China and France open a new chapter in joint exploration of nuclear energy after 40 years of partnership and trust

At the invitation of French President Emmanuel Macron, Chinese President Xi Jinping kicked off his state visit to France on May 5. It coincides with the 60th anniversary of the establishment of diplomatic ties between China and France, and is of great significance to building on past achievements and opening up new prospects for bilateral relations.

During this visit, achieving carbon neutrality goals will, once again, be an important consensus reaffirmed by China and France, in relation to which, the joint promotion of nuclear energy cooperation and development as an important cornerstone for the two countries to achieve carbon reduction goals has attracted great attention.

Yu Jianfeng, Chairman of China National Nuclear Corporation (CNNC), and Jean-Bernard Lévy, Chairman and Chief Executive Officer of Electricité de France (EDF) jointly released A Prospective Study on "Bluebook" on Nuclear Energy to Support for Low Carbon on Monday in Paris.

"China and France, as major nuclear energy-producing countries in the world, play an irreplaceable role in promoting nuclear energy to address climate change and low-carbon transformation," Yu said.

He noted that nuclear energy cooperation is an important part of the comprehensive strategic partnership between China and France. Under the strategic guidance of President Xi and President Macron, nuclear energy enterprises in the two countries have adhered to the principle of "walking on the two legs of technological cooperation and industrial cooperation," and have achieved fruitful results.

The Global Times learned from the CNNC that the cooperation between the CNNC and the EDF opens a new chapter in the two countries' nuclear energy cooperation. This not only reflects the concrete implementation of the important consensus reached by the top leaders of the two countries, but also marks the 40th anniversary of the two countries' nuclear energy cooperation and witnesses the 60th anniversary of the establishment of diplomatic relations between China and France.

The move will also support China in building an innovative nuclear energy international cooperation network. In the future, the two countries will leverage their strengths to build a new pattern of cooperation and development that is interconnected and driven by innovation, supported by industry to promote the improvement of global nuclear governance, and make greater contributions to the economic and social development of China and France, as well as the construction of a global community of shared future for mankind.

One of the most stable cooperation areas

The nuclear energy cooperation between China and France has a long history and continues to deepen. Since the signing of the first cooperation agreement on the peaceful use of nuclear energy in 1982, China and France have always adhered to the principle of equal emphasis on scientific and industrial cooperation. Nuclear energy cooperation has become one of the most stable cooperation areas between the two countries.

As one of the earliest international nuclear energy companies to cultivate business in China, the EDF has been operating in China for more than 40 years and has become one of the largest foreign investors in China's power generation and energy services industry.

For a long time, the EDF has developed and deepened its partnership with the CNNC. The two sides regularly hold high-level meetings, and their cooperation covers multiple areas such as nuclear power research and development, construction, operation and maintenance, and fuel, achieving numerous results.

The CNNC and the EDF have actively participated in the interactive activities of international organizations, sending experts to support the work of international organization technical groups, conducting international research projects, and promoting international coordination and standardization. For example, they participated in the International Atomic Energy Agency (IAEA)'s nuclear safety standards development work, especially the recent Nuclear Harmonization and Standardization Initiative (NHSI) small modular reactor regulatory forum activities initiated by the IAEA, which is aimed at promoting the development of universal standards for small modular reactors, coordinate unified regulatory requirements, and promote the safe and reliable deployment of small modular reactors worldwide.

The EDF and the CNNC have also made important contributions to the standardization work of international standardization organizations and the International Electrotechnical Commission.

As the main force of China and France's nuclear energy technology cooperation, the CNNC has established long-term friendly cooperation relationships with French partners and achieved fruitful cooperation results. In the more than 40 years of nuclear energy technology cooperation, the CNNC and the French Atomic Energy Commission have established seven collaborative laboratories in areas such as reactor thermal hydraulics, severe accident management, aging and life management of pressurized water reactors, fast reactors, nuclear fusion, geological disposal of high-level radioactive waste, decommissioning, and radioactive waste management. The two sides also signed and implemented over 500 special cooperation projects.

