The 9/11 Forum

Flash! Darkwing may have been right about entropy figuring into this, but not in some cracked imaginary way.

Of course I was correct lol!

There is nothing imaginary about matching theory to observation, that is how it is supposed to work. Every description of a physical system must obey the second law of thermodynamics at every level, but after that the correct theory to apply in a complex event is highly non-trivial, there are an infinite number of theories that may match any given observation at any given level of accuracy.

The problem lies in when you try to match observation to pre-selected theories. That is when the cracked imaginary things come in. Theories, you should recall, are things of our minds, physical systems NEVER obey physical laws as we formulate them. Physical laws are imaginary things conjured up match our observation physical systems which exist in reality. The universe no more obeys mathematical law than the spheres are actually producing musical harmony.

That is why physics is conducted on the basis of simple reproducible experiment and not on the basis of matching increasingly complex mathematical fomulae to half-known facts.

Lest I ramble...

The problem has always been this transition you speak of. You start with a semi-rigid block that first has to be broken up and then coalesce into a dense mass capable of performing a ROOSD style progression.

Actually there isn't even a problem with that, the way I see it.

The problem is this: Imagine you are pouring a lead bullet into a mold. The bullet is already liquid so it flows into the mold, increasing in density as it does so because the walls of container constrains its motion (assuming molten lead is compressible in this way for the sake of argument) and gravity forces it down.

So far so good, you now have your driver for ROOSD if you make the assumption that the fire somehow got the whole upper block to disintegrate completely and instantaneously so that it becomes quasi-liquid. As far as I understand it, this is OWE's concern.

But even if you grant this you have to contend the fact that our mold is being pushed open by the lead. The supposedly dense driver is splitting the sides of the mold, which in this case is the side of the building.

Once you observe that you can't assume that the bullet you are trying to pour will maintain it shape and density, like a hole in a damn wall it will prefer to spread and widen. This, essentially, is my issue.

If ROOSD was in fact occurring as the main driver you would expect the walls to be pulled inwards not shoved outwards. The fact that they are being shoved outwards indicates that the driver is expanding, flattening out like a bullet hitting a cinderblock and thus providing the lateral force. The fact that it is flattening out in the first place means that it isn't maintaning its shape in a through and through manner, nevermind coalescing. Put another way: A bullet fired straight downwards into a block of wood will lose energy and expand as it progresses.

(There is another, better, explanation for the lateral force, but it brings its own problems with the same result so I will ignore it here for the sake of simplicity).

So the question is, how can you keep the lead in the mold once the crack appears. How does the driver stay in the chute for ROOSD to be maintained once it starts providing this lateral force.

*Edit* It is, truth be told, possible that there is some amazing heretofore unobserved resonating dynamic equilibrium between the infalling material and the lateral force at the terminal velocity of the collapse.

But seriously postulating that means leaving the world of physics behind and entering the domain of absurdist pataphysics. As Russel said: "Whenever possible, substitute constructions out of known entities for inferences to unknown entities".

Such a supposed dynamic equilibrium falls well into the domain of unknown entities as far as I am concerned, since to the best of my knowledge such a thing has never been observed in a natural collapse of any kind.

DW,

You seem to have an problem with the fact that the destruction appears to you to be defined in discrete steps with ROOSD being on of them. There are no discrete steps I would contend but a process over time which when snap shotted (is that a word?) can show distinct characteristics and characteristics which are different from a earlier snap shot.

The initiating event for ROOSD would be to drop the required mass on a OOS floor and away it goes because the same mass plus 1 floor would then present to the floor below and so and and so on.

