The US Government released the so called "911 commission report", signed by Bush himself and it says:
"At 9:58:59, the South Tower collapsed in ten seconds"
Yes, I've read that. All it says is that it collapsed in ten seconds. It doesn't give a range of confidence for the collapse, doesn't mention the peak of the seismic data. Ten seconds is clearly not 9.2 seconds. Clearly, they rounded off. But up or down? It unquestionably looks like down. NIST estimated 11 seconds. What should I say?
Do you accept the government report?
Hmm. Do you? You accept the rough ten second estimate, but I wonder if you accept Chapter 7 of that report, where it discusses the identities of the 9/11 hijackers.
It's a free fall speed
They based their studies on seismic data not some guessing work like what you've done. Do you know what is seismic data? Have you learned it at university?
I use my eyes. They seem to work better. Here's the
actual seismograph from the incident:
Note the essentially flat line to the left of the graph under "1st Collapse" and "2nd Collapse". Good. Now, traverse right. The 'collapse stretch' is boxed in by the good fellows at PopMech. And it almost looks like a clean 10 and 8 seconds, doesn't it? Doesn't it? Especially when it's boxed in that way. Nice and clean. Ten seconds. Which is
almost 9.2 seconds! Which means free fall (even though the debris falls slower, but never mind that Rovian debris)!!!
Checkmate!
Uhh, with the exception of one
teensy problem.
See, my work involves reading electropherogram allele signatures, which look a lot like the seismic graphs in the PopMech review, and which I'm sure you wouldn't impugn, since they support your story, right?
Or, you
think they support you.
Traverse your eyes further still to the right. Now, this area looks odd, doesn't it? It's packed with noise compared to the left flat line. In fact, it's the remaining crashing of items hitting the ground, and - unfortunately for your thesis - would almost certainly obscure the sound of the remaining upper floors hitting the ground. It's a question of relative noise; the main body will create most of it, since it's massive, but the smaller body of the upper 30 or so floors won't, since it's relatively tiny and is hitting the body of the collapsed debris inefficiently, unlike the main body of the
building. So, the cutoffs set up by PopMech and the Commission are almost certainly - what? -
underestimated. I'd bet this is why Pop Mech considers 11 seconds as a more accurate estimate.
In other words, the tail of the noise distribution of the seismic data makes it almost impossible to say with certainty what the end of the collapse point was, since the impact of the smaller upper story mass would have probably been indistinguishable from that of the main body. Noise that looks like this occurs in an electropherogram, but it's not a problem for us since we correlatively score from parental genotypes. (Long story.) And also, since we don't
need to know where the
end of the noise is. We don't need to place it. But in this case, to decide on ten seconds, you
do need to place it. Not to mention that the collapse itself in the upper stories would have started slightly before the seismic data would have detected it - maybe as much as 0.3 seconds, or maybe a lot longer.
Or, in other words...
no free fall. Unless, again, you can explain why the
actually free-falling pieces of concrete coming off the Tower are falling faster than the Tower itself.
Now, even though we know it wasn't free fall (since it was at least 10% divergent from a free-fall), let's indulge you. Perhaps you'd care to back up your analysis with a proof about how collapse of a building must necessarily be slower than free-fall.
Why would demolition be faster than the free-fall of a massive body, as more weight on top of the falling point dictated less and less role of the inertia of the lower floors owing to their mass? (Pretty sure that's right; mass and inertia equations are an equality relationship, as I recall from my physics, long, long ago.) How many demolition points would there have to be? How would the seismic indications of the start of free collapse be different than demolition? Or could they be even
slower, since it takes time for the free-weight of the collapsing upper part to hit the lower part?
What do you make of this photo re: controlled demolition, which should "go straight down" in your words?
Oh, I have so many questions. For example: have
you gone to university? You allude to it several times. Which university did you attend?
Best regards,
Geoff
