Tuesday, March 8, 2011

The World Trade Center WAS a Controlled Demolition

Back in February of 2009, debunker Mark “Gravy” Roberts announced that the “9/11 ‘truth’ movement has dried up and blown away,” and that he wouldn’t be adding anything new to his site “unless big news arises.” Some of the “big news” Roberts last added was an honest mistake made by a contributor to this blog. Roberts had not added anything since March of 09, which is odd considering that two years worth of big news has occurred in the 9/11 truth community.

Well, after almost two years, Roberts has finally added something new to his site. He has uploaded an old video he made back in 2007 called “WTC Not a Demolition,” which is currently available at 911myths.com. He claims that his video “shows how absurd those claims (about controlled demolition) are from an audiovisual standpoint.” After reviewing his video myself, I have found that this claim is not even remotely true. Many of the arguments Roberts makes in his video are addressed in my extensive critique of the 9/11 Mysteries Viewer’s Guide. His video presents itself as offering sound refutations to controlled demolition theories. Here I will show that his video amounts to nothing more than petty insults and half-baked arguments. To address each section, I will use the video’s online index.

• 01:10 South tower inward bowing of exterior wall, no smoke-disturbing detonations precede collapse

The first section of Roberts’ video deals with the inward bowing of the South Tower’s perimeter columns. He claims that the ejections of debris we see coming from the building only appear after the collapse began. Based on this, he asserts that this proves that the ejections are being caused by the collapse and not vice versa. First of all, we have videos of ejections coming from the WTC before the collapse begins here and here. Second off, this argument about the inward bowing highlights a fundamental error Roberts constantly makes throughout his video: he assumes that the Towers would have been set up and executed like a traditional demolition. This shows his obvious ignorance of the possibilities of a covert demolition scenario that may have been set up for the buildings. Jim Hoffman has outlined a scenario where the inward bowing of the Towers’ columns would not only have been part of the demolition scenario, but also would have been an essential element:

Excerpt from “A Hypothetical Blasting Scenario: A Plausible Theory Explaining the Controlled Demolition of the Twin Towers Using Aluminothermic Incendiaries and Explosives with Wireless Ignition Means

Stage 1: Thermate Melts and Corrodes Core Steelwork

During Stage 1, extending from up to 10 minutes before T-0, thermate coatings on key parts of the core structure steelwork are ignited via the wireless ignition control system. The two areas attacked are: the core columns on a few floors below the crash zone, just above where most of the columns transition from box columns to wide-flange beams; and the inner portions of the hat truss that connect it to the core.

The thermal/corrosive attack on these two portions of the structure leaves the entire block of the core structure above the upper mechanical equipment floor "floating", with no major steel members to transfer its gravity loads to the lower portion of the core or to the perimeter walls: it is now supported by the web-trussed floor diaphragms. The upper core block now exerts massive inward forces on the perimeter walls due to the high degree of leverage involved in the translation of the core block's gravity loads into pulling on the perimeter walls. It is these forces that produce the inward bowing of portions of perimeter walls that NIST claims are due merely to the sagging of floor diaphragms still supported by the core.

As Hoffman also writes in his essay, “A key objective is to get the top of the Tower to move before explosive action is clearly evident to onlookers outside the building.” Thus, engineered in the correct way, the inward bowing of the Towers’ perimeter columns could very well have been an essential element in initiating the collapses.

• 01:53 South tower fake collapse audio promoted by truthers as real

The next section of Roberts’ video deals with the audio of the South Tower’s collapse. He shows a video of the collapse with fake audio and claims truthers have used this video as evidence. While the audio in that video is clearly fake, new videos of the WTC collapses have been released through FOIA requests, and show that explosive sounds are clearly audible.

• 02:32 What actual explosive demolitions look and sound like

Roberts then proceeds to show a long series of demolitions to emphasize how loud traditional demolitions are. Again, Roberts makes the error of assuming that the Towers were set up as traditional demolitions. The “sounds of explosions” issue has been raised by numerous debunkers. Before addressing the sound of the Towers’ collapses, let’s first look at how relevant the sound issue actually is.

