Introduction to the
Science of 9/11


Overview of 9/11

Events on 9/11
Timeline Since 9/11
The 9/11 Truth Movement

The Twin Towers

NIST's Final Report
Evidence Ignored by NIST
Evidence Summary

Building 7 (WTC7)

Introductory Video for WTC7
Official Investigations
Evidence Ignored by NIST

How Credible is NIST?

Political Agency
Molten Metal

Introduction to the Science of 9/11

This introduction describes the official story, in the case of the World Trade Center as researched by NIST, and contrasts it with the scientific findings of independent researchers.


The South Tower (WTC2) destruction looks like a violent explosion

South Tower

To read the newspapers or listen to the radio, one would think that questions about the official account of events of September 11, 2001 come only from a fringe group. But this is an illusion, consciously propagated, we believe, by government agents and their mouthpieces in the mainstream press. In a series of public opinion polls, roughly half of Americans were shown to doubt that the government is telling us the truth about 9/11, and the numbers are growing each year.

The truth is that among independent scientists with no axe to grind, a large proportion of those who look into the 9/11 evidence find grounds for doubt. A few have put their reputations and careers at risk in order to speak out about that evidence, and what they see. In 2010, larger numbers of scientists have joined together and contributed their expertise to create this web site.

It doesn't take a PhD to understand that the official account of the 9/11 attacks contains contradictions and physical impossibilities. One of the strongest reasons for doubting the official version is common sense. Still, sometimes our common sense can fool us, and, especially where such serious charges are being levelled, it is wise to consult scientific expertise as well.

One good place to begin is this video of the North Tower of the World Trade Center (WTC1). Does it look like a building collapsing under its own weight? Or does it look like a descending series of explosions, progressing at about the same rate as the falling debris? Jet planes are fueled with kerosene, which is not a high explosive and cannot sever steel or pulverize concrete.

Scientists for 9/11 Truth asks you to read and consider the evidence we present here. We ask you to present the arguments to an independent scientist of your acquaintance, someone whom you know and trust. Write back to us, please! Tell us what you think, and what you have heard from scientists whom you personally know and trust.

A word about "conspiracy theories". This term has been used to dismiss questions about 9/11, and to suggest that they are unworthy of serious debate. Professor Charles Pidgen has written: "[T]o call someone “a conspiracy theorist” is to suggest that he is irrational, paranoid or perverse. Often the suggestion seems to be that conspiracy theories are not just suspect, but utterly unbelievable, too silly to deserve the effort of a serious refutation. It is a common ploy on the part of politicians to dismiss critical allegations by describing them as conspiracy theories." (See "Conspiracy Theories and the Conventional Wisdom Revisited" from the Selected Publications of Charles Pigden, Otago University.)

But in the case of 9/11, there are hundreds of insiders who have come out to tell their piece of the story, sometimes at great personal cost. Some of these are police, firefighters, and first–responders. Some are 9/11 survivors, and the family members of those who died in the Twin Towers.

Both chairmen of the official 9/11 Commission have written to warn us that key questions were not answered in the 9/11 hearings, that they were not allowed to question witnesses, and that their conclusions were tainted. Much of the testimony by Khalid Sheikh Mohammed, accused of master-minding 9/11, was obtained through torture. The Commission was a governmental body whose chairman, Thomas Kean, was appointed by President George W. Bush; the other members were appointed by Congress; and the executive director, Philip Zelikow, was essentially a member of the Bush White House. Former New York Times writer Philip Shenon points out in his book, "The Commission," that Zelikow had secretly written a detailed outline of the Commission's report before his research staff had even begun its work.

The encylopedic evidence that refutes the official account of the events of September 11th is freely available in photos, videos, and government reports. Scientists for 9/11 Truth presents some of this evidence on its website, and is calling for an open debate.