The CNNC has also successfully held six nuclear energy technology innovation seminars with the EDF, achieving good results in areas such as severe accidents, additive manufacturing, and material research.

Furthermore, the CNNC has also formed a consortium with Framatome to successfully bid for and implement the main machine installation project of the International Thermonuclear Experimental Reactor (ITER), and have conducted good cooperation with the Orano Group in areas such as the research on uranium resources.
To jointly build "artificial sun"

Cooperation in the peaceful use of nuclear energy has become an important part of the comprehensive strategic partnership between China and France. The scope of nuclear energy cooperation between the two countries is wide-ranging and diverse, but the most "high-energy" project undoubtedly is the ITER large-scale scientific project that the two countries are jointly working on.

Referred to as the world's largest "artificial sun," the ITER project is currently the largest and most influential international scientific project in the world, carrying the hopes of humanity for the peaceful use of nuclear fusion energy.

The ITER device is a superconducting tokamak capable of producing large-scale nuclear fusion reactions, which will help humanity move further toward a continuous source of clean energy. Since its establishment in 2007, the ITER has been one of the largest international scientific engineering cooperation projects in the world. France is the location of the ITER project construction and headquarters, while China is one of the seven equal member parties of the ITER project, contributing 9.09 percent of the construction phase and 10 percent of the operation and decommissioning phase funding.

China joined the ITER project in 2006. Since the implementation of the project, China has always adhered to its international commitments, with Chinese enterprises and researchers bravely shouldering heavy responsibilities and working together with international counterparts to contribute Chinese wisdom and strength to the smooth progress of the project.

The CNNC has been actively involved in the development of the world's largest "artificial sun." In September 2019, a China-France consortium led by the CNNC signed the TAC-1 installation contract with the ITER, marking China's deep involvement in the installation of the core equipment of the tokamak device - the "heart" of the experimental reactor.

On February 29, 2024, the ITER organization signed a new the vacuum chamber module assembly contract with the consortium. China will once again undertake the installation of the core equipment, contributing wisdom and strength to the ITER project alongside France.

Shen Yanfeng, General Manager of the CNNC, said that the signing of the agreement means that the China-France consortium led by the CNNC has become the sole contractor for the main host installation of the ITER project. This demonstrates the CNNC's commitment to implementing President Xi's important instructions, opening up to the outside world, deeply participating in the global nuclear industry chain cooperation, building a new development pattern, promoting high-quality development of the nuclear industry, accelerating the advancement of China's modernization, and striving to create a vivid practice of a global community of shared future for mankind.

This will greatly enhance China's participation and contribution in international large-scale scientific projects, and help implement the "three-step" development strategy of nuclear energy - thermal reactors, fast reactors, and fusion reactors, Shen said.
Direction for nuclear energy development

The release of the "bluebook" undoubtedly takes the cooperation between China and France in the nuclear energy field to a new level.

The Global Times learned that the "bluebook" is the first strategic planning soft science cooperation between Chinese state-owned nuclear energy enterprises and partners in developed Western countries in recent years, marking a significant increase in China's nuclear industry strategic planning and soft science research capabilities and international influence, with obvious uniqueness and importance.

"The 'bluebook' is cooperation between China and France at the strategic research level in the field of nuclear energy, which has never happened before. It was included in the plan during French President Macron's visit to China in 2023," Luo Qingping, President of the China Institute of Nuclear Industry Strategy under CNNC, told the Global Times.

The release of the "bluebook" at the historical moment of the 60th anniversary of the establishment of diplomatic relations between China and France can also be seen as the opening of a new chapter in the nuclear energy cooperation of the two countries. In the future, China and France can combine the contents of the "bluebook" to deepen cooperation in promoting nuclear energy development, including cooperation in exploring third-party markets.

The Global Times found that the "bluebook" interprets the development ideas and practices of China and France in the field of nuclear energy through historical reviews and strategic research, providing an in-depth analysis of the future nuclear energy industry from a macro perspective.

The research mainly covers the current global status and trends of nuclear energy development, the role of nuclear power in addressing the climate change, progress in nuclear power safety and related technology standards, and measures to enhance the economic efficiency of nuclear power coupled with other new energy sources, systematically describing the current status of nuclear energy development and good practices in China and France.

