Hopewell Culture may have been destroyed by a comet

[Duncan Head]

News article at:
https://www.msn.com/en-us/news/world/comet-explosion-may-have-ended-ancient-native-american-culture-study/ar-AATBt5I?li=BBnb7Kz

Original study at:
https://www.nature.com/articles/s41598-022-05758-y

[Imperial Dave]

fascinating stuff Duncan, thanks

[Jim Webster]

My first thought when seeing the thread title was that it wiped out the dinosaurs they depended on for hunting   

[Imperial Dave]

My first thought when seeing the thread title was that it wiped out the dinosaurs

I prefer the '2000AD' theory 

[Justin Swanton]

I don't buy it. The Hopewell culture is supposed to have extended from the Great Lakes to Florida. That's a distance of about 2000km. The comet apparently exploded with a force of 12 megatons. Not a big deal when you remember that the Tsar bomba detonated with a 50 megaton blast. The Hopewell culture was pretty basic, living off crops and hunting, which meant it was resilient and should have taken a comet in its stride. Something else was needed to end it so suddenly.

[Erpingham]

As I understood the article, the idea was the Hopewell culture was a sophisticated trading culture of interdependent groups.  If you blew a hole in the "distribution chain" by nuking part of the network, would it recover or fragment?   Not saying I agree with it (looks like another demonstration of modern history's fascination with catastrophism to me) but I don't think it's well explained.

[Chuck the Grey]

As I understand it, comets are capable of causing widespread damage depending on their exact composition. I remember some comets being described as a dirty snowball consisting of ice and multiple rocks. When a comet breaks up in the atmosphere, the energy release and the impact of the rocks can cover a wide area. A good fictional description of this destruction can be found in the book Lucifer's Hammer by Larry Niven and Jerry Pournelle. Both authors are well versed in science and engineering. Good story tellers too.

[Justin Swanton]

I still find it difficult to believe. Hopewell culture was not sophisticated with all sorts of specialised industries such as we have. The network would have been villages, all pretty much making the same things, connected to each other by tracks. To disrupt it you would have to incinerate the entire area and a 12 MT comet isn't going to do that. Even if it did break up on impact I don't think it could lay waste an area 2000km long and hundreds of km wide.

The ash layer argues warfare to me, communities burned to the ground and a drastic disruption of political and social unity that made future interconnectedness impossible. Societies generally come to an end in a time of war - plenty of historical examples of that. There isn't much else, not even a plague like the Black Death, that can finish them off so thoroughly. You have to stop people wanting to work together and nothing accomplishes that quite like a war.

[RichT]

Well, as the (very good) Wikipedia article says, "Possible causes of a societal collapse include natural catastrophe, war, pestilence, famine, population decline, and mass migration."

So war is one possible cause, but only one among many ('natural catastrophe' includes climate change, not always natural). I would think that a major population concentration of a culture being wiped out by an act of god(s) would be a very likely trigger for collapse (combined no doubt with a year or two of bad harvests following). Aside from physical disruption, it would invite questions about 'why them' (or 'why us') which would be generally centrifugal in effect.

[Imperial Dave]

I agree Rich, it shouldnt be excluded from consideration

[Justin Swanton]

I read the very good Wikipedia article and found it hilarious. Looking the section on "Natural Disasters and Climate Change":

The drying of the Green Sahara not only turned it into a desert but also disrupted the monsoon seasons in South and Southeast Asia and caused flooding in East Asia, which prevented successful harvest and the development of complex culture. It coincided with and may have caused the decline and the fall of the Akkadian Empire in Mesopotamia and the Indus Valley Civilization.

No shred of proof that the formation of the Sahara collapsed any civilisations in the Fertile Crescent. Just a "may".

The highly advanced Indus Valley Civilization took roots around 3000 BC in what is now northwestern India and Pakistan and collapsed around 1700 BC. Since the Indus script has yet to be deciphered, the causes of its demise remain a mystery, but there is some evidence pointing to natural disasters.

Notice "remain a mystery". So there is no solid proof for what collapsed this civilisation. Just a lot of conjecture built on tenuous evidence.

Signs of a gradual decline began to emerge in 1900 BC, and two centuries later, most of the cities had been abandoned. Archeological evidence suggests an increase in interpersonal violence and in infectious diseases like leprosy and tuberculosis.

Diseases do not collapse a civilisation but warfare does which by Wikipedia's own admission seems indicated here.

Historians and archeologists believe that severe and long-lasting drought and a decline in trade with Egypt and Mesopotamia caused the collapse.

Bully for the historians and archaelogists, but can they prove their beliefs? Don't forget the "remain a mystery".

Evidence for earthquakes has also been discovered. Sea level changes are also found at two possible seaport sites along the Makran coast which are now inland. Earthquakes may have contributed to decline of several sites by direct shaking damage or by changes in sea level or in water supply.

Or earthquakes may have had no appreciable effect on the civilisation at all, just as earthquakes had no major effect on Roman, Chinese or other civilisations.

If climate completely lays waste a region by turning it into a desert or burying it underwater then, fine. But that wasn't the case with the comet.

