The American government could not conspire to buy a ham sandwich.

Conspiracy requires:

1) competency

and

2) secrecy.

If a guy can't get a blowjob under the Oval office desk without some ugly old secretary finding out about it and causing him to be impeached, there are no holographic planes and controlled demolitions.

Come on. At least one person who designed the holograms or set the explosives (or his disgruntled ex-wife) would be ready to cash in on the book deal.

--abc

Gravity, alas, was in play normally in New York that day. What was wrong from the moment WTC was designed on the cheap remember - that was its initial "selling point," were the floor "L" joints. It was a miracle they held their own floors for as long as they did, let alone others crashing on top. Remember too, the elevator columns were blown out, having never had reinforcement – so no internal support; just burned away ply board.

And Mr. Owen, do see "United 93" - well, see it, if you want to know about "where were the interceptors"? It's all there.

And all of us should have, by now, noticed we really don't have a military or any intelligence agencies capable of creating cleaverly designed alternatives to the truth, or more problematic recognizing cleaverly designed alternatives to the truth. Dream on.

Elementary HS physics may not quite be up to the task of explaining a large building's collapse.

Absolutely, but it can tell you about the upper limits of the possible speed of collapse, which is significantly less than free-fall. One of the limiting factors is the conservation of momentum. Gravity is the only force that speeds up the fall.

Conservation of momentum holds only in systems in which there are no forces acting on the masses.

I think you're thinking "no external forces" - i.e. no forces from outside the system. If we start considering gravity to be some mysterious unknowable force, or that anything can happen to momentum without forces acting, then we'd better stop flying for a start.

The reason it's relevant is because following the official "pancake theory", each floor was stationary when hit by the floor above, and the momentum of that floor would have slowed the falling mass from above. Gravity does not somehow cancel this effect.

The velocity of a falling object is a factor not only of the force of gravity and its mass (which, I suppose...

The acceleration due to gravity does not vary according to mass, as Galileo Galilei worked out some time ago. Air resistance, which you mention, brings mass into the velocity equation. However, it would cause the descent to slow down. The issue here is that the descent was too fast.

The slowdown experienced as a result of crushing a lower floor would likely be well within the margin of error for any reasonable estimate.

Oh well, if you say its likely to be within a reasonable estimate, then that's all right then isn't it. QED. Nicely argued. Now for the extra points, can you show your workings?

nerdnam chimes in with:

Think of a bullet going through a leaf.

Think again. So what are you saying here? - that the upper floors of the buildings were super heavy but the lower floors were much lighter? Paper? Novel building design.

It's impossible to prove anything true, but it only takes one counter-example to prove something false. If you need a counter-example with simpler and more intuitive physics, then the pools of red-hot molten metal at the bottom of the towers, weeks after 9-11, is all you need to know. Worry about the physics of falling buildings after you've debunked that mystery.

First of all thanks to those who at least attempt to refute what I and of course all the other "tin foil hat" wearers say. I am open to any point by point refutation of what I or others say in regard to explaining what happened that day. Some of the best, most detailed "conspiracy" posts here have only been sneered at, or the poster has been called names. And thank-you to abc for your supporting me against the attack that claimed I am insensitive to victims, "dangerous" even (so much for free speech). Quite the opposite, I have every respect for the victims, I seek only to do them the honour of seeking the truth about how they died and why. If I am wrong I am wrong, but I am not attacking or dishonouring anyone!

Mr. Levine also has done us a service by his analysis which is, at least, an honest attempt to refute my argument. I had not given much thought to air resistance, wrapped up as I was in considering the numerous eyewitnesses who heard and saw explosions in the basement, the lobby elevators, and the lower floors. My attention was also distracted by the fact that the tower that was hit second collapsed first - even though it is clear from the video that most of the aviation fuel blew out the side, and that the smoke had died down and turned black (indicating oxygen starvation and therefore less heat), just prior the "collapse". The idea that air may have appreciably slowed the progress of tonnes of debris slipped my mind as I focussed on the molten metal found in the basement, (molten metal which was still hot for weeks), and the debris that shot out from the sides of the building for hundreds of feet? I was distracted too, by the videos of smoke and dust plumes detonating just under the collapsing upper stories. My attention must have been diverted by wondering.. How is it that the towers were reduced to dust, and not simply shredded, twisted, and destroyed in a more "normal" manner, as the energy required to do that far exceeds that amount of energy allowed by the fall of the mass involved.

I wonder too what the "margin of error" is? The rate of fall is easily calculated. The video(s) are there for anyone with a stopwatch to see. Some people think that we can't even ascertain such basic information as the time to collapse because of the smoke and the dust. That's funny!

Just as important and even more suspicious, is the progressive collapse of WTC 7. Why did it collapse, and why did it collapse in exactly the same manner as towers one and two, even though it was a block away and only lightly damaged? And please don't tell me about the freaking generator in the basement - there is no record, no report about massive fire in WTC 7 - none. And even if there was a fire, why a collapse, and why a symmetric one? Google the Madrid Towers for a point of comparison.

In any normal plane crash the various parts of the aircraft are painstakingly reassembled (see Lockerbie). This never happened with the towers, flight 93, or the Pentagon! How is that possible? What possible reason is there for this? The steel from the towers was sent to China almost immediately! Can you say crime scene destruction? Why can't we see the the plane debris from the Pentagon? (for the record a plane hit the Pentagon)

The collapse of the towers in no way resembles a "bullet going through a leaf", what a silly analogy, and no wonder people are so easily fooled. And do you know what? If you did fire two identical bullets through two identical leaves, the bullet that hit the leaf would be travelling measurably slower than the one that did not. And if it went through 100 leaves it would be travelling slower yet.

And it does matter how many of my points are "debunked", I would posit however that calling me an "idiot" hardly constitutes a "debunking".

Search for the truth people, if your back yard shed just fell down one day, I am sure you would want a better explanation than we got for the towers. "What do mean a bird hit it and it just "fell down"? And okay, even if that is true, please explain why my garage collapsed too."

Oh, and while I am it, can someone, anyone, please please tell me... Where where the interceptors that day? America has thousands of interceptors. 10's of thousands. They are strategically stationed all over America. These planes have missles that can acquire, attack and destroy a target at distances out to 150 miles. The Pentagon was not hit till nearly an hour after the initial hijackings, Andrews air force base is 13 miles from the Pentagon. There were 125 interceptors there that day. Why were the skys above Washington not filled with jets, AWACS, helicopters et al? The White House Secret Service, quite reasonably has MANPADs - handheld anti-aircraft missles. I assume, with a high degree of confidence, that the Pentagon has the same. We have heard that the plane was being tracked. Why, WHY, was there not a single person on the lawn of the Pentagon with a stinger missle?

And for those of you who believe the official story, why are you not screaming for the heads of the real morons, the ones you elected and hired to protect you? The ones who could not stop the 19 real idiots (from your POV) who pretty much called the Pentagon before "dropping in" for a visit?