So can the kick off mass be aggregated from breaking the floor masses from the columns which support them? How would entire slabs be broken free? and then several of them one above (or below) so that the threshold mass is created to drive ROOSD? It seems unlikely that the pancake process could occur from natural fires. However we could assume that not all truss connections would have to fail for an entire slab to drop. Depending on the safety factor of the truss supports would determine how many of them could keep an entire floor in place. Clearly 1 or 5 or 10 out of 88 would not cause the floor to drop. But what would happen of 40 of them consecutive on one side for example. Could that cause that side to drop and then pull off the others ones? Or perhaps shatter the slab and a huge large chunk break free? Perhaps the threshold mass was created by the accumulation of local failures over multiple floors spread out over a larger or even the entire foot print resulting in a raining down of material causing local failures which accumulated to the threshold mass? Perhaps the kick off event was not a single event but occurred over the hour as the structure's connections failed leading to uploading of other connections which failed and so on... an increasingly rapid series of progressive failures which reach a tipping point and the upper structure "collapsed" and this mass became the threshold mass to kick off the ROOSD phase.

I don't know that this progression of failures leading to localized failures and then many of them reaching a tipping point can be observed as discrete steps. I suspect the process could be modeled, but it would be speculative. I suppose one could "prove" that, for example, if x number of beam stubs failed and Y number of core columns buckled... a progression of failures would occur and the top would come apart.

NIST tried to do that in bldg 7 by supposedly showing how the failed shear studs lead to the beams pushing a girder off its seat the floor dropping leaving columns unbraced which then buckled leading to more floor failures and so forth. They tried to match this hypothesis to the observations of the collapse of the East penthouse which was located above cc79, 80 and 81. The cause of all this was fire. This is very hard to buy, but if the cause was not fire but incendiaries and some explosives... could a progressive failure be kicked off? Why not? I am not saying how many engineered failures would be required... But I am saying that not every structural member had to be attacked by bombs and explosives for a structural failure to progress throughout the structure such that it can no longer stand.

So the ROOSD conundrum is not that it doesn't destroy floors, but what is the mechanism which creates the threshold for it to begin? What is the starter mechanism... Just like we use an electric motor battery driven to crank over the internal combustion engine to created the conditions where it can run on fuel... ROOSD start up is NOT ROOSD and likely doesn't even look like ROOSD. But it IS a part of and a kind of structural failure... lots of them.

Darkwing, welcome back! Things were getting a little quiet without you. Say, are you God? Or djinn? I mention "entropy" once and BAM there you are.

Darkwing wrote:Of course I was correct lol!

Have to give credit where credit was due. You brought entropy into this discussion, I don't recall anyone else having done so. My angle of attack is a bit different, as I believe you've noticed, but entropy may (should) figure heavily into this area.

There is nothing imaginary about matching theory to observation, that is how it is supposed to work. Every description of a physical system must obey the second law of thermodynamics at every level, but after that the correct theory to apply in a complex event is highly non-trivial, there are an infinite number of theories that may match any given observation at any given level of accuracy.

Agreed. Believe it or not, I've never sought to circumvent thermo, it's just that I believed the principles were well described by classical mechanics and could be dealt with in that way, even here with rubble. While that may be true, it occurs to me a different formulation may make parts of this easier, for wicked it is (not necessarily in the formal sense, but perhaps that, too).

The problem lies in when you try to match observation to pre-selected theories. That is when the cracked imaginary things come in.

Yes, true. Now I'd like to avoid stepping in the old dung. It may not have been obvious, but in our prior exchanges my contrarian role of defending someone else's theories was more about working on my chops than anything else. It was pre-selected, but not for purpose of adoption. Not ultimately. I don't know what happened, so it would be a little sleazy to pick a theory out of preference.

Theories, you should recall, are things of our minds, physical systems NEVER obey physical laws as we formulate them.

Yeah, I'm afraid that's going to work against the objectives of this thread, too. Difference is, it may be possible to supplement any analytical work with obviously meaningful physical experiment, not just simulacra. Could be fun.

Physical laws are imaginary things conjured up match our observation physical systems which exist in reality. The universe no more obeys mathematical law than the spheres are actually producing musical harmony.

Yes.

The problem has always been this transition you speak of. You start with a semi-rigid block that first has to be broken up...

For the record, I don't understand this process in WTC1. Not at the moment.

...and then coalesce into a dense mass capable of performing a ROOSD style progression.

