How to make recyclable plastics out of CO2 to slow climate change

It’s morning and you wake on a comfortable foam mattress made partly from greenhouse gas. You pull on a T-shirt and sneakers containing carbon dioxide pulled from factory emissions. After a good run, you stop for a cup of joe and guiltlessly toss the plastic cup in the trash, confident it will fully biodegrade into harmless organic materials. At home, you squeeze shampoo from a bottle that has lived many lifetimes, then slip into a dress fashioned from smokestack emissions. You head to work with a smile, knowing your morning routine has made Earth’s atmosphere a teeny bit carbon cleaner.

Sound like a dream? Hardly. These products are already sold around the world. And others are being developed. They’re part of a growing effort by academia and industry to reduce the damage caused by centuries of human activity that has sent CO2 and other heat-trapping gases into the atmosphere .
The need for action is urgent. In its 2022 report, the United Nations Intergovernmental Panel on Climate Change, or IPCC, stated that rising temperatures have already caused irreversible damage to the planet and increased human death and disease (SN: 5/7/22 & 5/21/22, p. 8). Meanwhile, the amount of CO2 emitted continues to rise. The U.S. Energy Information Administration predicted last year that if current policy and growth trends continue, annual global CO2 emissions could rise from about 34 billion metric tons in 2020 to almost 43 billion by 2050.

Carbon capture and storage, or CCS, is one strategy for mitigating climate change long noted by the IPCC as having “considerable” potential. A technology that has existed since the 1970s, CCS traps CO2 from smokestacks or ambient air and pumps it underground for permanent sequestration. Today, 27 CCS facilities operate around the world — 12 in the United States — storing an estimated 36 million tons of carbon per year, according to the Global CCS Institute. The 2021 Infrastructure Investment and Jobs Act includes $3.5 billion in funding for four additional U.S. direct capture facilities.

But rather than just storing it, the captured carbon could be used to make things. This year for the first time, the IPCC added carbon capture and utilization, or CCU, to its list of options for drawing down atmospheric carbon. CCU captures CO2 and incorporates it into carbon-containing products like cement, jet fuel and the raw materials for making plastics. Still in early stages of development and commercialization, CCU could reduce annual greenhouse gas emissions by 20 billion tons in 2050 — more than half of the world’s global emissions today, the IPCC estimates.

Such recognition was a big victory for a movement that has struggled to emerge from the shadow of its more established cousin, CCS, says chemist and global CCU expert Peter Styring of the University of Sheffield in England. Many CCU-related companies are springing up and collaborating with each other and with governments around the world, he adds.

The potential of CCU is “enormous,” both in terms of its volume and monetary potential, said mechanical engineer Volker Sick at a CCU conference in Brussels in April. Sick, of the University of Michigan in Ann Arbor, directs the Global CO2 Initiative, which promotes CCU as a mainstream climate solution. “We’re not talking about something that’s nice to do but doesn’t move the needle,” he added. “It moves the needle in many, many aspects.”
The plastics paradox
The use of carbon dioxide in products is not new. CO2 is used to make soda fizzy, keep foods frozen (as dry ice) and convert ammonia to urea for fertilizer. What’s new is the focus on making products with CO2 as a strategy to slow climate change. Today’s CCU market, estimated at $2 billion, could mushroom to $550 billion by 2040, according to Lux Research, a Boston-based market research firm. Much of this market is driven by adding CO2 to cement — which can improve its properties as well as reduce atmospheric carbon — and to jet fuel, which can lower the industry’s large carbon footprint. CO2-to-plastics is a niche market today, but the field aims to battle two crises at once: climate change and plastic pollution.

Plastics are made from fossil fuels, a mix of hydrocarbons formed by the remains of ancient organisms. Most plastics are produced by refining crude oil, which is then broken down into smaller molecules through a process called cracking. These smaller molecules, known as monomers, are the building blocks of polymers. Monomers such as ethylene, propylene, styrene and others are linked together to form plastics such as polyethylene (detergent bottles, toys, rigid pipes), polypropylene (water bottles, luggage, car parts) and polystyrene (plastic cutlery, CD cases, Styrofoam).
But making plastics from fossil fuels is a carbon catastrophe. Each step in the plastics life cycle — extraction, transport, manufacture and disposal — emits massive amounts of greenhouse gases, mostly CO2, according to the Center for International Environmental Law, a nonprofit law firm based in Geneva and Washington, D.C. These emissions alone — more than 850 million tons of greenhouse gases in 2019 — are enough to threaten global climate targets.

