If UA93 was composed of solid dense matter known for its hardness, toughness, and strength. Was UA93 composed of solid dense matter known for its hardness, toughness, and strength?
I reject your question out of hand.
You forget to remember that we are here looking at completely different scales of mass, momentum and kinetic energy. So if you want to actually
model the plane crash with a view to experimentally proving a point, we'd have to compute carefully the dimensions of our "model plane". I would expect that it would have to be an extremely thin-walled tube, but of far higher overall density, than the original plane (two design objectives that are very difficult to marry, I admit). As for the properties of the ground, I do not even start to have an intuition of how that would have to be to stand is as a fair model for the Shanksville refilled mine pit.
So, my point is merely to demonstrate that long, heavy things crashing at high speed and at a very steep trajectory can and do bury themselves beneath their own impact crater. Demonstrate, not prove this for UA93, particularly. It's to give the Truther who denies this could happen a visual that it CAN happen - and then the ball is back in their court to construct an argument why this rod could, while the plane could not.
However, have you considered that the plane is far
longer than the rod in the Veritasium experiment? The longer it is, the more mass it puts behind the impact area. This plays a major role.
However, the rod being "hard" and "tough" probably plays a very minor role - its mass and its density are far more important. See, they used lead for shotgun projectiles forever not because lead is particularly hard (it's known for being an unusually
soft metal), but because it is dense - you can project more mass onto a given target area with a lead bullet than with, say, an iron or stone bullet. But you can also project more mass by making the impactor longer, and that way heavier.
A 757-200 has a fuselage that is 47 m long.
I cannot find immediately a value for the cross section area of the fuselage - I'll leave this open and call it "A square meters". So the volume of the fuselage is approximately A*47 cubic meters.
A plane like this swims easily on water. I am pretty sure that the density of the fuselage is only a fraction that of water, let's say 0.2 tons per cubic meter. Then the mass of the fuselage would be 47*A*0.2 tons. The mass projected onto the ground area as the fuselage crashes is then (47*A*0.2)/A tons per square meter - A cancels out, and so UA93 projected a mass of about 10 tons per square meter onto the soil.
The rods in Veritasium's experiment - 100 kg, they say. They don't tell us the length nor diameter of their rods, nor their density. In a couple of shots, it appears that the rod is shorter than a man, but longer than half a man, so let's say about 1.2 meters long. The density of concrete is usually given as 2.4 tons per cubic meter. 100 kg or 0.1 tons of concrete thus have a volume of 0.1/2.4 = 0.041666 cubic meters. A rod of that volume and length 1.2 m then has a cross section area of 0.0347222 square meters. 0.1 tons projected onto 0.0347222 square meters is 28.8 tons per square meter. Roughly 3 times the mass per area than a 757/200. We are in the correct ball park with that number!
Now the rod impacted, so they say, at 350 km/h. UA93 impacted at 906 km/h according to NTSNB estimate, that's a factor of 2.6 for the momentum (both rod and plane hit with roughly equal momentum per unit of area), and a factor of 6.7 for kinetic energy (i.e. the plane projected more than twice as much energy on a unit of area).
Had both hit the same kind of ground, then I would expect that the rod would bury itself deeper (relative to their respective own lengths) in Shanksville, or that there'd be visible plane debris on the surface in the desert.
But te two did not hit the same ground: The denser object hit harder soil, the less dense object hit looser soil.
The quality of the ground plays a major role: The ground near Shanksville was relatively soft, with the soil being composed of finer particulates and probably a substantial proportion of water stored in it - you can probably easily shovel away that soil, many yards deep. The ground in the Veritasium experiment is probably also of a fine particulate, but evidently dry, and thus would resist a shovel much more. How exactly those differences affect a high-speed impact I can only guess.
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So, considering all that, I remain satisfied that the Veritasium experiment is a good-enough demonstration of what happened at Shanksville - a proof-of-concept, if you will, given that the per-area values are in the same ball park, and the soils are similar enough in quality, with the intuitively "right" kind of difference in loosenes, given the characteristics of plane and model.
