WTC2 photo series shows upward explosive forces

reply to post by Unkle Greggo
Yes indeed

Approx 60x60x400m amounts to something like in excess of 1000000m^3 of air per tower to be displaced in a little over 10 seconds and it's not going to go quietly. It's driving the vertical plumes of dust and smoke that behaved like a pyroclastic cloud as well the popped windows and finally created the avalanche of dust that rolled away from the collapse as it dissipated.

I still think it's unlikely that the air blast was sufficient to launch massive pieces of heavy material though. In all pictures of such ejections it's notable that there is no evidence of a blast behind it and they actually trail lighter dust behind them in a slipstream instead of the lighter material accelerating ahead. This is the exactly same behaviour that goes against the suggestion of explosions driving that material out of the collapse zone, it appears to be more like bouncing than blasting to me.

reply to post by Pilgrum


Why not. It's probably a higher volume of air moving at a comporable speed of a tornado. And the order of photographs in suspect, because I don't see a time stamp.

Originally posted by Pilgrum

Approx 60x60x400m amounts to something like in excess of 1000000m^3 of air per tower to be displaced in a little over 10 seconds and it's not going to go quietly. It's driving the vertical plumes of dust and smoke that behaved like a pyroclastic cloud as well the popped windows and finally created the avalanche of dust that rolled away from the collapse as it dissipated.

You're deeply through the looking glass here. First, even given the assumption that 1,000,000 cubic meters of tower, two of them, would "naturally" collapse like that, you are now giving air pressure the force to create the amazing feat of launching massive steel building members upwards and outwards at remarkable velocities. As well as sending smaller steel components shooting off like fireworks from the core after the collapse wave has passed them.

This is air after all you're talking about.

[typos]

[edit on 21-2-2008 by gottago]

reply to post by gottago


Air also creates lift. The force that keeps planes in tha air.

Originally posted by Unkle Greggo
reply to post by gottago

 

Air also creates lift. The force that keeps planes in tha air.

Funny, I always thought these kept planes in the air:




Learn something new every day.

Originally posted by Unkle Greggo
Air also creates lift. The force that keeps planes in tha air.

No it doesn't. Pressure creates lift. When air flows over a wing, a negative pressure is created on the top of the wing, forcing the wing to lift.

Blow over a piece of paper that you are holding. Even though you are blowing on the top of the paper, the paper will lift from the pressures induced. Same with a door. A door will still slam shut even if the draft is blowing against the door being shut.

It's pressure, not the physical air itself.

reply to post by Griff


Okay you got me there. But is ti being unresonable to say look at he amount of air and speed at which it was moving. It's more plausible than an explosion. After all wouldn't an explosion throwing objects up have a plume?

Originally posted by Unkle Greggo
After all wouldn't an explosion throwing objects up have a plume?

I'm the wrong person to ask. I'm not a demolitions (or explosives of any sort) expert.

Originally posted by Unkle Greggo
But is ti being unresonable to say look at he amount of air and speed at which it was moving. It's more plausible than an explosion. After all wouldn't an explosion throwing objects up have a plume?

It's much more unreasonable to posit that air pressure is throwing off major building components like that, and there are plumes coming off all of them. The buildings collapsed at about 70 mph, which in itself is astounding. The air pressure and speed of collapse aren't going to create the things you see in those photos.

Especially as many are occurring above the collapse wave--pressure gone.

Originally posted by gottago

You're deeply through the looking glass here. First, even given the assumption that 1,000,000 cubic meters of tower, two of them, would "naturally" collapse like that, you are now giving air pressure the force to create the amazing feat of launching massive steel building members upwards and outwards at remarkable velocities.

I think you missed the 2nd paragraph of my post where I pointed out that the displaced air would be highly unlikely to develop sufficient pressure on steel objects with a density of 8T/m^3 to levitate them, let alone lift them vertically. So, you see, I was not endowing air with remarkable properties at all.

The 1000000m^3 is simply a rough estimate of how much air was within each building and that surely can't be disputed but I believe it only acted on the less dense pieces like dust, smoke, paper, sheetmetal etc (like the suspended facade piece featured in another post).

