Science Megathread

[Frodo]

International team sketches first large-scale genomic portrait of pre-Columbian Andean civilizations

An international research team has conducted the first in-depth, wide-scale study of the genomic history of ancient civilizations in the central Andes mountains and coast before European contact.

The findings, published online May 7 in Cell, reveal early genetic distinctions between groups in nearby regions, population mixing within and beyond the Andes, surprising genetic continuity amid cultural upheaval, and ancestral cosmopolitanism among some of the region's most well-known ancient civilizations.

Led by researchers at Harvard Medical School and the University of California, Santa Cruz, the team analyzed genome-wide data from 89 individuals who lived between 500 and 9,000 years ago. Of these, 64 genomes, ranging from 500 to 4,500 years old, were newly sequenced—more than doubling the number of ancient individuals with genome-wide data from South America.

[Frodo]

Geometry guided construction of earliest known temple, built 6,000 years before Stonehenge

The sprawling 11,500-year-old stone Göbekli Tepe complex in southeastern Anatolia, Turkey, is the earliest known temple in human history and one of the most important discoveries of Neolithic research.

Researchers at Tel Aviv University and the Israel Antiquities Authority have now used architectural analysis to discover that geometry informed the layout of Göbekli Tepe's impressive round stone structures and enormous assembly of limestone pillars, which they say were initially planned as a single structure.

[T'Chenka]

The laws of entropy state that a lower energy state is preferred by matter,.and that matter will decay to a lower energy state when possible. The Higgs boson gives mass to everything and there is a non-zero chance of a Higgs boson somewhere in the universe decaying to a lower energy state and no longer giving mass to matter. Apparently this would cause a chain reaction causing all Higgs bosons to decay to this state and matter to lose all mass, and this chain reaction would spread out in all directions at the speed of light.

https://www.nbcnews.com/mach/science/stephen-hawking-fears-higgs-boson-doomsday-he-s-not-alone-n198766

[Blue3]

Except Higgs bosons don't actually give mass to particles, they're just indicators of it (it's complicated, I misunderstood this too for a long time).

[T'Chenka]

Except Higgs bosons don't actually give mass to particles, they're just indicators of it (it's complicated, I misunderstood this too for a long time).

Interesting.

Do you know then for what reason Stephen Hawkins predicted it could end the universe as we know it in his collection of essays and lectures titled "Starmus"?

[Blue3]

Except Higgs bosons don't actually give mass to particles, they're just indicators of it (it's complicated, I misunderstood this too for a long time).

Interesting.

Do you know then for what reason Stephen Hawkins predicted it could end the universe as we know it in his collection of essays and lectures titled "Starmus"?

No, never heard of Starmus. But I can share videos explaining the Higgs boson after it was actually confirmed to exist a few years ago.

[Frodo]

Don't rule out nuclear energy:

3D-printed nuclear reactor promises faster, more economical path to nuclear energy

[Frodo]

So apparently human-induced climate change could reach a tipping point in the latter part of this century, reawakening an El Niño/La Niña-like cycle in the Indian Ocean that was last active during the depths of the last ice age (or last glacial maximum, to be more precise):

Climate change could reawaken Indian Ocean El Nino

[Frodo]

Tiny plankton drive processes in the ocean that capture twice as much carbon as scientists thought

And this is how it works:

[Frodo]

It wasn't just unlucky timing and location that resulted in the worst mass catastrophe since the Permian Extinction Event:

Dinosaur-dooming asteroid struck Earth at 'deadliest possible' angle

The simulations show that the asteroid hit Earth at an angle of about 60 degrees, which maximised the amount of climate-changing gases thrust into the upper atmosphere.

Such a strike likely unleashed billions of tonnes of sulphur, blocking the sun and triggering the nuclear winter that killed the dinosaurs and 75 per cent of life on Earth 66 million years ago.

Drawn from a combination of 3D numerical impact simulations and geophysical data from the site of the impact, the new models are the first ever fully 3D simulations to reproduce the whole event - from the initial impact to the moment the final crater, now known as Chicxulub, was formed.

[Frodo]

Our deepest view of the X-ray sky

Over the course of 182 days, the eROSITA X-ray telescope has completed its first full sweep of the sky which it embarked upon about a year ago. This new map of the hot, energetic universe contains more than one million objects, roughly doubling the number of known X-ray sources discovered over the 60-year history of X-ray astronomy. Most of the new sources are active galactic nuclei at cosmological distances, marking the growth of gigantic black holes over cosmic time.