And the numbers are about to get much worse. A 2018 report by the Paris-based intergovernmental International Energy Agency projected that global demand for plastics will increase from about 400 million tons in 2020 to nearly 600 million by 2050. Future demand is expected to be concentrated in developing countries and will vastly outstrip global recycling efforts.

Plastics are a serious crisis for the environment, from fossil fuel use to their buildup in landfills and oceans (SN: 1/16/21, p. 4). But we’re a society addicted to plastic and all it gives us — cell phones, computers, comfy Crocs. Is there a way to have our (plastic-wrapped) cake and eat it too?

Yes, says Sick. First, he argues, cap the oil wells. Next, make plastics from aboveground carbon. Today, there are products made of 20 to over 40 percent CO2. Finally, he says, build a circular economy, one that reduces resource use, reuses products, then recycles them into other new products.

“Not only can we eliminate the fossil carbon as a source so that we don’t add to the aboveground carbon budget, but in the process we can also rethink how we make plastics,” Sick says. He suggests they be specifically designed “to live very, very long so that they don’t have to be replaced … or that they decompose in a benign manner.”

But creating plastics from thin air is not easy. CO2 needs to be extracted, from the atmosphere or smokestacks, for example, using specialized equipment. It often needs to be compressed into liquid form and transported, generally through pipelines. Finally, to meet the overall goal of reducing the amount of carbon in the air, the chemical reaction that turns CO2 into the building blocks of plastics must be run with as little extra energy as possible. Keeping energy use low is a special challenge when dealing with the carbon dioxide molecule.

A bond that’s hard to break
There’s a reason that carbon dioxide is such a potent greenhouse gas. It is incredibly stable and can linger in the atmosphere for 300 to 1,000 years. That stability makes CO2 hard to break apart and add to other chemicals. Lots of energy is typically needed for the reaction.

“This is the fundamental energy problem of CO2,” says chemist Ian Tonks of the University of Minnesota in Minneapolis. “Energy is necessary to fix CO2 to plastics. We’re trying to find that energy in creative ways.”

Catalysts offer a possible answer. These substances can increase the rate of a chemical reaction, and thus reduce the need for energy. Scientists in the CO2-to-plastics field have spent more than a decade searching for catalysts that can work at close to room temperature and pressure, and coax CO2 to form a new chemical identity. These efforts fall into two broad categories: chemical and biological conversion.

First attempts
Early experiments focused on adding CO2 to highly reactive monomers like epoxides to facilitate the reaction. Epoxides are three-membered rings composed of one oxygen atom and two carbon atoms. Like a spring under tension, they can easily pop open. In the early 2000s, industrial chemist Christoph Gürtler and chemist Walter Leitner of Aachen University in Germany found a zinc catalyst that allowed them to break open the epoxide ring of polypropylene oxide and combine it with CO2. Following the reaction, the CO2 was joined permanently to the polypropylene molecule and was no longer in gas form — something that is true of all CO2-to-plastic reactions. Their work resulted in one of the first commercial CO2 products — a polyurethane foam containing 20 percent captured CO2. Today, the German company Covestro, where Gürtler now works, sells 5,000 tons of the product annually in mattresses, car interiors, building insulation and sports flooring.

More recent research has focused on other monomers to expand the variety of CO2-based plastics. Butadiene is a hydrocarbon monomer that can be used to make polyester for clothing, carpets, adhesives and other products.

In 2020, chemist James Eagan at the University of Akron in Ohio mixed butadiene and CO2 with a series of catalysts developed at Stanford University. Eagan hoped to create a polyester that is carbon negative, meaning it has a net effect of removing CO2 from the atmosphere, rather than adding it. When he analyzed the contents of one vial, he discovered he had created something even better: a polyester made with 29 percent CO2 that degrades in high pH water into organic materials.
“Chemistry is like cooking,” Eagan says. “We took chocolate chips, flour, eggs, butter, mixed them up, and instead of getting cookies we opened the oven and found a chicken potpie.”

Eagan’s invention has immediate applications in the recycling industry, where machines can often get gummed up from the nondegradable adhesives used in packaging, soda bottle labels and other products. An adhesive that easily breaks down may improve the efficiency of recycling facilities.

Tonks, described by Eagan as a friendly competitor, took Eagan’s patented process a step further. By putting Eagan’s product through one more reaction, Tonks made the polymer fully degradable back to reusable CO2 — a circular carbon economy goal. Tonks created a start-up this year called LoopCO2 to produce a variety of biodegradable plastics.

