Military History of the West Since 1500 Quizlet Reading
September 2021: For the past xx years, conspiracy theories about the September 11, 2001 terrorist attacks against the The states have swept the nation. The destruction of the Twin Towers in New York City, for instance, was an inside chore, according to "truthers" who have propagated the claim for two decades.
It was in this climate that Pop Mechanics offset took on the job of debunking 9/xi myths. Our outset report appeared as the cover story for the March 2005 issue. The reporting grew into a 2006 book with a frontwards by Sen. John McCain, which was updated in 2011. Beneath, yous'll detect a lightly-edited version of the section on the World Trade Center.
Twenty years later, 9/11 conspiracy theories linger on. In the years following the report of this publication, truthers would launch of variety of attacks on Pop Mechanics, accusing the magazine of being a tool of the federal government and drawing tinfoil-hat diagrams to tie Popular Mechanics to the Bush-league Assistants and the supposed big conspiracy. If all this nonsense achieved anything, it was to presage our current era of "alternative facts" and attacking the messenger whenever the message clashes with one's predetermined beliefs.
The plummet of both World Trade Center (WTC) towers—and the smaller WTC 7 a few hours afterwards—initially surprised fifty-fifty some experts. Simply subsequent studies have shown that the WTC'southward structural integrity was destroyed by intense burn down too as the severe damage inflicted by the planes.
However, that caption hasn't swayed conspiracy theorists, who debate that all three buildings were wired with explosives in advance and razed in a series of controlled demolitions.
Widespread Damage
CLAIM: The showtime hijacked plane crashed through the 94th to the 98th floors of the World Merchandise Eye'southward 110-story North Tower; the second jet slammed into the 78th to the 84th floors of the 110-story South Tower. The impact and ensuing fires disrupted elevator service in both buildings. Plus, the lobbies of both buildings were visibly damaged before the towers collapsed. "There is NO WAY the impact of the jet caused such widespread damage 80 stories below," claims a posting on the San Diego Independent Media Center website (sandiego.indymedia.org). "It is OBVIOUS and irrefutable that OTHER EXPLOSIVES (... such equally concussion bombs) HAD ALREADY BEEN DETONATED in the lower levels of tower one at the aforementioned time equally the plane crash."
FACT: Following up on a May 2002 preliminary written report by the Federal Emergency Management Agency (FEMA), the National Institute of Standards and Technology (NIST)—a branch of the U.S. Department of Commerce—released another report in leap 2005. NIST shared its initial findings with Popular Mechanics at the time, and made its lead researcher available to our squad of reporters.
The NIST investigation revealed that plane debris sliced through the utility shafts at the Due north Tower's core, creating a conduit for called-for jet fuel—and fiery destruction throughout the building. "It's very difficult to document where the fuel went," says Forman Williams, a NIST adviser and a combustion expert, "but if it's atomized and combustible and gets to an ignition source, information technology'll go off."
Burning fuel traveling down the elevator shafts would have disrupted the lift systems and acquired all-encompassing damage to the lobbies. NIST heard first-person testimony that "some elevators slammed right down" to the basis floor. "The doors croaky open up on the entrance hall flooring and flames came out and people died," says James Quintiere, an engineering professor at the University of Maryland and a NIST adviser. A similar observation was made in the French documentary 9/11 by Jules and Gedeon Naudet. As Jules Naudet entered the North Tower lobby, minutes after the first aircraft struck, he saw victims on fire, a scene he constitute too horrific to picture show.
"Melted" Steel
CLAIM: "We have been lied to," announces the website AttackOnAmerica.cyberspace. "The outset lie was that the load of fuel from the aircraft was the cause of structural failure. No kerosene burn can burn hot enough to melt steel." The posting is entitled "Proof Of Controlled Demolition At The WTC."
FACT: Jet fuel burns at 800 to 1500 degrees Fahrenheit, non hot enough to melt steel (2750 degrees Fahrenheit). Nonetheless, experts agree that for the towers to collapse, their steel frames didn't need to melt, they just had to lose some of their structural strength—and that required exposure to much less heat. "I have never seen melted steel in a edifice fire," says retired New York deputy burn down principal Vincent Dunn, writer of The Plummet Of Burning Buildings: A Guide To Fireground Safety. "But I've seen a lot of twisted, warped, bent and sagging steel. What happens is that the steel tries to aggrandize at both ends, but when information technology can no longer aggrandize, information technology sags and the surrounding concrete cracks."