Introduction to the Science of 9/11

Overview of 9/11

Summary of Events on 9/11

Buildings at the World Trade Center, New York City, are designated as WTC1, WTC2, and so on. WTC1 and WTC2 (the Twin Towers) are each 110 stories high, while WTC7 (Building 7) is 47 stories high.

Four airliners go off course:

The World Trade Center Destructions ensue:

The Official Story is born:

There has been little or no official attempt to prove this story with physical evidence:

There is a multitude of evidence that refutes the official story.

Introduction to the Science of 9/11

Overview of 9/11

Timeline of Major Events Since 9/11

September 11, 2001: Two planes crash into the World Trade Center. Three major buildings (WTC1, WTC2 [the Twin Towers], and WTC7) are completely destroyed, and others are severely damaged.

May, 2002: FEMA (Federal Emergency Management Agency) issues its final report, finding high temperature corrosion and sulfidation of steel in the Towers and WTC7. The report stated that the best explanation of the collapse, namely fire, had a low probability of being correct. See Appendix C (Limited Metallurgical Examination) of the FEMA World Trade Center Building Performance Study.

May 30, 2002: Cleanup efforts end (after 261 days, 24 hrs/day). All debris is removed. Despite objections, very little of the debris is examined to determine the cause of the building collapses.

October 1, 2002: The National Institute of Standards and Technology (NIST) is commissioned to investigate the "collapses."

Congress charges NIST to:

"Determine why and how WTC1 and WTC2 collapsed following the initial impacts of the aircraft and why and how WTC7 collapsed;"

November 27, 2002: Congress and the President create the 9/11 Commission after 442 days of agitation by 9/11 victims' family members. The Commission is headed by Thomas H. Kean (Chair) and Lee H. Hamilton (Vice Chair). The Executive Director is Philip Zelikow, an indiviual with strong ties to the Bush Administration.

Stated aim of the 9/11 Commission: "to provide the fullest possible account of the events surrounding 9/11"

July 26, 2004: The 9/11 Commission Report (comprising 567 pages) is released. In the report, there is:

September, 2005: After an investigation consisting mainly of computer simulations, NIST releases its final report on WTC1 and WTC2.

NIST's Conclusion:

Aircraft and fire damage caused the "collapses," but "…we are unable to provide a full explanation of the total collapse."

August 26, 2008: In a public session on NIST's WTC7 preliminary report, a high school physics teacher, David Chandler, challenges NIST's assertion that free fall had not occurred. Chandler shows that for the first 105 feet, WTC7 was in fact in free fall. In its final report, NIST acknowledges this fact, but continues to deny that explosives were used.

November, 2008: NIST releases its final report on WTC7.

NIST's Conclusion:

Thermal expansion of steel from fires caused the "collapse." NIST's study of WTC7 was almost entirely computer simulated.

Introduction to the Science of 9/11

Overview of 9/11

The 9/11 Truth Movement

From the start, many individuals world–wide questioned the official story of 9/11 that was promulgated within 48 hours of the events themselves. Newscasters on 9/11/01 gave their impressions freely, likening the World Trade Center building collapses to known instances where explosives were used to knock a building down. Within 48 hours the candid observations of newscasters ceased. While the Tower destructions were shown over and over again on mainstream television channels, the fall of WTC7 was shown but once, and rarely thereafter. It was, and still is, a source of amazement to most people that the US government, having ostensibly failed to prevent the "attacks," was nevertheless able, within the space of a day or two, to name most of the so-called "hijackers" of the four airplanes. The names provided indicated a Middle Eastern origin.

Discrepancies in the official story appeared almost immediately. The flight lists released by the airlines involved contained no passengers with Middle Eastern names. As the events were studied, more and more questions arose, particularly about the speed and nature of the Twin Towers' "collapses." In a feat of apparent scholarship within two days of the events, Zdenek Bazant and Yong Zhou published a theoretical paper purporting to show how the Towers' collapse could have occurred from the damage caused by the airplane impacts and the ensuing fires. Subsequently, other scholars and scientists put forward substantial criticisms of this paper. From these beginnings, a world–wide movement, now known as the 9/11 Truth Movement, has emerged.