Microbial help
Researchers have also harnessed microbes to help turn carbon dioxide into useful materials including dress fabric. Some of the planet’s oldest-living microbes emerged at a time when Earth’s atmosphere was rich in carbon dioxide. Known as acetogens and methanogens, the microbes developed simple metabolic pathways that use enzyme catalysts to convert CO2 and carbon monoxide into organic molecules. In the atmosphere, CO will react with oxygen to form CO2. In the last decade, researchers have studied the microbes’ potential to remove these gases from the atmosphere and turn them into useful products.

LanzaTech, based in Skokie, Ill., uses the acetogenic bacterium Clostridium autoethanogenum to metabolize CO2and CO emissions into a variety of industrial chemicals, including ethanol. Last year, the clothing company Zara began using LanzaTech’s polyester fabric for a line of dresses.

The ethanol used to create these products comes from LanzaTech’s two commercial facilities in China, the first to transform waste CO, a main emission from steel plants, into ethanol. The ethanol goes through two more steps to become polyester. LanzaTech partnered with steel mills near Beijing and in north-central China, feeding carbon monoxide into LanzaTech’s microbe-filled bioreactor.

Steel production emits almost two tons of CO2 for every ton of steel made. By contrast, a life cycle assessment study found that LanzaTech’s ethanol production process lowered greenhouse gas emissions by approximately 80 percent compared with ethanol made from fossil fuels.

In February, researchers from LanzaTech, Northwestern University in Evanston, Ill., and others reported in Nature Biotechnology that they had genetically modified the Clostridium bacterium to produce acetone and isopropanol, two other fossil fuel–based industrial chemicals. Company CEO Jennifer Holmgren says the only waste product is dead bacteria, which can be used as compost or animal feed.

Other researchers are skipping the living microbes and just using their catalysts. More than a decade ago, chemist Charles Dismukes of Rutgers University in Piscataway, N.J., began looking at acetogens and methanogens as a way to use atmospheric carbon. He was intrigued by their ability to release energy when making carbon building blocks from CO2, a reaction that usually requires energy. He and his team focused on the bacteria’s nickel phosphide catalysts, which are responsible for the energy-releasing carbon reaction.

Dismukes and colleagues developed six electrocatalysts that are able to make monomers at room temperature and pressure using only CO2, water and electricity. The energy­-releasing pathway of the nickel phosphide catalysts “lowers the required voltage to run the reaction, which lowers the energy consumption of the process and improves the carbon footprint,” says Karin Calvinho, a former student of Dismukes who is now chief technical officer at RenewCO2, the start-up Dismukes’ team formed in 2018.

RenewCO2 plans to sell its monomers, including monoethylene glycol, to companies that want to reduce their carbon footprint. The group proved its concept works using CO2 brought into the lab. In the future, the company intends to obtain CO2 from biomass, industrial emissions or direct air capture.
Barriers to change
Yet researchers and companies face challenges in scaling up carbon capture and reuse. Some barriers lurk in the language of regulations written before CCU existed. An example is the U.S. Environmental Protection Agency’s program to provide tax credits to companies that make biofuels. The program is geared toward plant-based fuels like corn and sugar­cane. LanzaTech’s approach for making jet fuel doesn’t qualify for credits because bacteria are not plants.

Other barriers are more fundamental. Styring points to the long-standing practice of fossil fuel subsidies, which in 2021 topped $440 billion worldwide. Global government subsidies to the oil and gas industry keep fossil fuel prices artificially low, making it hard for renewables to compete, according to the International Energy Agency. Styring advocates shifting those subsidies toward renewables.

“We try to work on the principle that we recycle carbon and create a circular economy,” he says. “But current legislation is set up to perpetuate a linear economy.”
The happy morning routine that makes the world carbon cleaner is theoretically possible. It’s just not the way the world works yet. Getting to that circular economy, where the amount of carbon above ground is finite and controlled in a never-ending loop of use and reuse will require change on multiple fronts. Government policy and investment, corporate practices, technological development and human behavior would need to align perfectly and quickly in the interests of the planet.

In the meantime, researchers continue their work on the carbon dioxide molecule.

“I try to plan for the worst-case scenario,” says Eagan, the chemist in Akron. “If legislation is never in place to curb emissions, how do we operate within our capitalist system to generate value in a renewable and responsible way? At the end of the day, we will need new chemistry.”