In addition, the "bluebook" fully demonstrates China's strength in nuclear power construction, including its strength in third-generation nuclear power, fourth-generation nuclear power, small modular reactors, and the entire industry chain service capabilities.

It also describes important nuclear power products in China, such as the Hualong One, Linglong One, high-temperature reactors, and fast reactors, making it easier for the international community to understand China's nuclear power technology and product capabilities.

The release of the "bluebook" can expand the influence of Chinese nuclear power companies, especially the CNNC. Through the preparation of the "bluebook," China and France can reach a consensus on nuclear energy technology at the strategic level and enhance the international influence of nuclear energy technology in both countries.

The "bluebook" proposes three initiatives. First, China and France jointly advocate that every country in the world has the right to develop nuclear power, but safety must be the top priority in the development process, meaning that nuclear power must be developed under reliable safety supervision. Second, it points out to the world that nuclear energy can effectively support low-carbon development. China's future nuclear energy technologies such as small modular reactors and nuclear fusion are important solutions to the global energy problem. Third, it calls for urgent action to address the crisis caused by climate change, emphasizing that energy transformation is imperative, and the development of nuclear power is undoubtedly an effective approach.

Based on this "bluebook," there is a possibility of creating an internationally significant guiding document. The IAEA is also very interested in this "bluebook." Next, the CNNC will communicate with the IAEA to try to include the "bluebook" in their publication list for global promotion.

A green future for humanity

According to data in the "bluebook," as of the end of December 2023, France has an installed nuclear power capacity of 61.37 gigawatts in operation, ranking second in the world, with an additional 1.63 gigawatts under construction. China has an installed nuclear power capacity of 53.15 gigawatts in operation, ranking third in the world, with an additional 23.72 gigawatts under construction. Both China and France are major nuclear energy-producing countries, with CNNC and EDF as key players in global nuclear energy development, each having their own advantages in nuclear power construction, operation, maintenance, and fuel supply, accumulating rich experience in the development of nuclear energy.

The continued cooperation between the two countries will provide strong momentum for the utilization and development of global clean energy technologies. China and France will continue to deepen cooperation in multiple areas such as nuclear engineering, nuclear power operation, and nuclear fuel cycle. They will promote the synergy between nuclear energy and renewable energy, formulate public policies focusing on low-carbon growth, accelerate the development of renewable energy such as hydropower, wind power, solar power, and geothermal energy, extend the lifespan of existing nuclear power plants, initiate new nuclear power construction projects, and optimize the cost of energy transition.

Furthermore, the two sides will cooperate to promote advanced nuclear energy technologies such as small modular reactors and fusion reactors. They will work together to advance the commercial deployment of small modular reactors. They will also strengthen international cooperation in the field of nuclear fusion research, the Global Times learned from the CNNC.

At the same time, they will promote the comprehensive application of nuclear energy, popularize technologies such as nuclear heating, seawater desalination, and hydrogen production, diversify the forms of nuclear energy utilization, and reduce greenhouse gas emissions.

They will also conduct research on the impact of climate change using nuclear technology, playing a special role in addressing issues such as water scarcity, soil erosion, land degradation, and increased diseases and pests in plants and animals caused by climate change.

Looking to the future, the CNNC and the EDF have reached a consensus that nuclear energy development is a realistic and important choice in the transition to a clean, low-carbon, safe, and efficient modern energy system, especially as nuclear energy expands from electricity generation to heating, steam supply, hydrogen production, and other applications, potentially accelerating the decarbonization of high-emission industries. The deepening cooperation in the nuclear energy field between China and France will undoubtedly bring more solutions and surprises to humanity.

China, Egypt sign deals to boost lunar exploration, spacecraft launching

China and Egypt have signed cooperation documents in space exploration in Beijing on Wednesday to boost deep space exploration, spacecraft development and construction of space infrastructure, which is of great significance to foster a comprehensive strategic partnership between the two countries.

