Loose Change

[The_Fire]

<from a non-explosives/free fall expert>
Besides: wouldn't explosives etc. be placed ONTOP of the falling rubble and detonated from an ABOVE position in order to accelerate the falling rubble according to that theory?

That would mean visible evidence in the shape of the flash of small, continious explosions as the rubble falls and yet there are no evidence of that.

 

[Thanz]

Having hashed a lot of this out on the Loose Change forum recently, I can tell you there are different angles of speculation about the motive for 7: a) hiding evidence, b) insurance money, c) audacity. a & b are the main ones I've heard. c I really only heard once (I think Alek suggested it).

But they'll admit that they're just speculating about the true motive. The point is, they'll continue, for reasons x, y, and z it must have been a controlled demolition, and therefore they demand a criminal investigation.

None of those reasons actually holds any water. The explosives that they say must have been used would have to have been set up well in advance. What is the motive for doing that? Wouldn't motive be a necessary element here?

There's so much focus on it because: a) the official accounts of what happened to it are inconsistent and inconclusive, b) in the videos it looks a whole lot like controlled demolition, c) the fire and damage visible in the pictures and footage doesn't look like enough to take it down (even though I've never seen a shot of the south side, where the extensive damage is supposed to have been), d) WTC 6, which is closer to where the North tower stood, sustained significant damage and yet remained standing. The slightly less credulous stopped using argument d after I pointed out the fact that 6 is 1/4 the height of 7 and has a larger footprint, giving it a much more stable height/width ratio, and the fact that 6 wasn't burning.

Essentially, there's so much focus on 7 because it's the one event from that day that has the most convincing imagery and the most legitimate mystery.

That makes sense. It also distracts from the main issue of the two towers. I think it is an attempt to make the whole theory sound more credible by pointing to and emphasizing the one building that didn't get hit by a plane. Otherwise, they'd be left with only the two towers and trying to explain why they should have stayed standing despite being hit with, in essence, a massive bomb.

Over at the other forum, is mentioning "Occam's Razor" a bannable offence?

 

[Arkan_Wolfshade]

Because of momentum transfer, the impact velocities are slightly lower than the 8.6 m/s impact speed for the first floors hit: 8.1 m/s for WTC 1, and 8.3 m/s for WTC 2. (Original italics)

Is this a mistake on Dr. Greening's part? The concept of momentum transfer indicates that the mass is giving up kinetic energy in order to cause the stationary floor to collapse. In this paper, Dr. Greening cites a figure of 629 MJ to cause a single floor to collapse, although he uses a figure of 1 GJ in his calculations to be safe, I assume.

2.4 GJ of KE is available for the first impact of WTC1. That seems clear. Using the lower figure of 629 MJ to cause the first collapse, it seems there is plenty of energy to get the job done. The energy absorbed by the impact is 26.2% of available KE. However, according to Newton's Third Law of Motion, it seems undeniable that the available KE is being applied to both the impacted and the impacting floors. If one floor is absorbing this energy, the other floor must do the same, so that brings us to 1.258 GJ being absorbed, or 52.4% of available KE.

Yes, I am still nervous.

IANAP(1), but I believe it is not only the downward force being applied to the lower floor that contributed to its collapse, but also the total weight of the floors above it. So, even if the force of the impact would not cause loss of integrity, the sheer weight of the matter would.



(1) I Am Not A Physicist

 

[Hellbound]

<from a non-explosives/free fall expert>
Besides: wouldn't explosives etc. be placed ONTOP of the falling rubble and detonated from an ABOVE position in order to accelerate the falling rubble according to that theory?

That would mean visible evidence in the shape of the flash of small, continious explosions as the rubble falls and yet there are no evidence of that.

I made that point earlier. You'd also have to time explosions precisely to achieve the effect.

In short, if you wanted it to fall faster than freefall, it wouldn't be something that happened by accident. You would have to specifically plan for this, and set the charges accordingly.

That is something I'd like to hear a motive for.

Btw, I'm not a demolitions expert either, but I do have experience with it. I was military-trained in non-electric blasting, improvised munitions, and some instruction on demolitions (mostly for breeching walls, cutting columns, downing bridges, and similar work). Actually, I still have a copy of the military's "Engineer's Bible", that details some of the calculations for various breeches and charges.

 

[rwguinn]

IANAP(1), but I believe it is not only the downward force being applied to the lower floor that contributed to its collapse, but also the total weight of the floors above it. So, even if the force of the impact would not cause loss of integrity, the sheer weight of the matter would.