NASA’s Artemis I mission sets the stage for our return to the moon

When Artemis I blasts off into the early morning sky over Florida, it may launch a new era of lunar science and exploration with it.

The NASA mission, scheduled to launch in the next two weeks, is the first of three planned flights aimed at landing humans on the moon for the first time since 1972. No astronauts will fly on the upcoming mission. But the flight marks the first test of the technology — the rocket, the spacesuits, the watery return to Earth — that will ultimately take people, including the first woman and the first astronaut of color, to the lunar surface.
The test includes the first flight of NASA’s Space Launch System, or SLS, and its Orion spacecraft, a rocket and crew capsule that have been decades in the making. These craft have been delayed, blown through their budgets and been threatened with cancellation more than once. Even within the spaceflight community, a lot of people feared they would never fly.

To see a human-capable moon rocket finally on the launchpad is “pretty astonishing,” says Casey Dreier, a Seattle-based space policy expert at the Planetary Society. “This is a reality that most of us alive on Earth today have never experienced.”

And if the Artemis program works, opportunities for science will follow.

“Because humans have to come back, alive, you have a huge opportunity to bring samples back with you,” Dreier says. Sending human astronauts may be a wedge to open the door for pure learning.

The launch
Artemis I is slated to lift off on August 29 at 8:33 a.m. EDT. The SLS rocket will lift Orion into space, where the crew capsule will separate from the rocket and continue to an orbit around the moon. After circling the moon for about two weeks, Orion will slingshot back to Earth and splash down in the Pacific Ocean off the coast of San Diego. The whole mission will last about 42 days.

Orion will stay in space longer than any other human-rated spacecraft has without docking to another spaceship, like the International Space Station. At its closest approach, the spacecraft will fly about 100 kilometers above the lunar surface. It will also go up to 64,000 kilometers past the moon, farther from Earth than any spacecraft built for humans. The previous record, set by Apollo 13 in 1970, was 16,000 kilometers beyond the far side of the moon.
The main goal of the mission is to prove that everything works. That includes Orion’s heat shield, which will need to protect astronauts as the capsule comes screaming through Earth’s atmosphere at 40,000 kilometers per hour and heats up to more than 2700° Celsius on its return trip. It also includes the procedure for retrieving the capsule and its crew and cargo after splashdown.

Even though it has no astronauts, the mission won’t be flying empty. Just beneath the Orion capsule are 10 CubeSats, small, simple spacecraft each about the size of a shoebox. After Orion separates from the SLS rocket, those CubeSats will go their separate ways to study the moon, the radiation environment in space and the effects of that radiation on organisms like yeast. One CubeSat will unfurl a solar sail and take off to explore a near-Earth asteroid (SN: 8/26/11).

The “crew”
Inside the Orion capsule ride three humanoid passengers. In the commander’s seat is faux astronaut Moonikin Campos, named for Arturo Campos, a NASA engineer who played a key role in returning the Apollo 13 moon mission safely to Earth after its in-flight disaster in 1970. The “moonikin” — a mashup of moon and manikin — is based on a firefighter training rescue manikin, says NASA engineer Dustin Gohmert. Moonikin Campos will be wearing the new flight suit that was designed for the Artemis missions.
The spacesuit is like a personalized spacecraft, says Gohmert, of the Johnson Space Center in Houston, Texas. It’s meant to be worn during takeoff, landing and any time there is an emergency in the cabin. The suit may look familiar to anyone who watched space shuttle launches, Gohmert says, because it does a very similar job: “It’s an orange suit that acts like a balloon that’s shaped like your body.”

The main difference is that the Orion suit, plus the accompanying helmet, seat and connection to the Orion spacecraft itself, are designed to keep a crew member alive for up to six days, the time it could take to get back to Earth if something goes wrong in deep space. Astronauts visiting the International Space Station, by contrast, were never more than a few hours from Earth.

To help make that week tolerable, each suit will be custom fit to the astronaut. “I’d like to say the word ‘comfort,’ but that’s a difficult word to use,” Gohmert says. “Nothing will be comfortable about six days in a spacesuit, no matter what you do.”