Zhang Kejian, administrator of the China National Space Administration (CNSA) and Sherif Sedky, Chief Operating Officer of the Egyptian Space Agency (EGSA), signed a memorandum of understanding between the governments of the two countries on space cooperation and peaceful use of outer space and a cooperation agreement between the CNSA and the EGSA on the International Lunar Research Station (ILRS).

According to the cooperation documents, both sides will encourage joint researches and development cooperation in a variety of areas including lunar and deep space exploration, development and launch of spacecraft, construction of space infrastructure, satellite data reception and application, the BRICS Remote Sensing Satellite Constellation, space science and astronomical observation.

They will also collaborate on the joint demonstration and research of the ILRS, space missions, space systems and subsystems, space equipment, ground segments and applications, education and training and capacity building.

China and Egypt have achieved fruitful results in space cooperation. The China-assisted Egyptian Satellite Assembly, Integration and Test Center completed the acceptance checks in June this year. The China-funded MisrSat-2 satellite completed its assembly and testing at the center and was launched on Monday.

The satellite MisrSat-2, launched by a Long March-2C carrier rocket from the Jiuquan Satellite Launch Center in Northwest China's Gansu Province, will be used in Egypt's land and resource utilization, water conservancy, agriculture, and other fields. It is a landmark project of deep cooperation between China and Egypt in the field of aerospace high-tech, and is of milestone significance in aerospace cooperation between the two countries, according to the CNSA.

The signing of these space agreements between China and Egypt will guide future collaboration and play a significant role in advancing space technology and fostering comprehensive strategic partnerships between the two countries, said CNSA in a press release on Wednesday.

Italy: The Week of Italian Cuisine in the World kicks off in Beijing, Tianjin and Qingdao

The Week of Italian Cuisine in the World kicked off on Monday, with the aim to promote exquisite Italian cooking, the Mediterranean diet, Italian agri-food products and wine. In the 2023 edition, as in past years, the week will be further enhanced by activities organized by the Italian Embassy in China together with the Italian business community operating in China. 

Several Italian restaurants in Beijing, Tianjin, and Qingdao have been preparing special menus and typical dishes for Chinese friends and expatriates residing in China to enjoy throughout the Italian cuisine week that is set to run until November 19. Beijing's ABBOCCA restaurant, for instance, has provided a special selection for homemade fresh cheeses called "TRILOGY," which includes mozzarella, stracciatella, and ricotta, and has been dubbed a tasty journey through salty and sweet to stimulate all senses complete with fresh basil leaves, cherry tomatoes.

A new map exhibit documents evolving views of Earth’s interior

Much of what happens on the Earth’s surface is connected to activity far below. “Beneath Our Feet,” a temporary exhibit at the Norman B. Leventhal Map Center in the Boston Public Library, explores the ways people have envisioned, explored and exploited what lies underground.

“We’re trying to visualize those places that humans don’t naturally go to,” says associate curator Stephanie Cyr. “Everybody gets to see what’s in the sky, but not everyone gets to see what’s underneath.”
“Beneath Our Feet” displays 70 maps, drawings and archaeological artifacts in a bright, narrow exhibit space. (In total, the library holds a collection of 200,000 maps and 5,000 atlases.) Many objects have two sets of labels: one for adults and one for kids, who are guided by a cartoon rat mascot called Digger Burrows.

The layout puts the planet’s long history front and center. Visitors enter by walking over a U.S. Geological Survey map of North America that is color-coded to show how topography has changed over geologic time.
Beyond that, the exhibit is split into two main themes, Cyr says: the natural world, and how people have put their fingerprints on it. Historical and modern maps hang side by side, illustrating how ways of thinking about the Earth developed as the tools for exploring it improved.

For instance, a 1665 illustration drawn by Jesuit scholar Athanasius Kircher depicts Earth’s water systems as an underground network that churned with guidance from a large ball of fire in the planet’s center, Cyr says. “He wasn’t that far off.” Under Kircher’s drawing is an early sonar map of the seafloor in the Pacific Ocean, made by geologists Marie Tharp and Bruce Heezen in 1969 (SN: 10/6/12, p. 30). Their maps revealed the Mid-Atlantic Ridge. Finding that rift helped to prove the existence of plate tectonics and that Earth’s surface is shaped by the motion of vast subsurface forces.

