Monthly Archives: June 2019

Indian-origin NASA scientist finds baby Sun’s tantrums buried in moon’s crust

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When the Sun was just a baby four billion years ago, it went through violent outbursts of intense radiation, spewing particles across the solar system but these growing pains helped seed life on early Earth by igniting chemical reactions that kept Earth warm and wet. Ironic butthe same solar tantrums may have prevented life from forming on other planets such as Mars and Venus, by stripping them of atmospheres.

Prabal Saxena, an Indian-origin astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, has spent his time researching on how space weather, the variations in solar activity and other radiation conditions in space, interacts with the surfaces of planets and moons.

Now, he and other scientists are realizing that the Moon, where NASA will be sending astronauts by 2024, contains clues to the ancient mysteries of the Sun. “We didn’t know what the Sun looked like in its first billion years, and it’s super important because it likely changed how Venus’ atmosphere evolved and how quickly it lost water. It also probably changed how quickly Mars lost its atmosphere, and it changed the atmospheric chemistry of Earth,” Saxena said.

Prabal Saxena (Image courtesy his website)

The Sun-Moon Connection Saxena stumbled into investigating the early Sun’s rotation mystery while contemplating a seemingly unrelated one: Why, when the Moon and Earth are made of largely the same stuff, is there significantly less sodium and potassium in lunar regolith, or Moon soil, than in Earth soil?

This question, too, revealed through analyses of Apollo-era Moon samples and lunar meteorites found on Earth, has puzzled scientists for decades — and it has challenged the leading theory of how the Moon formed.

Our natural satellite took shape, the theory goes, when a Mars-sized object smashed into Earth about 4.5 billion years ago. The force of this crash sent materials spewing into orbit, where they coalesced into the Moon.

“The Earth and Moon would have formed with similar materials, so the question is, why was the Moon depleted in these elements?” said Rosemary Killen, an planetary scientist at NASA Goddard who researches the effect of space weather on planetary atmospheres and exospheres.

The two scientists suspected that one big question informed the other — that the history of the Sun is buried in the Moon’s crust.

Using sophisticated computer models, Saxena, Killen and colleagues think they may have finally solved both mysteries. Their computer simulations, which they described on May 3 in the The Astrophysical Journal Letters, show that the early Sun rotated slower than 50% of baby stars. According to their estimates, within its first billion years, the Sun took at least 9 to 10 days to complete one rotation.

Earth’s atmosphere was once very different from the oxygen-dominated one we find today. When Earth formed 4.6 billion years ago, a thin envelope of hydrogen and helium clung to our molten planet. But outbursts from the young Sun stripped away that primordial haze within 200 million years.

As Earth’s crust solidified, volcanoes gradually coughed up a new atmosphere, filling the air with carbon dioxide, water, and nitrogen. Over the next billion years, the earliest bacterial life consumed that carbon dioxide and, in exchange, released methane and oxygen into the atmosphere. Earth also developed a magnetic field, which helped protect it from the Sun, allowing our atmosphere to transform into the oxygen- and nitrogen-rich air we breathe today.

“Had our Sun been a fast rotator, it would have erupted with super flares 10 times stronger than any in recorded history, at least 10 times a day. Even Earth’s magnetic field wouldn’t have been enough to protect it. The Sun’s blasts would have decimated the atmosphere, reducing air pressure so much that Earth wouldn’t retain liquid water. “It could have been a much harsher environment,” Saxena noted.

Apollo samples and lunar meteorites are a great starting point for probing the early solar system, but they are only small pieces in a large and mysterious puzzle. The samples are from a small region near the lunar equator, and scientists can’t tell with complete certainty where on the Moon the meteorites came from, which makes it hard to place them into geological context.

Since the South Pole is home to the permanently shadowed craters where we expect to find the best-preserved material on the Moon, including frozen water, NASA is aiming to send a human expedition to the region by 2024.

Goodbye China? Minami Tori island off Japan finds huge treasure of rare earth materials

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A rare form of mud found in a Japanese island may turn out to be a treasure for the future scientists and it consists of huge quantity of rare earth materials, scientists say.

With an estimated 16 million tonnes of mud, the massive, “semi-infinite” stores of valuable rare earth minerals in the island off Japan shores in the Pacific Ocean could alter global economy, said Japanese researchers. The huge patch of mineral-rich deep sea mud lies near Minamitori Island, 1,200 km off the coast of Japan.