The suit and spacecraft will provide the astronauts with oxygen and scrub the astronauts’ air of carbon dioxide. The suit will also have a tube for the astronauts to eat liquid food and a way for them to collect urine and feces, although Moonikin Campos won’t test those aspects. He will be equipped with radiation sensors, while his seat will have sensors to detect acceleration and vibration throughout the mission.
The suit, helmet and seat all take safety lessons from the space shuttle Columbia disaster, Gohmert says (SN: 9/22/2003). A junior engineer at the time, Gohmert worked on the suits the Columbia astronauts wore and saw the seven-member crew off to the launchpad. “It was a pivotal point for all of us, of course, who were there at the time,” he says. “If we didn’t take lessons from that, we wouldn’t be doing them justice.”

Moonikin Campos will be accompanied by a pair of mockup female torsos named Helga and Zohar. Their mission is to report back on space risks that are unique to female bodies, which have never been near the moon. NASA plans to send a woman on the first crewed Artemis flight, and women have different cancer risks from space radiation than men.
The two torsos are figures used in medicine called anthropomorphic phantoms, which are made from materials that simulate human bone, tissue and organs. “They are in principle identical twins,” said physicist Thomas Berger of the German Aerospace Center in Cologne in a briefing on August 17. But Zohar — whose name means “light” or “radiance” in Hebrew — will wear a radiation protection vest provided by the Israel Space Agency and the private company StemRad, based in Tampa, Fla.

The vest is made of a polymer designed to deflect protons that the sun releases during solar storms and has more shielding over radiation-sensitive organs like breasts and ovaries. Each phantom will also carry more than 6,000 small radiation detectors to build a 3-D picture of the dose of charged particles a female astronaut might receive on a trip to the moon and back. Comparing the radiation levels each phantom receives will help refine the vest’s design for future astronauts.

Orion will also carry two other nonhuman passengers — the British stop motion television character Shaun the sheep and Snoopy, who will serve as an indicator of zero gravity.

The past and the future
SLS and Orion have had a checkered history. The program goes back to 2004, when President George W. Bush proposed sending astronauts to the moon and then to Mars. In 2010, President Barack Obama canceled that plan, and then in 2017 President Donald Trump directed NASA to retrain its sights on the moon.

All the while, Congress continued to fund the development of the SLS rocket. Originally, SLS was supposed to cost $6 billion and fly in 2016. It has so far cost $23 billion on the eve of its launch in 2022.

“The rhetoric has flip-flopped a bunch,” Dreier says, as political leaders kept changing their vision for NASA’s direction. “But if you look at the actual programs, very little changed. … The whole time, the money was going to a moon rocket and a moon capsule.”

The next Artemis mission, Artemis II, is scheduled to launch in 2024 and take astronauts — real, live, human astronauts — around the moon but not to its surface.

Artemis III will be the moon landing mission. On August 19, NASA announced 13 candidate landing regions, all near the moon’s south pole, an intriguing spot that has never been visited by humans (SN: 11/11/18). That mission is scheduled to launch in 2025, but there are still a lot of untested elements. Those include the actual lander, which will be built by SpaceX.

There are still a lot of things that can go wrong and a long way to go. But the Artemis I launch is an optimistic dawn for lunar science nevertheless. “The whole [human spaceflight] system has all been shifting to point at the moon,” Dreier says. “I think that’s profoundly exciting. There’s going to be really interesting lessons that happen no matter what comes out of this.”

‘Chameleon’ forces remain elusive in a new dark energy experiment

A chameleon-like force that shifts its nature based on its environment could explain a major physics quandary: how the mysterious substance called dark energy is compelling the cosmos to expand faster and faster. But a new experiment casts doubt on some chameleon theories, researchers report August 25 in Nature Physics.

The chameleon force would be a fifth type of force beyond the basic four: gravitational, strong, weak and electromagnetic. And like a chameleon changing its colors, the hypothetical fifth force would morph depending on the density of its surroundings. In dense environments like Earth, this fifth force would be feeble, camouflaging its effects. In the sparseness of space, the force would be stronger and long-ranged.
This force would result from a chameleon field — an addition to the known fields in physics, such as electric, magnetic and gravitational fields. A chameleon field with these morphing properties could drive the accelerating expansion of the universe without disagreeing with measurements on Earth.

But it’s a challenge to suss out such a changeling force. On Earth, says astrophysicist Jianhua He of Nanjing University in China, “it’s very, very tiny. That’s the most difficult part.”

So He and colleagues designed a detector to search for a subtle fifth force. A wheel with plastic films attached spins past another film sitting on a magnetically levitated piece of graphite. If a chameleon force really exists, the films spinning by would cause a periodic force on the levitating plastic, pulling it up and down. (Gravity also acts this way, but thanks to the device’s design, it should be much weaker than a chameleon force.)