On another wall, a 1794 topological-relief drawing of Mount Vesuvius — which erupted and destroyed the Roman city of Pompeii in A.D. 79 — is embellished by a cartouche of Greek mythological characters, including one representing death. The drawing hangs above a NASA satellite image of the same region, showing how the cities around Mount Vesuvius have grown since the eruption that buried Pompeii, and how volcano monitoring has improved.

The tone turns serious in the latter half of the exhibit. Maps of coal deposits in 1880s Pennsylvania sit near modern schematics explaining how fracking works (SN: 9/8/12, p. 20). Reproductions of maps of the Dakotas from 1886 may remind visitors of ongoing controversies with the Dakota Access Pipeline, proposed to run near the Standing Rock Sioux Reservation, and maps from the U.S. Environmental Protection Agency mark sites in Flint, Mich., with lead-tainted water.

Maps in the exhibit are presented dispassionately and without overt political commentary. Cyr hopes the zoomed-out perspectives that maps provide will allow people to approach controversial topics with cool heads.

“The library is a safe place to have civil discourse,” she says. “It’s also a place where you have access to factual materials and factual resources.”

A key virus fighter is implicated in pregnancy woes

An immune system mainstay in the fight against viruses may harm rather than help a pregnancy. In Zika-infected mice, this betrayal appears to contribute to fetal abnormalities linked to the virus, researchers report online January 5 in Science Immunology. And it could explain pregnancy complications that arise from infections with other pathogens and from autoimmune disorders.

In pregnant mice infected with Zika virus, those fetuses with a docking station, or receptor, for immune system proteins called type I interferons either died or grew more poorly compared with fetuses lacking the receptor. “The type I interferon system is one of the key mechanisms for stopping viral infections,” says Helen Lazear, a virologist at the University of North Carolina at Chapel Hill, who coauthored an editorial accompanying the study. “That same [immune] process is actually causing fetal damage, and that’s unexpected.”
Cells infected by viruses begin the fight against the intruder by producing type I interferons. These proteins latch onto their receptor on the surfaces of neighboring cells and kick-start the production of hundreds of other antiviral proteins.

Akiko Iwasaki, a Howard Hughes Medical Institute investigator and immunologist at Yale School of Medicine, and her colleagues were interested in studying what happens to fetuses when moms are sexually infected with Zika virus. The researchers mated female mice unable to make the receptor for type I interferons to males with one copy of the gene needed to make the receptor. This meant that moms would carry some pups with the receptor and some without in the same pregnancy.

Pregnant mice were infected vaginally with Zika at one of two times — one corresponding to mid‒first trimester in humans, the other to late first trimester. Of the fetuses exposed to infection earlier, those that had the interferon receptor died, while those without the receptor continued to develop. For fetuses exposed to infection a bit later in the pregnancy, those with the receptor were much smaller than their receptor-lacking counterparts.

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The fetuses without the receptor still grew poorly due to the Zika infection, which is expected given their inability to fight the infection. What was striking, Iwasaki says, is that the fetuses able to fight the infection were more damaged, and were the only fetuses that died.

It’s unclear how this antiviral immune response causes fetal damage. But the placentas—which, like their fetuses, had the receptor — didn’t appear to provide those fetuses with enough oxygen, Iwasaki says.

The researchers also infected pregnant mice that had the receptor for type I interferons with a viral mimic — a bit of genetic material that goads the body to begin its antiviral immune response — to see if the damage happened only during a Zika infection. These fetuses also died early in the pregnancy, an indication that perhaps the immune system could cause fetal damage during other viral infections, Iwasaki notes.

Iwasaki and colleagues next added type I interferon to samples of human placental tissue in dishes. After 16 to 20 hours, the placental tissues developed structures that resembled syncytial knots. These knots are widespread in the placentas of pregnancies with such complications as preeclampsia and restricted fetal growth.