(1) I Am Not A Physicist

not quite--The mass of the floors above the collapsing floor has always been there. When the collapsing floor is overloaded, it falls on to the next floor, along with the stuff above it. The mass supported from below hasn't changed- the force required is still F=Mg, but that force has been increased by the energy of the falling stuff impacting. the fact that it likely falls on a portion of the structure not designed to actually resist that load we will ignore for now! )
The ability of the lower structure to slow the rate of fall is a function of its force capability--remember F=MA? so if the force is very large, the capability of the structure to slow it down to less than free-fall speed becomes smaller and smaller as more floors collapse, to the point wher the load-carrying capability of the remaining structure issome infinitestimal portion of the loads imparted on it.
This is true -even though those lower floors had not been affected by the strength-reducing temperatures.

 

[bunker]

IANAP(1), but I believe it is not only the downward force being applied to the lower floor that contributed to its collapse, but also the total weight of the floors above it. So, even if the force of the impact would not cause loss of integrity, the sheer weight of the matter would.

The weight is what is being used to calculate the total available kinetic energy.

(1) I Am Not A Physicist

Good! Neither am I.

 

[DavidJames]

None of those reasons actually holds any water. The explosives that they say must have been used would have to have been set up well in advance. What is the motive for doing that? Wouldn't motive be a necessary element here?


That makes sense. It also distracts from the main issue of the two towers. I think it is an attempt to make the whole theory sound more credible by pointing to and emphasizing the one building that didn't get hit by a plane. Otherwise, they'd be left with only the two towers and trying to explain why they should have stayed standing despite being hit with, in essence, a massive bomb.

Over at the other forum, is mentioning "Occam's Razor" a bannable offence?

I haven't seen much explanation regarding their theories. They seem to be pretty much like creationists/IDers. They seem to feel finding a flaw in the "official" theory proves their theory. They don't seem to apply the same requirements for rigorous proofs to their own ideas as they do to others.

 

[chipmunk stew]

Over at the other forum, is mentioning "Occam's Razor" a bannable offence?

No, but they'll just flip it and tell you that Occam's Razor is on their side.

 

[chillzero]

OK. I don't really buy any of these weird conspiracy theories, but I thought I would watch a program that just started here on UK tv 15 mins ago - it's part of a series called 'Conspiracies..'. I wanted to watch the faces of the theorists as they made the claims, I guess.

First annoying thing is that the narrator keeps calling the theorists 'skeptics'. He keeps saying that the skeptics just would not stop asking questions, and uncovering facts... leading to stranger and stranger theories.

A few points have been made that I haven't previously seen:

The plane that crashed in Pennsylvania had a crash site of over 8 miles, which has never happened before with any other plane crash - ever. Apparently an engine was found 8 miles away from the main site, and a wing part (I think that was what he said) was found 4 miles away. Does anyone know if this is true?

President Bush did not react appropriately when told of the situation. To many he looks llike he is in shock, but the fact that he sits on for a further 7 minutes while the children's book is read apparently indicates that he is callous, and has just had his brain pushed into overload at the realisation of the whole plan. Yeah. He looked to me like he was in shock, and considering the best way to extract himself from the classroom. I do feel, however, that his advisors should have called him out from the room to discuss the events with him in private.

What makes me more upset about this, is that the news did an article this evening about the rescue workers from that day in New York. Most of them now suffer from breathing problems and illnesses caused by all the dust and things they breathed and swallowed while they worked. They made some points about what the dust was comprised of, that was really horrible to think about. But the worst thing was the clip they showed of Bush. He stood there a few days later and told them that he heard them all. That they would always be loved and remembered for their efforts, and would never be forgotten. NEVER be forgotten. The fact that these peoples' illnesses were not diagnosed until after a certain tight timeframe, means they are not entitled to any insurance coverage, and their drugs are costing them huge amounts of money. Most can't work any longer - it's called WTC cough - and many are already dead. Bush has not even discussed the issue with any of those trying to get help, and is doing nothing about obtaining free healthcare for them.

This is disgusting. Why can't the energy and efforts of these theorists be directed toward some good - like fighting to help the rescue workers? Why not do some good with all those noise raising skills they have? Why not combine their numbers to put pressure on the government for appropriate treatment of the 9/11 heroes? Why not try to create something good, from all the mess that this whole situation has created - whichever theory you believe in?

 

[Arkan_Wolfshade]

Well, I was trying to find documentation on the debris field, but I can't filter through all the CT websites to find neutral information on the subject.

 

[Gravy]

OK. I don't really buy any of these weird conspiracy theories, but ... A few points have been made that I haven't previously seen:

The plane that crashed in Pennsylvania had a crash site of over 8 miles, which has never happened before with any other plane crash - ever. Apparently an engine was found 8 miles away from the main site, and a wing part (I think that was what he said) was found 4 miles away. Does anyone know if this is true?

Nah. One engine tumbled downhill 300 yards after the impact, that's it. The 8-mile figure is only off by 4700%.

 

[CurtC]

So for all those people who say that the WTC7 collapse was obviously an intentional demolition, I have an observation/question.

