main towers

On September 11, the North Tower (WTC 1) was hit by American Airlines Flight 11 and the South Tower (WTC 2) by United Airlines Flight 175, both Boeing 767 aircraft. The South Tower collapsed 56 minutes after impact, and the North Tower collapsed 102 minutes later.[40] An investigation by NIST concluded that the collapse was caused by a combination of damage to support columns and fireproof insulation caused by aircraft impacts, and weakening of columns and floors caused by fires started by aircraft fuel.[21] NIST found "no evidence corroborating alternative hypotheses suggesting that the WTC towers were brought down by controlled demolition with explosives placed before September 11, 2001."[41]

Physicist Steven E. Jones, among others, points to many descriptions from people who worked on the World Trade Center rubble pile that suggest that the presence of molten steel in the pile,[6][10]​ as well as a jet of molten metal that came out of the south tower before the collapse,[3]​ prove that there were temperatures higher than those produced by the fire. Jones has argued that the molten metal may have been elemental iron, a product of a thermite reaction. Jones and other researchers analyzed dust samples from the World Trade Center buildings and published their results of testing for nano-thermite in the dust.[10] Jones informed NIST of his findings and NIST responded that there was no "clear chain of custody" proving that the dust actually came from the WTC site. Jones invited NIST to conduct its own studies with the dust in NIST custody, but NIST has not done so.[11]​.

At NIST they discovered that the condition of the steel in the tower debris does not provide conclusive information about the state of the building before the fall and concluded that the material from the south tower was molten aircraft aluminum, which would have melted at lower temperatures than steel. NIST also noted that cutting through vertical columns would require placing a huge amount of thermite discreetly in high-security buildings, then igniting it remotely while remaining in contact with the columns.[21] An analysis by the Energy Materials Research Center showed that conventional thermite was unable to melt a column much smaller than those used in the World Trade Center.[42] Jones and others have responded that they no longer believe thermite was used. conventional, but rather a form of thermite called nano-thermite, a nanoenergetic material developed for military, propellant, explosive or pyrotechnic use. Historically, explosive applications of traditional thermites have been limited due to their relatively low energy release rates. But because nano-thermite is created from reactant particles as they approach the vicinity of the atomic scale, the energy release rates are much higher.[43]​.

The NIST report provides an analysis of the structural response of the building, only up to the point at which collapse begins, and states that the enormous kinetic energy transferred by the downward part of the building makes progressive collapse inevitable once an initial collapse occurs. A paper by Zdeněk Bažant) indicates that once the collapse began, the kinetic energy imparted by a section of the upper drop to the floor below was an order of magnitude greater than what the lower part could support.[2]​.

Engineers who have investigated the collapse generally disagree that controlled demolition is necessary to understand the structural response of buildings. Although the top of one of the towers tilted significantly, it could not have fallen into the street, they explain, because such a tilt would create enough stress on the ground floor (which acts as a pivot) that it would collapse long before the top had sufficiently shifted its center of gravity. In fact, they argue, there is very little difference between a progressive collapse with or without explosives in terms of the resistance that the structures can offer after the fall begins. Controlled demolition is traditionally carried out by starting from the bottom of buildings rather than the top, although there are exceptions depending on the structural design. Few dispute that the collapse began high at the point where the aircraft struck. Furthermore, any type of explosive would have to withstand the impact of airplanes.[6]​.

Members of the group Scholars for 9/11 Truth") have collected testimonies[46]​ of flashes and loud explosions immediately before the fall.[14]​[47]​ Eyewitnesses have repeatedly reported explosions occurring before the fall of the World Trade Center towers, and the organization "International Center for 9/11 Studies" has published videos obtained from NIST, along with indications of when those explosions were heard.[48]​ There are many types of loud, high-pitched noises that are not caused by explosives,[49]​ and seismographic records of the event show no evidence of explosions.[50]​ Physicist Steven E. Jones and others have argued that horizontal puffs of smoke seen during the collapse of the towers indicate that the towers had been brought down by controlled explosions.[51]​[52]​[53]​ NIST attributes these puffs to air pressure, created by the decrease in volume of the building that fell overhead, traveling through elevator shafts and emerging from one of the elevator doors that open on the lower levels.[54]​.