[Frodo]

New maps offer detailed look at 'lost' continent of Zealandia
The maps show how volcanism and tectonic motion have shaped the submerged landmass over millions of years.

Earth's mysterious eighth continent doesn't appear on most conventional maps. That's because almost 95 percent of its land mass is submerged thousands of feet beneath the Pacific Ocean.

Zealandia — or Te Riu-a-Māui, as it's referred to in the indigenous Māori language — is a 2 million-square-mile (5 million square kilometers) continent east of Australia, beneath modern-day New Zealand. Scientists discovered the sprawling underwater mass in the 1990s, then gave it formal continent status in 2017. Still, the "lost continent" remains largely unknown and poorly studied due to its Atlantean geography.

[True Federalist (진정한 연방 주의자)]

Fortunately, most of Zealandia is already claimed as part of various EEZs, so whether it really is a continent or a microcontinent won't affect seabed rights that might cause a dispute between New Zealand, Australia, or New Caledonia.

[Frodo]

It appears that the hotspot that created a string of supervolcanic eruptions beginning in the Miocene epoch around 16 million years ago (and is currently at the Yellowstone Caldera) is losing steam so to speak, according to a recent geological study:

What the New Discovery of Ancient Super-Eruptions Indicates for the Yellowstone Hotspot

(...) in a study published in Geology, researchers have announced the discovery of two newly identified super-eruptions associated with the Yellowstone hotspot track, including what they believe was the volcanic province’s largest and most cataclysmic event. The results indicate the hotspot, which today fuels the famous geysers, mudpots, and fumaroles in Yellowstone National Park, may be waning in intensity.

Both of the newly discovered super-eruptions occurred during the Miocene, the interval of geologic time spanning 23–5.3 million years ago. “These two new eruptions bring the total number of recorded Miocene super-eruptions at the Yellowstone–Snake River volcanic province to six,” says Knott. This means that the recurrence rate of Yellowstone hotspot super-eruptions during the Miocene was, on average, once every 500,000 years.

By comparison, Knott says, two super-eruptions have—so far—taken place in what is now Yellowstone National Park during the past three million years. “It therefore seems that the Yellowstone hotspot has experienced a three-fold decrease in its capacity to produce super-eruption events,” says Knott. “This is a very significant decline.”

We may not have to worry about a super eruption from Yellowstone for another 900,000 years.  

[Frodo]

Polynesians, Native Americans made contact before European arrival, genetic study finds

Through deep genetic analyses, Stanford Medicine scientists and their collaborators have found conclusive scientific evidence of contact between ancient Polynesians and Native Americans from the region that is now Colombia—something that's been hotly contested in the historic and archaeological world for decades.

(...) Before this study was conducted, proponents of Native American and Polynesian interaction reasoned that some common cultural elements, such as a similar word used for a shared agricultural staple, hinted that the two populations had mingled before Europeans settled in South America. Those who disagreed pointed to studies with contrasting conclusions and the fact that the two groups were separated by thousands of miles of open ocean.

This new study is the first to show, through conclusive genetic analyses, that the two groups indeed encountered one another, and did so before Europeans arrived in South America. To conduct the study, Ioannidis and a team of international researchers collected genetic data from more than 800 living Indigenous inhabitants of Colombia and French Polynesia, conducting extensive genetic analyses to find signals of common ancestry. Based on trackable, heritable segments of DNA, the team was able to trace common genetic signatures of Native American and Polynesian DNA back hundreds of years.

[Frodo]

Blast sends star hurtling across the Milky Way

An exploding white dwarf star blasted itself out of its orbit with another star in a "partial supernova" and is now hurtling across our galaxy, according to a new study from the University of Warwick.

It opens up the possibility of many more survivors of supernovae traveling undiscovered through the Milky Way, as well as other types of supernovae occurring in other galaxies that astronomers have never seen before.

Reported in Monthly Notices of the Royal Astronomical Society, the research, funded by the Leverhulme Trust and Science and Technology Facilities Council (STFC), analyzed a white dwarf that was previously found to have an unusual atmospheric composition. It reveals that the star was most likely a binary star that survived its supernova explosion, which sent it and its companion flying through the Milky Way in opposite directions.

