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Saturday, 11 December 2010

Comet catastrophe(s) and Neanderthal sex, 2010

Today:

  1. Was a giant comet responsible for a North American catastrophe in 11000 BC?
  2. European-looking mummies found in China, shown in Calif.
  3. 4,200 year-old grave excavation reveals eternal embrace
  4. Indus Valley east theory challenged
  5. Complete Neanderthal genome yields insights into human evolution and evidence of interbreeding
And also few quite interesting shorties in the end. 

    Was a giant comet responsible for a North American catastrophe in 11000 BC?

    April 1, 2010 by Robert Massey
    (PhysOrg.com) -- 13,000 years ago the Earth was struck by thousands of Tunguska-sized cometary fragments over the course of an hour, leading to a dramatic cooling of the planet, according to astronomer Professor Bill Napier of the Cardiff University Astrobiology Centre.

    The cooling, by as much as 8°C, interrupted the warming which was occurring at the end of the last and caused glaciers to readvance. Evidence has been found that this catastrophic change was associated with some extraordinary extraterrestrial event. The boundary is marked by the occurrence of a "black mat" layer a few centimetres thick found at many sites throughout the United States containing high levels of soot indicative of continental-scale wildfires, as well as microscopic hexagonal diamonds (nanodiamonds) which are produced by shocks and are only found in meteorites or impact craters. These findings led to the suggestion that the catastrophic changes of that time were caused by the impact of an asteroid or 4 km across on the Laurentide ice sheet, which at that time covered what would become Canada and the northern part of the United States.
    The cooling lasted over a thousand years, and its onset coincides with the rapid extinction of 35 genera of North American mammals, as well as the disruption of the Palaeoindian culture. The chief objection to the idea of a big impact is that the odds against the Earth being struck by an asteroid this large only 13,000 years ago are a thousand to one against. And the heat generated by the rising fireball would be limited by the curvature of the horizon and could not explain the continent-wide occurrence of wildfires.
    Professor Napier has now come up with an astronomical model which accounts for the major features of the catastrophe without involving such an improbable event. According to his model, the Earth ran into a dense trail of material from a large disintegrating comet. He points out that there is compelling evidence that such a comet entered the inner planetary system between 20 000 and 30 000 years ago and has been fragmenting ever since, giving rise to a number of closely related meteor streams and comoving asteroids known as the Taurid Complex.
    In the course of the giant comet's disintegration, the Earth would probably have run through at least one dense swarm of cometary material. The new model indicates that such an encounter would last for about an hour during which thousands of impacts would take place over continental dimensions, each releasing the energy of a megaton-class nuclear bomb, generating the extensive wildfires which took place at that time. The nanodiamonds at the extinction boundary would then be explained as having come in with the comet swarm.
    One recent meteorite is known which may have come from this giant comet progenitor: the Tagish Lake meteorite, which fell over Yukon Territory in January 2000. It has the highest abundance of nanodiamonds of any so far analysed. source
    My comment: First of all, the argument that the odds against a big comet hitting the Earth in the last 15000 years are low, is ridiculous. The odds of many things (mostly unpleasant) are very low, but yet they happen. So this cannot be serious argument. What I find for more serious is that from time to time, new evidences of giant impact sites around the world appear. So I personally find it more plausible to believe that we're not speaking of one crash, but of many. Whether it was a comet trail or something artificial is another question, but people very conveniently tend to forget how powerful can actually be such crashes. And for mysterious reasons, every time someone claims to have solved the puzzle, 10 new people appear proving s/he's wrong. But for me, there's no question about whether there were such crashes or not. The only question is what caused them. And why.

    European-looking mummies found in China, shown in Calif.