World Trade Center 7

Proponents of World Trade Center demolition theories allege that World Trade Center Building 7—a 47-story skyscraper that stood on Vesey Street north of the main portion of the World Trade Center site—was intentionally destroyed with explosives. Unlike the Twin Towers, World Trade Center 7 was not hit by a plane, although it was hit by debris from the Twin Towers and damaged by unfought fires that burned for seven hours, until it completely collapsed around 5:20 p.m. on September 11 (a new building has been erected in the place of the old one, opened in May 2006). Several videos of the collapse event exist in the public domain, allowing for comparative analysis from different perspective angles.[55] Proponents often point out that the collapse of 7 World Trade Center was not mentioned in the 9/11 Commission report and that the federal government body tasked with investigating the case, NIST, needed seven years to conduct an investigation of all the buildings and issue a report.[56]

In the PBS documentary America Rebuilds, which aired in September 2002, Larry Silverstein, owner of WTC 7 and tenant and insurance policy holder for the rest of the World Trade Center complex, recalled a conversation with the fire department in which doubts were expressed about containing the fires. Silverstein recalled saying: "We've had such a terrible loss of life, maybe the smartest thing to do is to pull out." "They made that decision to pull," he recalled, "and we saw the building collapse." Silverstein issued a statement saying it was the firefighting equipment, not the building, that was being pulled.[57][58][59]​.

In November 2010, Fox News journalist Geraldo Rivera invited members of a television ad campaign called "BuildingWhat?," a series of ads in which family members asked questions about 7 World Trade Center and called for an investigation into its collapse. Rivera stated that, "if explosives were involved, it would mean that the nastiest protesters of recent years [...] were right."[60] Days later, Rivera appeared on the Freedom Watch program with legal analyst and judge Andrew Napolitano on the Fox Business Network to discuss the "BuildingWhat?" ad campaign. Napolitano said: "It's hard for me to believe that [7 World Trade Center] collapsed on its own. It was gratifying to see that Geraldo Rivera is investigating it."[61] Fox News was heavily criticized by webcast shows Media Matters and Newsbusters, questioning the motives for the collapse of 7 World Trade Center by the media.[61]

Some proponents of the controlled demolition theories of the World Trade Center indicate that the 7th World Trade Center may have been demolished because it may have served as an operations center for the demolition of the Twin Towers, while others suggest that people in the government may have wanted to destroy key files located in the building pertaining to corporate fraud. The World Trade Center buildings housed dozens of federal, state, and local government agencies.[62] According to a statement reported by the BBC, film producer Dylan Avery of Loose Change believes that the destruction of the building was suspicious, as it housed some unusual tenants, including a clandestine CIA laboratory on the 25th floor, a detachment of the US Secret Service, the Securities and Exchange Commission, and the New York Command Center. emergencies.[62]​ Former chief counterterrorism advisor to the President, Richard Clarke, does not believe that 7 World Trade Center is a mystery, and said anyone could have rented space in the building.[57]​.

The 9/11 Commission Structural Engineering Community Rejects the Controlled Demolition Conspiracy Theory. The consensus is that the collapse of the World Trade Center buildings was fire-induced, driven by the severity of the collapse, an explanation that does not involve the use of explosives.[2][70]​.

The Institute of Structural Engineering of the American Society of Civil Engineers issued a statement calling for discussion of the NIST recommendations,[71]​ and the Institution of Structural Engineers of Great Britain published a statement in May 2002 upon receipt of the FEMA report, noting that the report expressed views similar to those of its professional group.[72]​.

Following Jones' publication of the article "Why, in fact, did the WTC buildings completely collapse?" Brigham Young University responded to Jones' "increasingly speculative and accusatory" statements by sending him on paid leave, and he was stripped of two classes in September 2006 pending a review of his statements and the investigation. Six weeks later, Jones withdrew from the university.[18]​ The structural engineering faculty at the university issued a statement saying that they "do not support Professor Jones' hypothesis."[3][19]​ On September 22, 2005, Jones gave a seminar on the hypothesis to a group of his colleagues in the Department of Physics and Astronomy at Brigham Young University. According to Jones, all but one of his colleagues agreed after the seminar that an investigation was in order and the only The dissident agreed to Jones's suggestions the next day.[19]

Civil Engineering Professor Zdeněk Bažant of Northwestern University, who was the first to offer a peer-reviewed publication of collapse theory, wrote "a few foreigners alleging a conspiracy with planted explosives" as an exception. Bažant and Verdure trace such "strange ideas" to a "false impression" that safety margins in the design would make collapse impossible. One of the effects of a more detailed model of progressive decay, They say, it could be the one that "ends the myth of planted explosives." In fact, Bažant and Verdure have proposed examining data from controlled demolitions in order to improve the progressive collapse model of towers, suggesting that progressive collapse and controlled demolition are not two different modes of failure (as the controlled demolition conspiracy theory assumes).[2]​.

