The 9/11 Forum

User "AlreadyPublished" on 911blogger claimed, about a month ago, that the pressure pulses that could be seen along the North and East facade of WTC 1 during the impact of UA175 into WTC 2, were synchronistically timed explosions. I invited him to this forum but he refused, citing earlier encounters here that were somehow unsatisfactory.

I told him:

Could you tell me exactly why the pressure pulse from the massive fuel-air explosion from the impact of UA 175 could not be responsible for the observed phenomena?

Because I see no compelling reason whatsoever why I should believe anything else at this point.

To which he replied the following:

Yes I can, 6 times!

1) a pressure pulse will push things, not pull.

2) the classic air-fuel explosion typically requires dispersal of the fuel in a mist over a large area prior to ignition, and that is not what occurred.

3) a flash immediately precedes ejection of black smoke from a new area:


4) the smoke peeling upwards in regions above and surrounding the puffs is unaffected, and

5) a flame blows out a window on the opposite face, while the smoke peeling upwards on that side remains unpulled:


6) the jet-fuel explosion hasn't even had a chance to expand before these thing occur:


small frames from Xenomorph911WTC's compilation on the subject:
http://www.youtube.com/watch?v=aYwW3o4-Ztk

Now, w.r.t. (6), this is a still from Xenomorph911WTC/Nate Flach's compilation, which starts with an interview with FDNY luitenant John Schroeder, proceeds with one angle and a replay with zoom, another angle and a replay with zoom, and then arrives at the clip the still is taken from.

This clip, like many, is filmed from a worm's eye perspective in relation to the WTC, and a building is blocking the view of the camera. The clip following it is similar in perspective and location, including a building blocking view. In all cases, the objective is to make it look like the protruding flame on the west facade is succeeded, not preceded, by the impact of UA 175, thereby probably eliminating a causal relationship.

Yet, (6) can be quickly dealt with: in this other compilation by Nate Flach:
http://www.youtube.com/watch?v=EFiEgwLQVJk

The third clip in this compilation is labeled "3. CBS LIVE (CBS What We Saw DVD)" by Justin Keogh, and shows that the fire expulsion does occur simultaneously with, or shortly after UA175 impact.

So, eliminating (6), (1) through (5) remain.

Any comments/ideas? What are the characteristics of a fuel/air explosion? Will it pull, then push? Is there any literature on the subject?

Great questions and thanks for posting it here.

Here is the Xenomorph clip with the best views of the phenomena.
http://www.youtube.com/watch?v=aYwW3o4-Ztk&feature=related

I don't believe #6 can be explained so simply.

Important to note that the small 98th fl NW corner ejections are along the same elevation that the corner later fails.

The smoke ejections are not due to the fireball but due to the airplane impact. The massive kinetic energy of the airplane (130 tons, 252 m/s, 1 ton of TNT equivalent) being transfered into other forms of energy.
The airpressure at the windows of WTC2 IZ must have reached at least 3 kPa or higher, the shockwave then reached those windows in less than a 1/3 of a second after the impact.

Any blasting that synchornized would be technically impossible, you simply can not guess the right time. Anyway, there were no visible changes right after the WTC2 impact..no hanging floors..nothing.

Good points. It's interesting. I would expect pulses that affects smoke and air to affect more than just a few isolated pockets.

If a pulse, I'd expect to see more evidence for it in the moving smoke. Some global effect.

MT, the gap between the rising smoke and the wall is so small that destructive interference of the shockwave occurs, those holes in the wall (broken windows) cancel this effect.

Nice comments.

Hi, SnowCrash. I've looked at these things before, but confess to not reexamining in light of the six points. Just want to offer some thoughts.

SnowCrash wrote:I invited him to this forum but he refused, citing earlier encounters here that were somehow unsatisfactory.

Odd. Encounters here?

1) a pressure pulse will push things, not pull.

There are a couple of things to consider.

The first doesn't matter so much. A pressure wave is a longitudinal wave of sinusoidal form. Typically there's rarefaction following compression in both sound waves and shock waves. An overpressure in atmosphere is essentially unbounded on the high side and clamped to zero at minimum, so the pure sinusoidal form need not apply to extreme overpressure events. As an overpressure wave (pulse, if you will) approaches, the pressure will "push" in the direction of motion and, as it passes, it will push in the opposite direction.

Which direction is the pressure wave coming from? Inside or outside? Have to know to define push and pull.