Lead author Professor Boris Gaensicke from the Department of Physics at the University of Warwick said, "This star is unique because it has all the key features of a white dwarf but it has this very high velocity and unusual abundances that make no sense when combined with its low mass. It has a chemical composition which is the fingerprint of nuclear burning, a low mass and a very high velocity: all of these facts imply that it must have come from some kind of close binary system and it must have undergone thermonuclear ignition. It would have been a type of supernova, but of a kind that that we haven't seen before."

[Frodo]

The African continent is very slowly peeling apart. Scientists say a new ocean is being born.
New satellite measurements are offering valuable tools to study the tectonic rift in one of the most geologically unique spots on the planet.

In one of the hottest places on Earth, along an arid stretch of East Africa’s Afar region, it’s possible to stand on the exact spot where, deep underground, the continent is splitting apart.

This desolate expanse sits atop the juncture of three tectonic plates that are very slowly peeling away from each other, a complex geological process that scientists say will eventually cleave Africa in two and create a new ocean basin millions of years from now. For now, the most obvious evidence is a 35-mile-long crack in the Ethiopian desert.

The African continent’s tectonic fate has been studied for several decades, but new satellite measurements are helping scientists better understand the transition and are offering valuable tools to study the gradual birth of a new ocean in one of the most geologically unique spots on the planet.

“This is the only place on Earth where you can study how continental rift becomes an oceanic rift,” said Christopher Moore, a Ph.D. doctoral student at the University of Leeds in the United Kingdom, who has been using satellite radar to monitor volcanic activity in East Africa that is associated with the continent’s breakup.

It’s thought that Africa’s new ocean will take at least 5 million to 10 million years to form, but the Afar region’s fortuitous location at the boundaries of the Nubian, Somali and Arabian plates makes it a unique laboratory to study elaborate tectonic processes.

Here is one theory on what the African continent will look like 10 million years from now:

https://twitter.com/simongerman600/status/1006619696807010304
 

[Frodo]

Stone artifacts hint that humans reached the Americas surprisingly early
Archaeologists date their finds in Mexico to as early as about 33,000 years ago

Humans may have arrived in North America way earlier than archaeologists thought.

Stone tools unearthed in a cave in Mexico indicate that humans could have lived in the area as early as about 33,000 years ago, researchers report online July 22 in Nature. That’s more than 10,000 years before humans are generally thought to have settled North America. This controversial discovery enters a new piece of evidence into the fierce debate about when and how the Americas were first populated.

“A paper like this one is really stirring up the pot,” says coauthor Eske Willerslev, an evolutionary biologist at the University of Cambridge. It “will no doubt get a lot of arguments going.”

For decades, archaeologists thought the Americas’ first residents were the Clovis people — big game hunters known for their well-crafted spearpoints who crossed a land bridge from Asia to Alaska about 13,000 years ago (SN: 8/8/18). Recent, well-accepted archaeological discoveries suggest that North America’s first settlers actually arrived a few thousand years before the rise of the Clovis culture, by about 16,000 years ago (SN: 10/24/18), says Vance Holliday, an archaeologist the University of Arizona in Tucson not involved in the new work.

So if the first humans arrived in North America as early as 33,000 years ago, then they could have arrived by both the coastal and overland routes since the Laurentide and Cordilleran icesheets would not have reached their fullest extent for another 12,000 years. 

[Meclazine for Israel]

New maps offer detailed look at 'lost' continent of Zealandia
The maps show how volcanism and tectonic motion have shaped the submerged landmass over millions of years.

Earth's mysterious eighth continent doesn't appear on most conventional maps. That's because almost 95 percent of its land mass is submerged thousands of feet beneath the Pacific Ocean.

Zealandia — or Te Riu-a-Māui, as it's referred to in the indigenous Māori language — is a 2 million-square-mile (5 million square kilometers) continent east of Australia, beneath modern-day New Zealand. Scientists discovered the sprawling underwater mass in the 1990s, then gave it formal continent status in 2017. Still, the "lost continent" remains largely unknown and poorly studied due to its Atlantean geography.

That's nonsense from a geological perspective. That dark blue subduction zone is pushing west bringing everything up as it disappears.

These are colliding pieces of mafic Oceanic Crust, around 6-8km thick moving west at 10-18cm a year.