Nor that. Not fully, anyway. The trash compactor requires a delicate dynamic equilibrium, too, but I see you're getting to that.

Actually there isn't even a problem with that, the way I see it.

I don't have a problem with it because I don't understand it. If I ever come to understand, to the point that it can be sorted into one of certain-likely-plausible-possible-impossible, then I might be willing to take a stand on something.

The problem is this: Imagine you are pouring a lead bullet into a mold. The bullet is already liquid so it flows into the mold, increasing in density as it does so because the walls of container constrains its motion (assuming molten lead is compressible in this way for the sake of argument) and gravity forces it down.

So far so good, you now have your driver for ROOSD if you make the assumption that the fire somehow got the whole upper block to disintegrate completely and instantaneously so that it becomes quasi-liquid. As far as I understand it, this is OWE's concern.

Yes.

But even if you grant this you have to contend the fact that our mold is being pushed open by the lead. The supposedly dense driver is splitting the sides of the mold, which in this case is the side of the building.

Yes.

Once you observe that you can't assume that the bullet you are trying to pour will maintain it shape and density, like a hole in a damn wall it will prefer to spread and widen. This, essentially, is my issue.

Time to get to it.

If ROOSD was in fact occurring as the main driver you would expect the walls to be pulled inwards not shoved outwards.

I very much lean the other way on this (pardon pun), mainly because there's a factor which wasn't present in your blocks experiment - the lateral bracing of the intact floors below. Out would seem to require less energy than in, on the whole, and if drivers exist for both directions but at different times, out can win. But I'm not sure, and it is an open question, and one I'd like to address in detail before coming to a conclusion. This is something which might be amenable to physical testing as well.

The fact that they are being shoved outwards indicates that the driver is expanding, flattening out like a bullet hitting a cinderblock and thus providing the lateral force.

Yes.

The fact that it is flattening out in the first place means that it isn't maintaning its shape in a through and through manner, nevermind coalescing. Put another way: A bullet fired straight downwards into a block of wood will lose energy and expand as it progresses.

Yes. One task will be to distinguish formally between systems which are cascading or dissipative with respect to energy available to do mechanical work in failing the structure.

So the question is, how can you keep the lead in the mold once the crack appears. How does the driver stay in the chute for ROOSD to be maintained once it starts providing this lateral force.

See next.

*Edit* It is, truth be told, possible that there is some amazing heretofore unobserved resonating dynamic equilibrium between the infalling material and the lateral force at the terminal velocity of the collapse.

Very perceptive. Aside from making 'resonating' optional, this is precisely the mechanism which might account for it. I leave open the possibility that a single transition is sufficient rather than a series of transitions as in resonance. The polarity shift and temporal component is still there, but it degenerates to a single half-pulse with temporal asymmetry providing the means to bias the final spatial direction. Note that I'm not implying the time asymmetry can induce broken spatial asymmetry; there would still be necessary conditions such as conservation of momentum. I only see the possibility that the final geometric distribution of mass might make sense in light of such a mechanism, as yet formally unspecified.

But seriously postulating that means leaving the world of physics behind and entering the domain of absurdist pataphysics. As Russel said: "Whenever possible, substitute constructions out of known entities for inferences to unknown entities".

No matter how absurd it may seem, if it can be so, it might be so. Let's not let our limited imaginations prematurely dictate where the boundary of absurd is.

Such a supposed dynamic equilibrium falls well into the domain of unknown entities as far as I am concerned, since to the best of my knowledge such a thing has never been observed in a natural collapse of any kind.

That's what I'm talking about. I've seen evidence of this in multiple domains, so it doesn't seem absurd to me at all. The question of whether it applies here is a major focus of this investigation. It may go nowhere. In all likelihood, that's how it will be.

SanderO, here's where I'm going to part company with you a bit. There is more to this problem than the binary decision of whether ROOSD (if preconditions are satisfied) can account for the observed final state of the pile, there is the matter of whether it can account for the time evolution of the system to its final state. It's true that Major_Tom has painstakingly listed the qualitative features which are in agreement (or appear to be) with the transient observables. The question is, is it consistent with all of them, particularly those more quantitative?