Thomas Eager, professor of materials science and engineering at the Massachusetts Institute of Technology (MIT), also rejected the controlled demolition conspiracy theory.[3] Eagar remarked: "These people (in the 9/11 truth movement) use the reverse scientific method. They determine what happened, throw out all the data that doesn't fit their conclusion, and then hail their results as the only possible conclusion."[74]

Preparing a building for controlled demolition takes a lot of time and effort.[75]​ The walls of the tower would have had to be opened on dozens of floors.[6]​ Thousands of pounds of explosives, fuses and ignition mechanisms would have to be hidden from security and placed in the towers[6][76]​ without tens of thousands of people working at the World Trade Center noticing. account.[1]​[45]​[75]​[76]​[77]​[78]​ Referring to a conversation with Stuart Vyse, a psychology professor, in an article in the Hartford Advocate he asks: "How many hundreds of people would you need to acquire the explosives, plant them in the buildings, prepare the planes for the crash [...] and, perhaps most implausible of all, not breathe a single word of it conspiracy?".[79]​.

Larry Silverstein said, "We hope this report puts to rest the various 9/11 conspiracy theories that dishonor the men and women who lost their lives on that terrible day." Richard Gage, leader of the 9/11 Truth Group Architects and Engineers for the Truth, said: "How much longer do we have to endure the cover-up of how Building 7 was destroyed?" James Quintiere, a professor of fire protection engineering at the University of Maryland, who does not believe that explosives brought down the towers, questioned how the agency reached its conclusions, because, he notes, "They don't have the expertise in explosives," adding, however, that NIST wasted time hiring outside experts to consider such a thing.[80]​.

Issues surrounding the technical details of the fall of the World Trade Center buildings have been debated for years.[12] Theories of controlled demolition first appeared in October 2001.[1] Eric Hufschmid's book "Painful Questions: An Analysis of the September 11th Attack" in which the theory of controlled demolition is explicitly stated defended, was published in September 2002.[1]​ David Ray Griffin and Steven E. Jones") are the two most prominent defenders of the theory.[1]​ Griffin's book[13]​ The New Pearl Harbor, published in 2004,[14]​ has become a reference work for the 9/11 truth movement.[15]​ In the same year, Griffin published the book The 9/11 Commission Report: The omissions and distortions, in which he argues that flaws in the commission's report amount to a cover-up by government officials and says that the Bush administration was complicit in the 9/11 attacks.[16]​.

Steven E. Jones has been a leading academic voice for proponents of demolition theories.[17] In 2006, he published the article "Why did the WTC buildings completely collapse?" Brigham Young University reacted to Jones' "increasingly speculative and accusatory" statements by sending him on paid leave and excluding him from two classes in September 2006, pending a review of his statements and the research. Six weeks later, Jones withdrew from the university.[18]​ The structural engineering faculty at the university issued a statement saying that they "do not support Professor Jones' hypothesis."[3][19]​.

David Ray Griffin has questioned the "pancake collapse" theory suggested in the building performance study produced by the Federal Emergency Management Agency (FEMA).[20] The NIST report on the collapse of the WTC towers rejected that same theory in favor of a theory involving column failure.[21] In its final report, NIST stated that it "found no evidence to corroborate the alternative hypothesis suggesting that the WTC towers were toppled." by controlled demolition with explosives placed before September 11, 2001"[22]​ and published an FAQ (Frequently asked questions) on issues related to the topic on its website in August 2006.[21]​ The main elements of demolition theory have been refuted by mainstream engineering academics,[23]​ where the proponents are considered "foreigners".[2]​ Popular magazine Mechanics challenged the theories in the special report "Debunking the 9/11 Myths".[24]