Even though Minamitori Island is thousand miles away from the Japanese capital, it is still technically a part of Tokyo, in the village of Ogasawara, and falls within Japan’s economic borders or EEZ.

Rare earth minerals, used in smartphones and other high-tech devices like missile systems, radar devices and hybrid vehicles and China has been the only exporter and has long controlled these exports to Japan.

Yttrium, one of such metals can be used to make camera lenses, superconductors and cell phone screens and this is available in huge quantity in Japan now. The 16 million tonnes of mud in Japan’s island could contain 780 years worth of yttrium, 620 years worth of europium, 420 years worth of terbium and 730 years worth of dysprosium, said Japanese scientists.

Upbeat scientists declared that the island “has the potential to supply these materials on a semi-infinite basis to the world.”

Such concentration of rare earth material in one island is really rare, according to the US Geological Survey, which says though these minerals are relatively abundant, they have “much less tendency to become concentrated in exploitable ore deposits.” The new find and its huge scale is makes Japan new source of rare earth materials now.

Currently, only China holds a tight grip on the rare earth minerals — controlling about 95 per cent of global rare earths production as of 2015, which has caused concern for Japan and other countries which rely on China’s tight control over the price and availability.

Now that Japan has complete economic control over the new supply, the Japanese scientists are confident that the island could be exploited soon.​

These natives experimented flats, city lifestyle 9000 years ago

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The ancient ruins of Çatalhöyük, in modern Turkey, revealed that its inhabitants – 3,500 to 8,000 people at its peak – experienced overcrowding, infectious diseases, violence and environmental problems almost 9,000 years ago, said an international team of bioarchaeologists after 25 years of study.

The results paint a picture of what it was like for humans to move from a nomadic hunting and gathering lifestyle to a more sedentary life built around agriculture, said Clark Spencer Larsen, lead author of the study, and professor of anthropology at the Ohio State University.

“Çatalhöyük was one of the first proto-urban communities in the world and the residents experienced what happens when you put many people together in a small area for an extended time,” Larsen said. “It set the stage for where we are today and the challenges we face in urban living.”

Çatalhöyük, in what is now south-central Turkey, was inhabited from about 7100 to 5950 B.C. First excavated in 1958, the site measures about 32 acres, with nearly 21 meters of deposits spanning 1,150 years of continuous occupation.

Researcher Nada Elias excavating an adult skeleton at Catalhoyuk. Credit:Scott Haddow

 

Çatalhöyük began as a small settlement about 7100 B.C., likely consisting of a few mud-brick houses in what researchers call the Early period. It grew to its peak in the Middle period of 6700 to 6500 B.C., before the population declined rapidly in the Late period and was abandoned at about 5950 BC.

Farming was always a major part of life in the community. The researchers analyzed a chemical signature in the bones – called stable carbon isotope ratios – to determine that residents ate a diet heavy on wheat, barley and rye, along with a range of non-domesticated plants.

Larsen, who began fieldwork at the site in 2004, said,”They were farming and keeping animals as soon as they set up the community, but they were intensifying their efforts as the population expanded,” Larsen said.

Other research suggests that the climate in the Middle East became drier during the course of Çatalhöyük’s history, which made farming more difficult. Besides, they suffered from a high infection rate, most likely due to crowding and poor hygiene.

During its peak in population, houses were built like apartments with no space between them – residents came and left through ladders to the roofs of the houses.Excavations showed that interior walls and floors were re-plastered many times with clay.

“They are living in very crowded conditions, with trash pits and animal pens right next to some of their homes. So there is a whole host of sanitation issues that could contribute to the spread of infectious diseases,” Larsen said.

The crowded conditions in Çatalhöyük may have also contributed to high levels of violence between residents, according to the researchers.

In a sample of 93 skulls from Çatalhöyük, more than one-fourth – 25 individuals – showed evidence of healed fractures. Larsen said the significance of Çatalhöyük is that it was one of the first Neolithic “mega-sites” in the world built around agriculture.

“We can learn about the immediate origins of our lives today, how we are organized into communities. Many of the challenges we have today are the same ones they had in Çatalhöyük – only magnified.”

Their paper was published on June 17, 2019 in the Proceedings of the National Academy of Sciences.