According to the NFPA 921 Guide, the actual “sound” of an explosive does not define an explosive event.

Although an explosion is almost always accompanied by the production of a loud noise, the noise itself is not an essential element in the definition of an explosion. The generation and violent escape of gases are the primary criteria of an explosion. –NFPA 921 Guide, Chapter 18 - Explosions, 18.1

Therefore, by the standards of the National Fire Protection Association, the “sound” of an explosion does not define an explosion. This of course makes sense, as sound evidence would technically fall under the category of witness evidence, as sounds have to be attested to by witnesses in an investigation. What should be tested for is the forensic evidence for explosives. NIST has admitted numerous times that they never tested for residues of explosives or incendiaries, and they dismissed the idea of explosives being used based on the “sound” argument.

“Was the steel tested for explosives or thermite residues?”

NIST did not test for the residue of these compounds in the steel.

“Did investigators consider the possibility that an explosion caused or contributed to the collapse of WTC 7?”

Yes, this possibility was investigated carefully. NIST concluded that blast events inside the building did not occur and found no evidence supporting the existence of a blast event. In addition, no blast sounds were heard on the audio tracks of video recordings during the collapse of WTC 7 or reported by witnesses.

If other investigations were carried out by NIST and Roberts’ standards, then the police would have to rule out being shot as a cause of death if nobody hears a gunshot, even if the person has a very obvious bullet wound.

Even with videos that have the clearest audio from 9/11, it is probably still hard to appreciate just how loud the Towers’ collapses really were without actually being there. Although we cannot be sure of exactly how many types of explosives were used, we have evidence of one explosive: nanothermite. The authors of the Active Thermitic Material paper mention that in April 2001 the American Chemical Society held a symposium on the defense applications of nanomaterials in which they stated:

At this point in time, all of the military services and some DOE and academic laboratories have active R&D programs aimed at exploiting the unique properties of nanomaterials that have potential to be used in energetic formulations for advanced explosives…. nanoenergetics hold promise as useful ingredients for the thermobaric (TBX) and TBX-like weapons, particularly due to their high degree of tailorability with regards to energy release and impulse management.

The authors then go on to point out that:

The feature of ‘impulse management’ may be significant. It is possible that formulations may be chosen to have just sufficient percussive effect to achieve the desired fragmentation while minimizing the noise level.

In other words these materials, in any form that they are used, are perfect for covert demolition in which one would want to reduce the loud pops of conventional demolitions.

Of course, other types of explosives could have been used, and explosive sounds would probably not have been 100% preventable. However, Jim Hoffman has suggested a way that the demolitions would not have produced distinct explosive sounds.

Regardless of what Roberts believes, the collapse of the Towers produced enormous explosive sounds that could be heard miles away.

• 06:17 North tower audio deception in Loose Change

Roberts then proceeds to take issue with a video of the North Tower’s collapse in the film Loose Change. While I agree that the shaking was not caused by some pre-collapse explosion, explosive sounds can be heard in videos of the North Tower’s collapse.

• 07:24 "I heard a bomb" – witnesses using figures of speech to describe loud sounds. Includes interview with Hursley Lever, witness to the north tower elevator shaft fireball.

Roberts’ video next goes on to examine the issue of the witness testimony of explosions on 9/11. He claims that out of all the testimonies he’s examined, only 11% described the Towers’ collapses as explosions. However, Graeme MacQueen has estimated a higher percentage:

I do not know whether the FDNY witnesses constitute a representative sample of 9/11 witnesses, but it is possible that they do. Certainly, there is no lack of testimony to explosions from those outside the FDNY, and I see no obvious reason why firefighters and medics would be more prone than others to feel that they were witnessing explosions. If they constitute a representative sample, then a minimum of 23% of all witnesses to the Towers’ collapses appear to have perceived, or thought they perceived, explosions that brought down the Towers.