    Updated 3/19/2010 1:57 PM

    The mummies from western China's arid Tarim Basin are so well-preserved that the viewer can see their intricate clothing and eyelashes, and also that they are distinctly non-Asian in appearance.
    One mummy, affectionately dubbed the "Beauty of Xiaohe"(3,800-years-old!!!) by archaeologists, is so lifelike that she looks as if she's taking a nap. She has fair skin, round eyes, and a felt hat resembling an alpine head covering with a long feather stuck in the top.
    The mummies' Caucasian appearance suggests that Bronze Age nomads speaking Indo-European languages from perhaps Russia and Ukraine brought culture, physical features and genes to parts of western China and may have also been the first to domesticate the horse, says Spencer Wells, who has studied the Tarim mummies.
    Some artifacts found with the mummies, including bronze and sheep bones, hint that Europeans brought technologies such as metallurgy and some domesticated animals to China, which may explain the European appearance of the mummies and suggest that trade between Europe and Asia existed nearly 4,000 years ago, Mair says.
    Mair adds that recent DNA research suggests that men from the West were "linking up with local women, the people in the central part of Asia."
    Although the artifacts imply that trade between Europe and Asia existed during the Bronze Age, the Silk Road, a trade route between different parts of Asia, Europe and Africa, did not formally develop until about 138 B.C., during the Han Dynasty, Mair says.
    The exhibit features not only artifacts from the mummies and the early formation of the Silk Road but also from the first millennium, including intricate silk shoes, Mair says. source
    My comment: Very conveniently, the article omits the age of the mummy and it appears only under the picture of the mummy. But anyway, it's 3 800 years! That's a hell lot! And how does it go with "Although the artifacts imply that trade between Europe and Asia existed during the Bronze Age, the Silk Road (..) did not formally develop until about 138 B.C."  So from one side, we have European mummies, obviously considered important-enough to be buried and preserved like this and from the other side, we claim that although they were there at such early times, there wasn't really serious trade between the East and the West. Also, how did we know they brought the technology to the East and not the other way around? Did we merely assume so, because Europeans were so much more developed than Asians at that time (and what Europeans exactly were there at 3 000 years ago?!!!) or we have some evidences pointing in that direction. Also, the article doesn't mention explicitly what is the genetic original of the mummies. It says "perhaps Russia or Ukraine". Why? What was in Russia or Ukraine during that periods that can point in that direction? Or it just sounds better than thinking who in Europe was advanced enough to trade with Asians. For me, the whole story sounds more like a fairy-tale than actual science. Because people very stubbornly deny the fact that there were many civilization centers on Eurasia, some of which, probably on the Balkans (pelasgians, Thracians and so on)

    4,200 year-old grave excavation reveals eternal embrace

    13:54, March 26, 2010
    In the ruins of a city that was once Rome's neighbor, archaeologists last summer found a 1,000-pound lead coffin.

    Who or what is inside is still a mystery, said Nicola Terrenato, the University of Michigan professor of classical studies who leads the project---the largest American dig in Italy in the past 50 years.
    The sarcophagus will soon be transported to the American Academy in Rome, where engineers will use heating techniques and tiny cameras in an effort to gain insights about the contents without breaking the coffin itself.
    "We're very excited about this find," Terrenato said. "Romans as a rule were not buried in coffins to begin with and when they did use coffins, they were mostly wooden. There are only a handful of other examples from Italy of lead coffins from this age---the second, third or fourth century A.D. We know of virtually no others in this region."
    This one is especially unusual because of its size.
    "It's a sheet of lead folded onto itself an inch thick," he said. "A thousand pounds of metal is an enormous amount of wealth in this era. To waste so much of it in a burial is pretty unusual."
    Human remains encased in lead coffins tend to be well preserved, if difficult to get to. Researchers want to avoid breaking into the coffin. The amount of force necessary to break through the lead would likely damage the contents. Instead, they will first use thermography and endoscopy. Thermography involves heating the coffin by a few degrees and monitoring the thermal response. Bones and any artifacts buried with them would have different thermal responses, Terrenato said. Endoscopy involves inserting a small camera into the coffin. But how well that works depends on how much dirt has found its way into the container over the centuries.
    If these approaches fail, the researchers could turn to an MRI scan---an expensive option that would involve hauling the half-ton casket to a hospital.
    The dig that unearthed this find started in summer 2009 and continues through 2013.
    The site of Gabii, situated on undeveloped land 11 miles east of Rome in modern-day Lazio, was a major city that pre-dates Rome but seems to have waned as the Roman Empire grew.
    sourceMy comment: What I don't understand is why such discovery that may be considered as national treasure for Italy will go to the American Academy for research. I'm not trying to be anti-American with this, but you never know what's hidden in the lead. It could be everything. So why letting it in the hands of foreigners. This discovery belongs to Italy and it should be kept safe. Maybe I sound little paranoid, but in the case, those are simple precautions. Because gold coffins were once found in Bulgaria. And now nobody knows where they are. All that's left from them are the memories of people seeing choppers taking away our national treasure. How about this?