As well as sending smaller steel components shooting off like fireworks from the core after the collapse wave has passed them.

This is air after all you're talking about.

See, this evidence actually refutes 'explosive' theories rather than supporting them IE what would be the point of the charge exploding after the collapse wave has passed?
Such a charge capable of launching a massive object occuring above the collapse wave would not go un-noticed (even miles away) and the blast effect on all that smoke and dust just isn't there in any pictures. I don't know what the exact mechanism was producing the ejections but I'm certain it's not explosives. Like I said earlier, it looks more like they're bouncing out due to the lack of evidence of a force propelling them.

[edit on 22/2/2008 by Pilgrum]

Originally posted by Pilgrum
See, this evidence actually refutes 'explosive' theories rather than supporting them IE what would be the point of the charge exploding after the collapse wave has passed?

Why does everything on each floor have to go at the same instant? It doesn't. And in the videos, you can see, things fly out from the core after the perimeter structure on the same floor has already given away. Nothing at all is "refuted," because "refuted" suggests you have actually disproved something. A lack of imagination is not disproving something.

I don't know what the exact mechanism was producing the ejections but I'm certain it's not explosives.

Not TNT or C4. You're right.

Like I said earlier, it looks more like they're bouncing out due to the lack of evidence of a force propelling them.

It's impossible for them to move laterally without a force being present. By definition of "force."

Originally posted by bsbray11
It's impossible for them to move laterally without a force being present. By definition of "force."

Well not exactly. There's no evidence of an active force driving from behind the ejected pieces at the instant they were observed but they are displaying kinetic energy from a force applied slightly earlier. Those 'streamers' of dust trailing them make it clear there is no gas pressure pushing from behind them whether from an explosion or high pressure draft (which are basically the same thing). The velocity they have was gained from some other process and bouncing is best way I can describe what I see.

You may not believe it but I'd be pleased to see evidence of real explosions in the collapses but so far I haven't and I know I'm not blind.

Originally posted by Pilgrum
Those 'streamers' of dust trailing them make it clear there is no gas pressure pushing from behind them whether from an explosion or high pressure draft

www.batguano.com...

Look at this picture and tell me there can't be "streamers" trailing debris from an explosion.

I believe that pic has been posted before and it's an underground test of a huge conventional explosion. The chunks are travelling in perfect ballistic arcs in relatively clean air because they're far enough away from the blast that gave them that initial momentum to have clear slipstreams drawing dust behind them. If that blast had been in an aboveground structure like a WTC tower the material would have been ejected radially around the centre of the explosion.

Looking at ground level in the pic you can see the shockwave propagating away from the explosion and this feature was absent in the tower collapses.

Originally posted by Pilgrum
Well not exactly. There's no evidence of an active force

You mean a conservative force? Why would a conservative force ever be acting anywhere but straight down in this situation?

but they are displaying kinetic energy from a force applied slightly earlier.

Exactly. I just don't get how bouncing explains where that came from.

Originally posted by bsbray11
You mean a conservative force? Why would a conservative force ever be acting anywhere but straight down in this situation?

Seems I'm not adequately explaining it but yes - the only force acting on those pieces at the time of the picture is gravity and they are no longer being accelerated in any other direction than straight down. The horizontal component of their velocity was acquired shortly before the picture was taken and is no longer acting on them BUT the distance from the source of the horizontal force is very small (hence the expired time is also very small) and yet there's no evidence of any artifacts of that force if you want to suggest it was explosive in nature.

I just don't get how bouncing explains where that came from.

Bouncing is a property of elastic materials (conservation of momentum) and structural steel is highly elastic although it might be difficult to imagine a 20 ton mass of steel bouncing on collision with similar material that has much higher inertia due to greater mass - it most definitely can.

I know you'll be falling off your seat laughing
Have you tried this experiment I suggested with 2 balls that demonstrates the kinetic transfer principle?

IE hold a tennis ball on top of a basketball and drop the 2 from a modest height like 5' so that the tennis ball is in intimate contact with the basketball when it strikes the ground. Tell me if you think the tennis ball defies Newtons laws or confirms them.

Originally posted by Pilgrum
Seems I'm not adequately explaining it but yes - the only force acting on those pieces at the time of the picture is gravity and they are no longer being accelerated in any other direction than straight down.