Figuring out which of the hundreds of antiviral proteins made when type I interferon ignites the immune system can trigger placental and fetal damage is the next step, says Iwasaki. That could provide more understanding of miscarriage generally; other infections that cause congenital diseases, like toxoplasmosis and rubella; and autoimmune disorders that feature excessive type I interferon production, such as lupus, she says.

By 2100, damaged corals may let waves twice as tall as today’s reach coasts

A complex coral reef full of nooks and crannies is a coastline’s best defense against large ocean waves. But coral die-offs over the next century could allow taller waves to penetrate the corals’ defenses, simulations suggest. A new study finds that at some Pacific Island sites, waves reaching the shore could be more than twice as high as today’s by 2100.

The rough, complex structures of coral reefs dissipate wave energy through friction, calming waves before they reach the shore. As corals die due to warming oceans (SN: 2/3/18, p. 16), the overall complexity of the reef also diminishes, leaving a coast potentially more exposed. At the same time, rising sea levels due to climate change increasingly threaten low-lying coastal communities with inundation and beach erosion — and stressed corals may not be able to grow vertically fast enough to match the pace of sea level rise. That could also make them a less effective barrier.

Researchers compared simulations of current and future sea level and reef conditions at four sites with differing wave energy near the French Polynesian islands of Moorea and Tahiti. The team then simulated the height of a wave after it has passed the reef, known as the back-reef wave height, under several scenarios. The most likely scenario studied was based on the Intergovernmental Panel on Climate Change’s projections of sea level height by 2100 and corresponding changes in reef structure.

Under those conditions, the average back-reef wave heights at the four sites would be 2.4 times as high in 2100 as today, the team reports February 28 in Science Advances. That change would be largely due to the decrease in coral reef complexity rather than rising sea levels, the simulations suggest. Coastal communities around the world will likely see similar wave height increases, dependent on local reef structures and extent of sea level rise. The finding, the researchers say, shows that conserving reefs is crucial to protecting coastal communities in a changing climate.

Forget Pi Day. We should be celebrating Tau Day

As a physics reporter and lover of mathematics, I won’t be celebrating Pi Day this year. That’s because pi is wrong.

I don’t mean that the value is incorrect. Pi, known by the symbol π, is the number you get when you divide a circle’s circumference by its diameter: 3.14159… and so on without end. But, as some mathematicians have argued, the mathematical constant was poorly chosen, and students worldwide continue to suffer as a result.

A longtime fixture of high school math classes, pi has inspired books, art (SN Online: 5/4/06) and enthusiasts who memorize it to tens of thousands of decimal places (SN: 4/7/12, p. 12). But some contend that replacing pi with a different mathematical constant could make trigonometry and other math subjects easier to learn. These critics — including myself — advocate for an arguably more elegant number equal to 2π: 6.28318…. Sometimes known as tau, or the symbol τ, the quantity is equal to a circle’s circumference divided by its radius, not its diameter.

This idea is not new. In 2001, mathematician Bob Palais of the University of Utah in Salt Lake City published an article in the Mathematical Intelligencer titled “ π is wrong!” The topic gained more attention in 2010 with The Tau Manifesto, posted online by author and educator Michael Hartl. But the debate tends to reignite every year on March 14, which is celebrated as Pi Day for its digits: 3/14.
The simplest way to see the failure of pi is to consider angles, which in mathematics are typically measured in radians. Pi is the number of radians in half a circle, not a whole circle. That makes things confusing: For example, the angle at the tip of a slice of pizza — an eighth of a pie — isn’t π/8, but π/4. In contrast, using tau, the pizza-slice angle is simply τ/8. Put another way, tau is the number of radians in a full circle.

That factor of two is a big deal. Trigonometry — the study of the angles and lines found in shapes such as triangles — can be a confusing whirlwind for students, full of blindly plugging numbers into calculators. That’s especially true when it comes to sine and cosine, two important functions in trigonometry. Many trigonometry problems involve calculating the sine or cosine of an angle. When graphed, the two functions look like a series of wiggles, shaped a bit like an “S” on its side, that repeat the same values every 2π. That means pi covers only half of an S. Tau, on the other hand, covers the full wiggle, a more intuitive measure.