No continental geological processes will work on that block until it joins Australia and thickens up
through orogenesis and accretion (crust thickening through thrust slices stacking on top of one another).

Given that NZ is sitting on a transform fault, there is no guarantee that that slab will ever grow higher out of the ocean unless that Eastern slab subducts underneath and produces volcanism similar to that process creating the Andes Mountain chain in South America.

If you look to the south-east, you can see a block of oceanic crust in blue moving towards NZ in the NW direction. This is causing the general uplift of the oceanic crust east of NZ.

Keep in mind Continental Crust is 35km thick. The most likely outcome for these oceanic slabs is accretion with the existing Continent to the left. You can already see the shape of the Australian continent in one slab affected. It is the next part to join the Australian continent. All of Eastern Australia was 'accreted' onto Australia. It's just happening again. It's not another continent.

We don't call the gap from Alaska to Russia another continent. If an oceanic crustal slab starting uplifting short of South America, that is not a new continent.

If these slabs do come out of the water, they will attach to NSW, Victoria and Tasmania over 200 million years and be 4 times thinner in an E-W direction and 4 times thicker (guess) in a vertical direction. But there is a lot of volcanism which will go on before that process is finished (i.e. generating felsic Continental Crust from recycling Oceanic crust)

We essentially have a process where 8km thick Oceanic crust will morph into 32km Continental crust (at 16cm per year roughly), after which, NZ will be closer to Australia and connected to us.

There won't be any legal territorial disputes as we will all be wiped out by a virus by that stage anyway.

It will just be all cute Kangaroos and Koalas and birds.

[Frodo]

Are we off the hook?

Ancient genomes suggest woolly rhinos went extinct due to climate change, not overhunting


source

The extinction of prehistoric megafauna like the woolly mammoth, cave lion, and woolly rhinoceros at the end of the last ice age has often been attributed to the spread of early humans across the globe. Although overhunting led to the demise of some species, a study appearing August 13 in the journal Current Biology found that the extinction of the woolly rhinoceros may have had a different cause: climate change. By sequencing ancient DNA from 14 of these megaherbivores, researchers found that the woolly rhinoceros population remained stable and diverse until only a few thousand years before it disappeared from Siberia, when temperatures likely rose too high for the cold-adapted species.

"It was initially thought that humans appeared in northeastern Siberia fourteen or fifteen thousand years ago, around when the woolly rhinoceros went extinct. But recently, there have been several discoveries of much older human occupation sites, the most famous of which is around thirty thousand years old," says senior author Love Dalén (@love_dalen), a professor of evolutionary genetics at the Centre for Palaeogenetics, a joint venture between Stockholm University and the Swedish Museum of Natural History. "So, the decline towards extinction of the woolly rhinoceros doesn't coincide so much with the first appearance of humans in the region. If anything, we actually see something looking a bit like an increase in population size during this period."

[Frodo]

Rice genetically engineered to resist heat waves can also produce up to 20% more grain

As plants convert sunlight into sugar, their cells are playing with fire. Photosynthesis generates chemical byproducts that can damage the light-converting machinery itself—and the hotter the weather, the more likely the process is to run amok as some chemical reactions accelerate and others slow. Now, a team of geneticists has engineered plants so they can better repair heat damage, an advance that could help preserve crop yields as global warming makes heat waves more common. And in a surprise, the change made plants more productive at normal temperatures.

“This is exciting news,” says Maria Ermakova of Australian National University, who works on improving photosynthesis. The genetic modification worked in three kinds of plants—a mustard that is the most common plant model, tobacco, and rice, suggesting any crop plant could be helped. The work bucked conventional wisdom among photosynthesis scientists, and some plant biologists wonder exactly how the added gene produces the benefits. Still, Peter Nixon, a plant biochemist at Imperial College London, predicts the study will “attract considerable attention.”

And now the same climate-change adaptation is being done with wheat, beginning in Western Australia (WA):

Long coleoptile wheat could help farmers adapt to climate change

After more than two decades of searching, Australian scientists may have found the most significant climate change adaption for wheat growers.

And a determined Western Australian farmer, who wants access to the new wheat genetics, which could allow farmers to crops in hotter and drier environments, has trials of the new wheat varieties on his farm.

Wheat is the largest crop grown by Australian farmers, but climate change is threatening grain production.