The evidence for the central conclusion of the 9/11 Truth Movement — that the official story is false — has been created by thousands of individuals who care deeply about the truth. This movement includes citizens from all walks of life in most countries of the world. Many professional organizations have grown up, as can be seen through an internet search based on the words "for 9/11 Truth." Independent research is on-going in many different areas.

One of the more significant discoveries by independent scientists is that of red-gray chips containing unreacted nano-thermite in the WTC dust.

January, 2008: Independent scientists confirm the presence in the WTC dust of micro-spheres with high iron content, along with other species requiring extremely high temperatures. The iron micro-spheres had previously been observed by other laboratories. Iron micro-spheres are formed as a result of the thermite reaction. These scientists noted that the "temperatures required for the molten sphere-formation and evaporation of materials as observed in the WTC dust are significantly higher than temperatures associated with the burning of jet fuel and office materials in the WTC buildings."

March, 2009: A team of nine international scientists announces that WTC dust samples contain unreacted nano–thermite. (The by–products of the thermite reaction, iron–rich microspheres, were discovered earlier by several different investigators).

In the remainder of this Introduction to the Science of 9/11, we focus almost exclusively on the World Trade Center. We hope eventually to have material on other features of 9/11, including the Pentagon and the event at Shanksville, Pa.

Introduction to the Science of 9/11

The Twin Towers, WTC1 and WTC2

Construction of the Twin Towers

Figure 1: WTC Towers Floor Plan

This figure shows the floor plan with core area and truss layout. Additional trusses spanned the entire width of the building, and also ran parallel to the core short sides.

WTC Towers floor plan

Figure 2: WTC Towers Core Column Cross–section

This figure shows the cross–section of a smaller core column, about halfway up. At the base of the building, the steel was 5 inches thick, and core columns were 54 inches x 22 inches. At the top, the core columns were ¼ inch thick.

WTC Core Column Cross–section

Figure 3: WTC Towers Spandrel Plates and Floor Trusses

This figure shows the perimeter column/spandrel assembly and floor structure.

The perimeter columns were connected in groups of three, three stories high, using spandrel plates. The perimeter columns were square, 14 inches on a side. Note the floor trusses and steel fluted floor decking. Knuckles/straps handle shear transfer.

WTC Spandrel Plates and Floor Trusses

Figure 4: WTC North Tower During Construction

This figure shows the 236 outer steel columns (aluminum clad), and 47 massive steel core columns.

WTC North Tower During Construction

Introduction to the Science of 9/11

The Twin Towers, WTC1 and WTC2

NIST's Final Report on the Destruction of the Twin Towers

Congress' Charge to NIST:

"Determine why and how WTC1 and WTC2 collapsed following the initial impacts of the aircraft and why and how WTC7 collapsed;"

NIST's Final Report on WTC1 and WTC2 was published in September, 2005.

NIST's Plan:

Because of the "scarcity of physical evidence," NIST's plan was to:

Steel Temperatures and Fire:

Under the best conditions, jet fuel (kerosene) fires would not reach above 1000° C. WTC1 and WTC2 fires were probably no hotter than 650 to 700° C (MIT professor Thomas Eagar). Evidence shows the fires were probably much less hot.

NIST Experiments/Testing did not substantiate NIST's model:

NIST's treatment of the Actual Collapses:

In NIST's 10,000 page report, there is less than one page on the actual collapse. In NCSTAR1 Section 6.14.4, Events Following Collapse Initiation, NIST makes the following points and claims:

  1. "structure below … offered minimal resistance"
  2. "potential energy released by … the large building mass far exceeded the capacity of the intact structure below to absorb [it]"
  3. "building section came down essentially in free fall"
  4. the" falling mass … compressed the air … forcing … smoke and debris, out the windows"
  5. "No corroborating evidence … for controlled demolition using explosives"

Response of independent scientists to NIST's (numbered) points above:

  1. Why minimal resistance? This is an observation that requires explanation.
  2. NIST needs a calculation. Independent calculations show this is not true (Hoffman).
  3. Another observation. But where is the explanation?
  4. This does not explain the ejection of tons of steel beams laterally for hundreds of feet.
  5. NIST ignored all eye–witness accounts of explosions, the molten steel, corroded steel with sulfidation, and never tested the dust for explosive residue or its by–products.

