Historical Footage Of All The Largest Nuclear Explosions In History

Historical Footage Of All The Largest Nuclear Explosions In History

The first hydrogen bomb was tested in 1952, delivering a blast many times more powerful than any weapon used in World War II. This sparked a worldwide arms race to develop the most deadly weapons known to man.

Check out the most awe-inducing explosions ever seen on this planet!

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Reasons You’ll Be Glad You Don’t Live In Medieval Times

Reasons You’ll Be Glad You Don’t Live In Medieval Times

Many contemporary historians and schoolbooks portray the Middle Ages as a time of poverty, backwardness, and religious arbitrariness, from which the people were freed only by the Renaissance and later the Industrial Revolution.

On the other hand, there have been a few historians who paint a much different picture and insist that the Middle Ages weren’t as bad as some claim, and that in some ways they were better than most other historical periods.

Here are 25 facts about this “dark” and controversial era that will help you make up your mind concerning which category you belong to: the lovers or the haters of Medieval times.

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New Study Zeros In On Plate Tectonics’ Start Date

New Study Zeros In On Plate Tectonics’ Start Date

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The image at left depicts what Earth might have looked like more than 3 billion years ago in the early Archean. The orange shapes represent the magnesium-rich proto-continents before plate tectonics started–although it is impossible to determine their precise shapes and locations. The ocean appears green due to a high amount of iron (Fe[II]) ions in the water at that time. The timeline traces the transition from a magnesium-rich (mafic) upper continental crust (UCC) to a magnesium-poor (felsic) UCC. Credit: Ming Tang/UMD

Earth has some special features that set it apart from its close cousins in the solar system, including large oceans of liquid water and a rich atmosphere with just the right ingredients to support life as we know it. Earth is also the only planet that has an active outer layer made of large tectonic plates that grind together and dip beneath each other, giving rise to mountains, volcanoes, earthquakes and large continents of land.

Geologists have long debated when these processes, collectively known as plate tectonics, first got underway. Some scientists propose that the process began as early as 4.5 billion years ago, shortly after Earth’s formation. Others suggest a much more recent start within the last 800 million years. A study from the University of Maryland provides new geochemical evidence for a middle ground between these two extremes: An analysis of trace element ratios that correlate to magnesium content suggests that plate tectonics began about 3 billion years ago. The results appear in the January 22, 2016 issue of the journal Science.

“By linking crustal composition and plate tectonics, we have provided first-order geochemical evidence for the onset of plate tectonics, which is a fundamental Earth science question,” said Ming Tang, a graduate student in geology at UMD and lead author of the study. “Because plate tectonics is necessary for the building of continents, this work also represents a further step in understanding when and how Earth’s continents formed.”

The study zeros in on one key characteristic of Earth’s crust that sets it apart geochemically from other terrestrial planets in the solar system. Compared with Mars, Mercury, Venus and even our own moon, Earth’s continental crust contains less magnesium. Early in its history, however, Earth’s crust more closely resembled its cousins, with a higher proportion of magnesium.

At some point, Earth’s crust evolved to contain more granite, a magnesium-poor rock that forms the basis of Earth’s continents. Many geoscientists agree that the start of plate tectonics drove this transition by dragging water underneath the crust, which is a necessary step to make granite.

“You can’t have continents without granite, and you can’t have granite without taking water deep into the Earth,” said Roberta Rudnick, former chair of the Department of Geology at UMD and senior author on the study. Rudnick, who is now a professor of earth sciences at the University of California, Santa Barbara, conducted this research while at UMD. “So at some point plate tectonics began and started bringing lots of water down into the mantle. The big question is when did that happen?”

A logical approach would be to look at the magnesium content in ancient rocks formed across a wide span of time, to determine when this transition toward low-magnesium crustal rocks began. However, this has proven difficult because the direct evidence–magnesium–has a pesky habit of washing away into the ocean once rocks are exposed to the surface.