Pi has become so embedded in mathematics that it could be hard to excise. A more practical approach may be to introduce tau as a teaching tool alongside pi, rather than a replacement. Education is where tau’s impact is most likely to be felt: Professional scientists and mathematicians can comfortably handle the factors of two that crop up with pi in equations.

You might argue that multiplying by two isn’t that hard, even for students. But it isn’t the arithmetic that concerns me. Trigonometry is notorious for creating a divide between the math-fluent and math-phobic. But helping more people understand and enjoy mathematics isn’t some pie-in-the-sky fantasy. Everyone is capable of doing math. We just need to work smarter, and speak more clearly, to help those who struggle.

So here’s to June 28 — Tau Day.

The great Pacific garbage patch may be 16 times as massive as we thought

We’re going to need a bigger trash can.

A pooling of plastic waste floating in the ocean between California and Hawaii contains at least 79,000 tons of material spread over 1.6 million square kilometers, researchers report March 22 in Scientific Reports. That’s the equivalent to the mass of more than 6,500 school buses. Known as the great Pacific garbage patch, the hoard is four to 16 times as heavy as past estimates.

About 1.8 trillion plastic pieces make up the garbage patch, the scientists estimate. Particles smaller than half a centimeter, called microplastics, account for 94 percent of the pieces, but only 8 percent of the overall mass. In contrast, large (5 to 50 centimeters) and extra-large (bigger than 50 centimeters) pieces made up 25 percent and 53 percent of the estimated patch mass.
Much of the plastic in the patch comes from humans’ ocean activities, such as fishing and shipping, the researchers found. Almost half of the total mass, for example, is from discarded fishing nets. A lot of that litter contains especially durable plastics, such as polyethylene and polypropylene, which are designed to survive in marine environments.
To get the new size and mass estimates, Laurent Lebreton of the Ocean Cleanup, a nonprofit foundation in Delft, the Netherlands, and his colleagues trawled samples from the ocean surface, took aerial images and simulated particle pathways based on plastic sources and ocean circulation.
Aerial images provided more accurate tallies and measurements of the larger plastic pieces, the researchers write. That could account for the increase in mass over past estimates, which relied on trawling data and images taken from boats, in addition to computer simulations. Another possible explanation: The patch grew — perhaps driven by an influx of debris from the 2011 tsunami that hit Japan and washed trash out to sea (SN: 10/28/17, p. 32).

Hayabusa2 has blasted the surface of asteroid Ryugu to make a crater

Hayabusa2 has blasted the asteroid Ryugu with a projectile, probably adding a crater to the small world’s surface and stirring up dust that scientists hope to snag.

The projectile, a two-kilogram copper cylinder, separated from the Hayabusa2 spacecraft at 9:56 p.m. EDT on April 4, JAXA, Japan’s space agency, reports.

Hayabusa2 flew to the other side of the asteroid to hide from debris that would have been ejected when the projectile hit (SN: 1/19/19, p. 20). Scientists won’t know for sure whether the object successfully made a crater, and, if so, how big it is, until the craft circles back. But by 10:36 p.m. EDT, Hayabusa2’s cameras had captured a blurry shot of a dust plume spurting up from Ryugu, so the team thinks the attempt worked.
“This is the world’s first collision experiment with an asteroid!” JAXA tweeted.

Hayabusa2 plans to briefly touch down inside the crater to pick up a pinch of asteroid dust. The spacecraft has already grabbed one sample of Ryugu’s surface (SN Online: 2/22/19). But dust exposed by the impact will give researchers a look at the asteroid’s subsurface, which has not been exposed to sunlight or other types of space radiation for up to billions of years.

If all goes as planned, Hayabusa2 will return to Earth with both samples in late 2020. A third planned sample pickup has been scrapped because Ryugu’s boulder-strewn surface is so hazardous for the spacecraft.
Comparing the two samples will reveal details of how being exposed to space changes the appearance and composition of rocky asteroids, and will help scientists figure out how Ryugu formed (SN Online: 3/20/19). Scientists hope that the asteroid contains water and organic material that might help explain how life got started in the solar system.

