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Sun, 18 Nov 2018
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Giant impact crater found under Greenland ice, possibly 12,000 years old - UPDATE

Greenland impact crater
© Kjær, et al
The Greenland impact crater, superimposed over Paris.
Scientists have discovered a crater beneath Greenland's Hiawatha Glacier that they say could be one of the 25 largest impact structures on Earth.

It's a 31-kilometre-wide circular bedrock depression up to a kilometre below the ice and was likely caused by a fractionated iron asteroid about a kilometre wide.

Its impact would have had substantial environmental consequences in the Northern Hemisphere and perhaps even more widely, say the researchers, led by led by Kurt Kjær from the University of Copenhagen, Denmark.

The crater is the only one of its size that retains a significant portion of its original surface topography.

Comment: The Guardian reports a few more intriguing details:
Crater appears to be result of mile-wide iron meteorite just 12,000 years ago

Nasa/Cryospheric Sciences Lab/Natural History Museum of Denmark

An illustration of the ice-filled crater discovered in Greenland.
A huge impact crater has been discovered under a half-mile-thick Greenland ice sheet.

The enormous bowl-shaped dent appears to be the result of a mile-wide iron meteorite slamming into the island at a speed of 12 miles per second as recently as 12,000 years ago.

The impact of the 10bn-tonne space rock would have unleashed 47m times the energy of the Little Boy nuclear bomb dropped on Hiroshima in 1945. It would have melted vast amounts of ice, sending freshwater rushing into the oceans, and blasted rocky debris high into the atmosphere.

At 19.3 miles wide, the crater ranks among the 25 largest known on Earth and is the first to be found beneath an ice sheet.

"You have to go back 40 million years to find a crater of the same size, so this is a rare, rare occurrence in Earth's history," said Kurt Kjær, of the Natural History Museum of Denmark in Copenhagen.

Scientists first suspected a crater in 2015 when they spotted a huge depression in Nasa radar images of the bedrock beneath the Hiawatha glacier in north-west Greenland. Kjær, who passes a 20-tonne meteorite to reach his office every day, wondered if such a space rock might be the culprit. "It all snowballed from there," said Joseph MacGregor, a senior scientist on the team at Nasa's Goddard Space Flight Center in Maryland.

greenland crater
It so happened that researchers at the Alfred Wegener Institute in Germany were about to test a powerful new ice-penetrating radar system that was operated from the air. In May 2016 the scientists flew over the Hiawatha glacier and used the radar to map the underlying rock in unparalleled detail.

The images revealed all the hallmarks of an impact crater. "It became very clear that this was a circular feature with a rim around it and an elevated central region," said Kjær. The basin itself was more than 300 metres deep, according to a report in the journal Science Advances.

To search for solid proof of an impact, the researchers flew out to the glacier and collected sediments that had washed from the crater on to a nearby floodplain. Among the gathered grains, the scientists found particles of shocked quartz and other materials that are typically produced by the violence of a extraterrestrial impact. Geochemical tests of the grains suggest the meteorite was made of iron.

So far it has been impossible to put a firm age on the crater, but its condition suggests it formed after ice began to cover Greenland about 3 million years ago. But the crater may have formed much more recently. The radar images show that while the surface layers of the glacier immediately above the crater look normal, deeper layers that are older than 12,000 years are badly deformed and strewn with rocks, with some lumps as big as trucks.

"When it happened is the $64,000 question," said MacGregor. For a final answer, the researchers will need to drill through half a mile of ice and collect crater material for dating, or wait for rocks from the impact basin to be brought to the surface as the glacier flows to the sea. Either way, the scientists have a wait on their hands.

"We live on a planet where you can survey anything and you think you know everything," said Kjær. "But when you see such a big thing as this hiding in plain sight, you realise that the age of discovery is not over yet."
And for more on the evidence of what was happening back then, check out: Of Flash Frozen Mammoths and Cosmic Catastrophes


NASA says human flights to Mars could take place in 25 years if radiation shielding technology created

mission to mars
NASA has said that the first human flights to Mars could take place in 25 years, as long as someone comes up with the technology to properly shield astronauts from deadly radiation.

With Mars around 140 million miles from Earth, sending humans there poses difficulties far beyond anything faced by the Apollo missions to the moon. With current rocket technology, Mars is a nine month journey, during which astronauts would be at the mercy of solar radiation and muscle decay from prolonged exposure to zero gravity conditions.

