Official 33 - lecture 1

Archaeology class.

Archaeology 考古学

Paleontology 古生物学

the Great Pyramid of Giza in the Egypt might be the most famous building in the world.

The Great Pyramid of Giza 胡夫金字塔

we know exactly when it was built, construction started in 2547 BCE about 4500 years ago.

we know who had it built , that was Pharaoh Khufu, we know know oversaw its construction: Pharaoh's brother.

Pharaoh Khufu: 法老胡夫

we know so many things about it, but the funny thing is that we still don't know exactly how it was built

this picture will give you an idea of the size of pyramid, and the size of blocks it's made out of.

about 2 million stone blocks were used to build the Great pyramid.

and they were incredibly massive, the average weight is two and a half tons.

the problem that has puzzled scholars for centuries is: how were these blocks lifted up the height of the massive structure and then fit into place?

of course, there have been a lot of theories over the centuries.

the oldest recorded one is by the Greek Historian Herodotus.

He visited Egypt around 450 B.C.E. when the pyramid was already 2000 years old.

his theory was that cranes was used.

crane 吊车，塔吊

much like that we use cranes today to construct tall buildings.

and Herodotus may has been seeing Egyptians using cranes made of wood.

but the problem with this theory has to do with simple mechanics.

a crane needs a wide and sturdy base to stand on, or it will fall over.

sturdy: (of a person or their body) strongly and solidly built.

synonyms of sturdy: hard, hardened, hardy, inured, rugged, strong, tough, vigorous

As you get to the top of pyramid, there's really no place for a crane to stand.

the stone blocks are too narrow to provide a base.

well so much for that theory.

the next one has to do with the use of a ramp, that would allow workers to drag a stone blocks up the side of structure.

ramp: a sloping way or plane.

of course the ramp can't to steep.

it has to have long gentle slope.

and that's the problem.

if you built a ramp with slight slope at the top of pyramid that over 130 meters high, it would have to be almost 2 kilometers long.

well the pyramid is built at flat area called the Giza Plateau.

the Plateau is simply not big enough to accommodate a 2 kilometers long ramp.

OK so what now?

if you had ever driven on the mountain road , you know that has a lot of twist and turns and bends in it, because that's how engineers keep the road from having to be to steep.

so why not wrap the ramp around the pyramid, building the ramp surround it as you go.

wrap: to cover especially by winding or folding, enfold, embrace

sounds like a pretty good idea.

except it's got a serious problem.

what one of the most remarkable things about the Great Pyramid , it's how accurate the proportions are.

The dimensions are almost perfect.

To get that perfection, the engineer must have to measure the it repeatedly during construction.

And way you'd measure it is from the four corners on the base.

if you got ramp spiraling up from the base to the pyramid, those corners would be buried by that ramp during construction.

spiral: winding around a center or pole and gradually receding from or approaching it.

helical

who says the ramp has to be outside of the pyramid.

and now we get to the latest idea.

if the ramp were on the inside the pyramid, the corners at the base would be exposed, so the engineers could do their measurements while they were building.

an architect named Houdin, has spent few years working on making computer models of the building of the pyramid.

and what Houdin believes is that an exterior straight ramp was used to construct the bottom third of the pyramid.

this ramp would've be fairly short, it probably rose less than 50 meters.

the the rest of pyramid was constructed using a internal ramp aspiral inside the pyramid.

how can you test this idea?

there are several ways to look inside the pyramid.

one's called microgravimetry.

microgravimetry is the technique that's used to detect the voice inside the structure.

you can then take the data and generate an image that shows any empty spaces in the interior.

in 1983 French scientist completing a microgravimetry survey of the pyramid.

and one the image they produced, showed the empty spiral-shaped space inside it.

the shape of that space corresponds exactly to what Houdin thought the ramp would look like.

I think Herodotus can be convinced,

we might very well be at the end of century guessing.