The team was able to rule out a category of chameleon theories. In the future, the researchers hope to improve their results by chilling their device to allow for more sensitive measurements.

7-million-year-old limb fossils may be from the earliest known hominid

In 2001, researchers unearthed a partial fossil leg bone and two forearm bones in the central African nation of Chad. Those fossils come from the earliest known hominid, which lived around 7 million years ago, and reveal that the creature walked upright both on the ground and in the trees, a new study proposes.

But a lively debate surrounds the fossils, concerning whether they actually belong to the hominid species, known as Sahelanthropus tchadensis, or to an ancient ape, and to what extent either species could have adopted a two-legged gait. These have become vexing questions as scientists increasingly suspect that ape and hominid species evolved a variety of ways to walk upright, some more efficient than others, around 7 million years ago.
Since its discovery, the leg bone has also triggered competing accusations of scientific misconduct and an official investigation by the French government–funded research organization CNRS in Paris.

Previously, skull, jaw and tooth finds uncovered at the Chad site in 2001 and 2004 were classified as remnants of S. tchadensis (SN: 4/6/05). The finds are the only other fossils attributed to the species, though some researchers have also since suggested that those fossils represent an ancient ape instead.

Analyses of the three limb bones show that they belong to the previously identified Sahelanthropus species, say paleontologists Guillaume Daver and Franck Guy, both of the University of Poitiers in France, and their colleagues. And internal and external features of the leg bone indicate that Sahelanthropus walked upright, the scientists report August 24 in Nature. Shapes and structures of the two forearm bones suggest that the hominid moved on two legs through trees while grasping branches with its hands, the team says.

“The Chadian species has a set of anatomical features that clearly indicate that our oldest known [hominid] representative [walked] on the ground and in the trees,” Guy says. It’s hard to tell how efficiently or how fast Sahelanthropus moved on two legs, he adds.

Guy’s team studied 3-D digital models of the fossils derived from CT scans. The leg bone was compared with fossils of ancient apes and other hominids and with modern apes and humans. Traits including thickening of the leg bone’s tough outer layer at key points and the presence of an internal bony projection near the hip joint signal an upright stance, the scientists say.

Fossils from the African site, including the three limb bones, suggest that Sahelanthropus was the earliest known hominid, agrees paleoanthropologist Kristian Carlson of the University of Southern California in Los Angeles, who did not participate in the new study. But exactly how it moved while upright remains unknown, he says. Sahelanthropus exhibits a mix of upper leg and forearm traits that differs from those of living apes and humans, suggesting it adopted a novel posture and limb movements while walking.

Whatever stance Sahelanthropus assumed, it probably resembled that of two other early hominids, roughly 6-million-year-old Orrorin tugenensis and more than 5-million-year-old Ardipithecus kadabba, says paleoanthropologist Yohannes Haile-Selassie, director of the Institute of Human Origins at Arizona State University in Tempe (SN: 9/11/04; SN: 3/3/04). Walking abilities of those hominids remain poorly understood due to limited fossils — a partial leg bone for O. tugenensis and a toe bone for the Ardipithecus species.

Haile-Selassie regards all three hominids as part of a single genus that evolved from around 7 million to 5 million years ago. On that issue, “the debate is open, even between members of our team,” Guy says.

Another debate concerns the upper leg’s internal bony projection that the researchers cite as crucial for standing upright. That trait sometimes appears in modern African apes and occasionally is absent in humans, paleoanthropologist Marine Cazenave of the American Museum of Natural History in New York City and colleagues report in the June Journal of Human Evolution. The presence of this bony growth does not definitively show that Sahelanthropus walked upright, Cazenave says.

Other researchers contend that the leg bone most likely comes from an ancient ape — not a hominid — that may have occasionally walked upright. Shape measurements, including curvature of the fossil’s shaft, closely resemble those of modern chimps’ upper leg bones, University of Poitiers paleoanthropologist Roberto Macchiarelli and colleagues reported in December 2020 in the Journal of Human Evolution.

“There may have been ancient apes that had distinctive types of [upright movement] unlike any living apes, including humans,” says paleoanthropologist Bernard Wood of George Washington University in Washington, D.C., who was a coauthor of the 2020 study.

Here is where charges of scientific misconduct come into play. The 2020 study was based on measurements of the Sahelanthropus leg fossil taken in 2004 by a University of Poitiers graduate student conducting a project on how fossilization affects bones.