"The cost of solving those means that under current budgets, or slightly expanded budgets, it's going to take about 25 years to solve those," former astronaut Tom Jones - a veteran of four space shuttle missions - told reporters in Washington DC on Tuesday.

Cutting down on travel time is one way the agency hopes to make Mars missions a reality. Jones said that nuclear propulsion systems could negate the physical hardship of the journey.

Comment: See also: Russia unveils reusable nuclear rocket engine for Mars mission: 'Elon Musk is using old tech'


China creates nuke-powered fake sun that burns hotter than the real deal

EAST artificial sun machine
© Institute of Plasma Physics Chinese Academy of Sciences
EAST artificial sun machine
Chinese researchers pushing to find a major clean energy source have created an incredible artificial sun that can reach temperatures of 100 million degrees Celsius - a heat so intense it makes the real sun seem merely lukewarm.

The earth-based solar simulator has reached mind-bending temperatures of 100 million degrees Celsius, the research team announced Tuesday. Now, that's hot. For comparison, the real sun's core is about 15 million degrees Celsius.

The Institute of Plasma Physics, affiliated with the Chinese Academy of Sciences, said it has been testing an "artificial sun," known as the Experimental Advanced Superconducting Tokamak (EAST). The sci-fi-sounding contraption has been designed to replicate the way in which the star at the center of our solar system generates its colossal energy.


Russia unveils reusable nuclear rocket engine for Mars mission: 'Elon Musk is using old tech'

russia nuclear rocket engine
© Facebook / ROSCOSMOS
Computer model of the proposed nuclear engine.
A leading Russian space research center has posted a video of its nuclear-powered rocket, that will be able to land on Mars after seven months, and can be re-launched into space just 48 hours after landing.

"A mission to Mars is possible in the very near future, but that's not an aim in itself. Our engines can be the foundation for a whole range of space missions that currently seem like science fiction," Vladimir Koshlakov, who heads Moscow's Keldysh Research Center told Rossiyskaya Gazeta.

The institute, which is famous for developing the Katyusha rocket launched during World War II, has been working on what it says is a "unique" propulsion system since 2009. From past descriptions, it comprises a gas-cooled fission reactor that powers a generator, which in turn feeds a plasma thruster.

Comment: Russia places top priority on high-quality, widely available advanced education. In 2017 it graduated double the number of engineers as the US. It's no wonder it has overtaken the rest of the world in developing its space program.

Microscope 2

How an outsider in Alzheimer's research bucked the prevailing theory (and he's probably right)

Robert Moir
© Aram Boghosian for STAT
Robert Moir prepares a microbial broth in his lab at Massachusetts General Hospital's Genetics and Aging Research Unit.
Robert Moir was damned if he did and damned if he didn't. The Massachusetts General Hospital neurobiologist had applied for government funding for his Alzheimer's disease research and received wildly disparate comments from the scientists tapped to assess his proposal's merits.

It was an "unorthodox hypothesis" that might "fill flagrant knowledge gaps," wrote one reviewer, but another said the planned work might add little "to what is currently known." A third complained that although Moir wanted to study whether microbes might be involved in causing Alzheimer's, no one had proved that was the case.

As if scientists are supposed to study only what's already known, an exasperated Moir thought when he read the reviews two years ago.

Comment: It seems like true innovators always have to fight to have their ideas heard (let alone accepted). But thanks to the tenacity of people like Moir, humanity can come to accept new models and overturn firmly entrenched dogmas to allow for new understandings.

See also:


Bread-crust bubbles: Scientists discover new type of volcanic ash

lava bread-crust bubbles
© S. Quane and B. Andrews/Smithsonian Institution
LAVA BUBBLES Researchers have discovered a new kind of ash, dubbed bread-crust bubbles, which are tiny spheres of ash no more than a millimeter in diameter that form deep underground.
Bread-crust bubble
Bred krəst ˈbəb(ə)l n.

Tiny, gas-filled beads of volcanic ash with a scaly surface.
Scientists have identified a new type of volcanic ash that erupted from a volcano in central Oregon roughly 7 million years ago. The particles are similar to larger bread-crust bombs, which form as gases trapped inside globs of lava expand, cracking the bombs' tough exterior. Bread-crust bubbles, each no more than a millimeter wide, have a distinctly crackled surface that can reveal secrets about how volcanoes erupt, researchers reported November 4 at the Geological Society of America annual meeting in Indianapolis.

