“Archaeological research has now conclusively shown that the sweet potato was introduced to Central Polynesia by approximately A.D. 1200 to 1300 , most likely by Polynesian voyagers who reached South America and subsequently spread the crop to the widely dispersed islands of the Polynesian triangle”
And I remembered this thread. I initially thought this was new info but it looks like it’s from 2013.
After the Fukishama etc earthquake , we saw boats from Japan wash up on USA … transfer of food plants, seeds, etc, may be inadvertent, and not evidence that live humans travelled that distance. So no need to consider if the seed or plant can float and survive the trip, it can get a ride in a log canoe that is left adrift unmanned by some event.
As for americans travelling west toward Asia vs austronesians travelling east.
no evidnece of americans west …
why would they ? but compare to Austronesians. The animals on the islands tend to be smaller, and easier to hunt… and there is a lot of islands near Malaysia… eg Borneo… those Austronesians that set sail can get to the Indonesian and Phillipines archipelligoes… they can get out to small islands and escape when food runs out… No such strong incentive to take the risk at the west of the americas.?? A few… and far less chance of surviving if they tried… open ocean, not the somewhat protected seas of Melanesia … Polynesians got to Easter Island, and they may well have visited the americas and some may have then returned back to the Pacific Islands… Its impossible to say… no archeology…
It doesn’t take a large leap of thought to imagine several someones in different places piling up some rocks and thinking “Heyyyyyy, I could do this with much bigger rocks and really have something!”
For some people, it apparently does because they seem to think it is far more likely that Egyptians, not historically known for their naval exploits, sailed around the world building pyramids just for the hell of it. LOL
The Bent Pyramid, for example, was a learning experience for the Egyptians - as you increase the height, things tend to fall down if they are too vertical. They started at a steeper angle and then half way had to switch to a lesss steep angle.
Presumably, this is a lesson any aspiring monument maker realizes after about the second or third failure. It’s even more obvious for those, like the Mound Builder culture in central N. America, who used earth to build.
The pyramids in Egypt were specifically tombs for a “provide excessively for the afterlife” cult. They were smooth and pointy in the extreme, when originally finished. The Mayan (and Aztec) pyramids are built with steps, meant to be climbed, platform on top, and appear to be intended to get closer to heaven for ceremonies.
I think it was in Mann’s book 1491 he describes the evolution of the American pyramids from the U-shaped raised platform construction around a plaza that seemed to be common up and down Central and west coast South America.
Thor Heyerdahl tried to sail a reed boat across from Egypt to the Caribbean to show the trip was possible, and described his trip in The Ra Expedition. The book is most notable that even more than 50 years ago, his main observation was how much garbage was seen floating all across the Atlantic. In the end, his boat fell apart and sank just before it would have reached the nearest island - which doesn’t bode well for suggesting regular travel happened.
Not a crackpot theory. Just so happens it was wrong. Lots of hypothesis turn out to be wrong. However, the prevailing wisdom of the time was that it was impossible to traverse the Pacific in a balsa raft, and so they were wrong. True, later DNA analysis proved Heyerdahl wrong.
Since this is an older thread, might I digress a bit?
I’ve never understood the above. I’m not doubting it, per se, but I don’t understand why. As long as the block on top overlapped the center of gravity (to the inside) it seems like wouldn’t matter how height they were stacked. In other words, why does the bottom half hold but higher blocks wouldn’t?
Bulge, I guess. Of course, some of the cheaper-built later pyramids were filled with rubble, which exacerbated the problem.
The actual issue is if a block fails - in a vertical wall, it allows the blocks above to fail too. A vertical wall will fail more dramatically. There is a side component of pressure to some extent on a massive construction. I think one of the issues too with some pyramids, was they were built on sand foundations. (Is there a Bible quote about this?) Also, Egypt suffered from periodic earthquakes. The key to modern structures’ stability is the quality of their foundations. Nothing produces foundation problems like a massive amount of weight on them. The Giza pyramids were on a nice outcropping of rock, so very stable. But shifting foundations lead to unsettled constructions, and there was a limit how deep the foundations could be dug - that’s a lot of brick that doesn’t even show, just to get started.
Vertical columns, like on the Parthenon, can stand successfully for thousands of years. If they perform that well then I think it is reasonable to say that a non-optimal pyramidal shape should be pretty awesome.
But, that being said, what we’re seeing today is not the actual reality of these pyramids. We’re looking at “step” pyramids; large, rectanguloid blocks that are stacked on top of one another. During the time in question, these structures were flattened off and covered with a thinner layer of more precious stones.
In the best case, the cross section of this coating would look like a sequence of right triangles. They would be sitting firmly on the steps. But imagine that one of the lips of this wedge cracks and breaks off. The steeper the slope, the more likely that those sections will topple over and slide down - breaking off other material. The shallower the slope, the less likely that will happen and the slower they’ll be as they slide down the side.
In the worst case, you’ve got a flat layer of tile or some other coating, slapped onto the surface of the pyramid. In this case, you do basically have an equivalent setup as a sand pile. It will inherently want to topple and achieve a natural resting slope, once there’s any damage to the structure.
As I understand, the sides were finished with polished limestone -same as the blocks, but nicely finished. You can still see the remains of that toward the top of the middle pyramid of Giza (Khafre’s pyramid). There are the weathered remaining blocks. Variously weather, earthquakes, and likely people looking for acheap source of already cut stone may have taken the rest. If someting came loose, it would have happily slid all the way to the base at first.
There are suggestions that the ultimate cap, a pyramidal(!) capstone, was gold plated.