According to data from the WA Department of Primary Industries, rainfall in wheat-growing regions is rapidly shifting from autumn and spring into more summer rain, which is essentially wasted moisture for winter crops.

In addition, there has been a 20 per cent drop in May to July rainfall in southern parts of the state.

[Frodo]

Predicting drought in the American West just got more difficult

People hoping to get a handle on future droughts in the American West are in for a disappointment, as new USC-led research spanning centuries shows El Niño cycles are an unreliable predictor.

Instead, they found that Earth's dynamic atmosphere is a wild card that plays a much bigger role than sea surface temperatures, yet defies predictability, in the wet and dry cycles that whipsaw the western states. The study, published Monday in Science Advances, is a detailed assessment of long-term drought variability.

The findings are significant for water management, agriculture, urban planning and natural resources protection. Recent droughts have claimed many lives and caused damaging crop losses, making drought forecasting a high priority. Meanwhile, the West faces rapid population growth at the same time that forecasts show dry times ahead due to global climate change.

"The main finding is not terribly hopeful for short-term drought prediction," said Julien Emile-Geay, a study author and associate professor of Earth sciences at the USC Dornsife College of Letters, Arts and Sciences. "We found that, historically speaking, year-to-year droughts in the western United States were less predictable than previous studies have claimed."

New study examines 1,000 years of droughts in the West and beyond.

[Frodo]

They've narrowed it down -the age of the Earth's inner core is between 1 billion and 1.3 billion years old:

The age of the Earth's inner core revised

By creating conditions akin to the center of the Earth inside a laboratory chamber, researchers have improved the estimate of the age of our planet's solid inner core, putting it at 1 billion to 1.3 billion years old.

The results place the core at the younger end of an age spectrum that usually runs from about 1.3 billion to 4.5 billion years, but they also make it a good bit older than a recent estimate of only 565 million years.

What's more, the experiments and accompanying theories help pin down the magnitude of how the core conducts heat, and the energy sources that power the planet's geodynamo—the mechanism that sustains the Earth's magnetic field, which keeps compasses pointing north and helps protect life from harmful cosmic rays.

"People are really curious and excited about knowing about the origin of the geodynamo, the strength of the magnetic field, because they all contribute to a planet's habitability," said Jung-Fu Lin, a professor at The University of Texas at Austin's Jackson School of Geosciences who led the research.

The results were published on August 13th in the journal Physical Review Letters.

[Frodo]

Was anyone else aware that Stonehenge (when it was still complete, and not in ruins) had special acoustic effects?  

Stonehenge enhanced sounds like voices or music for people inside the monument
Scientists created a scale model one-twelfth the size of the ancient site to study its acoustics

Welcome to Soundhenge. Better known as Stonehenge, this ancient monument in southern England created an acoustic space that amplified voices and improved the sound of any music being played for people standing within the massive circle of stones, a new study suggests.

Because of how stones were placed, that speech or music would not have projected beyond Stonehenge into the surrounding countryside, or even to people standing near the stone circle, scientists report in the October Journal of Archaeological Science.

To explore Stonehenge’s sound dynamics, acoustical engineer Trevor Cox and colleagues used laser scans of the site and archaeological evidence to construct a physical model one-twelfth the size of the actual monument. That was the largest possible scale replica that could fit inside an acoustic chamber at the University of Salford in England, where Cox works. This room simulated the acoustic effects of the open landscape surrounding Stonehenge and compacted ground inside the monument.

[Frodo]

Land conservation could play a huge part in solving human-induced climate change:

Protecting half the planet could help solve climate change and save species
A new map shows where new land protections could complement existing conserved areas

Earth faces two interrelated crises: accelerating loss of biodiversity and climate change. Both are worsened by human development of natural lands that would otherwise allow species to flourish and would store atmosphere-warming carbon, stabilizing the climate.

A new study argues that nations can help avert the biodiversity and climate crises by preserving the roughly 50 percent of land that remains relatively undeveloped. The researchers dub that conserved area a “Global Safety Net,” mapping out regions that can meet critical conservation and climate goals in a study published September 4 in Science Advances.

(...) Much of the land identified as important for biodiversity also stores a lot of carbon, underlining the connection between conservation and climate goals. But the researchers found an additional 4.7 percent of land, including forests in the northeastern United States, that would help keep climate-warming carbon out of the atmosphere.