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Sprawling Mayan network discovered under Guatemala jungle

bbc.com

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Re: Sprawling Mayan network discovered under Guatemala jungle

#51

Post by DubiousPusher »

brett40324 wrote: post #7

This highly corroborates Charles C Mann's book 1491: https://en.m.wikipedia.org/wiki/1491:_New_Revelations_of_the... From wikipedia: The book presents recent research findings in different fields that suggest human populations in the Western Hemisphere—that is, the indigenous peoples of the Americas—were more numerous, had arrived earlier, were more sophisticated culturally, and controlled and shaped the natural land…

I'm reading this now and it's excellent. It has the important characteristic so many popular revisionist histories lack, restraint. Later day American archaeology practically oozes with opportunities to speculate. Actual physical discoveries beg to be contextualized by our modern imaginations. Mann does visit some of these tangents of the imagination but he is also very careful to bracket these with explanations of what is known for a fact and what is not.

Re: Sprawling Mayan network discovered under Guatemala jungle

#52

Post by hutzlibu »

jackhack wrote: post #47
baron816 wrote: post #21

Earlier quoted context omitted.

I wonder how much city life biases us to think the planet is smaller than it is. Perhaps it explains fears of overpopulation.

I would say quite a lot. A private small-aircraft flight over any populated area (other than the biggest cities) reveals just how sparse most towns are. Travel almost any direction away from a main highway and in a minute or two you'll be looking at trees, trees, trees (or desert/mountains/fields). It helps give one an entirely new perspective when we're used to traveling along roads and seeing unyielding flows of ci…

Ahem, but the trees you then see are usually very civilized ones. Cultivated and harvested like an ordinary field.

There are very few wild areas left. Usually only at far off areas or very steep terrain.

see also:

https://xkcd.com/1338/

Re: Sprawling Mayan network discovered under Guatemala jungle

#53

Post by Dangeranger »

ziotom78 wrote: post #38

The is one thing I don't understand. The article reports the use of lasers to map the ground, yet they mention the presence of foliage in situ . Assuming that they use optical or infrared lasers, foliage should be completely opaque at these wavelengths. How did they manage to map the asperities and characteristics of the ground?

LiDAR wavelengths are returned at various depths from within the forest canopy. In order to get a return on the ground you simply filter the returns down to the last value.

Sometimes however you want to keep the other returns and so you filter the values down to say 10% of all returns from a given depth, with a constraint between the depths of say 10cm so that you can see the density of the layers.

Re: Sprawling Mayan network discovered under Guatemala jungle

#54

Post by jcranmer »

DubiousPusher wrote: post #51
brett40324 wrote: post #7

This highly corroborates Charles C Mann's book 1491: https://en.m.wikipedia.org/wiki/1491:_New_Revelations_of_the... From wikipedia: The book presents recent research findings in different fields that suggest human populations in the Western Hemisphere—that is, the indigenous peoples of the Americas—were more numerous, had arrived earlier, were more sophisticated culturally, and controlled and shaped the natural land…

I'm reading this now and it's excellent. It has the important characteristic so many popular revisionist histories lack, restraint. Later day American archaeology practically oozes with opportunities to speculate. Actual physical discoveries beg to be contextualized by our modern imaginations. Mann does visit some of these tangents of the imagination but he is also very careful to bracket these with explanations of w…

Mann does pick the most optimistic ranges of estimates to try to paint a particular narrative, but he is also very frank that he is doing that, and he repeats this fact several times throughout the book. It would be wonderful if more books were willing to do that sort of guarding to emphasize how much the evidence really supports the thesis. Considering that pre-Columbian America tends to get the short-end of the stick in history, I'm willing to tolerate the constant pushing on the narrative to help emphasize that the popular view of pre-Columbian American is more often incorrect to correct.

Re: Sprawling Mayan network discovered under Guatemala jungle

#55

Post by utefan001 »

mholt wrote: post #28
utefan001 wrote: post #25

The link below may be interesting to look at (or laugh at?) since the LDS church's famous book claims to be about 3 civilizations that lived somewhere in north,central or south america. As far as I understand, one or more LDS leaders years ago decided (for arguably valid reasons) that all of the Book of Mormon events occurred between 600 BC to about AD 400. This has made it more difficult for the church to say "look,…

The Book of Mormon never claims that everyone died in the Americas at AD ~400. Nor does it claim that its account of the peoples there is comprehensive. In fact, it says the opposite: that splinter groups settled elsewhere, that there were other bands of people in the land, and that after the destruction of the Nephites, the millions of remaining Lamanites continued to sprawl over the land.