Not everything is directly observable. However, we know what the initial and final configurations are, plus a fair bit about what must be true at any given time (e.g. nothing above WTC1 NW corner after a given time, NW corner taken out at a specific time, perimeter peeling patterns, etc). Moreover, we can reason about the action of a granular media based on building contents and the fine work of the people in soil mechanics and the food processing industry, among others.

To be blunt, I have a hard time with a localized rubble driven collapse producing all that's seen. Incredulity is hardly an argument, though. I just want to get a true idea of the plausibility, not simply accept it because explosives are believed to be unnecessary. Perhaps the hypothetical perps didn't understand it wasn't necessary!

The particular action I have in mind, the race-ahead in the WTC1 SW corner, superficially looks like explosives. As you probably know, I am not a CD proponent, so I'm not looking at this with an eye towards demonstrating that it must be. Hardly. I doubt that's possible, anyway. From the mechanician's point of view, it is a condundrum which begs explanation. Even if this were indisputably known by all to be explosives-free, it would still be the same conundrum and still merit the same examination.

I may not be the one to do it.

If I put on my CD cap for a moment, it doesn't make a whole lot of sense from that perspective, either. Some, maybe; I suppose deliberate misdirection and obfuscation are unaccountable (I think I recently started a thread about that). Unlike most people, I'm content with not knowing, but only after a suitable hack at the problem myself.

OneWhiteEye wrote:.. it may be possible to supplement any analytical work with obvious meaningful physical experiment, not just simulacra.

I wish to stress that there WILL be simulations, both mine and others.

Relevant physical experimentation abounds in the literature, often highly targeted and very well funded. This is preferred to something cobbled together haphazardly. Of course, physical models are welcome, including and especially simple ones. I do request that, if anyone does contribute a physical model, that they be amenable to criticisms of its applicability and scope. Designing a useful physical experiment is not trivial. If the effort is trivial, you can be assured the result is equally so. Just because the effort is significant, though, doesn't mean the reward scales accordingly.

OWE,
The time of collapse is something which needs to looked at and not glossed over and certainly the mechanism which grinds all except thick steel to dust. I don't have a good feel for the distribution and mass of the debris. What I see is lots of dust and lots of steel and little else. I imagine that there was "something in between" size wise. This too would need to be explained and we might be scant on survey data about the pile as you call it.

And yes not everything which initiated the collapses (phase I - the upper part and phase II the lower part) is visible and so teasing out data from the observations is quite the challenge which MT has done brilliantly with, but much remains shrouded in mystery. Attributing all to explosives, incendiaries, etc. is the easy way out for those trying to explain the gross observations, but if it was planned it required engineering ... and perhaps more so to make it look as natural as it did.

ROOSD does explain in a gross way that certain structures can be destroyed by a progressive floor collapse.. but as Mies said, "God is in the details."

SanderO wrote:This too would need to be explained and we might be scant on survey data about the pile as you call it.

Excellent point, I'm sure that's true.

Say, are you God? Or djinn? I mention "entropy" once and BAM there you are.

Hehe, not a djinn last I checked, "gin" may be more like it, though I'm a single malt man myself most days.


You and I have a difference in theoretical approach probably becuase you think like an engineer and I don't:

The way I understand it though is that this isn't an engineering problem but a physics problem. We are not trying to reconstruct the collapse, we are trying to find out if there are any forces required to produce the collapse that cannot be accounted for by gravity.

I don't know what happened, so it would be a little sleazy to pick a theory out of preference.

I don't have a problem with it because I don't understand it.

The way I read Occam's razor it says you should do the exact opposite to this. Once you understand a part of the mechanism it is no longer of interest and you should ignore it. The only things that are of interest are the things you don't understand. That, as far as I understand, was Feynman's approach.

It should go:

observation -> theoretical model -> technical exposition of model -> theory and prediction -> empirical testing -> model revision

ROOSD has gotten to the theory and prediction part but in my mind it is not a satisfactory explanation because it cannot formally decide between the infalling and push-out scenario's which (to me) is really the central issue here.