When buildings are intentionally demolished, they use just enough explosives to take out some key supports, and let the building's weight do the rest. A building wants to fall straight down, because that's the way gravity is pulling. Once it loses its structural integrity, it collapses straight down. The demo teams attempt to do it so that the middle falls first, that way the outer walls are pulled inwards a little, and fall inside the building's footprint.

But you can see when the small blasts occur, they're strategically located - they don't obliterate the whole structure, they take out just enough at key points to make sure that it falls. Then gravity simply pulls the building down on top of itself.

If a tall building for any reason fails from the lower center portion, I don't see any reason that it would look any different from a controlled demolition. So I would like to ask an inside-jobber: what would you expect that a tall building would look when it falls due to structural failure? Wouldn't it look pretty much like an intentional demolition, especially if its first failure point were low and in the middle?

 

[CurtC]

Nah. One engine tumbled downhill 300 yards after the impact, that's it. The 8-mile figure is only off by 4700%.

I read recently that there were some papers found about a mile and a half away, in a lake that was downwind of the crash site. That's the farthest I've heard, and it's not surprising.

 

[bunker]

Because of momentum transfer, the impact velocities are slightly lower than the 8.6 m/s impact speed for the first floors hit: 8.1 m/s for WTC 1, and 8.3 m/s for WTC 2. (Original italics)

Is this a mistake on Dr. Greening's part? The concept of momentum transfer indicates that the mass is giving up kinetic energy in order to cause the stationary floor to collapse. In this paper, Dr. Greening cites a figure of 629 MJ to cause a single floor to collapse, although he uses a figure of 1 GJ in his calculations to be safe, I assume.

2.4 GJ of KE is available for the first impact of WTC1. That seems clear. Using the lower figure of 629 MJ to cause the first collapse, it seems there is plenty of energy to get the job done. The energy absorbed by the impact is 26.2% of available KE. However, according to Newton's Third Law of Motion, it seems undeniable that the available KE is being applied to both the impacted and the impacting floors. If one floor is absorbing this energy, the other floor must do the same, so that brings us to 1.258 GJ being absorbed, or 52.4% of available KE.

Yes, I am still nervous.

I apologize for the shameless self-quotation, but I need to continue this thought. The figure of 629 MJ does not include the energy necessary to crush the concrete to any given particulate size. In Appendix 2, Dr. Greening calculates the energy required to crush all 48,000,000 kg of concrete in one tower to 60 um would be 3.2 x 10^11 J. Divide that by 110, the number of floors, and we get 2.9 GJ. Of course the size of the resulting particles is inversely proportional to the energy input, so he is certainly consistent when he says on page 13 that we have 1.2 GJ available to crush the concrete of one floor of WTC1 to 175 um particles.

The problem I see is that we cannot possibly be talking about crushing only one floor with the calculated 2.4 GJ of available energy. Everyone knows "for every action there is an equal and opposite reaction", so when these two floors of the same building meet and start "reacting", they will react in similar ways, much like two similar cars colliding head on. That is, they will crush each other. But the energy required to do this remains the same for each floor, and I don't see much, if any, energy leftover to continue this collapse after we take the concrete into account.

This paper becomes even more confounding when on page 17, Dr. Greening states:

"It is finally worth noting that because E1(energy required to collapse one floor) is a small fraction of the available kinetic energy, the WTC collapse times would not substantially increase even if we allow for the simultaneous crushing of two floors – the floor impacted by the falling mass and the floor just above the lowest floor of the falling mass."

Small fraction? Even completely discounting the energy absorbed by the second floor and the energy to crush the concrete of the first and second floor, we end up with 26.2% of the available 2.4 GJ of KE being absorbed. Add in the absorption of the impacting floor, and we get 52.4%. Add to that the concrete of just one floor, and I'm not sure we have enough energy to continue this collapse at all, much less accelerate it all the way to the ground.

 

[hellaeon]

So the ...
...were all cooperating in a widespread conspiracy to conduct a controlled demolition, thereby reducing the WTC to a pile of rubble, provide misinformation to the American public, and divert attention from the REAL culprits -- the government?

RayG

hahahahaha put that way it sounds even more ridiculous.

 

[hellaeon]

I'm the 666th reply to the original thread.... Just more fuel for the conspiracy fire.

god damn it, that should have been me

 

[Manny]

If a tall building for any reason fails from the lower center portion, I don't see any reason that it would look any different from a controlled demolition. So I would like to ask an inside-jobber: what would you expect that a tall building would look when it falls due to structural failure? Wouldn't it look pretty much like an intentional demolition, especially if its first failure point were low and in the middle?

I'm no inside jobber, of course, but I'll give this one a crack and see what the real engineering types have to say about it. I think the CTers are erroneously assuming that all steel-column buildings are created equal.