    Indus Valley east theory challenged



    New Delhi, April 5: A study of hundreds of ancient Indus Valley civilisation sites has revealed previously unsuspected patterns of growth and decline that challenge a long-standing idea of a solely eastward-moving wave of Indus urbanisation.
    Researchers at the Institute of Mathematical Sciences (IMS), Chennai, combined data from archaeology, radiocarbon dating, and river flows to study how settlements around the Indus Valley region had evolved from around 7000 BC till 1000 BC.
    Their analysis of 1,874 Indus region settlements has shown that the Indus urbanisation had three epicentres — Mehrgarh in present-day Baluchistan, Gujarat, and sites along an ancient river called the Ghaggar-Hakra in Haryana and Punjab.
    The findings, published in Current Science, a journal of the Indian Academy of Sciences, dispute suggestions by international researchers that farming and urbanisation in the region was driven by a “wave of advance” moving eastward.
    The 7000 BC site at Mehrgarh, Baluchistan, provides the earliest evidence for wheat and barley farming on the Indian subcontinent. But the new study and earlier archaeological data suggest that the Indus civilisation may have picked up rice cultivation from eastern India.
    “This work provides new evidence to suggest that the Indus Valley civilisation had influences from the west and from the east — it was not a one-way west-to-east flow,” said Vasant Shinde, an archaeologist with Deccan College, Pune, who was not associated with the study.
    Shinde said archaeological excavations had pointed to rice cultivation near present-day Gorakhpur in around 7000 BC — the same period as wheat and barley farming in Mehrgarh.
    The analysis by Adhikari and his colleagues shows a dense distribution of Indus Valley sites around 2500 BC which marks the beginning of the mature period of the civilisation — lasting about 600 years until about 1900 BC.
    The researchers believe it is during this period of high stability that the civilisation’s culture matured, leading to its script, the design of seals, and weights and measures. Adhikari said it was still unclear what kind of political organisation contributed to this uniformity in culture.
    The study shows a “catastrophic reduction” in the number of sites in the Ghaggar-Hakra region around 1900 BC.  But the decline around Mehrgarh and Gujarat occurred at a much slower pace.
     Archaeologists say the findings are consistent with the idea that a slow decline of the Indus urbanisaton eventually gave way to the growth of settlements along the Gangetic plain.
    source
    My comment: (Indus-like inscription on South Indian pottery from Thailand) Another very interesting article. It basically gives very early time for beginning of farming in India - basically 9 000 years ago, which is surprisingly near the start of farming in the Fertile crescent 10 000 years ago. If they manage to drive that timing only 1000 years, some theories will be in SERIOUS trouble. Not to my displeasure, of course. Before that, however, that dating should be confirmed properly. Somehow, I don't have doubts that will happen. It makes sense after all. We read article after article, how human development has started earlier and earlier, we have to expect farming to go back too. It's just matter of time. (And more on the historical context of the area, read here: 3,000-year-old history unearthed, archaeologists believe Jajmau mound could be holding more - they found well-organised village of brick-houses with kitchens and bathrooms 3000-4000 years ago. For comparison, the Aryan theory claims the invasion happened around 1700 to 1300 BCE. It's close...very close.

    Complete Neanderthal genome yields insights into human evolution and evidence of interbreeding