Agreed. But this is also completely irrelevant, because it would be true either way.

The horizontal component of their velocity was acquired shortly before the picture was taken and is no longer acting on them BUT the distance from the source of the horizontal force is very small (hence the expired time is also very small) and yet there's no evidence of any artifacts of that force if you want to suggest it was explosive in nature.

The lateral velocity itself is evidence of a powerful non-conservative force acting on the steel. Gravity only "pulls" down. No arc trajectories.

What you think caused this motion is the problem.

Bouncing is a property of elastic materials (conservation of momentum) and structural steel is highly elastic

This isn't going to cut it. You aren't going to be able to convince me that the steel pieces were bouncing off each other like bouncy balls. They are elastic but not like that. That is not an explanation. That is like people saying the molten steel was from friction as the steel columns rubbed against each other.

Steel's elasticity comes more into play when it's heated, expands, cools, and then takes back its original shape. And then there is a point where it will no long return to its original shape, and that is the yield strength of the steel (when permanent deformation begins, and this strength decreases on a cruve with temperature). Quick impact-loading even increases the yield strength of steel because the material has less time to respond and behaves as though it's more brittle than usual when dynamically loaded.

although it might be difficult to imagine a 20 ton mass of steel bouncing on collision with similar material that has much higher inertia due to greater mass - it most definitely can.

That isn't bouncing, that's an impact/collision. It's better than trying to tell me it was a feature of the steel's elasticity but considering that at least 80% of the masses of the towers were thrown outwards, where is all the mass always coming from to keep knocking this stuff out? One or two pieces being impacted by a large, intact section, ok. But almost two entire buildings being sent out sideways from that? I don't buy it, because it doesn't make sense.

Have you tried this experiment I suggested with 2 balls that demonstrates the kinetic transfer principle?

I did this in a physics class, had to calculate what would happen, and then do it experimentally and get the actual data, then calculate the % error between the theoretical values and my actual experimental data. I had to do this every week on different concepts in physics and then write up a multi-page paper complete with charts and tables that would then be anally scrutinized by my professor. It was a pain in my ass.

[edit on 23-2-2008 by bsbray11]

Well now I know I'm not the only one with memories of fastidious physics professors although my experiences with them were in the early 1970s

I also wouldn't be alone in not being able to provide a universally adequate explanation of the mechanism of those tower collapses but I give it a shot anyway. Would you agree that all the ejected material appears to have left the confines of the outer walls only after falling to where the real action was going on IE at the collapse front ?

The collapse moved unexpectedly fast but it did demonstrate resistance (just not enough for most analysts) and a lot of heavy debris free-falling from above, virtually all of it steel, easily caught up with it.

Originally posted by Pilgrum
Would you agree that all the ejected material appears to have left the confines of the outer walls only after falling to where the real action was going on IE at the collapse front ?

No, that's exactly the point of posting these photographs. Please look at them. There are huge hunks of building being ejected up and away from the collapse front. And lesser pieces spewing in upward arcing parabolas.

The collapse moved unexpectedly fast but it did demonstrate resistance (just not enough for most analysts) and a lot of heavy debris free-falling from above, virtually all of it steel, easily caught up with it.

...Even though some of it went up before it went down...

[typos]

[edit on 23-2-2008 by gottago]

Originally posted by gottago
No, that's exactly the point of posting these photographs. Please look at them. There are huge hunks of building being ejected up and away from the collapse front. And lesser pieces spewing in upward arcing parabolas.

That's exactly what I see - all the ejected material took part in the collapse before a small percentage of the total amount of available heavy steel sections was thrown out. Much of the cascade of debris close to the walls appears to be spilling over the edges like a fluid with very laminar flow characteristics and undisturbed by explosive blasts (remember the infamous 'bathtub' theory). Heavy pieces with an upward inititial trajectory are the only ones capable of clearing the edge of the remaining outer wall and any with a flatter trajectory would simply smash into the outer wall causing its progressive failure a few floors above where the collapse is most active.

About 80% of the total mass landed outside the footprint but virtually all of that took an active part in the central collapse first.