The researchers had been sifting through other types of volcanic ash in the lab when they spotted the strange ash formations. Viewing the bits of ash through a scanning electron microscope revealed their crusty texture, indicating the gas bubbles expanded rapidly on their way up to Earth's surface, but did not pop. Analysis of the texture also indicated the bubbles' depth when they first exploded in the foamy magma. In the case of the Oregon sample, says volcanologist Ben Andrews of the Smithsonian Institution in Washington D.C., the frothy ash formed roughly 500 to 2,000 meters deep - a short distance, geologically - and erupted from the volcano at a rate of about 30 to 80 meters per second.

Comment: Perhaps this will provide some insight into the different kinds of volcanic activity that has occurred on our planet, and what we can expect should we start seeing this kind of ash again.

See also:

Microscope 1

Autonomic nervous system directly controls stem cell proliferation, study shows

Somatic stem cells are microscopic workhorses, constantly regenerating cells throughout the body: skin and the lining of the intestine, for example. And to University of Illinois neuroscientists, they represent untapped potential.

"If we could find a way to target and control stem cell proliferation in the body, there could be potential medical benefits, including turning off the proliferation of cancer stem cells or inducing proliferation of somatic stem cells where we want to grow tissue," says Elizabeth Davis, doctoral researcher in the Neuroscience Program at U of I and lead author of a study that demonstrates, for the first time, that stem cell proliferation is directly controlled by the autonomic nervous system (ANS).

The ANS controls all of our unconscious functions: breathing, blood flow, digestion, and so forth. Its two major networks of nerve fibers run from the brain through the entire body, with neurons reaching into nearly every organ. These neurons release chemicals called neurotransmitters, which can affect target cells directly or indirectly.

People 2

Biggest sex differences study ever confirms men more interested in systems, women more interested in people

men women bathroom signs
© Getty Images / Julen Garces Carro / EyeEm
Scientists are set to stir up debates around sex and gender after publishing a study which found differences in the brain between the sexes; men prefer 'systems' while women are more interested in people and emotions.

Conducting the largest ever study of sex differences, interviewing some 650,000 people, Cambridge scientists said their study confirmed that, on a population level, men will be more interested by systems, while women will have higher degrees of emotional intelligence - the so-called empathizing-systemizing theory of sex differences.

Secondly, the scientists found that the brains of autistic people were more 'masculine' compared to what is typical for their sex, confirming, they argue, the extreme male brain theory.

The study comes at a time of heated debate around sex and gender norms, and the confirmation of the theories - described by some as 'neuro-sexism' - has risked controversy.

Scientists at the prestigious university, led by renowned clinical psychologist Simon Baron Cohen (who is incidentally the cousin of comedian Sacha Baron Cohen), interviewed 671,606 people, the majority of whom were from Britain.


Heavy weather: Earth to be battered by 'dark matter hurricane' for next million years

dark matter ring galaxy cluster Cl 0024+17
© Global Look Press
Hubble composite image showing the ring of dark matter in the galaxy cluster Cl 0024+17.
As California burns, the Gulf Coast rebuilds and Indonesia is still reeling from a tsunami, what else could possibly go wrong? Well, apparently a 'hurricane' of dark matter travelling at 500 kilometers per second (310 mps).

Scientists studying the nature of gravity and the movement of stars and planets discovered that the space between galaxies contains something else that we can't yet account for. Enter: Dark matter, an invisible and as-yet undetectable phenomenon believed to make up the bulk of matter across the universe.

While we have never directly detected dark matter, and we're not entirely sure what it is, we know 'something' must be there. Think of it like wind in the sails of a ship: we can see its impact on the world right in front of us, but it might be difficult to point it out directly.

Snowflake Cold

NASA scientist: Lack of sunspots to bring record cold

"It could happen in a matter of months," says Martin Mlynczak of NASA's Langley Research Center

"The sun is entering one of the deepest Solar Minima of the Space Age," wrote Dr Tony Phillips just six weeks ago, on 27 Sep 2018.

Sunspots have been absent for most of 2018 and Earth's upper atmosphere is responding, says Phillips, editor of spaceweather.com.

Data from NASA's TIMED satellite show that the thermosphere (the uppermost layer of air around our planet) is cooling and shrinking, literally decreasing the radius of the atmosphere.

To help track the latest developments, Martin Mlynczak of NASA's Langley Research Center and his colleagues recently introduced the "Thermosphere Climate Index."
Thermosphere Climate Index
The Thermosphere Climate Index by Mlynczak and colleagues.
Displays times of Cold, Cool, Neutral, Warm, and Hot since 1940.