Another Pyramid Mystery Solved

There have been many theories proposed to explain how the Egyptians were able to move the enormous stones used to construct the pyramids. In the last few decades it has been discovered that much of Egyptian technology employed two specific components: sand and water. With the Nile River, the Mediterranean Sea, and the North African desert nearby, the Egyptians had access to plenty of both.

First, it was discovered that the secret to erecting gigantic obelisks was to lay the obelisk on the ground, dig the hole into which it would stand, and then start piling sand under the far end. Once the slope is high enough, the obelisk slides into place. A second piece of "pyramid tech" is the water saw that we now know was used to cut the stones. By passing a circular blade through a trough of water, the saw can reach much higher speeds without overheating. In both of these cases, it's unlikely that the aliens had anything do with it.

Recently a group of scientists worked out the method used to move the stones across the desert, and it's no big surprise that the trick once more involves sand and water. Illustrations like the one above clearly depict pyramid stones and large stone monuments being transported on what look like giant sleds, but experimenters found that building a similar sled and just putting a pyramid stone on it didn't work. The sand "bermed up" in front of the sled, slowing it down to the point where it became extremely difficult to move.

The trick, as it turns out, was water. By wetting the sand to the proper level, not only will it stop collecting in front of the sled, but the force necessary to slide it along is also greatly reduced. This friction reduction was far more dramatic than experimenters expected, making it quite feasible that the stones were moved exactly as depicted in ancient Egyptian illustrations.

The question of just how an ancient civilization—without the help of modern technology—moved the 2.5 ton stones that made up their famed pyramids has long plagued Egyptologists and mechanical engineers alike. But now, a team from the University of Amsterdam believes they've figured it out, even though the solution was staring them in the face all along.

It all comes down to friction. See, the ancient Egyptians would transport their rocky cargo across the desert sands, from quarry to monument site with large sleds. Pretty basic sleds, basically just large slabs with upturned edges. Now, when you try to pull a large slab with upturned edges carrying a 2.5 ton load, it tends to dig into the sand ahead of it, building up a sand berm that must then be regularly cleared before it can become an even bigger obstacle.

Wet sand, however, doesn't do this. In sand with just the right amount of dampness, capillary bridges—essentially microdroplets of water that bind grains of sand to one another through capillary action—form across the grains, which doubles the material's relative stiffness. This prevents the sand from berming in front of the sled and cuts the force required to drag the sled in half. In half.

I don't know if any of you have ever seen this at a science museum, but at the one we have here in the Twin Cities there's a display that features a car crushed down into a cube placed on a platform that creates a cushion of air under it. Basically it works just like an air hockey table, but in reverse with the air vents pointed downward. The cushion of air eliminates the friction, and with it on the car is quite easy to move back and forth even though it weighs more than two tons, comparable with the mass of pyramid stones. If the friction drops low enough, it's easy to see how very large stones could be moved without great difficulty, and again, I don't think the aliens were involved.

I suppose it's always possible that flying saucer landed on the Giza Plateau and its occupant delivered a lecture to everyone in attendance on the properties of wet sand, but as the ancient Egyptians were just as intelligent as we are today it's infinitely more likely that one of their engineers just figured it out. While this method still doesn't solve the problem of how the stones were lifted to such great heights, scientists are working on that as well and I'm confident that a definitive solution will eventually reveal itself.