NIST's Statement:

"Some 200 technical experts—including about 85 career NIST experts and 125 leading experts from the private sector and academia—reviewed tens of thousands of documents, interviewed more than 1,000 people, reviewed 7,000 segments of video footage and 7,000 photographs, analyzed 236 pieces of steel from the wreckage performed laboratory tests and sophisticated computer simulations of the sequence of events that occurred from the moment the aircraft struck the towers until they began to collapse."

Despite all this, a high school physics teacher, David Chandler, found a simple but MAJOR error and possible fraud in NIST's "science."

NIST's Conclusions:

NIST: "… we are unable to provide a full explanation of the total collapse."

Summary and Rebuttal:

Never before or since September 11, 2001, has a steel–framed building collapsed from the effects of fire. NIST's models depend on stripping of insulation and fire temperatures of 1000° C.

However, there is no actual physical evidence for NIST's proposed:

The towers were built to withstand the impact of a Boeing 707 traveling at 600 mph. The Boeing 767s, though 20% larger, were traveling more slowly (400 and 540 mph) and would have been less destructive.

NIST (Final report, p. 144): "To the extent that the simulations deviated from the photographic evidence or eyewitness reports, the investigators adjusted the input."

The Towers' "collapses" defied all expectations. One would expect:

Instead, there was catastrophic, rapid, total destruction:

NIST 's investigation ended before the actual "collapses" began and ignored the many independent pieces of evidence that point to controlled demolition. Most indicators of the controlled demolition of a structure appear after collapse begins.This evidence is discussed in the following sections.

Introduction to the Science of 9/11

The Twin Towers, WTC1 and WTC2

Comparison with Other Steel–framed Building Fires

Steel is a good conductor of heat, and quickly transmits heat to other, cooler portions of the steel structure.

1988: First Interstate Bank Building in Los Angeles. Fires raged for 3.5 hours and gutted 5 of this building's 62 floors, but there was no significant structural damage (FEMA, 1988).

1991: Philadelphia's One Meridian Plaza. Huge fire lasted for 18 hours and gutted 8 of the building's 38 floors, but, said the FEMA report, although "[b]eams and girders sagged and twisted . . . under severe fire exposures. . . , the columns continued to support their loads without obvious damage" (FEMA, 1991).

2004: Caracas, 50–story building. Fire raged for 17 hours, completely gutting the building's top 20 floors, and yet it did not collapse (Nieto, 2004).

These fires, unlike the Towers' fires, were hot enough to break windows. The Towers' fires lasted for only 56 (WTC2) and 101 (WTC1) minutes.

2005: The Windsor building in Madrid, a 32–storey, steel–reinforced concrete building, burned for almost 24 hours, completely engulfing the upper 10 stories.

Figure 5: Windsor building fire

This figure shows the Windsor building before and after a fire.

Windsor building during fire

Windsor building, Madrid, steel–reinforced concrete. February, 2005. Concrete, a poor conductor of heat, is much more susceptible to fire damage.

Windsor building after fire

Result: Six upper floors partially collapsed

Introduction to the Science of 9/11

The Twin Towers, WTC1 and WTC2

Evidence for the Twin Towers Ignored or Unexplained by NIST

Explosions Before and During the Destruction

Figure 6: North Tower "Collapse" at Start

The North Tower is consumed in a vast eruption as would be produced by a choreographed cascade of thousands of small blasts.