"Steel loses about 50 percentage of its forcefulness at 1100 [degrees Fahrenheit]," notes senior engineer Farid Alfawak-hiri of the American Constitute of Steel Construction. "And at 1800 [degrees] information technology is probably at less than x percent." NIST also believes that a great bargain of the spray-on fireproofing insulation was likely knocked off the steel beams that were in the path of the crashing jets, leaving the metallic more vulnerable to the heat.
But jet fuel wasn't the but affair burning, notes Forman Williams, a professor of engineering at the University of California, San Diego, and one of seven structural engineers and fire experts that Popular Mechanics consulted. He says that while the jet fuel was the catalyst for the WTC fires, the resulting inferno was intensified past the combustible material inside the buildings, including rugs, curtains, furniture and paper. NIST reports that pockets of fire hit 1832 degrees Fahrenheit.
"The jet fuel was the ignition source," Williams tells Popular Mechanics. "It burned for perhaps ten minutes, and [the towers] were nonetheless standing in 10 minutes. Information technology was the rest of the stuff called-for afterward that was responsible for the heat transfer that eventually brought them down."
Puffs of Dust
CLAIM: Equally each tower collapsed, clearly visible puffs of dust and debris were ejected from the sides of the buildings. An advertisement in The New York Times for the book Painful Questions: An Analysis Of The September 11th Attack made this claim: "The physical clouds shooting out of the buildings are not possible from a mere collapse. They practise occur from explosions." Numerous conspiracy theorists cite Van Romero, an explosives expert and vice president of the New United mexican states Plant of Mining and Technology, who was quoted on 9/11 past the Albuquerque Journal equally proverb "there were some explosive devices inside the buildings that caused the towers to collapse." The commodity continues, "Romero said the collapse of the structures resembled those of controlled implosions used to demolish old structures."
FACT: Once each belfry began to plummet, the weight of all the floors above the collapsed zone diameter downward with pulverizing force on the highest intact flooring. Unable to absorb the massive energy, that floor would neglect, transmitting the forces to the flooring beneath, allowing the collapse to progress downward through the building in a chain reaction. Engineers call the process "pancaking," and it does not crave an explosion to begin, according to David Biggs, a structural engineer at Ryan-Biggs Associates and a fellow member of the American Guild of Ceremonious Engineers team that worked on the FEMA report.
Like all role buildings, the WTC towers contained a huge volume of air. As they pancaked, all that air—along with the concrete and other debris pulverized by the force of the plummet—was ejected with enormous free energy. "When yous have a meaning portion of a floor collapsing, it's going to shoot air and concrete dust out the window," NIST lead investigator Shyam Sunder tells Pop Mechanics. Those clouds of dust may create the impression of a controlled demolition, Sunder adds, "but it is the floor pancaking that leads to that perception."
✅ Get the Facts: 9/xi Conspiracy Theories
Demolition proficient Romero regrets that his comments to the Albuquerque Journal became forage for conspiracy theorists. "I was misquoted in saying that I thought it was explosives that brought down the building," he tells Pop Mechanics. "I only said that that's what it looked like."
Romero, who agrees with the scientific conclusion that fire triggered the collapses, demanded a retraction from the Journal. Information technology was printed Sept. 22, 2001. "I felt like my scientific reputation was on the line." But emperors-clothes.com saw something else: "The paymaster of Romero's research found is the Pentagon. Directly or indirectly, pressure was brought to deport, forcing Romero to retract his original statement." Romero responds: "Conspiracy theorists came out saying that the authorities got to me. That is the uttermost thing from the truth. This has been an albatross around my neck for 3 years."
Seismic Spikes
CLAIM: Seismographs at Columbia Academy'southward Lamont-Doherty Globe Observatory in Palisades, New York, 21 miles north of the WTC, recorded the events of 9/11. "The strongest jolts were all registered at the outset of the collapses, well before falling droppings struck the earth," reports the website WhatReallyHappened.com. A columnist on Prisonplanet.com, a website run by radio talk show host Alex Jones, claims the seismic spikes (boxed area on Graph 1) are "indisputable proof that massive explosions brought down" the towers. The site says its findings are supported by two seismologists at the observatory, Won-Young Kim and Arthur Lerner-Lam. Each "sharp spike of curt duration," says Prisonplanet.com, was consistent with a "demolition-style implosion."
