I have personally made a successful cell phone call from the top of Humphreys Peak, at 12,637’.
Not to aid CTers, but an unshielded person standing still is a different beast from a person moving at 500 MPH encased in a metal shell so far as cellphone communications are concerned.
I am neither a structural engineer nor materials expert nor even a construction expert. My experience in large buildings such as these are limited to designing control systems for the HVAC, including a number of buildings surrounding the WTC site. But this one is easy enough to offer up since I had just rewatched the Nova documentary Why the Towers Fell (originally broadcast in 2002). During the documentary they interviewed Leslie Robertson extensively. Robertson was one of the chief structural engineers in the design of the World Trade Center.
Because I was curious, while I was watching the documentary the other day, I ran some very very rudimentary numbers. AA Flight 11, which crashed into the North tower, was a 767-200ER. Since the documentary wasn’t specific about which variant of the 707 was modeled, I assumed a 707-120B. I also assumed, approximately 2/3s of Maximum Take Off Weight for each plane. I did assume different speeds, based on something I had heard during the discussions of why the towers fell. During the modeling of the impact of a 707 into the tower, the test assumed the impact would be an accident and that the plane would be flying at a relatively low speed ie. misdirected landing attempt. The didn’t envision a madman with the throttles redlined. I found a Boeing Airport Reference and Approach Speeds sheet for various Boeing aircraft and assumed approximately 140kt.
PLANE MASS VELOCITY KINETIC ENERGY
707-120B 76,000kg 72m/s 197,000,000 joules
767-200ER 120,000kg 205m/s 2,522,000,000 joules
The building absorbed almost 13 times the amount of energy just from the impact of the plane than for which it had been designed. That does not include any of the effects of the fuel load, which had not been anticipated in the design and testing.
Charles Thornton is a structural engineer also interviewed for the documentary.
Note: Takeoff weights were calculated from the values in the plane’s respective Wikipedia pages, quotes from Why the Towers Fell are taken from the transcript on the PBS website.
The Burj Dubai is made of steel reinforced concrete. 
Another thing about buildings that size falling sideways, won’t anyone think of Newton? The amount of force needed to accelerate a friggin’ 110 story building sideways is mind boggling.
I’m not an engineer and have a hard time with math in general, but let’s say that we want one of the towers to topple sideways, as in it falls flat on its side. It comes to reason that the top of the building has to be accelerated laterally at the same rate it is accelerated downwards by gravity so it would travel the same distance sideways as downward in the same time, right? So, the force acting downward is equal to the weight of the whole building, ergo, the force necessary to accelerate it sideways so that it falls on it’s side as a fridge toppling over would have to be more or less equal to the weight of the whole building.
From what I’ve read each WTC tower weighted 500.000.000 kilos, so you’ll need (bear in mind is a wild ass hypothetical scenario) at least 500 million kilos of force get it to land sideways. As a point of reference you could get that amount of force by sticking about 40 Space Shuttle solid rocket boosters (12.5 million kilos of thrust each) on the side of the building.
Perhaps someone more number oriented than me could juggle the numbers more gracefully, but I think it serves to illustrate the argument of why big buildings don’t fall on their side.
While true, you’re ignoring that there is something with the whole weight of the building acting on the building: The building.
If I chip away at the base of a tree, it will likely fall over on its side. I didn’t fetch King Kong to push it over, I just let its own weight pull it down. The difference between the tree and the WTC buildings, is that a tree can’t be compacted in on itself. Once it starts falling, it doesn’t smash through its own stump. The stump is strong enough to keep supporting it, and so the tree stays aloft. But if it’s even the slightest bit off balance, it will start to lean, and from that point, its own weight is quite enough to make it fall.
I would be way more willing to buy “Our government let 9/11 happen deliberately,” than “Our government blew the buildings up.”
Intelligence failure IS the simplest explanation-stupidity usually is; but I would believe it this side of possible the hijackers were allowed to fly the planes into the buildings.
If documentation that 9/11 was allowed to occur comes out when I hit 65 or so, I will be one unsurprised and grimly satisfied old person.
As far as the heat potential…
I was working a jobsite, and a hydraulic trash compactor caught fire. By the time the fire department got there, the flames were 30 feet high, and the heat was spalling the concrete wall behind the compactor. I believe that takes around 1100 degrees-and, y’all know, those planes had hydraulic fluid and jet fuel, which then got splashed onto all sorts of paper and hot-burning goodies.