WTC North Tower at Start of Collapse

Sudden onset of "collapse"

The Towers fell straight down through the path of greatest resistance

Horizontal ejection of materials – but force of gravity is vertical

Figure 7: Impaled Steel Columns

Steel columns impaled in floor 20 of the World Financial Center building 3 (WFC3) hundreds of feet from the Towers.

Impaled Steel Columns

Figure 8: WTC Debris Fields

Schematic depiction of areas of collapse debris impact, based on aerial photographs and documented damage (FEMA, 2002). Striped areas indicate predominant locations of exterior steel columns. Inner circles indicate approximate radius of exterior steel columns and other heavy debris. Outer circles indicate approximate radius of aluminum cladding and other lighter debris. Heavy Xs show where exterior steel columns were found outside the predominant debris areas.

The Towers were 208 ft x 208 ft (floor area). Small debris circle diameter = 735 ft. Large debris circle diameter = 1080 ft.

WTC Debris Fields

For another map showing the location of debris that fell on the Winter Garden, see this diagram. Note: To determine the scale, use 208 feet for each side of the Twin Towers.

Demolition rings

The towers fell at near free–fall acceleration

Most materials (concrete, steel floor decking, furniture, bodies) were pulverized

Huge, pyroclastic dust flows – similar to those from volcanic eruptions

Figure 9: North Tower "Collapse" – One Minute After Start

Within one minute of the North Tower's collapse, the mammoth cloud of thick dust engulfed most of the southern end of Manhattan.

North Tower

Evidence of extremely high temperatures – molten steel present

Anomalous spikes of chemicals in the WTC air

The above observations are best explained by the physical release of materials from energetic nano–composites.

Long–burning Fires

WTC Dust (inches thick over wide areas) contains:

Figure 10: Red–Gray Chip

Red–Gray Chip

Red–Gray Chip

Introduction to the Science of 9/11

The Twin Towers, WTC1 and WTC2

Summary of Evidence for the Twin Towers

The Scientific Method

The scientific method considers ALL the observations, data, results of experiments, and so on, and seeks the theory that addresses and explains all or most of the relevant data.

Table 1
Summary of Evidence for the Twin Towers

Observation NIST Theory
Damage, fire, gravity–driven
Controlled Demolition
Using explosives
Addressed? Can explain? Addressed? Can explain?
Steel–framed buildings have never
before or since collapsed from fire
Explosions before/during collapse NO NO YES YES
Sudden onset of collapse NO NO YES YES
Steel beam ejection NO NO YES YES
Demolition rings NO NO YES YES
Near free fall NO NO YES YES
Pulverization of materials NO NO YES YES
Pyroclastic dust flows NO NO YES YES
Molten steel NO NO YES YES
Steel corrosion NO NO YES YES
Air anomalies NO With difficulty YES YES
Long–burning fires NO With difficulty YES YES
Iron microspheres in dust NO NO YES YES
Nano–thermite in dust NO NO YES YES

NIST's Investigation Was Unscientific!

George Bush (2001): Let us not tolerate "outrageous conspiracy theories about the attacks of 11 September."

Which of the Above Theories is Outrageous?

Introduction to the Science of 9/11

Building 7, WTC7

Introductory Video for WTC7

Architects & Engineers - Solving the Mystery of WTC 7 - :

This 15 minute video is an excellent introduction to the science of the destruction of WTC7. It is narrated by well-known actor Ed Asner, and features many of our members.

Introduction to the Science of 9/11

Building 7, WTC7

Official Investigations of What Happened to WTC7

FEMA Investigation Of WTC7's Destruction:

After 9/11, FEMA, the Federal Emergency Management Agency, was given sole discretion to investigate WTC7. However:

Timeline of the NIST Investigation of WTC7:

NIST's November 2008 Final Report – read the report:

During the public comment period, August 2008:

NIST's Solution was entirely computer modeled. NIST maintained that:

Figure 11: NIST's WTC7 Plan view of regions for collapse initiation

The diagram reflects NIST's theory of the "collapse." According to NIST, there was some damage from falling debris from WTC1 that started some small fires. This caused an unprecedented "collapse" of a steel–framed building. "Collapse" occured at 5:20 pm on 9/11, after many warnings.