The common objection to MacQueen’s analysis is that he has taken numerous testimonies out of context. However, MacQueen has addressed these objections. Roberts also shows the testimony of Hursely Lever to demonstrate that truthers use some testimonies of witnesses who are using a figure of speech. Still, this is only one person’s testimony, and numerous other witnesses are quite clear about what they heard. He also shows a crane collapse as evidence that non-explosive events can produce explosive sounds. Again, none of the objections Roberts has raised warrants refusing to test for explosive residues. As stated by firefightersfor911truth.org:

Explosion sounds can be explained away. But, only after a thorough investigation. When there is this much witness testimony, evidence, and explosive use by terrorists on this very same complex, there is no excuse for refusing to test for explosive residue.

• 09:35 Use and effects of steel cutter charges.

The next section of the video deals with how conventional demolitions are set up. Again, the Towers were obviously far from conventional demolitions. The demolitions of the Towers could have been set up in any way needed. That’s why it’s called a CONTROLLED demolition.

• 11:55 A few pounds of cutter charges = huge boom and flash.

Roberts then expands on this point by showing how explosive demolitions create loud explosions and bright flashes. We have already covered how the sound levels could have been decreased, and that witnesses did report enormous explosions that could be heard for miles. And the fact of the matter is that flashes have been found in videos of the South Tower’s collapse. But this is an irrelevant point, as bright flashes do not always occur in controlled demolitions.

Roberts also raises the point about how many pounds of explosives would have been needed to demolish the Towers. However, as civil engineer Jonathan Cole has demonstrated, a minimum amount of thermite/thermate could have been used, even when it has not been formulated to be explosive.

• 13:16 Structural Engineer, collapse expert, and Weidlinger Associates WTC investigator Matthys Levy on conspiracy theories

Roberts then decides to reference Matthys Levy and the Weidlinger Associates investigation. This may not be the wisest decision, as the Weidlinger report strongly contradicts the NIST report on the collapse of the WTC.

Roberts also claims that truthers have misrepresented the size of the fires in the Towers. Roberts claims “Conspiracists like to claim that the fires were almost out just before collapse.” For someone who accuses people of misrepresenting others’ claims, Roberts does a fine job of doing that himself. What most in the Truth Movement claim is that the fires in the SOUTH Tower were almost out before collapse. And videos and photographs confirm this. Roberts believes the explosives wouldn’t have been able to survive the plane impacts and the fires. This is also false.

• 14:37 North tower "squibs" compared to explosive blasts

The next section of Roberts’ video deals with the squibs from the Towers. He asserts the dubious claim constantly repeated by debunkers and NIST that these squibs were simply air pressure ejected from the Towers. He points to one squib and claims that it is not blasting out, but flowing out of the building. However, squibs can eject from buildings at varying speeds, depending on how the gases are ejected from the explosives. Also, this one squib should not be representative of all the squibs from the Towers, as physicist David Chandler has shown that several of these ejections did shoot out of the building the exact way explosives behave, starting out strong and then loosing speed.

Also, careful calculations done by Dr. Crockett Grabbe show that the horizontal ejection rate of these squibs is disproportional to the vertical fall rate.

The video frame in Figure 4 of the World Trade Center North Tower taken by KTLA channel 5 news shows a "squib" -- a line of ejecting material from the tower -- right before it collapsed. Such squib ejections are driven by massive overpressure inside the building relative to the atmospheric pressure outside, and that overpressure is created by explosions. A number of squibs were observed coming from all 3 of Buildings 1, 2, and 7 a short second or 2 after each one started to collapse, and there are several websites that show photograph of them on all 3 buildings. The one displayed as Figure 4 shows ejecting material (bits of material large enough to have little air resistance) streaming out of the North Tower, which has traveled a distance from the tower in the horizontal direction, whereas the distance it has descended in the vertical direction because of gravitation pull is small.