Tang, Rudnick and Kang Chen, a graduate student at China University of Geosciences on a one and a half-year research visit to UMD, sidestepped this problem by looking at trace elements that are not soluble in water. These elements–nickel, cobalt, chromium and zinc–stay behind long after most of the magnesium has washed away. The researchers found that the ratios of these elements hold the key: higher ratios of nickel to cobalt and chromium to zinc both correlate to higher magnesium content in the original rock.

“To our knowledge, we are the first to discover this correlation and use this approach,” Tang said. “Because the ratios of these trace elements correlate to magnesium, they serve as a very reliable ‘fingerprint’ of past magnesium content.”

Tang and his coauthors compiled trace element data taken from a variety of ancient rocks that formed in the Archean eon, a time period between 4 and 2.5 billion years ago, and used it to determine the magnesium content in the rocks when they were first formed. They used these data to construct a computer model of the early Earth’s geochemical composition. This model accounted for how magnesium (specifically, magnesium oxide) content in the crust changed over time.

The results suggest that 3 billion years ago, the Earth’s crust had roughly 11 percent magnesium oxide by weight. Within a half billion years, that number had dropped to about 4 percent, which is very close to the 2 or 3 percent magnesium oxide seen in today’s crust. This suggested that plate tectonics began about 3 billion years ago, giving rise to the continents we see today.

“It’s really kind of a radical idea, to suggest that continental crust in Archean had that much magnesium,” said Rudnick, pointing out that Tang was the first to work out the correlation between trace element ratios and magnesium. “Ming’s discovery is powerful because he found that trace insoluble elements correlate with a major element, allowing us to address a long-standing question in Earth history.”

“Because the evolution of continental crust is linked to many major geological processes on Earth, this work may provide a basis for a variety of future studies of Earth history,” Tang said. “For example, weathering of this magnesium-rich crust may have affected the chemistry of the ancient ocean, where life on Earth evolved. As for the onset of plate tectonics, I don’t think this study will close the argument, but it certainly adds a compelling new dimension to the discussion.”


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The above post is reprinted from materials provided by University of Maryland. Note: Materials may be edited for content and length.

Charting The Growth of One of The World’s Oldest Babies

Charting The Growth of One of The World’s Oldest Babies

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The discovery of a juvenile Chasmosaurus–one of the rarest dinosaur discoveries–made headlines around the world in late 2013: Professor Philip Currie from the University of Alberta and his colleagues have now published the results of their scientific findings in an alpha-level taxonomic description in the Journal of Vertebrate Paleontology.

“For the first time ever, we have a complete skeleton of a baby ceratopsid,” says Currie of the roughly 75-million-year-old dinosaur found in 2010 in Dinosaur Provincial Park in Alberta, Canada. “We’ve only had a few isolated bones before to give us an idea of what these animals should look like as youngsters, but we’ve never had anything to connect all the pieces. All you need is one specimen that ties them all together. Now we have it!”

Currie notes that the discovery allows for the refinement of previous findings and provides the opportunity to fill in gaps in the evolution of other horned dinosaurs, such as Triceratops.

“One of the greatest benefits is that we can now look at the different body proportions for Chasmosaurus as it grew up,” Currie explains. “We now have an anchor point with the baby that we can compare with all other specimens of this species, and from that comparison can calculate the dimensions, body weights, and ages for all other ceratopsid species. We can start filling in missing pieces.”

Currie says this new publication holds incredible value not only for paleoecological studies but also for understanding the life history, biomass, population structure, growth rates, variation, and physiology of these animals. “Unless you’ve got that basic anatomical information, you’re kind of shooting in the dark with all of these other calculations.”

He says the biggest surprises came in the comparisons of shapes and relative proportions with adult Chasmosaurus. “There was no doubt in our minds that a baby would have had a much shorter frill relative to its skull length than an adult. But what we couldn’t see is that it also has a different shape. Now with a full skull of a juvenile in which the bones actually articulate with each other, we can see that in Chasmosaurus, the back of the frill isn’t broad and squared off the same way that it is in an adult. In fact, the frill narrows towards the back. And instead of being flat on top from one side to the other, the frill is arched and has a ridge running down the middle of it,” says Currie. “It is very different than I expected.”