When you say, about the dynamic equilibrium:

I've seen evidence of this in multiple domains, so it doesn't seem absurd to me at all. The question of whether it applies here is a major focus of this investigation. It may go nowhere. In all likelihood, that's how it will be.

I agree, but if you look carefully at domains where this sort of thing happens it is usually a highly sensitive process. If you blow into a bottle like an occarina you get a nice dynamical equilibrium, but open a small hole in the middle of the bottle and the state is very quickly disrupted and cannot be regained. [I should say: cannot be regained by chance processes in terms of the second law]

In short, I don't think it is reasonable to expect these idealized sorts of conditions to have pertained in this case, too many loose ends.

By analogy, it would be like having an avalanche knock off ALL the snow on a mountain, leaving nothing but bare rock behind. Of course it could happen, but it is so extremely unlikely in practice that it fails as an explanation. It posits too many chance events that are unnecessary to explain it once you consider the teams of diggers with snow shovels who happened to check into the hotel last week.

People often think of thermite as an unknown element in this context, but it isn't. We know that using thermite in the way way demonstrated by Cole will produce the effects we are witnessing. So that stands, in my mind as the simplest hypothesis with the least unknown elements invoked and, as such, I must accept it in terms of Occam's razor.

But I would love to test things like fall-in/push-out experimentally somehow. I still want to build that spaghetti/macaroni tower we discussed some time ago. You would need a big box of spaghetti, a vernier caliper, something to represent the floors and joints, and a truckload of patience. I fear the blocks experiment stretched my model building capability already, so don't hold your breath.

Just thinking about floor analogue in that model:

I was thinking of lasagna slabs to go with the whole Eyetalian theme (yuck-yuck, couldn't resist), but I think if you want to model the rubble driven collapse aspect properly the best material may be a metal foil of some sort, maybe lead foil.

You need something that you can make trusses and floor slabs out of such that when you take that mass and drop it onto a floor element it breaks that element.

Lead foil seems the best candidate that I can can think of.

But I don't think it is necessary to be that exact in the end. Any physical process that has a runaway character that consumes itself in the process would do. The only ones I can think of are explosive. So maybe that is why it seems that the building "exploded".

I would be satisfied with any explosive analogue using gravitational potential rather than chemical potential I suppose, or maybe a nuclear chain reaction analogue would be a better description. It can't just release the latent potential, it must "activate" it too to model the rubble compaction required by ROOSD (like a candle "activates" the wax by vaporizing it, which then allows ignition).

The kind of thing I'm thinking of would be like a pile of eggs stacked on top of each other where you drop one egg on top and it breaks the whole pile. Avalanches are not good analogies because they don't consume themselves in the process, i.e. there is still a lot of snow left in the original state afterwards, even in the direct path of avalanche, something which is necessitated by the nature of an avalanche initiation. That, and the fact that an avalanche does not "activate itself" but rather follows pre-existing paths of weakness.

In the WTC the rubble pile had to be activated (that is: broken up into rubble) before it could become part of the rubble driver.

DW,

Engineering IS physics - applied real world materials based physics. Euler's work is a direct derivative of Newton's work.

The collapse is an engineering problem. It is a structural failure problem - a materials failure problem and on a macro and micro level a physics problem or series of them. The towers, their contents and the fires, plane strikes and other energy inputs that day including wind for example all played a part in producing the outcome.

Break...

Why are you so concerned about the inward collapse as opposed to an outward collapse of the core? I suppose explosives INSIDE might argue for the facades being blasted away. But if the structure is wasted inside it might have the affect of pulling the facade inward.

We do see the core largely survive which seems to indicate that floor collapse was not a column collapse - buckling - destruction "demolition"... at least up to the level that the core survived (halfway and more). The floors were destroyed and seem to drop down and likely push/spill outward like any flow in a confined tube or container. Pressure is exerted against the walls (as well as down by gravity) and in this case the walls were the facade and the shaft walls of the core perimeter. Both of these barrier walls were destroyed by the floor collapse/destruction. The facade was push out and the floor debris likely pushed into the core and destroyed bracing inside the core which led to the core collapse from Euler buckling and column instability.

