them from the heat-weakened perimeter columns. You'd have to concede that the core didn't have higher temperatures, and it begs the question: is this possibility supported or contradicted by the findings of the investigations?

I'm not sure I understand what you're trying to say there; could you possibly mean "So while the perimeter fires could have "insulated" the core and slowed the rate of cooling, they could not have contributed to the high temperatures in the core unless those [core] temperatures were, in fact, higher than those of the perimeter."?

The type of structural steel used in the Towers loses roughly 85% of its strength at temperatures of only ~600°C.

It is known that structural steel begins to soften around 425°C and loses about half of its strength at 650°C.

...

Even with its strength halved, the [WTC] steel could still support two to three times the stresses imposed by a 650°C fire.

http://www.tms.org/pubs/journals/JOM/0112/...Eagar-0112.html

Why couldn't it be, as the NIST report asserts, a combination of the two factors?

To tell how hot the fires actually got i think you need to look at the smoke. If the fire was to reach those temperature the smoke would have to be pretty 'clean' surely?

Im sure someone else will be able to explain this better (AUL).

Let's say (for the sake of argument) that office material (desks, computers, filing cabinets, copiers, etc.) was fairly evenly distributed across the floors. Let's not take into account any bulldozing effect the planes may have taken while crashing, which may have pushed more material up against the floors. If the flammables were evenly distributed, and all was on fire, the heat would radiate outward from the centers of the fires, no? This leads me to postulate that the centers of the fires (around the cores) reached higher temperatures than the peripheries (where heat was radiating away).

Thank you AUL, i new i could rely on you Nice post.

I'd like to see your source for that. It contradicts what I've heard in the past:

I think this thread sheds some light on my theories....those buildings were imploded...the fire wasnt hot enough; and the physics dont make sense.....

Give me a break.

Once again AUL brings up a strawman. And once again I'll say that we don't believe fire alone brought the buildings down.

Sorry, AUL, but I'm going choose to not respond to you until you can speak to me without flamebaiting.

I'm trying to adhere to the new rules of this forum, and I'd appreciate it if you could make the same attempt.

Let me point out, you "debunkers" dont believe fire is "the only factor" which contributed to the buildings collapse

but you all DO believe fire is the sole cause of the collapse.

There can be many different factors working together which could have caused the buildings to collapse,

but inevitablely the "1st cause" of those causes contributing to the collapse in the first place is FIRE!

In another words, fire is the main support column of the official story's argument, there is no way around it.

You all believe the initial impact cut through core of the buildings, dislogged the fireproofing, caused a RAGING INFERNO inside the towers which weakend or melted the steel which later caused the floors to sag then trusses to buckle, then eventually the buildings collapsed

So as I pointed out, yes you all do believe fire is the sole cause of the collapse.

uh....no. The damage from the planes happened before the fires. So, the "first cause of those causes contributing to the collapse" would be the damage from the planes.

QUOTE
In another words, fire is the main support column of the official story's argument, there is no way around it.


No matter how you word it, you still can't take away the fact that I believe the damage from the airplanes (and the damage from the collapsing tower) was a significant contributing factor of the collapses.

After first describing the highly redundant structural system that kept the 110-story twin towers standing for decades despite hurricane-force winds and a terrorist truck bomb, the engineers then delineated how that system was breached and finally overcome on that fateful day when America was attacked. The main culprits in bringing the famously lofty buildings down, they concluded, were the two intensely hot infernos that erupted when tens of thousands of gallons of aviation fuel spilled from the doomed airliners. Once high temperatures weakened the towers' supporting steel structures, it was only a matter of time until the mass of the stories above initiated a rapid-sequence "pancaking" phenomena in which floor after floor was instantly crushed and then sent into near free fall to the ground below. Significantly, the panel stated that any mitigating reinforcements and redundancies added to these buildings could have only delayed the inevitable failure, though they would have bought more time for the evacuation of the occupants. No existing or foreseeable economically viable skyscraper structure, they agreed, could have withstood this kind of cruel onslaught. Clearly, prevention is the best defense against this kind of assault.