Currie and his co-authors Michael Ryan (Cleveland Museum of Natural History), Rob Holmes (University of Alberta), and Clive Coy (University of Alberta), worked with paleo-artist Michael Skrepnick to create a life reconstruction of what the animal might have looked like.

“Alberta has long been known as one of the centres for ceratopsian research,” says Michael Ryan, one of the world’s top ceratopsian dinosaur researchers and Curator of Vertebrate Paleontology at the Cleveland Museum of Natural History. “The discovery and publication of the babyChasmosaurus cements Alberta’s leadership in this area.” Ryan is also one of Currie’s former students.

What are the next steps for these researchers and this dinosaur? “We still haven’t plumbed the depths of the anatomical description,” says Currie, noting that the specimen will provide scientists with unparalleled opportunities to study the growth, changes, and variation of a single species. “Over the next few years, I will assign different parts of the body to different students who will then focus on growth changes and their implications within ceratopsids.”

Currie also has immediate plans to examine the brain case through advanced CT scanning in Japan. In fact, the baby will be on exhibit in Tokyo at the National Museum of Nature and Science later this year, the first opportunity anyone outside Alberta will have to see it. The baby dinosaur has previously been exhibited at Dinosaur Provincial Park and at the University of Alberta.


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The above post is reprinted from materials provided by University of Alberta. The original item was written by Jennifer Pascoe. Note: Materials may be edited for content and length.

 

Pathogens Found in Ice Man’s Stomach

Pathogens Found in Ice Man’s Stomach

This is a picture of the Iceman (reconstruction by Adrie and Alfons Kennis). Credit: Reconstruction by Kennis © South Tyrol Museum of Archaeology, Foto Ochsenreiter

This is a picture of the Iceman (reconstruction by Adrie and Alfons Kennis).
Credit: Reconstruction by Kennis © South Tyrol Museum of Archaeology, Foto Ochsenreiter

Scientists are continually unearthing new facts about Homo sapiens from the mummified remains of Ötzi, the Copper Age man, who was discovered in a glacier in 1991. Five years ago, after Ötzi’s genome was completely deciphered, it seemed that the wellspring of spectacular discoveries about the past would soon dry up. An international team of scientists working with paleopathologist Albert Zink and microbiologist Frank Maixner from the European Academy (EURAC) in Bozen/Bolzano have now succeeded in demonstrating the presence ofHelicobacter pylori in Ötzi’s stomach contents, a bacterium found in half of all humans today. The theory that humans were already infected with this stomach bacterium at the very beginning of their history could well be true. The scientists succeeded in decoding the complete genome of the bacterium.

When EURAC’s Zink and Maixner first placed samples from the Iceman’s stomach under the microscope in their ancient DNA Lab at EURAC, almost three years ago, they were initially sceptical.

“Evidence for the presence of the bacterium Helicobacter pylori is found in the stomach tissue of patients today, so we thought it was extremely unlikely that we would find anything because Ötzi’s stomach mucosa is no longer there,” explains Zink. Together with colleagues from the Universities of Kiel, Vienna and Venda in South Africa as well as the Max Planck Institute for the Science of Human History in Jena, the scientists tried to find a new way to proceed. “We were able to solve the problem once we hit upon the idea of extracting the entire DNA of the stomach contents,” reports Maixner. “After this was successfully done, we were able to tease out the individualHelicobacter sequences and reconstruct a 5,300 year old Helicobacter pylorigenome.”

The scientists found a potentially virulent strain of bacteria, to which Ötzi’s immune system had already reacted. “We showed the presence of marker proteins which we see today in patients infected with Helicobacter,” said the microbiologist.

A tenth of infected people develop further clinical complications, such as gastritis or stomach ulcers, mostly in old age. “Whether Ötzi suffered from stomach problems cannot be said with any degree of certainty,” says Zink, “because his stomach tissue has not survived and it is in this tissue that such diseases can be discerned first. Nonetheless, the preconditions for such a disease did in fact exist in Ötzi.”