Air currents set up by deflagration both inside and outside the south tower can set up complex time-varying pressure conditions at perimeter locations on the north tower. Obviously. The buildings are connected underground and are standing next to each other in open air. There are both internal and external overpressures from the deflagration, the external one being fairly mild. There is external underpressure associated with drawing of air towards the fireball and the convection induced by rising heated air and combustion products. Even internally, a rarefaction wave can be present to briefly suck smoke back into windows, while another area is expelling.

3) a flash immediately precedes ejection of black smoke from a new area:

Flashes must always be taken against the backdrop of a perimeter which is nearly half glass. If a flash precedes a smoke expulsion on a wall exposed to sunlight, how can reflection from a broken pane be ruled out? An overpressure need not even be responsible for breaking the pane. If smoke follows immediately, there could be fire behind the window! Fire breaks glass, smoke follows. This is a natural circumstance which is to be expected here. In any particular case, one may believe otherwise but there should be some distinctive signature to separate from normal phenomena in a burning skyscraper.

4) the smoke peeling upwards in regions above and surrounding the puffs is unaffected

I've seen some localized action which seems bizarre. Maybe there's something to this aspect worth investigating further, but concluding "synchronistically timed explosions" seems a leap. It really reeks of already believing it was a CD based on no evidence, therefore there must be some evidence, somewhere, and the minutiae (little puffs and such) are being grasped as straws. Did minutiae really take down these behemoths, and NOT airplane impact and fires?

5) a flame blows out a window on the opposite face, while the smoke peeling upwards on that side remains unpulled:

The expulsion of 5 and 6... I believe this is an event which has coincident timing with the impact. What it is, I don't know. Is it random coincidence? Don't know. I'd like to know what happened there.

I've created an animated gif to explain why, in principle, I reject (6).

I think the animated gif speaks for itself.

Source: CBS LIVE (CBS What We Saw DVD) from:
http://www.youtube.com/watch?v=EFiEgwLQVJk
Download link: http://www.megaupload.com/?d=8SUE9579

Animated gif at: http://s941.photobucket.com/albums/ad257/snow__crash/?action=view&current=wtc_2_impact_wtc_1_alleged_explosion_animation_w_indicators.gif



Note that of course, I cannot reject (6) completely, because correlation does not mean causation, but I think it has been clearly established that AlreadyPublished's claim "the jet-fuel explosion hasn't even had a chance to expand before these thing occur" is deceptive because the video footage used to support the claim is inadequate and there is no basis for asserting that a (fireball from) a fuel air explosion should reach a certain volume before it can affect its surroundings in the first place. In fact, the footage used for this animated gif lacks a complete picture as well, so we can't know how long the fireball has been expanding before it creeps into view, and so we can't even approximate the t=0 point.

BTW, thanks for all the replies and such, kinda busy right now, figured getting this up took precedence before replying specifically. Cheers, bbl.

SnowCrash wrote:we can't know how long the fireball has been expanding before it creeps into view, and so we can't even approximate the t=0 point.

We can synchronise to another view to build the full picture for completeness.

Will sort it soon as I have time.

OneWhiteEye wrote:Nice comments.

Hi, SnowCrash. I've looked at these things before, but confess to not reexamining in light of the six points. Just want to offer some thoughts.

SnowCrash wrote:I invited him to this forum but he refused, citing earlier encounters here that were somehow unsatisfactory.

Odd. Encounters here?

The discussion starts about here:
http://911blogger.com/news/2010-09-14/wtc-employee-discusses-pre-911-power-downs#comment-237511

A little further below, he then says, after refusing an invitation here:

AlreadyPublished wrote:I didn't want to comment further.. but, the only "the911forum" I can find most likely to fit your reference (correct me if I'm wrong), is here:
http://the911forum.freeforums.org/portal.php

Topics per day: 0
Posts per day: 15 (?)
Users per day: 0

With Dr. G(reening) , David B. Benson, and "onewhiteeye" on the list of most prolific posters apparently not posting anymore, I'm not sure there would be much value in accepting your courteous invitation, assuming I am correct about the address that you neglected to include with it.
I already wasted a lot of time in a futile effort to extract plausible explanations from those same NISTorians - in 2006!

So... he labels you a "NISTorian". I haven't counted the number of times where your posts contradict NIST's positions, but I believe there are many, so if anything, this seems to be an expression of frustration not encumbered by any knowledge of your writings. Ditto for Dr. G, given his vocal dismissal of the WTC 7 report, can't say I know the exact viewpoints of David Benson.

He may still decide to come here, but I wasn't going to settle for his no show. The issue deserves to be discussed in depth, because otherwise it's obviously going to be promoted by some without much real scrutiny.

