Science Megathread

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Dark Emulator: AI Predicts the Structure of the Universe to Help Solve Mysteries of Dark Matter and Dark Energy

The origin of how the Universe created its voids and filaments can now be studied within seconds after researchers developed an artificial intelligence tool called Dark Emulator.

Advancements in telescopes have enabled researchers to study the Universe with greater detail, and to establish a standard cosmological model that explains various observational facts simultaneously. But there are many things researchers still do not understand. Remarkably, the majority of the Universe is made up of dark matter and dark energy, of which no one has been able to identify their nature. A promising avenue to solve these mysteries is the structure of the Universe. Today’s Universe is made up of filaments where galaxies cluster together and look like threads from far away, and voids where there appears to be nothing (image 1). The discovery of the cosmic microwave background has given researchers a snapshot of what the Universe looked like close to its beginning, and understanding how its structure evolved to what it is today would reveal valuable characteristics about what dark matter and dark energy is.

A team of researchers, including Kyoto University Yukawa Institute for Theoretical Physics Project Associate Professor Takahiro Nishimichi, and Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) Principal Investigator Masahiro Takada, used the world’s fastest astrophysical simulation supercomputers ATERUI and ATERUI II to develop the Dark Emulator. Using the emulator on data recorded by several of the world’s largest observational surveys allows researchers to study possibilities concerning the origin of cosmic structures, and how dark matter distribution could have changed over time.

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From New York University's Abu Dhabi campus:

NYUAD researchers find new method to allow corals to rapidly respond to climate change
Reef-building corals transmit epigenetic adaptations to their offspring that can combat the effects of global warming

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New study (this one is based on canine teeth) confirms dog domestication during the Pleistocene:

New Study Results Consistent With Dog Domestication During Ice Age

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A Rainforest Flourished in Antarctica 90 Million Years Ago, Study Suggests
A remarkably well-preserved soil sample leads researchers to believe the frozen continent was once home to a swampy ecosystem.

Hidden beneath Antarctic ice lies evidence of an ancient swampy rainforest that sprawled far before humans roamed the Earth. Researchers were unaware an ecosystem of this nature ever existed on the frozen continent — that is, until one team got a closer look at the decayed plant matter dug out from under ice and hoisted aboard an expedition ship.

Dating back 83 million to 92 million years, the prehistoric soil is strangely well preserved. “If you were to go to a forest close to your house and dig a hole several feet in the ground, it would look like this sample,” says Johann Klages, a geologist with the Alfred Wegener Institute for Polar and Marine Research in Germany who helped author a recent paper on the findings.

The soil reveals a range of plant life that flourished in what researchers think was a waterlogged and humid ecosystem. Published this week in Nature, the findings suggest that during the hottest period in the last 140 million years, Earth wasn’t just too warm to support ice at the South Pole. Instead, the planet boasted a rainforest similar to those in New Zealand today.

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Discovery of life in solid rock deep beneath sea may inspire new search for life on Mars

Newly discovered single-celled creatures living deep beneath the seafloor have given researchers clues about how they might find life on Mars. These bacteria were discovered living in tiny cracks inside volcanic rocks after researchers persisted over a decade of trial-and-error to find a new way to examine the rocks.

Researchers estimate that the rock cracks are home to a community of bacteria as dense as that of the human gut, about 10 billion bacterial cells per cubic centimeter (0.06 cubic inch). In contrast, the average density of bacteria living in mud sediment on the seafloor is estimated to be 100 cells per cubic centimeter.

"I am now almost over-expecting that I can find life on Mars. If not, it must be that life relies on some other process that Mars does not have, like plate tectonics," said Associate Professor Yohey Suzuki from the University of Tokyo, referring to the movement of land masses around Earth most notable for causing earthquakes. Suzuki is first author of the research paper announcing the discovery, published in Communications Biology.

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From King Abdullah University of Science and Technology (KAUST) in Saudi Arabia:

Landmark study concludes marine life can be rebuilt by 2050

An international study recently published in the journal Nature, led by KAUST Professors Carlos Duarte and Susana Agustí, lays out the essential roadmap of actions required for the planet's marine life to recover to full abundance by 2050.

The project brings together the world's leading marine scientists working across four continents, in 10 countries and from 16 universities, including KAUST, Aarhus University, Massachusetts Institute of Technology, Colorado State University, Boston University, Pontificia Universidad Catolica de Chile, Sorbonne Universite, James Cook University, The University of Queensland, Dalhousie University and the University of York.

"We are at a point where we can choose between a legacy of a resilient and vibrant ocean or an irreversibly disrupted ocean," said Carlos Duarte, KAUST professor of marine science and the Tarek Ahmed Juffali research chair in Red Sea ecology.

"Our study documents recovery of marine populations, habitats and ecosystems following past conservation interventions. It provides specific, evidence-based recommendations to scale proven solutions globally," Duarte added.

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Dr. Albert Einstein was right!

Very Large Telescope sees star dance around supermassive black hole, proves Einstein right

Observations made with ESO's Very Large Telescope (VLT) have revealed for the first time that a star orbiting the supermassive black hole at the centre of the Milky Way moves just as predicted by Einstein's general theory of relativity. Its orbit is shaped like a rosette and not like an ellipse as predicted by Newton's theory of gravity. This long-sought-after result was made possible by increasingly precise measurements over nearly 30 years, which have enabled scientists to unlock the mysteries of the behemoth lurking at the heart of our galaxy.

"Einstein's General Relativity predicts that bound orbits of one object around another are not closed, as in Newtonian Gravity, but precess forwards in the plane of motion. This famous effect—first seen in the orbit of the planet Mercury around the Sun—was the first evidence in favour of General Relativity. One hundred years later we have now detected the same effect in the motion of a star orbiting the compact radio source Sagittarius A* at the centre of the Milky Way. This observational breakthrough strengthens the evidence that Sagittarius A* must be a supermassive black hole of 4 million times the mass of the Sun," says Reinhard Genzel, Director at the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching, Germany and the architect of the 30-year-long programme that led to this result.

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Expect the Northwest Passage (having just opened a decade ago) to become a regularly traveled route as this century progresses:

North Pole soon to be ice free in summer

The Arctic Ocean in summer will very likely be ice free before 2050, at least temporarily. The efficacy of climate-protection measures will determine how often and for how long. These are the results of a new research study involving 21 research institutes from around the world, coordinated by Dirk Notz from the University of Hamburg, Germany.

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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.”

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Digging Up Regolith: Why Mining the Moon Seems More Possible Than Ever
For decades, the idea of mining the moon was pure science fiction for most and a wild concept for even the most ardent believers. Now technical advances and rare political support are making it an actual possibility.

Human beings set foot on the moon 50 years ago, but since then, no one has really figured out how best to utilize Earth's closest celestial neighbor. Earlier this month, with an executive order allowing U.S. companies to mine the moon, the Trump administration opened the door to a possible commercial future on the lunar surface.

It was a moment many proponents of lunar commercialization never thought they’d see.

“You have direct interest from the White House in making this happen right now, which is sort of remarkable,” George Sowers, a space mining researcher and professor of engineering at the Colorado School of Mines, tells Popular Mechanics. “From that standpoint I think the future's pretty rosy.”

This executive order put an exclamation point on the debate over the U.S’s attitude toward The Outer Space Treaty of 1967. Signed during the Cold War, the treaty banned national sovereignty over off-world bodies but didn’t forbid their commercialization.

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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.

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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.

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Don't rule out nuclear energy:

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

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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

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

And this is how it works:

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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.

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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.

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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.

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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.  

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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.

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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."

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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
 

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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. 

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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."

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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.