Articles, letters, and comments by demolition advocates have been published in scientific and engineering journals. In April 2008, Steven E. Jones, Frank Legge, Kevin Ryan, Anthony Szamboti and James Gourley published a letter titled "Fourteen Points of Agreement with Official Government Reports on the Destruction of the World Trade Center" in The Open Civil Engineering Journal from Bentham Science Publishers.[25] A few months later, in July 2008, an article titled "Environmental Anomalies at the World Trade Center: Materials Testing" [26] Later that year, in October 2008, a commentary by James R. Gourley describing what he considers the fundamental errors was published in an article by Bažant and Verdure in the Journal of Engineering Mechanics. [27] And in April 2009, Danish chemist Niels H. Harrit, from the University of Copenhagen, and eight other authors published a paper in The Open Chemical Physics Journal from Bentham Science Publishers"), titled "Active thermitic material discovered in dust from the 9/11 WTC disaster." The article suggests that partially reacted chips of super-thermite, or nano-thermite, could be present in the dust samples.[28]​[29]​.

Internet sites and videos have contributed to the growth of the movement of people who support the theory that explosives destroyed the World Trade Center. The Architects and Engineers for 9/11 Truth website (AE911Truth) lists more than 1,700 architects and engineers as members.[30] The demolition theory often includes accusations that people within the US government planned or participated in the destruction of the Twin Towers to justify the invasion of Iraq and Afghanistan.[31] The theory features prominently in popular entertainment films such as Loose. Change,[32]​ as well as other more documentary-type films, such as 9/11: Blueprint for Truth, by San Francisco-area architect Richard Gage, which rely primarily on presenting scientific and engineering evidence for the demolition theory.[33]​.

While the mainstream press has a history of disparaging labels, descriptions, and interpretations of proponents of the demolition theory (for example, in 2006, New York magazine reported that a generation of "new conspiracy theorists are working on a secret history of New York's most terrible days."[34]​), the theory has been supported by a number of popular actors, musicians and politicians, including Charlie Sheen,[35]​[36]​ Willie Nelson,[37]​ former Minnesota Governor Jesse Ventura,[38]​ host Rosie O'Donnell,[39]​ and actors Ed Asner and Daniel Sunjata.

main towers

On September 11, the North Tower (WTC 1) was hit by American Airlines Flight 11 and the South Tower (WTC 2) by United Airlines Flight 175, both Boeing 767 aircraft. The South Tower collapsed 56 minutes after impact, and the North Tower collapsed 102 minutes later.[40] An investigation by NIST concluded that the collapse was caused by a combination of damage to support columns and fireproof insulation caused by aircraft impacts, and weakening of columns and floors caused by fires started by aircraft fuel.[21] NIST found "no evidence corroborating alternative hypotheses suggesting that the WTC towers were brought down by controlled demolition with explosives placed before September 11, 2001."[41]

Physicist Steven E. Jones, among others, points to many descriptions from people who worked on the World Trade Center rubble pile that suggest that the presence of molten steel in the pile,[6][10]​ as well as a jet of molten metal that came out of the south tower before the collapse,[3]​ prove that there were temperatures higher than those produced by the fire. Jones has argued that the molten metal may have been elemental iron, a product of a thermite reaction. Jones and other researchers analyzed dust samples from the World Trade Center buildings and published their results of testing for nano-thermite in the dust.[10] Jones informed NIST of his findings and NIST responded that there was no "clear chain of custody" proving that the dust actually came from the WTC site. Jones invited NIST to conduct its own studies with the dust in NIST custody, but NIST has not done so.[11]​.

At NIST they discovered that the condition of the steel in the tower debris does not provide conclusive information about the state of the building before the fall and concluded that the material from the south tower was molten aircraft aluminum, which would have melted at lower temperatures than steel. NIST also noted that cutting through vertical columns would require placing a huge amount of thermite discreetly in high-security buildings, then igniting it remotely while remaining in contact with the columns.[21] An analysis by the Energy Materials Research Center showed that conventional thermite was unable to melt a column much smaller than those used in the World Trade Center.[42] Jones and others have responded that they no longer believe thermite was used. conventional, but rather a form of thermite called nano-thermite, a nanoenergetic material developed for military, propellant, explosive or pyrotechnic use. Historically, explosive applications of traditional thermites have been limited due to their relatively low energy release rates. But because nano-thermite is created from reactant particles as they approach the vicinity of the atomic scale, the energy release rates are much higher.[43]​.

