Thursday, February 17, 2005

Mixed Nuts

Quite a lot has been written about 9/11 and its aftermath, and about what we as a nation should do about it. Most of it has been serious commentary.

Some of it, on the other hand, is pure bat puckey.

Conspiracy theorists simply cannot live in a world without contrived drama. In their fevered tin-foil-hat world, there's a Man In Black lurking around every corner, just waiting for the chance to zap unsuspecting dunces with his Top-Secret Cheese Ray. Or perpetrating a Very Clever Plan to blow up their own headquarters with a missile, then blame it on some poor, unsuspecting Arabs.

Deuced clever, those Men In Black. You can't turn your back on 'em for a second. But there's just a tiny problem with their story ...

Let's assume for the sake of argument that the airplane was hijacked, and then flown at its maximum speed into the side of a building at or near ground level. Then, we'll see what falls out of that logically, and compare that to what we know happened, based on the physical evidence.

There is an important and vital difference between what happened with Flight 77 and the ordinary sort of crash on landing (or attempted landing): your ordinary sort of crash occurs at a fairly slow speed, around 120 knots or so if on final approach.

Remember two things here. One, the vehicle makes contact with the ground at a speed upwards of 600 knots. Two, its tanks are full, or very nearly so.

Metal will burn if it gets hot enough. Even in the low-speed crash pictures, you don't see much of the structure intact, because anything that's been doused with fuel and left to burn is not normally found in a recognizably intact condition. The empennage might skid to a stop and be reasonably intact, which is why some say it's safer to sit in the tail section of the airplane. It usually survives a landing mishap intact. (It's also bloody loud back there, and if you're susceptible to motion sickness the dutch roll might make you hurl ... not that I've ever cared a lot about either. I'm an exit row man, myself.)

Now: increase the velocity by a factor of four, and the kinetic energy of collision by a factor of SIXTEEN. (KE scales with the square of the velocity.)

Intact wreckage? HAH! I scoff. SCOFF, I say!

Virtually nothing will survive intact. There's just too much energy involved, and too little time and space for deceleration. The whole thing accordions up. The wings, too -- and that's where some of the fuel tanks are. The whole thing wads itself up on impact, and mixes itself up with all that unused jet fuel. Which promply ignites, of course.

Not that it does so purely outside of the building. Its velocity puts it into the building just like a high-speed APDS round slices through steel. Give a wad of metal enough good ol' kinetic energy, and you don't need any stinking warhead.

So what I'd expect to see is a mucking great explosion, leaving behind a hole roughly as wide as the airplane that made it.

And what we see in the pictures is ... a mucking great explosion, leaving behind a hole roughly as wide as the airplane that made it.

Occam's Razor, ladies and gentlemen; the simplest explanation is almost always true. Conspiracy theorists don't shave well, or often.

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