That student, Aude Bergeret-Medina, was given access to fossils from the Sahelanthropus site that Daver and Guy’s team had tagged as neither hominid nor, more generally, as primate. She noted that one specimen — the leg bone — looked like it belonged to a primate, possibly an ape. Macchiarelli confirmed her observation. Plans for Bergeret-Medina to cut open the bone to study its mineral content were halted.

Macchiarelli informed his university and CNRS of the fossil’s identity. He spent the next 16 years, he says, sending repeated complaints to those institutions that the Sahelanthropus discoverers were violating codes of scientific conduct by not providing information about the leg bone in scientific papers or talks.

Then, CNRS launched an investigation of possible misconduct by Macchiarelli himself when the 2020 study appeared before the Sahelanthropus team published findings on the leg bone in its possession. No ruling has been made yet.

In supplementary information published with the new study, Guy and colleagues write that they identified the forearm bones among stored fossils after Macchiarelli brought the leg bone’s identity to their attention. Further excavations in Chad were conducted before launching a detailed study of the three limb fossils in 2017, the team says.

But the Sahelanthropus team does not cite Bergeret-Medina — now the curator of the Muséum d’Histoire Naturelle Jacques de La Comble in Autun, France — by name for her role in the leg bone’s identification. The investigators write that “a master’s student in taphonomy” received various fossils for a research internship in early 2004 before those finds had been carefully examined by senior scientists. The student, “seeking expertise,” gave the leg fossil to Macchiarelli who identified it as a hominid, Daver and colleagues say.

That’s incorrect, Macchiarelli contends. Bergeret-Medina initially identified the fossil as a primate’s upper leg bone followed by his confirmation of her observation. No claim was made that the fossil came from a hominid, he says. But without Bergeret-Medina’s insightful fossil observation, the new study would never have happened, Macchiarelli asserts.

A new seasoning smells like meat thanks to sugar — and mealworms

A spoonful of sugar may help the mealworms go down.

Adding sugars to powdered, cooked mealworms creates a seasoning with an appetizing “meatlike” odor, researchers report August 24 at the American Chemical Society fall meeting in Chicago.

Some insects have been found to be an environmentally friendly alternative to other animal protein because they require less land and water to raise (SN: 5/11/19). But many people in the United States and other Western countries, where insects aren’t eaten widely, generally find the idea of chomping down on bugs unappetizing.
“There aren’t a lot of people ready to fry up a whole skillet of crickets and eat them fresh,” says Julie Lesnik, a biological anthropologist at Wayne State University in Detroit who wasn’t involved in the new research. Finding out how to make insect-based foods more appealing could be key to making them more mainstream.

And one successful insect-based product could have a snowball effect for similar food. “It’s really great that this research is happening, because at any point this might be the thing that people figure out and then it explodes,” says Brenden Campbell, an insect agriculturist based in Eugene, Ore. He has studied mealworms and created a company called Planet Bugs to, in part, make insect-based food products.

In a previous study, chemist In Hee Cho of Wonkwang University in South Korea and colleagues analyzed the odors given off by mealworms that were steamed, roasted or deep-fried. Steamed mealworms produced a sweet smell, like corn, while roasted and fried mealworms released chemicals more similar to meat and seafood.

In their latest work, the team then keyed in on what combinations of water, sugars and cooking time produced a particularly meaty smell, and tested these concoctions with volunteers to figure out which smelled the most appealing.

Using insects ground up or in seasonings, like Cho’s team did, could help people get past their hesitations about eating whole bugs, says Amy Wright, who has written a book on eating bugs. (She, for one, has no qualms. A literature professor at Austin Peay State University in Clarksville, Tenn., Wright used to keep mealworms in her apartment, which she would use in sandwiches and guacamole.)

“There are plenty of things that are disgusting to us, but we have engineered around it,” Lesnik says. “We’re just seeing insects being treated like any other food, and yeah, we’re talking aroma … but that’s what the engineers of Doritos are doing.”

50 years ago, genes eluded electron microscopes

Molecular biologists can now visualize the larger structures of the cell, such as the nucleus and chromosomes, under the powerful electron microscope. But they have not been able to obtain images of genes (DNA) on the chromosomes. Nor have they been able to see RNA … or the intricate details of cell membranes, enzymes and viruses.