The NIST report provides an analysis of the structural response of the building, only up to the point at which collapse begins, and states that the enormous kinetic energy transferred by the downward part of the building makes progressive collapse inevitable once an initial collapse occurs. A paper by Zdeněk Bažant) indicates that once the collapse began, the kinetic energy imparted by a section of the upper drop to the floor below was an order of magnitude greater than what the lower part could support.[2]​.

Engineers who have investigated the collapse generally disagree that controlled demolition is necessary to understand the structural response of buildings. Although the top of one of the towers tilted significantly, it could not have fallen into the street, they explain, because such a tilt would create enough stress on the ground floor (which acts as a pivot) that it would collapse long before the top had sufficiently shifted its center of gravity. In fact, they argue, there is very little difference between a progressive collapse with or without explosives in terms of the resistance that the structures can offer after the fall begins. Controlled demolition is traditionally carried out by starting from the bottom of buildings rather than the top, although there are exceptions depending on the structural design. Few dispute that the collapse began high at the point where the aircraft struck. Furthermore, any type of explosive would have to withstand the impact of airplanes.[6]​.

Members of the group Scholars for 9/11 Truth") have collected testimonies[46]​ of flashes and loud explosions immediately before the fall.[14]​[47]​ Eyewitnesses have repeatedly reported explosions occurring before the fall of the World Trade Center towers, and the organization "International Center for 9/11 Studies" has published videos obtained from NIST, along with indications of when those explosions were heard.[48]​ There are many types of loud, high-pitched noises that are not caused by explosives,[49]​ and seismographic records of the event show no evidence of explosions.[50]​ Physicist Steven E. Jones and others have argued that horizontal puffs of smoke seen during the collapse of the towers indicate that the towers had been brought down by controlled explosions.[51]​[52]​[53]​ NIST attributes these puffs to air pressure, created by the decrease in volume of the building that fell overhead, traveling through elevator shafts and emerging from one of the elevator doors that open on the lower levels.[54]​.

World Trade Center 7

Proponents of World Trade Center demolition theories allege that World Trade Center Building 7—a 47-story skyscraper that stood on Vesey Street north of the main portion of the World Trade Center site—was intentionally destroyed with explosives. Unlike the Twin Towers, World Trade Center 7 was not hit by a plane, although it was hit by debris from the Twin Towers and damaged by unfought fires that burned for seven hours, until it completely collapsed around 5:20 p.m. on September 11 (a new building has been erected in the place of the old one, opened in May 2006). Several videos of the collapse event exist in the public domain, allowing for comparative analysis from different perspective angles.[55] Proponents often point out that the collapse of 7 World Trade Center was not mentioned in the 9/11 Commission report and that the federal government body tasked with investigating the case, NIST, needed seven years to conduct an investigation of all the buildings and issue a report.[56]

In the PBS documentary America Rebuilds, which aired in September 2002, Larry Silverstein, owner of WTC 7 and tenant and insurance policy holder for the rest of the World Trade Center complex, recalled a conversation with the fire department in which doubts were expressed about containing the fires. Silverstein recalled saying: "We've had such a terrible loss of life, maybe the smartest thing to do is to pull out." "They made that decision to pull," he recalled, "and we saw the building collapse." Silverstein issued a statement saying it was the firefighting equipment, not the building, that was being pulled.[57][58][59]​.

In November 2010, Fox News journalist Geraldo Rivera invited members of a television ad campaign called "BuildingWhat?," a series of ads in which family members asked questions about 7 World Trade Center and called for an investigation into its collapse. Rivera stated that, "if explosives were involved, it would mean that the nastiest protesters of recent years [...] were right."[60] Days later, Rivera appeared on the Freedom Watch program with legal analyst and judge Andrew Napolitano on the Fox Business Network to discuss the "BuildingWhat?" ad campaign. Napolitano said: "It's hard for me to believe that [7 World Trade Center] collapsed on its own. It was gratifying to see that Geraldo Rivera is investigating it."[61] Fox News was heavily criticized by webcast shows Media Matters and Newsbusters, questioning the motives for the collapse of 7 World Trade Center by the media.[61]