The support structures melting enough to give way is just the simplest explanation here. Iron oxide and aluminum being present? paint, rust, anti-rust paint, plane parts are made of aluminum, all sorts of sources for those materials.
I read an explanation online once of why this was unlikely. I don’t know how accurate this is or how many holes could be poked in it, so take it for what it’s worth. Basically, from what I remember, the argument went roughly like this:
The way intelligence gathering works, some 20-something kid would probably be the first to know about this. I believe we’re assuming things like communication intercepts and reception of annonymous tips here (how else would we find out about it?) He would tell his boss (or bosses), who would tell their boss (or bosses), repeat several times before it gets to the top. By the time it gets to the president, far too many people know to keep them all quiet.
Yes, I’m aware of that and should had added it to my post but I was in a bit of a rush at the time. The reasoning I had and didn’t write up is that, unlike a tree, as you said, the building if tipped over would crumble on itself without falling sideways… that is, as they pretty much did.
If you would want them to fall sideways like a box pushed over, then you need to move the mass of the building sideways with some external, more or less uniform force because it’s not going to leverage itself over the side. Just the simple lateral acceleration involved in moving sideways would disintegrate the building since you would have an acceleration gradient going from top to the bottom, trying to bend the structure.
You are aware that you can search via Google or any other search engine without any delay, yes? Punch “site:boards.straightdope.com search criteria” into a search field and go to town.
Although I have not made a cell phone call from an aircraft, I have received voicemail via cellular signal at 20-odd thousand feet to a phone accidentally left in active mode. In fact, the reason airline passengers are instructed to turn off phones isn’t that they’ll interfere with aircraft communications (which are not only much higher signal power but also on a completely different frequency band) but because rapid switching between cells tasks cellular networks. The “metal shell” of the aircraft is effectively transparent to the microwave frequencies used by cellular networks, as is demonstrated by the hordes of passengers checking their phone messages and e-mail the moment the aircraft lands and starts to taxi to the jetway.
You know the old saw about how if you build something that is foolproof they’ll just build a better fool? Same thing with crackpots, only moreso. There is no damn fool theory so utterly implausible that you won’t find conspiracy theorists streaming out of the wainscoting to proclaim it to be the One And Only Truth.
Stranger
It depends on 110 million lbs of steel for structural integrity.
I’d much rather see a video of the experiment you suggested to Mozart!
I’m aware that people say that. But I almost never get any good results when I try it. It doesn’t seem like the index is very complete.
And at least two Bentham editors have quit, claiming their employer had no integrity. One of them quit in the wake of the gibberish article.
And bodies hitting pavement.
The compactification hardly even matters. If you had a tree the size of the World Trade Center, and you chopped away at one side of the base of the trunk, it still wouldn’t fall over sideways. It’d break up into pieces, and the pieces would fall more-or-less straight down. The only difference that the tree being solid would make is that the rubble pile would be bigger.
Actually that happens to sequoia trees sometimes, and they’re only about 1/5th the height of the WTC towers, and presumably some far smaller fraction of the mass. I saw it in the Mariposa Grove near the south end of Yosemite National Park last year, and somewhere I even have a photograph of a plaque describing the phenomenon.
Thanks, I was wondering whether any trees were actually tall enough for that to happen.
This is true. In fact, you’re pretty much required not to be an expert to see that. Because all the experts are pretty near unanimous that what happened to the WTC was nothing like a controlled demolition.
Hell, even the one demolition expert who the “Truth” Movement could find to agree with them regarding any controlled demolitons that day says the Towers weren’t! Then said he had no explanation for 7 after being told it was on fire for several hours.
Actually, Miller, he’s right in a few ways.
First, the odds are astronomical. Divide 1 - the number of days on which jumbo jets were intentionally flown into supertall skyscrapers - by the number of days on which jumbo jets were not intentionally flown into supertall skyscrapers, and you will come up with a pretty staggering figure.
Secondly, the collapses of the WTC towers were very much like controlled demolitions in one key sense-- that being that the exact same force brought them down: gravity.
So we really should be applauding Mozart1220’s largely correct post.