Note the quantitative information that can be gathered from the ejection photograph in Figure 4. We can estimate that, at the front end, the ejecting plume has apparently fallen no more than roughly 3 feet (an estimate that might have up to a factor of 2 in error), whereas the horizontal distance of the front from building is about 1/3 the width of the North Tower, or about 70 feet. If we neglect air friction resistance over the length of the streamer, from fall distance s=0.5gt2, where g=32 feet/sec2 is the gravitational acceleration, we estimate 0.43 sec as the time since the front end first ejected from the building. That means that material in that squib is traveling horizontally at roughly 163 feet/sec, which means the squibs are effectively "bullets" of bits of material produced by the explosions.

Roberts also references calculations done by Dr. Zdenek Bazant et al to explain away the squibs. Kevin Ryan, in his comprehensive analysis of the squibs, has this to say about Dr. Bazant’s calculations.

Bazant, Le, Greening and Benson estimated the velocity of escaping air to be as high as 340 m/s, or 1100 fps. Of course they were trying to establish an argument for the bursts having reached the speed of sound, in order to explain away the witness testimony to explosions.

Several refutations of Bazant’s work have been published by members of the Truth Movement.

• 16:52 Explosive demolitions eject debris, sometimes dangerously.

At this point Roberts asserts that explosives would have caused shrapnel to be ejected everywhere out of the Towers at high speeds. He claims that explosives powerful enough to destroy the Towers would have done this. However, as even his video shows, there are ways of preventing that from happening. One of the ways this could have been prevented is by limiting the areas attacked by explosives in the Towers. Mechanical engineer Tony Szamboti has suggested that the two main sections of the Towers that were attacked were the outer core columns and the corner perimeter columns.

This could very well have limited the amount of small debris ejected far and fast. Regardless, Dr. Grabbe has shown evidence that much of the debris from the Towers was ejected great distances.

A table below summarizes some typical values of α for various material parameters.

Table: Values of α for selected material parameters




Solving (1) for v(t) by separation of variables yields the downward velocity vd and downward distance y:

(4) vd(t)= (g/α )1/2 tanh [(g α )1/2t]

(5) y(t) = (1/α) ln cosh [(g α )1/2t]

So where does this squib material hit the ground? If we take y to be the height of the ejection, we can solve the last equation for t, the time the material remains in the air. Multiply that t by the horizontal velocity vh of the squib material, and we have the horizontal distance x it travels. The equation of motion for the horizontal movement of the material is:

(6) a = dv/dt = - α v2

which solves by separation of variables, yielding:

(7) vh(t)= vo/(1 + α vot)

(8) x(t) = (1/α)

ln (1 + α vot) where vo is the velocity of initial ejection from the tower. Taking t to be the time the material remains in the air from (5) (solving for t after setting y=h) gives x(t) = xhit, the distance the material travels away from the tower. Graphs of that distance xhit versus the α for the material are shown in Figures 5 and 6 for ejections from about 1304 feet (400 meters) and 489 feet (150 m).

Thus, Dr. Grabbe shows that much of the material from the ejections would have been shot out up to 1/4 mile or more from the Towers.

• 18:05 Les Robertson, Twin Towers head engineer, on conspiracy claims

Roberts proceeds to quote WTC engineer Leslie Robertson and his objections to the idea that the Twin Towers were demolished. Gregg Roberts has addressed Robertson’s statements.

ROBERTSON: …I've not participated in the NIST Report directly, although of course I've read it, as have thousands of other structural engineers and other interested persons.

GR: Robertson offers no evidence to support this claim about how many people have read the NIST report. NIST published about 10,000 pages about the tower collapses. The Summary Report itself took up 248 pages plus 43 pages of front matter. Jim Hoffman’s critique of the Report notes that the Summary Report flatly contradicted some of the most important evidence presented deep in the 10,000 pages. Whistleblower Kevin Ryan calls all this the TiNRAT approach: “They’ll Never Read All This.”