Volcanic eruptions can abruptly influence the climate. During a large eruption, sulfur dioxide (SO2) is expelled into the stratosphere, where it could stay for years and gradually get oxidized into sulfate aerosols. Being highly reflective, sulfate aerosols reduce the incident sunlight and cool the Earth's surface. By drilling into glaciers and ice sheets, scientists can access the archives of the history of atmospheric composition. A team of multidisciplinary researchers led by Joseph McConnell of the Desert Research Institute in Reno, Nevada deduced that a volcanic eruption occurred in 43 BC, a year after the assassination of Julius Caesar on the Ides of March (March 15) in 44 BC, which left a power vacuum and led to bloody civil wars. According to historical accounts, it was also a period of poor weather, crop failure, widespread famine, and disease. Analyses of tree rings and cave stalagmites from different parts of the globe provided complementary data. The Northern Hemisphere got drier, but the Southern Hemisphere became wetter. Indeed, the Greek historian Appian recorded that there was a lack of flooding in Egypt, which also faced famine and pestilence. Rome's interest in Egypt as a source of food intensified, and the aforementioned problems and civil unrest weakened Egypt's ability to resist. Egypt came under Roman rule after Cleopatra committed suicide in 30 BC. While it is difficult to say for certain whether Egypt would have become a Roman province if Okmok volcano (in modern-day Alaska) had not erupted, the eruption likely hastened the process.

This is all fluff. Volcanoes had nothing to do with the Civil wars or Egypt's weakness. The course of those political events is well documented. Rome had civil wars because the Republic as a viable political system was bankrupt and an increasingly autonomous army with autonomous generals was filling the power vacuum, ending in the Principate. Egypt went down because everything around the Mediterranean was going down before Rome. Might as well say that Caesar conquered Gaul because a volcano erupted somewhere. This is real thumb-sucking.

More generally, recent research pointed to climate change as a key player in the decline and fall of historical societies in China, the Middle East, Europe, and the Americas. In fact, paleoclimatogical temperature reconstruction suggests that historical periods of social unrest, societal collapse, and population crash and significant climate change often occurred simultaneously. A team of researchers from Mainland China and Hong Kong were able to establish a causal connection between climate change and large-scale human crises in pre-industrial times. Short-term crises may be caused by social problems, but climate change was the ultimate cause of major crises, starting with economic depressions.

This all affirmation and no proof.

The Mongol conquests corresponded to a period of cooling in the Northern Hemisphere between the thirteenth and fourteenth centuries, when the Medieval Warm Period was giving way to the Little Ice Age,

What did Mongols have to do with colder weather?! Mongols had to do with Genghis Khan who was the first to unite the tribes and create a military hierarchy based on merit and not blood. So what if the Mongols arrived during the Little Ice Age? Prove there is any link between the two!

A more recent example is the General Crisis of the Seventeenth Century in Europe, which was a period of inclement weather, crop failure, economic hardship, extreme intergroup violence, and high mortality because of the Little Ice Age.

The Crisis did not collapse any civilisations in Europe.

Episodes of social instability track the cooling with a time lap of up to 15 years, and many developed into armed conflicts, such as the Thirty Years' War (1618–1648),[30] which started as a war of succession to the Bohemian throne. Animosity between Protestants and Catholics in the Holy Roman Empire (in modern-day Germany) added fuel to the fire.

Bunk! The 30 Years War was all about animosity between Protestants and Catholics, or more precisely Protestant princes in the north of the Empire and a Catholic Emperor in the south. It had zippo to do with the weather.

Tropical countries with high carrying capacities and trading economies did not suffer much because the changing climate did not induce an economic depression in those places.

Rubbish. States that did not suffer were those that weren't part of the Holy Roman Empire and weren't faced with a choice of submitting to or opposing a Catholic Emperor. France, Spain and Portugal did fine because they were not in the throes of a religious civil war. Again, war caused all the trouble, not bad weather.

Moreover, by the mid-eighteenth century, as global temperatures started to rise, the ecological stress faced by Europeans also began to fade. Mortality rates dropped and the level of violence fell, which paved the way for the Pax Britannica, a period that witnessed the emergence of a variety of innovations in technology (which enabled industrialization), medicine (which improved hygiene), and social welfare (such as the world's first welfare programs in Germany), making life even more comfortable

What has this got to do with climate? Europe got rich (and comfortable) thanks to the creation of her colonial empires and improvements to her economic infrastructures. The weather was irrelevant - so long as crops could grow and be harvested Europeans got along fine.

A really pathetic collection of non sequiturs. I rest my case.

[RichT]

A really pathetic collection of non sequiturs. I rest my case.

Justin, it's so lovely to have you back.

[Justin Swanton]

I was trying to be good, Richard, really I was...

[RichT]

"If you can't say something nice, don't say nothing at all."

[Justin Swanton]

"In order to be able to think, you have to risk being offensive." - Jordan Peterson.

PS: Strength and honour to you, Rich! It's Wikipedia I pick a bone with.