NIST's WTC7 Plan view of regions for collapse initiation

There are many problems with NIST's theory that suggest fraud. See David Ray Griffin's "The Mysterious Collapse of World Trade Center 7," Olive Branch Press, 2010.

NIST's Theory for WTC7 is almost pure speculation. There is no direct evidence for high temperature fires, expansion of girders, or failure of columns due to fire.

Introduction to the Science of 9/11

Building 7, WTC7

Evidence for WTC7 Ignored or Unexplained By NIST

Physical Evidence for the Controlled Demolition of WTC7 includes:

Eye–witness Evidence for the Controlled Demolition of WTC7 includes:

Anecdotal Evidence for the Controlled Demolition of WTC7:

Circumstantial Evidence for the Controlled Demolition of WTC7 includes:


NIST postulated the least likely explanation for the destruction of WTC7, and ignored all other physical and other evidence.

NIST's assumptions or inputs used in its computer modeling are open to severe criticism. Also, the details of the modeling program are not available for independent review.

NIST's theory and approach lack scientific credibility.

Introduction to the Science of 9/11

How Credible is NIST Scientifically?

NIST As a Political Agency

NIST is an agency of the United States Department of Commerce.

During the period 2004 – 2006, more than 15,000 scientists, including 52 Nobel laureates and 63 recipients of the National Medal of Science, signed a statement accusing the current administration of "distortion of scientific knowledge for partisan political ends."

NIST and Molten Metal

NIST's 2005 Final report for the Towers ignores the issue of molten metal. The 2006 NIST AFAQ (Answers to Frequently–Asked Questions) publication has this exchange:

Q: "Why did the NIST investigation not consider reports of molten steel in the wreckage from the WTC towers?"

A: "NIST investigators and [other] experts … found no evidence that would support the melting of steel in a jet–fuel ignited fire in the towers prior to collapse."

As can be seen, NIST completely avoids the question. It was the "collapse" mechanism that produced the molten steel!

NIST on WTC7 Freefall

In their August 26, 2008 Technical Briefing/Draft for Public Comment, NIST claimed that 17 floors of WTC7 disappeared from view in 5.4 seconds – about 1.5 seconds, or 40%, more time than for free fall to happen. This, NIST stated, is "consistent with physical principles."

The lead NIST investigator, Shyam Sunder, stated: "[A] free fall time would be an object that has no structural components below it." "there was structural resistance … in this particular case."

In the NIST (November 2008) Final report on WTC7, NIST conceded a period of free fall. They recognized three stages: (1) a period of slow descent (2) a period of free fall – 105 feet for 2.25 seconds (3) a period of decreasing acceleration. Total time 5.4 seconds for 17 floors to disappear from view.

There is now no mention anywhere of this being "consistent with physical principles." NIST admits free fall occurred, but never addresses the physical implications of free fall!

NIST and Explosives

Even though National Fire Protection Agency guidelines (NFPA 921) require that, in the case of "high–order" damage, tests be made for explosives, NIST made no such tests.

When NIST spokesperson Michael Newman was challenged by Hartford Advocate reporter Jennifer Abel on this glaring omission in the WTC report, the following dialog ensued:

ABEL: "… what about that letter where NIST said it didn't look for evidence of explosives?"

NEWMAN: "Right, because there was no evidence of that."

ABEL: "But how can you know there's no evidence if you don't look for it first?"

NEWMAN: "If you're looking for something that isn't there, you're wasting your time … and the taxpayer's money."

Newman's response is completely at odds with the NFPA guidelines, as well as with the scientific method.

There is something there! – unexploded nanothermite and the by–products of a thermite reaction – iron–rich microspheres!