Note the compound category, in which the relative numbers for the two categories of people who have read the Report are not provided. Maybe it’s three structural engineers and thousands of 9/11 skeptics! But as usual throughout the interview, we’re supposed to believe this because of who Robertson is and because he speaks confidently, rather than because of evidence and logic.
He is clearly implying that if only a few engineers have publicly challenged the official story, they are unlikely to be right. The idea of taking a majority vote of experts appeals to Americans’ sense of democratic values, but it has absolutely nothing to do with who is more likely to be right.

ROBERTSON: But the collapse mechanism of the Trade Center is as we had anticipated it would be when we first designed it. It was not – please don't misunderstand me – it was not designed to collapse. But any prudent engineer looking at the future has to think about, what are the mechanisms that cause collapse, and how to go about strengthening the building so as to minimize that circumstance. So sure, we spent time looking at that kind of event, and that which was observable from the photographs and so forth is reasonably consistent with that which we thought would be the case.

HOST: Why did it fall so straight down?

ROBERTSON: Well, that's kind of the nature of that kind of failure.

GR: This statement is reminiscent of the pre-scientific Aristotle: "It's in the nature of things to fall.” Throughout this response (continued below) Robertson says “uh” and makes other stuttering sounds and false starts more than in any other statement during the show. He misspeaks, saying that burning a sofa creates smoke capacity.

• 19:35 WTC 7: deceptive claims made by conspiracists, collapse expected by media

After almost 20 minutes, Roberts finally addresses the issue of World Trade Center 7. He starts out by showing a clip from Loose Change that compares the collapse of WTC7 with a controlled demolition. Roberts criticizes this part of the film because the audio of the demolition was omitted. Again, we have already addressed the sound issue. And as it turns out, David Chandler has found evidence of explosive sounds preceding WTC7’s collapse in the very video Roberts uses to claim that no explosions were heard.

Roberts then criticizes Dr. Steven Jones and his claims about squibs ejecting from the building. While I agree that the southwest corner of WTC7 showed no ejections, the north side of the facade clearly exhibited ejections of dust and debris. Of course, Roberts simply hand waves away any ejections from the building, claiming that it was due to… you guessed it. Air pressure. However, any pulverized debris would not have been formed until the building had already collapsed to that level. And the ejections could not have been smoke from the fires since, according to the NIST report on WTC7, the fires never reached that level of the building and the sprinklers were working on the upper floors. Also, the smoke from the lower floors could not have reached that level of the building, according to the FEMA report.

Concrete floor slabs provided vertical compartmentalization to limit fire and smoke spread between floors. -FEMA report, section 5.3.3

Roberts also makes issue of the east penthouse collapsing into WTC7, not realizing that the collapse of the penthouse is problematic enough on its own.

By simply selecting these few issues concerning WTC7, Roberts conviently ignores several other characteristics of the building’s collapse that point to demolition, including:

• The collapse started from the bottom.
• The onset of the collapse was sudden.
• The collapse was total.
• The building fell in a near-symmetrical fashion.
• Its acceleration approximated that of a free-falling object.
• The debris from the building ended up in a fairly small pile almost entirely within its footprint.

These are all standard features of a demolition that Roberts makes no mention of.

• 22:48 FDNY Chief Daniel Nigro on conspiracist claims

This next part of Roberts’ video is simply a statement from Chief Daniel Nigro concerning his thoughts on conspiracy theories. This merely a person’s opinion, and addresses none of the scientific evidence which points to demolition.

• 23:00 Collapse of WTC 7 expected by all. On-scene account by FDNY firefighter Miller of Ladder 15, says building leaning, no way to fight fires, pull back from WTC 7

At this point, Roberts chooses to address the issue of the foreknowledge of WTC7’s collapse. He asserts that because the firefighters expected the building to collapse, the collapse was not unusual. However, Professor Graeme MacQueen has demonstrated that the foreknowledge of the buildings collapse is extremely suspicious. Also, any structural damage Building 7 might have sustained is irrelevant, as NIST claims that the fires alone brought the building down and that it would have collapsed even with no damage.