Revisionists say sharp spikes (graph i, to a higher place) mean bombs toppled the WTC. Scientists disagree with the claim.
FACT: "There is no scientific basis for the conclusion that explosions brought downwards the towers," Lerner-Lam tells Popular Mechanics. "That representation of our work is categorically incorrect and not in context."
The report issued past Lamont-Doherty includes diverse graphs showing the seismic readings produced by the planes crashing into the two towers as well as the later collapse of both buildings. WhatReallyHappened.com chooses to display merely one graph (Graph 1), which shows the readings over a 30-infinitesimal fourth dimension span.
On that graph, the 8- and x-2d collapses appear—misleadingly—every bit a pair of sudden spikes. Lamont-Doherty'due south 40-second plot of the aforementioned data gives a much more detailed picture: The seismic waves—bluish for the Southward Tower, cherry-red for the North Tower—start pocket-size and and then escalate every bit the buildings rumble to the ground. Translation: no bombs.
WTC 7 Collapse
Claim: 7 hours after the ii towers fell, the 47-story WTC 7 collapsed. According to 911review.org: "The video conspicuously shows that information technology was not a plummet subsequent to a fire, but rather a controlled sabotage: amongst the Cyberspace investigators, the jury is in on this one."
WTC 7 stands among the rubble of the recently complanate Twin Towers. Damaged past falling debris, the building so endures a fire that rages for hours. Experts say this combination, non a demolition-style implosion, led to the roofline "kink" that signals WTC 7'south progressive collapse.
FACT: Many conspiracy theorists betoken to FEMA's preliminary written report, which said there was relatively light damage to WTC seven prior to its collapse. With the benefit of more time and resources, NIST researchers now back up the working hypothesis that WTC vii was far more compromised by falling debris than the FEMA study indicated. "The most important thing we found was that there was, in fact, concrete damage to the due south face of building vii," NIST's Sunder tells Popular Mechanics. "On about a third of the confront to the middle and to the bottom—approximately 10 stories—almost 25 percent of the depth of the building was scooped out." NIST besides discovered previously undocumented damage to WTC vii's upper stories and its southwest corner.
NIST investigators believe a combination of intense burn and astringent structural harm contributed to the plummet, though assigning the exact proportion requires more than research. Merely NIST's analysis suggests the fall of WTC 7 was an example of "progressive collapse," a procedure in which the failure of parts of a structure ultimately creates strains that cause the unabridged edifice to come down. Videos of the fall of WTC 7 evidence cracks, or "kinks," in the edifice's facade merely before the two penthouses disappeared into the structure, one after the other. The unabridged edifice fell in on itself, with the slumping east side of the structure pulling downwardly the westward side in a diagonal collapse.
Co-ordinate to NIST, there was one chief reason for the building'due south failure: In an unusual design, the columns nearly the visible kinks were carrying exceptionally big loads, roughly 2000 square feet of floor expanse for each floor. "What our preliminary analysis has shown is that if you have out just 1 column on one of the lower floors," Sunder notes, "it could cause a vertical progression of collapse so that the unabridged section comes down."
There are two other possible contributing factors still under investigation: Outset, trusses on the 5th and seventh floors were designed to transfer loads from one set up of columns to another. With columns on the south confront apparently damaged, high stresses would probable have been communicated to columns on the building'due south other faces, thereby exceeding their load-bearing capacities.
Second, a fifth-floor burn down burned for up to vii hours. "There was no firefighting in WTC 7," Sunder says. Investigators believe the fire was fed by tanks of diesel fuel that many tenants used to run emergency generators. Most tanks throughout the building were fairly small, merely a generator on the fifth floor was connected to a large tank in the basement via a pressurized line. Says Sunder: "Our current working hypothesis is that this pressurized line was supplying fuel [to the fire] for a long period of time."
WTC 7 might have withstood the physical damage it received, or the burn that burned for hours, just those combined factors—along with the building'southward unusual construction—were enough to prepare off the concatenation-reaction collapse.
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