Thanks for your technical explanations, I need to meditate on that for a while.

I'm currently of the opinion that the expulsions are somehow caused by the impact of UA175, but I'm not entirely sure how. And until I understand how, I'm not entitled to claim this as factual.

It has been known that thermobaric bombs can suck to a near vacuum the surroundings they are dropped on. They are also said to deliver large pressure fronts. So I'm looking for data or publications that investigate the over/underpressure effects of fuel-air explosions for application here... in other words: what are the effects to be expected from UA175's fuel-air explosion and can they account for the smoke/fire squibs? And if they can, then why do we see selectivity in the locations of these effects?

femr2 wrote:

SnowCrash wrote:we can't know how long the fireball has been expanding before it creeps into view, and so we can't even approximate the t=0 point.

We can synchronise to another view to build the full picture for completeness.

Will sort it soon as I have time.

Hmmm, thanks, that would be awesome. Do you actually think you can do it based on that austere, cropped material from CBS?

SnowCrash wrote:Do you actually think you can do it based on that austere, cropped material from CBS?

For sure

SnowCrash wrote:The discussion starts about here:

Thanks, that puts it all together. I guess AlreadyPublished is MMC at physorg. That was a pretty rollicking place back then, but I didn't post at the time.

So... he labels you a "NISTorian".

That's pretty humorous.

I haven't counted the number of times where your posts contradict NIST's positions, but I believe there are many, so if anything, this seems to be an expression of frustration not encumbered by any knowledge of your writings. Ditto for Dr. G, given his vocal dismissal of the WTC 7 report, can't say I know the exact viewpoints of David Benson.

I don't think AlreadyPublished is talking about me, the run-ins were undoubtedly with Greening and Benson (or adoucette and Grumpy!). I don't argue NIST with people, except to screech at stinking apologists once in a while, so it can't be me. Dr. G is no fan of NIST. DBB has made extensive use of the material in argumentation, I'm sure - but a lot of people do, even people who've taken the time to rigorously challenge specific points in NIST reports. It's probably not all crap. It's X-ty thousand pages of "fire brought three buildings down".

Several members here have looked closely at one or more aspects (including Dr. G) and have come to different conclusions than NIST, or are at least able to cast doubt or raise legitimate questions. What can be bad about that? Why come to a dead forum? Why would a forum want dead people? Sometimes numbers don't tell the whole story.

He may still decide to come here, but I wasn't going to settle for his no show. The issue deserves to be discussed in depth, because otherwise it's obviously going to be promoted by some without much real scrutiny.

A lot of things are. Most.

Thanks for your technical explanations, I need to meditate on that for a while.

You're welcome. Nothing new there. From the 911blogger discussion you linked, it seems AlreadyPublished has faced some of these and still believes otherwise. Any anomalous puff or ejection could be a sign of something. There are events and actions without easy explanation, some will probably remain unexplained no matter how much effort is applied. adoucette at physorg tried to tell me the expulsions racing down the SW corner of WTC1 might have been due to 'industrial solvents' stored on the mechanical floors (or perhaps in office supply cabinets). Really. There's lack of imagination and then there's too much, the middle road seems to work better but one often has to be satisfied with no answer.

I'm currently of the opinion that the expulsions are somehow caused by the impact of UA175, but I'm not entirely sure how. And until I understand how, I'm not entitled to claim this as factual.

Very sensible. The thoughts I offered above are only thoughts, any or none might be the explanation.

...in other words: what are the effects to be expected from UA175's fuel-air explosion and can they account for the smoke/fire squibs? And if they can, then why do we see selectivity in the locations of these effects?

Good questions. Familiar with exhaust headers?

The idea behind an exhaust header is to eliminate the manifold's back pressure. Instead of a common manifold that all of the cylinders share, each cylinder gets its own exhaust pipe. These pipes come together in a larger pipe called the collector. The individual pipes are cut and bent so that each one is the same length as the others. By making them the same length, it guarantees that each cylinder's exhaust gases arrive in the collector spaced out equally so there is no back pressure generated by the cylinders sharing the collector.

Point being there is the possibility of over/under pressure with resonance effects, different path lengths through the interior and exterior, reflections, and so on. As peterene1 pointed out, there is an enormous amount of energy liberated. Ruling out impact as cause would seem to be pretty difficult. Like Major_Tom, I have reservations about #6 being impact-caused, but not because it precedes the impact (as you showed, that seems not to be the case anyway). Given that, what's a few more oddball puffs?

'nough said