• 25:08 Brent Blanchard of Protec, who spoke with demolitions experts on the scene and documented the clean-up process, on conspiracist claims

Roberts then features a statement by Protec employee Brent Blanchard. Several of Blanchard’s claims about the collapse of the WTC have long been refuted by Jim Hoffman.

• 25:45 WTC 7 structural engineer Irwin Cantor on conspiracist claims

At this point of Roberts’ video, he shows a statement from Irwin Cantor, WTC7’s structural engineer. It’s important to note that Cantor makes no mention of “conspiracist claims.” Others have studied NIST’s claims about what caused the collapse and have found numerous problems.

• 26:00 New WTC 7: safety and structural features

Roberts then shows us a video about how the new WTC7 is being constructed. Regardless of whatever upgrades were given to the new WTC7, no building like the original WTC7 has ever collapsed from fire.

• 27:47 "Architect for 9/11 truth" Richard Gage gives presentation including audio deception

The video proceeds to criticize Richard Gage for using a video of a demolition with no audio. Again, we have already covered that the sound issue is explainable. If this is greatest flaw Roberts can find in Gage’s presentation, then he’s a long way away from debunking anyone.

• 28:36 AE911Truth and STJ911truth member and mechanical engineer Tony Szamboti claims Silverstein said WTC 7 was brought down for safety reasons, and claims the towers showed upward explosions.

Roberts then goes on to criticize Tony Szamboti for his claims about Larry Silverstein and the ejections of debris from the Towers. While there does appear to be no upward ejections from the Towers, there are outward and even downward ejections that are clearly smoking guns. As for Silverstein, I have never seen the program Szamboti is referring to, but we now have conformation that Silverstein did discuss demolishing Building 7 on 9/11. Roberts addresses none of Szamboti’s scholarly technical essays on the collapse of the Towers, and decides to simply attack some of his lesser claims.

• 29:49 Leading conspiracists claim pyroclastic flows resulted from use of mysterious explosives.

Roberts next criticizes members of the Truth Movement for claiming the huge dust clouds from the collapse of the Towers were “pyroclastic flows.” Again, here is an instance where I agree with one of Roberts’ claims. The dust clouds were clearly not pyroclastic flows, but they were extremely reminiscent of the types of dust clouds produced by controlled demolitions. As David Ray Griffin points out in his book Debunking 9/11 Debunking:

This is a common feature of collapses produced by explosives, as can be seen in videos of controlled demolitions of structures such as Seattle’s Kingdome and the Reading Grain Facility, which are available on the Web. The dust clouds produced at the Twin Towers differ only by being much bigger, which is what could have been predicted, given the fact that these buildings were much larger, so they would have required more powerful, and a greater number of, explosives. –Debunking 9/11 Debunking, pg. 188

Also, several members of the movement have only referred to the clouds as “pyroclastic-like,” including Richard Gage on his updated AE9/11Truth website.

• 32:49 Was all or most of the WTC tower concrete turned to a fine powder?

Roberts goes on to address one of the more controversial issues about the collapse of the WTC: the pulverization of the concrete. Admittedly, the pulverization of the concrete has been exaggerated by members of the movement. However, although the concrete was not completely pulverized, the concrete at Ground Zero appears to be very similar to concrete after a controlled demolition.



• 34:55 Conspiracists claim tons of explosives – or a sci-fi mystery weapon was used. Video of 100-ton TNT blast

Roberts then takes issue with the fact that the types of explosives Dr. Jones and others have suggested were used would not have pulverized the concrete anyway. However, this is not necessarily true. Given the moisture content of concrete, elevating it to a sufficient temperature would cause explosive spalling. If large quantities of aluminothermics such as thermate and nanothermite were used to sever structural members, the excess heat could have caused such spalling.