After completing their stomach biopsy, the two EURAC scientists transferred the genome data for analysis by their colleague Thomas Rattei from the University of Vienna. Rattei, in collaboration with geneticists from the USA, South Africa and Germany, came to a surprising conclusion: “We had assumed that we would find the same strain of Helicobacter in Ötzi as is found in Europeans today,” explains the computational biologist. “It turned out to be a strain that is mainly observed in Central and South Asia today.”

The scientists assume that there were originally two strain types of the bacterium, an African and an Asian one, which at some point recombined into today’s European version. Since bacteria are usually transmitted within the family, the history of the world’s population is closely linked to the history of bacteria. Up till now, it had been assumed that Neolithic humans were already carrying this European strain by the time they stopped their nomadic life and took up agriculture. Research on Ötzi, however, demonstrates that this was not the case.

“The recombination of the two types of Helicobacter may have only occurred at some point after Ötzi’s era, and this shows that the history of settlements in Europe is much more complex than previously assumed,” says Maixner.

Further studies will be needed to show to what extent these bacteria living inside the human body can help us understand how humans developed. The current investigations, the results of which have just been published inScience magazine, invite further research.

“Now that we are aware of how it works,” says Zink, “we are keen to continue.” Several research projects to take place in South America and Asia are currently at the planning stage.


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The above post is reprinted from materials provided by European Academy of Bozen/Bolzano (EURAC). Note: Materials may be edited for content and length.

Same Growth Rate Shown For Farming, Non-Farming Prehistoric People

Same Growth Rate Shown For Farming, Non-Farming Prehistoric People

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Prehistoric human populations of hunter-gatherers in a region of North America grew at the same rate as farming societies in Europe, according to a new radiocarbon analysis involving researchers from the University of Wyoming and the Harvard-Smithsonian Center for Astrophysics.

The findings challenge the commonly held view that the advent of agriculture 10,000-12,000 years ago accelerated human population growth. The research is reported this week in the Proceedings of the National Academy of Sciences.

“Our analysis shows that transitioning farming societies experienced the same rate of growth as contemporaneous foraging societies,” says Robert Kelly, University of Wyoming professor of anthropology and co-author of the PNAS paper. “The same rate of growth measured for populations dwelling in a range of environments, and practicing a variety of subsistence strategies, suggests that the global climate and/or other biological factors — not adaptability to local environment or subsistence practices — regulated long-term growth of the human population for most of the past 12,000 years.”

The lead author of the paper is Jabran Zahid of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. Erick Robinson, post-doctoral researcher in the University of Wyoming’s Department of Anthropology, also participated in the research.

While the world’s human population currently grows at an average rate of 1 percent per year, earlier research has shown that long-term growth of the prehistoric human population beginning at the end of the Ice Age was just 0.04 percent annually. That held true until about 200 years ago, when a number of factors led to higher growth rates.

For their research, the UW and Harvard-Smithsonian scientists analyzed radiocarbon dates from Wyoming and Colorado that were recovered predominantly from charcoal hearths, which provide a direct record of prehistoric human activity.

For humans in the region that is now Wyoming and Colorado between 6,000 and 13,000 years ago — people who foraged on animals and plants to survive — the analysis showed a long-term annual growth rate of 0.041 percent, consistent with growth that took place throughout North America. During that same period, European societies were farming or transitioning to agriculture, yet the growth rate there was essentially the same.

“The introduction of agriculture cannot be directly linked to an increase in the long-term annual rate of population growth,” the researchers wrote.

In general, similar rates of growth — around 0.04 percent — were measured for prehistoric human populations across a broad range of geographies and climates, the scientists say. “This similarity in growth rates suggests that prehistoric humans effectively adapted to their surroundings such that region-specific environmental pressure was not the primary mechanism regulating long-term population growth.”

Instead, the factors that controlled long-term population growth during that period likely were global in nature, such as climate change or biological factors affecting all humans, such as disease.

While concluding that population growth held steady overall at about 0.04 percent annually for thousands of years, the paper acknowledges that there were short-term fluctuations in human growth rates in certain regions lasting from a few hundred to 1,000 years. The authors suggest further statistical analysis of radiocarbon dates of human remains to study the mechanisms regulating population growth.


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The above post is reprinted from materials provided by University of Wyoming. Note: Materials may be edited for content and length.