Do you have a problem with the remaining core collapsing from "self buckling" instability... or do you think there is another explanation for it falling over... and dropping down?

If the facade faced similar loss of bracing on the inside are you arguing that the facade should be pulled in as opposed to forced out? The facade was like a column with a fixed base... albeit moving down as the collapse progressed. Watch the spire columns to see how a too tall column with a fixed base behaves... they buckle down or teeter over. Also notice how the top Phase I does not show this characteristic peeling or falling away in large sheets as seen in the bottom. Why would that be? Perhaps because it was a crush up and the facade columns were no longer fixed at their base. They went for a ride.

Darkwing wrote:Hehe, not a djinn last I checked, "gin" may be more like it, though I'm a single malt man myself most days.

Ha!

You and I have a difference in theoretical approach probably becuase you think like an engineer and I don't:

A long time ago, I was a physicist, and I've tended to approach my engineering that way. You haven't seen much of that - yet.

The way I understand it though is that this isn't an engineering problem but a physics problem. We are not trying to reconstruct the collapse, we are trying to find out if there are any forces required to produce the collapse that cannot be accounted for by gravity.

Yes. This is where the physics comes in.

The way I read Occam's razor it says you should do the exact opposite to this. Once you understand a part of the mechanism it is no longer of interest and you should ignore it. The only things that are of interest are the things you don't understand.

Would I look too stupid at this point if I said there's a huge amount I don't understand?

ROOSD has gotten to the theory and prediction part but in my mind it is not a satisfactory explanation because it cannot formally decide between the infalling and push-out scenario's which (to me) is really the central issue here.

True, it doesn't decide and can't decide at that level of detail. Follow-on work is needed. I have another issue I'll describe after this post.

I agree, but if you look carefully at domains where this sort of thing happens it is usually a highly sensitive process. If you blow into a bottle like an occarina you get a nice dynamical equilibrium, but open a small hole in the middle of the bottle and the state is very quickly disrupted and cannot be regained. [I should say: cannot be regained by chance processes in terms of the second law]

In short, I don't think it is reasonable to expect these idealized sorts of conditions to have pertained in this case, too many loose ends.

Understood. It seems unusual to me, too, especially against the backdrop of granular flow. Though by no means impossible or absurd at first inspection.

People often think of thermite as an unknown element in this context, but it isn't. We know that using thermite in the way way demonstrated by Cole will produce the effects we are witnessing.

Once again, I must insist there be clear distinctions between a relatively slow acting process which culminates in a loss of capacity and one which acts in milliseconds. The subject of the Cole video, as I recall, concerns relatively slow cutting and/or fast heating. Neither of these processes account for what is seen in either the east face of the south tower or the southwest corner the north tower. These are fast and violent processes, whatever they are. Even if not natural, the process of heating and cutting does not explain it. Explosive thermite maybe, but why not generic explosives?

Here, I'm not even addressing the issue of how cutting of any sort, fast or slow, might result in many floor slabs or the top section falling into the lower. The issue is how it keeps going once that happens, and what the expected characteristics might be. If all there was for evidence was the debris pile, then a slow cutting agent could not be ruled out. But there is a video record, and it indicates a very tight sequential progression jumping out ahead. This could be timed charges, but a cutting process with time uncertainty of the order of seconds starts to venture into territory somewhere between 10 successive heads in fair coin toss and Shakespearean monkeys.

But I would love to test things like fall-in/push-out experimentally somehow. I still want to build that spaghetti/macaroni tower we discussed some time ago. You would need a big box of spaghetti, a vernier caliper, something to represent the floors and joints, and a truckload of patience. I fear the blocks experiment stretched my model building capability already, so don't hold your breath.