Some proponents of the controlled demolition theories of the World Trade Center indicate that the 7th World Trade Center may have been demolished because it may have served as an operations center for the demolition of the Twin Towers, while others suggest that people in the government may have wanted to destroy key files located in the building pertaining to corporate fraud. The World Trade Center buildings housed dozens of federal, state, and local government agencies.[62] According to a statement reported by the BBC, film producer Dylan Avery of Loose Change believes that the destruction of the building was suspicious, as it housed some unusual tenants, including a clandestine CIA laboratory on the 25th floor, a detachment of the US Secret Service, the Securities and Exchange Commission, and the New York Command Center. emergencies.[62]​ Former chief counterterrorism advisor to the President, Richard Clarke, does not believe that 7 World Trade Center is a mystery, and said anyone could have rented space in the building.[57]​.

The 9/11 Commission Structural Engineering Community Rejects the Controlled Demolition Conspiracy Theory. The consensus is that the collapse of the World Trade Center buildings was fire-induced, driven by the severity of the collapse, an explanation that does not involve the use of explosives.[2][70]​.

The Institute of Structural Engineering of the American Society of Civil Engineers issued a statement calling for discussion of the NIST recommendations,[71]​ and the Institution of Structural Engineers of Great Britain published a statement in May 2002 upon receipt of the FEMA report, noting that the report expressed views similar to those of its professional group.[72]​.

Following Jones' publication of the article "Why, in fact, did the WTC buildings completely collapse?" Brigham Young University responded to Jones' "increasingly speculative and accusatory" statements by sending him on paid leave, and he was stripped of two classes in September 2006 pending a review of his statements and the investigation. Six weeks later, Jones withdrew from the university.[18]​ The structural engineering faculty at the university issued a statement saying that they "do not support Professor Jones' hypothesis."[3][19]​ On September 22, 2005, Jones gave a seminar on the hypothesis to a group of his colleagues in the Department of Physics and Astronomy at Brigham Young University. According to Jones, all but one of his colleagues agreed after the seminar that an investigation was in order and the only The dissident agreed to Jones's suggestions the next day.[19]

Civil Engineering Professor Zdeněk Bažant of Northwestern University, who was the first to offer a peer-reviewed publication of collapse theory, wrote "a few foreigners alleging a conspiracy with planted explosives" as an exception. Bažant and Verdure trace such "strange ideas" to a "false impression" that safety margins in the design would make collapse impossible. One of the effects of a more detailed model of progressive decay, They say, it could be the one that "ends the myth of planted explosives." In fact, Bažant and Verdure have proposed examining data from controlled demolitions in order to improve the progressive collapse model of towers, suggesting that progressive collapse and controlled demolition are not two different modes of failure (as the controlled demolition conspiracy theory assumes).[2]​.

Thomas Eager, professor of materials science and engineering at the Massachusetts Institute of Technology (MIT), also rejected the controlled demolition conspiracy theory.[3] Eagar remarked: "These people (in the 9/11 truth movement) use the reverse scientific method. They determine what happened, throw out all the data that doesn't fit their conclusion, and then hail their results as the only possible conclusion."[74]

Preparing a building for controlled demolition takes a lot of time and effort.[75]​ The walls of the tower would have had to be opened on dozens of floors.[6]​ Thousands of pounds of explosives, fuses and ignition mechanisms would have to be hidden from security and placed in the towers[6][76]​ without tens of thousands of people working at the World Trade Center noticing. account.[1]​[45]​[75]​[76]​[77]​[78]​ Referring to a conversation with Stuart Vyse, a psychology professor, in an article in the Hartford Advocate he asks: "How many hundreds of people would you need to acquire the explosives, plant them in the buildings, prepare the planes for the crash [...] and, perhaps most implausible of all, not breathe a single word of it conspiracy?".[79]​.

Larry Silverstein said, "We hope this report puts to rest the various 9/11 conspiracy theories that dishonor the men and women who lost their lives on that terrible day." Richard Gage, leader of the 9/11 Truth Group Architects and Engineers for the Truth, said: "How much longer do we have to endure the cover-up of how Building 7 was destroyed?" James Quintiere, a professor of fire protection engineering at the University of Maryland, who does not believe that explosives brought down the towers, questioned how the agency reached its conclusions, because, he notes, "They don't have the expertise in explosives," adding, however, that NIST wasted time hiring outside experts to consider such a thing.[80]​.