A typical steel-column building is peppered throughout with structural colums. In the building I'm sitting in, they're about 20 feet apart one way, 40 feet apart the other. Each of these columns bears some load. Now weaken a big swath of them with fire. The load those columns were bearing now is transferred to the neighbors. If there's enough load transfer, those columns in turn would collapse, sending the load further out, etc.

Yes, the direction the building would fall is "down." But I imagine it wouldn't be all at once, and I certainly don't imagine that it would be symmetrical. If I were to take out a bunch of columns in the north-center of the building, say half way up, I'd expect the building to kind of fall into that -- the upper floors push down on the damaged columns AND the undamaged ones neighboring first, then gradually pulling the building in that direction. It wouldn't slump very far -- no "toppling over" or anything like that, but I imagine that it would look different from a controlled demolition where all the columns are taken out at once. Additionally, with shearing and the wider initial distribution of load, I suspect there would be a lesser potential of a full collapse -- the north face of the building might fall, leaving the rest of the building unstable but still standing, at least for a bit. Or the remaining columns might hold up the whole building, leaving damaged steel where it was weakened but an intact structure.

7 World Trade (and 1 and 2, for that matter, but let's leave them out for now because they got hit by planes) was different. It didn't have spaced out columns like in traditional steel structures. All the "columns" were in the very center of the building. Here, I would expect that a catastrophic failure would look a lot like a controlled demolition. Why? Because wherever the failure occurred, it would have to be near the center of the building, and the columns' neighbors (the next ones to fail) would also be at the center, and so on until the last column failed. So the only direction for the building to be pulled is "in," not "toward the north" or whatever. And the only way for the building to fail is for all of it to fail -- no partial collapses unless the failure were very high in the structure.

 

[Arkan_Wolfshade]

I apologize for the shameless self-quotation, but I need to continue this thought. The figure of 629 MJ does not include the energy necessary to crush the concrete to any given particulate size. In
<snip for brevity>
concrete of just one floor, and I'm not sure we have enough energy to continue this collapse at all, much less accelerate it all the way to the ground.

If I am reading your interpretation correctly, you are saying that there would be insufficient energy left over, after floor x and x-1's concrete had been crushed to allow for floor x-1 to collapse. This would be incorrect, as there is nothing preventing floor x-1 to collapse prior to the complete crushing of the concrete. All is needed is for there to be sufficient force to cause x-1 to lose structural integrity. The concrete from floor x and x-1 can finish being crushed any time between floor x-1 and ground level.

ETA: It, I believe, is also needed to take in to account the energy input into the structure from the impact of the aircraft themselves and the effect of that on load bearing structure.

 

[delphi_ote]

You don't wanna go there. A lot of people believe that Christ visited America and other religious things, and it would be a mistake to conflate the two disagreements. Keep to the science, and let the religionists keep to the religion. You certainly wouldn't want the other side to start discrediting structural engineers simply because they also believe, for example, that they consume the literal body and blood of Christ every Sunday.

Even if they're "researching" it and posting his research to his university website? And teaching a course in the subject?

http://www.physics.byu.edu/faculty/jones/rel491/fossils.htm
http://www.physics.byu.edu/faculty/jones/rel491/neardeath.491.htm
http://www.physics.byu.edu/faculty/jones/rel491/taitpaper.r491.htm
http://www.physics.byu.edu/faculty/jones/rel491/TheCreationSalisbury.htm

I think I do want to go there. The man does not understand what "science" and "evidence" mean. He's also speaking from the lecture podium and using his title as a physics professor to bolster data mining. From what I've read so far of his 9/11 research, this seems to be a trend:

An intriguing photograph (below right) taken by Rob Miller, photojournalist with the New York Post, provides additional photographic evidence (Swanson, 2003) for the use of thermite or a sulfur-containing derivative such as thermate. We see debris and dust as WTC 1 collapses, with WTC 7 seen in the foreground, across the street from WTC 1. The photograph on the left shows, for comparison, the thermite reaction with a grayish-white aluminum-oxide dust plume extending upwards from the white-hot molten iron "blob" from the reaction

He has abused his credentials and is not to be taken seriously.

 

[Regnad Kcin]

...Go with the flow. Indeed. Follow the lemmings off of the cliff.

Even though I have the gent on Ignore, others will quote him, giving me fun glimpses into his continued thoughts.

So why quote the above? Because it illustrates the importance of a little thing I like to call proof.

Has "lemmings" entered the vernacular anyway, and thus become immune to a need for a factual basis? Yes. But it's a change that harms and bothers no one (except, maybe, the Lemming Anti-Defamation League). On the other hand, it's important to remain vigilant against those who would cry "Wolf!" at the slightest provocation, thereby diminishing the need when the situation actually warrants the response.