• 36:02 Steven Jones, David Ray Griffin, and Richard Gage can't make up their minds: explosives, thermate, or super-secret mystery weapons?

Roberts next proceeds to criticize members of the movement for claiming different types of explosives were used in the demolition of the Towers. As Roberts puts it they “can’t make up their minds.” However, Richard Gage has responded to these weak criticisms.

• 37:51 Tons of TNT equivalent were stored in the towers – gravitational potential energy

Roberts’ video then goes into the fact that there was already an enormous amount of energy in the buildings to begin with: gravitational potential energy. He claims that because the Towers fell at less than the rate of free fall, the buildings actually absorbed a huge amount of energy. However, this is the case in any controlled demolition. Buildings brought down with explosives rarely, if ever, fall at the rate of free fall and their collapses clearly absorb a large amount of energy. But according to the official reports, no explosives were used to demolish the Towers, so how did they collapse in time intervals consistent with controlled demolitions?

• 38:27 Mysteriously-expanding dust clouds? Alex Jones accuses, Jim Hoffman investigates.

The next part of Roberts’ video deals mainly with Jim Hoffman’s calculations about the expansion of the North Tower’s dust clouds. He claims that Hoffman did not take air pressure into account in his analysis. While Hoffman has acknowledged that his calculations are not perfect, he did in fact take air into account in his analysis.

Given that the Twin Towers' dust clouds behaved like pyroclastic flows, with distinct boundaries and rapidly expanding frontiers (averaging perhaps 35 feet/second on the ground for the first 30 seconds), it is doubtful that mixing with ambient air accounted for a significant fraction of their volume.

Note that Hoffman claims the clouds only behaved like pyroclastic flows, not that they actually were pyroclastic flows.

The idea that the falling debris could have caused the expansion of the clouds seems unlikely, as videos show that most of the debris hit the ground before the dust reached the ground.

• 41:05 So what caused THESE dust clouds?

Roberts next claims that the expansion of the clouds were not unusual because they happen in other controlled demolitions. Really. As we have already seen, this characteristic appears to be very consistent with explosive demolition.

• 43:05 Conspiracist papers published in engineering journals

This small section of Roberts’ video simply makes fun of the Truth Movement for not having any papers published in any science journals. However, the Truth Movement now currently has six papers published in peer-reviewed journals, with three of them being published in the Journal of Engineering Mechanics.

• 43:26 The conspiracists' best and brightest run from. a tour guide

At this point, Roberts simply makes fun of the fact that members of the movement have not debated him. First of all, Richard Gage has debated Roberts. But perhaps the reason that many in the movement aren’t debating with Mr. Roberts is because they’ve been busy debating with actual scientists.

• 44:34 AE911truth & STJ911truth website statistics graphed

Here Roberts ridicules AE9/11Truth and STJ9/11Truth for their low statistics online. This clearly is in no way representative of how many people question the official story of 9/11. Polls show a broad skepticism among Americans of the official story of 9/11.

• 44:55 Structural engineer and WTC investigator Gene Corley on conspiracist methods – or lack thereof.

Roberts then shows a video of Gene Corley claiming that the Truth Movement has no “engineering basis for its conclusions. Nothing could be further from the truth. There are currently over 1400 architects and engineers from around the world who agree we need a new investigation into the collapse of the three WTC skyscrapers.

• 45:40 Suggestions for study: Bazant, Greening, Mackey, Rogers

The last part of Roberts’ video simply suggests that people read the works of debunkers such as Dr. Bazant, Ryan Mackey, and Dr. Frank Greening, all of whom have been responded to.

Conclusions:

As I said at the beginning, Roberts’ video provides nothing more than half-baked arguments and petty insults. His video does nothing to answer the question of why those buildings really collapsed. Ultimately, I would say Roberts wasted his time putting this video back online, and that this misguided tour guide should really try to rethink his position.