Not my post but I think this sums it up pretty good:
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9/11 conspiracy theories are easy to buy into when you know just enough about the events to be dangerous and are exposed to people who sound like they know what they're talking about. I have known some very smart people who believed some of them, and I'll admit that I fell victim to the illogic of "Find the Boeing" when I was in high school.
My belief in stupid things when I was younger took a 180 in college, leading to my almost fanatical skepticism. In college, I took a class that was essentially the professor teaching conspiracy theories. Fortunately, he loved to argue and debate anyone who could provide evidence for their argument, and I did real research and convinced him and most of the class that the official version of events is true as far as WTC 1, 2, and 7 collapsing solely due to the plane crashes and that a plane did actually hit the pentagon.
The towers' collapse looks a lot like controlled demolitions people have seen over and over again on TV. The hole in the side of the Pentagon is a lot smaller than the cross-section of a plane and coincidentally lines up with a line of debris on the lawn from construction. The 9/11 Commission report, like many huge government investigations, is full of mixups and little inaccuracies that could be signs of a coverup, but more likely are from important people trying to cover their assses and escape any blame.
Why the towers collapsed
Each tower was constructed with a central core that housed elevators, stairs, and utility connections. Reinforced concrete floors were attached to this and the exterior "steel cage" with angle brackets.
As the fires burning from tens of thousands of pounds of jet fuel and office furnishings softened structural steel (this is important, because while jet fuel and office furnishings do not burn hot enough to melt steel, yield strength and modus of elasticity are inversely proportional to temperature below the melting point, see the image at the end of the post,) and as reinforcing steel flexed and concrete cracked, the floors began to snap away from the angle brackets.
As the brackets failed in large numbers, weight transferred to others, which were overloaded and broke. This caused a cascade of failures, unsurprisingly beginning near the areas of heaviest damage. Significant portions of at least one floor detached from the core and the cage, crashing into the floor below it. This overloaded the supports of the floor below as well as unbalancing the distribution of forces on the core. As each floor fell from its supports, the air displaced blew out windows, leading to the appearance of secondary explosions occurring
Because the area affected by fire and impact damage was not confined to one floor, the already weakened floor below was unable to take the weight of the first collapsing floor and separated from the core and outer cage. After lower floors dropped out, floors above the initial point of failure that had already been weakened by fire and the impact were unable to stand with large amounts of the steel cage and core missing.
At some point in the few seconds after the initial floor's collapse, the core failed catastrophically due to the insufficiently supported weight above the first floor that collapsed. At this point, complete collapse was inevitable because of the increasing weight as each floor failed in sequence. "Explosions" were reported before the collapse were floors falling before the process was visible from the outside. Seriously, use some loving common sense, a skyscraper falling down isn't exactly a quiet sequence of events.
If your friend mentions nano-thermite, punch him in the balls. Presence of barium nitrate, the supposed smoking gun of the thermite theory, is indicative of either thermite-induced demolition or burning of computer circuit boards. I can't imagine where a bunch of burned computers would come from in an office building that was on fire.
WTC 7
Let me start with one thing: "A steel framed building has never collapsed from fire alone."
This is often accompanies a picture of a building that was hit by a plane and burned for hours, I think it was a hotel in Sweden or something like that. For the Pentagon part of today's lesson, note that there is no identifiable part of the plane visible. Now about that claim about fire, let me present Delft University's Architecture building, which collapsed after an fire sparked by a shorted out coffee machine burned out of control for over 5 hours. There wasn't even a plane crash! Nobody was hurt, and contrary to initial reports, the extensive library was unharmed by fire and smoke.
http://www.liveleak.com/view?i=ff1_1210707903
Watch this video. At about 9 seconds, the building buckles in the middle and collapses as would be expected from a controlled demolition. Might as well leave the window open, we're going to come back to it in a minute.
http://whatreallyhappened.com/IMAGES...ocked.down.wmv
WTC 7 suffered damage from fire and impact of debris from the towers. I'm not sure if truthers are still claiming that it was undamaged from the outside, but it was. a section 10 floors high was scooped out to a depth of 1/4 to 1/3 of the building's area. In fact, the pictures reminded me of the damage done to the Alfred Murrah Federal Building in the 1995 terrorist attack, but on a smaller scale.
First of all, the fire burned for 15 hours. The sprinkler systems required manual activation of pumps and everyone had already evacuated. NIST reports indicate that a pressurized diesel fuel line running to the 5th floor generators was not a major cause as previously theorized, but that fire was fueled constantly until fuel tanks were empty.
WTC 7 was constructed with a combination of support beams and transfer girders. Upon structural failure of any support, the load would be transfered to surrounding beams. Column 72 on the 13th floor was the first to fail due to decreased strength from fires. Loads were transferred toward the east end of the building, and the east penthouse collapsed, overloading support structures and allowing collapse to progress toward the west of the building.
WTC7 did not collapse at freefall speeds. Go back to the video, and look at the top left of the building as the video starts. What you see at 2-3 seconds is the East Penthouse collapsing. For the next 7 seconds, columns are failing until they can no longer support the building and it collapses in on the most heavily damaged part, with intact sections holding up the longest.
"We decided to pull it" is another truther favorite, claiming that it means they were going to demolish the building. Unfortunately for them, this is not a phrase used by demolition contractors. On the other hand, if "it" refers to emergency services' attempts to save a building that was already a complete write-off due to extensive structural damage and several floors engulfed in flames in addition to a fire on the 5th floor fed by a pressurized diesel line (used to supply generators) with tens of thousands of gallons of fuel oil in the basement and no way to safely shut it off, it makes a lot more sense.
The Pentagon
A hijacked plane full of people disappears shortly after two more hijacked planes were crashed into buildings, radar shows the plane disappearing as a huge explosion occurs at the Pentagon, hundreds of eyewitnesses including at least one professional pilot have gone on the record reporting that they saw a plane crash into the Pentagon, and there is a trail of damage the width of a plane leading up to the impact site, and a 40,000 pound generator was hit by something big enough to knock it off its mounts and move it toward the damaged area. But the plane didn't cartoonishly punch an outline of itself through a reinforced wall intended to stand up to anything short of a direct nuclear strike, so it must have been a missile. Some people even say there were holograms involved!
Debris found include several clearly identifiable plane parts, and eyewitnesses report that bits of aluminum identified as the plane's skin rained down for as much as 45 minutes after the impact. Not to mention that there's a missing plane and all its passengers and crew.
http://www.abovetopsecret.com/forum/thread79655/pg1 This guy sums it all up very well.
Flight 93
It crashed in Pennsylvania. Seriously, there's nothing to discuss. The engine was "found 6 miles away" because the distance was calculated by Mapquest for driving directions, it's a lot closer if you're a big chunk of metal flying through the air then bouncing and rolling from a crash site
Your belief about September, 11th, 2001