Not being critical, only pointing out every time their is a big discovery like this, some level of time and effort is spent trying to align the discovery with the BOM. The wiki article has a lot of references in it that are related to the topic.

Re: Sprawling Mayan network discovered under Guatemala jungle

#56

Post by bradneuberg »

Dangeranger wrote: post #49
52-6F-62 wrote: post #14

Earlier quoted context omitted.

This is not my field of expertise, but why wouldn't we just run LIDAR scans of as much of the earth's surface as possible? Is it prohibitively expensive at this point? Is the computation [relatively] expensive? Is there a sound reason we don't race to do more? I get the feeling this kind of data could inspire generations of new archaeologists and historians. There are also some pseudo-archeological and pseudo-histori…

LiDAR collection is pretty dense from a data perspective. When I was working with helicopter collection teams we would regularly collect 1TB of point data per day at around 120 points per square meter. Based on the density of the canopy in Central America, the teams are probably using a density greater than that, and are using "multiple return" depth mapping so that they can see through the forest. Processing LiDAR d…

Perhaps neural networks can help with filtering and segmenting the point clouds as well?

Re: Sprawling Mayan network discovered under Guatemala jungle

#57

Post by hinkley »

digi_owl wrote: post #9
empath75 wrote: post #4

You see overgrown mounds all over central america, and not all of them are volcanic. There's an immense amount of undiscovered history there.

Yeah i think we are heavily underestimating how quickly nature can retake cultivated land.

In some hiking circles you see people posting pictures of basements or fallen chimneys in the middle of nowhere in a wooded area.

If you passed more than fifty feet away you might miss them.

Re: Sprawling Mayan network discovered under Guatemala jungle

#58

Post by greeneggs »

utefan001 wrote: post #25

The link below may be interesting to look at (or laugh at?) since the LDS church's famous book claims to be about 3 civilizations that lived somewhere in north,central or south america. As far as I understand, one or more LDS leaders years ago decided (for arguably valid reasons) that all of the Book of Mormon events occurred between 600 BC to about AD 400. This has made it more difficult for the church to say "look,…

You might enjoy this recent Science story:

"How a Mormon lawyer transformed archaeology in Mexico—and ended up losing his faith"

http://www.sciencemag.org/news/2018/01/how-mormon-lawyer-tra...

Re: Sprawling Mayan network discovered under Guatemala jungle

#59

Post by jccooper »

mmjaa wrote: post #11
digi_owl wrote: post #9

Earlier quoted context omitted.

Yeah i think we are heavily underestimating how quickly nature can retake cultivated land.

This is something that has always fascinated me - just how do the processes which cover a landscape with, say, layers and layers of sediment - or jungle cover - really work? I mean, I get it - you leave something out, a few weeks later its going to get covered in a layer of dust/sediment. But how is it that entire cities get buried under 10's of meters of dirt? I'm sure geologists have this all figured out, but it al…

There are lots of depositional (and erosive) processes happening. They're all subject to local conditions. But the most common (in no particular order) are: accumulation of plant matter, flood deposits, human-generated organic and building debris, and earthworm casts. You can also see other things, like volcanic activity and wind-blown material, in fewer places.

Re: Sprawling Mayan network discovered under Guatemala jungle

#60

Post by mirimir »

acjohnson55 wrote: post #30
baron816 wrote: post #21

Earlier quoted context omitted.

I wonder how much city life biases us to think the planet is smaller than it is. Perhaps it explains fears of overpopulation.

To me, fears of overpopulation have less to do with how much of the earth serves as living space, but how much human activity currently impacts nearly every corner of the planet. I think it's plausible that we can lessen human impact without actually decreasing population. Not sure it's likely, though.

I recall a letter to Science from the mid 70s, rebutting The Limits to Growth. I have tried to find it more-or-less lately, with no luck. As I recall, its author argued that the Earth could support well over 10^8 people in Trantor style. He assumed unlimited energy from fusion, and substantial food synthesis. Only humans, pets, crops, livestock, and requisite insects and microorganisms would survive. The planetary surface would support a building ~16 km high. At that height, the surface would be in thermal equilibrium at ~1500°C.

But hey, if that were doable, why not just build space habitat's?

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