A Greek skull may belong to the oldest human found outside of Africa

A skull found in a cliffside cave on Greece’s southern coast in 1978 represents the oldest Homo sapiens fossil outside Africa, scientists say.

That skull, from an individual who lived at least 210,000 years ago, was encased in rock that also held a Neandertal skull dating to at least 170,000 years ago, contends a team led by paleoanthropologist Katerina Harvati of the University of Tübingen in Germany.

If these findings, reported online July 10 in Nature, hold up, the ancient Greek H. sapiens skull is more than 160,000 years older than the next oldest European H. sapiens fossils (SN Online: 11/2/11). It’s also older than a proposed H. sapiens jaw found at Israel’s Misliya Cave that dates to between around 177,000 and 194,000 years ago (SN: 2/17/18, p. 6).

“Multiple Homo sapiens populations dispersed out of Africa starting much earlier, and reaching much farther into Europe, than previously thought,” Harvati said at a July 8 news conference. African H. sapiens originated roughly 300,000 years ago (SN: 7/8/17, p. 6).
A small group of humans may have reached what’s now Greece more than 200,000 years ago, she suggested. Neandertals who settled in southeastern Europe not long after that may have replaced those first H. sapiens. Then humans arriving in Mediterranean Europe tens of thousands of years later would eventually have replaced resident Neandertals, who died out around 40,000 years ago (SN Online: 6/26/19).

But Harvati’s group can’t exclude the possibility that H. sapiens and Neandertals simultaneously inhabited southeastern Europe more than 200,000 years ago and sometimes interbred. A 2017 analysis of ancient and modern DNA concluded that humans likely mated with European Neandertals at that time.

The two skulls were held in a small section of wall that had washed into Greece’s Apidima Cave from higher cliff sediment and then solidified roughly 150,000 years ago. Since one skull is older than the other, each must originally have been deposited in different sediment layers before ending up about 30 centimeters apart on the cave wall, the researchers say.
Earlier studies indicated that one Apidima skull, which retains the face and much of the braincase, was a Neandertal that lived at least 160,000 years ago. But fossilization and sediment pressures had distorted the skull’s shape. Based on four 3-D digital reconstructions of the specimen, Harvati’s team concluded that its heavy brow ridges, sloping face and other features resembled Neandertal skulls more than ancient and modern human skulls. An analysis of the decay rate of radioactive forms of uranium in skull bone fragments produced an age estimate of at least 170,000 years.

A second Apidima fossil, also dated using uranium analyses, consists of the back of a slightly distorted braincase. Its rounded shape in a digital reconstruction characterizes H. sapiens, not Neandertals, the researchers say. A bunlike bulge often protrudes from the back of Neandertals’ skulls.
But without any facial remains to confirm the species identity of the partial braincase, “it is still possible that both Apidima skulls are Neandertals,” says paleoanthropologist Israel Hershkovitz of Tel Aviv University. Hershkovitz led the team that discovered the Misliya jaw and assigned it to H. sapiens.

Harvati and her colleagues will try to extract DNA and species-distinguishing proteins (SN: 6/8/19, p. 6) from the Greek skulls to determine their evolutionary identities and to look for signs of interbreeding between humans and Neandertals.

The find does little to resolve competing explanations of how ancient humans made their way out of Africa. Harvati’s suggestion that humans trekked from Africa to Eurasia several times starting more than 200,000 years ago is plausible, says paleoanthropologist Eric Delson of City University of New York’s Lehman College in an accompanying commentary. And the idea that some H. sapiens newcomers gave way to Neandertals probably also applied to humans who reached Misliya Cave and nearby Middle Eastern sites as late as around 90,000 years ago, before Neandertals occupied the area by 60,000 years ago, Delson says.

Hershkovitz disagrees. Ancient humans and Neandertals lived side-by-side in the Middle East for 100,000 years or more and occasionally interbred, he contends. Misliya Cave sediment bearing stone tools dates to as early as 274,000 years ago, Hershkovitz says. Since only H. sapiens remains have been found in the Israeli cave, ancient humans probably made those stone artifacts and could have been forerunners of Greek H. sapiens.