    May 6, 2010
    After extracting ancient DNA from the 40,000-year-old bones of Neanderthals, scientists have obtained a draft sequence of the Neanderthal genome, yielding important new insights into the evolution of modern humans.
    Among the findings, published in the May 7 issue of Science, is evidence that shortly after early migrated out of Africa, some of them interbred with , leaving bits of Neanderthal scattered through the genomes of present-day non-Africans.
    "We can now say that, in all probability, there was from Neanderthals to modern humans," said the paper's first author, Richard E. (Ed) Green of the University of California, Santa Cruz.
    The researchers identified a catalog of genetic features unique to modern humans by comparing the Neanderthal, human, and chimpanzee genomes. Genes involved in cognitive development, skull structure, energy metabolism, and skin morphology and physiology are among those highlighted in the study as likely to have undergone important changes in recent human evolution.
    The Neanderthal DNA signal shows up not only in the genomes of Europeans, but also in people from East Asia and Papua New Guinea, where Neanderthals never lived.
    "The scenario is not what most people had envisioned," Green said. "We found the genetic signal of Neanderthals in all the non-African genomes, meaning that the admixture occurred early on, probably in the Middle East, and is shared with all descendants of the early humans who migrated out of Africa."
    The study did not address the functional significance of the finding that between 1 and 4 percent of the genomes of non-Africans is derived from Neanderthals. But Green said there is no evidence that anything genetically important came over from Neanderthals.
    The draft sequence of the Neanderthal genome is composed of more than 3 billion nucleotides--the "letters" of the genetic code (A, C, T, and G) that are strung together in DNA. The sequence was derived from DNA extracted from three Neanderthal bones found in the Vindiga Cave in Croatia; smaller amounts of sequence data were also obtained from three bones from other sites. Two of the Vindiga bones could be dated by carbon-dating of collagen and were found to be about 38,000 and 44,000 years old.
    The Neanderthal bones were not well preserved, and more than 95 percent of the DNA extracted from them came from bacteria and other organisms that had colonized the bone. The DNA itself was degraded into small fragments and had been chemically modified in many places.
    The draft Neanderthal sequence is probably riddled with errors, Green said, but having the human and chimpanzee genomes for comparison makes it extremely useful despite its limitations. Places where humans differ from chimps, while Neanderthals still have the ancestral chimp sequence, may represent uniquely human genetic traits. The evidence for more recent gene flow between Neanderthals and humans came from an analysis showing that Neanderthals are more closely related to some present-day humans than to others. Looking at a diverse set of modern humans--including individuals from Southern Africa, West Africa, Papua New Guinea, China, and Western Europe--the researchers found that the frequency of Neanderthal matches is higher for non-Africans than for Africans.
    According to Green, even a very small number of instances of interbreeding could account for these results. The researchers estimated that the gene flow from Neanderthals to humans occurred between 50,000 and 80,000 years ago. The best explanation is that the admixture occurred when early humans left Africa and encountered Neanderthals for the first time.
     sourceMy comment: Ha ha ha. So much about Neanderthals being THAT different from humans. After all, humans found them similar enough to mate and create offspring, that certainly makes them a lot less animal-like than some scientists want to believe. As for "no important traits were passed from Neanderthals" - they honestly admit they barely scratched the surface of the Neanderthal genome and yet they are so sure as to claim nothing good came from it? Is it pride or prejudice? Or both. I don't quite get what's the origin of the belief Neanderthals didn't have anything valuable to offer to humans, but it sounds very premature and unscientific to me. After all, we don't understand completely even our own genome, how could we know what's valuable or not. It might like like garbage today, it could be extremely important tomorrow. Who knows.
    DNA reveals origins of first European farmers - A team of international researchers led by ancient DNA experts from the University of Adelaide has resolved the longstanding issue of the origins of the people who introduced farming to Europe some 8000 years ago.
    A detailed genetic study of one of the first farming communities in Europe, from central Germany, reveals marked similarities with populations living in the Ancient Near East (modern-day Turkey, Iraq and other countries) rather than those from Europe. - The main question here for me, is why did they decide that German farmers were among the first in Europe. If what they found is correct, then the first farmers were on the way from Turkey to Central Europe. Meaning, on the Balkans. And that's kind of well-known. Again pride and prejudices...

    35,000-year-old axe head places Aboriginal ancestors at the cutting edge of technology - Unearthed from a sandstone cave in a remote part of south-west Arnhem Land (Australia) in May, the basalt axe piece measuring 4 centimetres in length has been radio-carbon dated at 35,000 years old.
    The discovery is significant as it predates by at least 5000 years the oldest known examples of other ground-edge implements from Japan and Australia, which have been dated at 22,000 to 30,000 years old. By comparison, the earliest ground-edge axes from Europe, West Asia and Africa are about 8,500 years old. - I hope you all note the name Australia in the brackets. How did that technology go to Australia so long ago? Very very odd.

    Mycenaean tombs discovered might be evidence of classless society - The team were surprised to find a lack of burial goods in the tombs. The Mycenaean civilization is known for its rich elite burials, but the goods found at Ayia Sotira were modest.
    A third possibility is that these people lived in a classless society – that despite being close to a rich city, the people of this settlement, for whatever reason, had no elites. - 
    Stone Age Scandinavians unable to digest milk - The hunter-gatherers who inhabited the southern coast of Scandinavia 4,000 years ago were lactose intolerant. - I was surprised to know how many people are still lactose intolerant. I wonder how that tolerance developed and why. And how come it spread out so quickly. It's a small miracle...
    'Java Man' takes age to extremes - After convincing most of their colleagues that H. erectus may have persisted on the Indonesian island of Java as recently as 30,000 years ago — late enough to have coexisted in Asia with modern humans for more than 100,000 years — anthropologists presented new analyses April 14 suggesting the fossils in question may actually predate Homo sapiens by hundreds of thousands of years.
    But a new analysis, based on measurements of radioactive argon’s decay in volcanic rock above and below the fossils, puts H. erectus’ age on Java at roughly 550,000 years. It’s not clear why these estimates differ so dramatically and which one is more accurate, Antón said.

    Archeological Findings back to 10th Millennium B.C. - "one of these panels portrayed an eagle with wings spread wide and snake-form sculptures on the two sides. Another panel has an abstract sculpture of three eagle sculptures spreading their wings behind which the sun appears."- wow, that sounds so much Thracian like and Mexico like. Obviously, this motif was very important, so that it could spread across time and space like this. I wonder why...

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