I'm not, don't worry. You shouldn't, either. But some cool things may emerge from time to time. Remember, too, we can let our fingers do the walking on YouTube. If someone else has done something that demonstrates even a wee principle, it's one step closer to understanding (or endless debate over interpretation, but at least the *work* part is excluded).

Darkwing wrote:Any physical process that has a runaway character that consumes itself in the process would do. The only ones I can think of are explosive. So maybe that is why it seems that the building "exploded".

That's the issue here.

I would be satisfied with any explosive analogue using gravitational potential rather than chemical potential I suppose, or maybe a nuclear chain reaction analogue would be a better description. It can't just release the latent potential, it must "activate" it too to model the rubble compaction required by ROOSD (like a candle "activates" the wax by vaporizing it, which then allows ignition).

Exactly. A process can be catalyzed by lowering the potential barrier to the lower energy state, or it can be initiated by adding energy to overcome the initial barrier.

The rest all good points.

I said "I have another issue I'll describe after this post." Here it is.

The ability of a rubble-driven collapse to lead the progression is a primary issue for me. The erosive action on the lower NE corner of the south tower collapse is directly visible. When you see the rivers of debris attacking the remnant of the NE corner of the south tower with your own eyes, it's not at all difficult to posit that's what swept the corner down. By extension, it seems reasonable that this condition would exist in places where it can't be seen. Fine. That's after the collapse is really rolling. (the flow, incidentally, is outwards)

What I see in the north tower, independent of anything else, is something ripping down a corner in a local and cohesive fashion through many, many floors. The near terminal velocity measured during the midphase of this progression indicates a dynamic equilibrium has already been achieved. Because mass is potentially and likely a variable, the equilibrium need not be expressed as a balance of forces, rather a balance of momentum transfer in a debris zone which is defined by net motion more than it is constituent masses which can enter and leave the system.

The externally freefalling panels are by and large playing catch-up during this time. How does a progression which is relatively slow ever appear to be ahead? It can start:

• earlier
• lower
• faster

There's a practical limit to the first two, since videos cover most of the tower.

There are some curious events but nothing that could be called an early interior onset of catastrophic collapse which deviates much from the accepted timing for global collapse. Mass expulsion does start ahead of the uniform downward displacement of the top by a second or two maybe (femr2 can correct me if I'm wrong), but that's not enough. (ref)

There's no evidence of catastrophic initiation below a certain level, nor should there be in a natural collapse.

Conclusion: the progression in that region needs to cover a lot of ground really fast from a standing start then change to a quasi-stationary state in the blink of an eye.

This gets my attention. Especially if it's to be rubble as driver. If rubble is not the driver, what is? A remnant wedge from the upper block? One or more elevator motors? A nicely compacted plug from just a few seconds drop? Is it motion of mass at all? The longstanding explanation is overpressurization. I will no longer dignify that with a response after having a debunker propose to me it could be explained by overpressure from combustibles stored in the building. Not explosives planted by operatives, but janitorial supplies!

Well, if Pine-sol can do that, who needs operatives?

There are other possibilities. Fracture ahead of material motion. And so on. The head swims.

I agree with all points of the last post. That early motion is strange.


I don't see the ROOSD idea requiring perimeter panels always fan outward. Many panels do many things. There is no one set rule but there are general tendencies.

I can't defend anything I can't see. I can see what you can see.

I have seen perimeter panels that just stay standing for a while, a few that fall inward, pretty amazing sheet motion in "phase 2" fls 44 to earth. The lower perimeter is just standing straight up suspended. No out, no in, just standing...then falling.


At no time do I want to be seen as embracing any theories which assume more than is visible.

I have noted 2 cases of HTFCPNST-class movement and sheet layout. It was probably visible from orbit.


I peck and peck at the visible. There is no point in closing our minds around some stuck belief.

Direct observation has provided a gold mine of information so far.

We have already shown with certainty that nobody knows sh*t. 10 years of academic and professional sh*t. That is not opinion. It has already been proven.


As long as we don't pretend to know something we do not new things will continue to surface.

Raw, direct observation, unfiltered by preconceptions.