Update
Electron m­icroscopes have become much more powerful over the last 50 years. For instance, in 1981, biophysicist Jacques D­ubochet discovered that tiny biological structures super­cooled with ethane could be observed in their natural state under an electron microscope. That finding paved the way for cryo-electron micro­scopy, which scientists use to visualize proteins, viruses and bacteria at the molecular level (SN: 10/28/17, p. 6). Capturing detailed images of genes remains elusive, but scientists are inching closer. In 2021, researchers reported using an electron microscope and the molecular scissors CRISPR/Cas9 to visualize proteins transcribing DNA instructions for two genes into RNA.

Sleep deprivation may make people less generous

Lack of sleep has been linked to heart disease, poor mood and loneliness (SN: 11/15/16). Being tired could also make us less generous, researchers report August 23 in PLOS Biology.

The hour of sleep lost in the switch over to Daylight Savings Time every spring appears to reduce people’s tendency to help others, the researchers found in one of three experiments testing the link between sleep loss and generosity. Specifically, they showed that average donations to one U.S.-based nonprofit organization dropped by around 10 percent in the workweek after the time switch compared with four weeks before and after the change. In Arizona and Hawaii, states that do not observe Daylight Savings Time, donations remained unchanged.
With over half of the people living in parts of the developed world reporting that they rarely get enough sleep during the workweek, the finding has implications beyond the week we spring forward, the researchers say.

“Lack of sleep shapes the social experiences we have [and] the kinds of societies we live in,” says neuroscientist Eti Ben Simon of the University of California, Berkeley.

To test the link between sleep loss and generosity, Ben Simon and her team first brought 23 young adults into the lab for two nights. The participants slept through one night and stayed awake for another night.

In the mornings, participants completed a standardized altruism questionnaire rating their likelihood of helping strangers or acquaintances in various scenarios. For instance, participants rated on a scale from 1 to 5, with 1 for least likely to help and 5 for most likely, whether they would give up their seat on a bus to a stranger or offer a ride to a coworker in need. Participants never read the same scenario more than once. Roughly 80 percent of participants showed less likelihood of helping others when sleep-deprived than when rested.

The researchers then observed participants’ brain activity in a functional MRI machine, comparing each participant’s neural activity in a rested versus sleep-deprived state. That showed that sleep deprivation reduced activity in a network of brain regions linked to the ability to empathize with others.

In another experiment, the researchers recruited 136 participants online and had them keep a sleep log for four nights. Each participant then completed subsets of the altruism questionnaire before 1 p.m. the next day. The researchers found that the more time participants spent awake in bed, a measure of poor sleep, the lower their altruism scores. That drop in altruism held true both when comparing individuals to themselves and when averaging scores across the group.

In the final experiment focused on Daylight Savings Time, the researchers looked at charitable donations from 2001 to 2016 to Donors Choose, a nonprofit that raises money for school projects across the United States. When the team excluded Hawaii and Arizona, as well as outliers like very large donations, more than 3.4 million donations remained. In the workweek following the time change, total donations, which typically averaged roughly $82 per day, dropped to about $73 per day, Ben Simon says.

There’s always a possibility that some other variable besides sleep is causing this dip in generosity, says behavioral economist David Dickinson of Appalachian State University in Boone, N.C. But this “triple methodology approach” enabled the researchers to draw a convincing line from changes to the brain that appear during sleep deprivation to real-world behavior. “This puts a more comprehensive story on how inefficient sleep affects decisions in this domain of helping others,” he says.

Chronic sleep deprivation in the modern world is a serious problem, Ben Simon says (SN: 3/1/19). But unlike many other large-scale problems — think climate change or political polarization — this one has a ready solution. “If you think about promoting sleep and letting people get the sleep they need, what an impact that could have on the societies we live in.”

A shot of immune proteins may protect against malaria for months

A single shot that could provide months-long protection against malaria has proven effective and safe in a small, early clinical trial of adults.

The shot, which contains monoclonal antibodies, would primarily be intended for infants and children in countries with the most malaria transmission, the team who conducted the trial says. These young children have the highest risk of dying from severe malaria.

In the clinical trial, 15 of 17 participants who received the monoclonal antibodies did not become infected after being exposed to mosquitoes with malaria in the lab, the researchers report in the Aug. 4 New England Journal of Medicine. All six people who did not receive the medicine developed infections.
The clinical trial tested different doses and delivered the medicine intravenously or as a shot. Based on a computer model of how the medicine is taken up, distributed and then cleared by the body, the researchers estimate that one shot may protect against malaria for six months.

“What we’ve always been looking for is some sort of intervention that will prevent infection reliably and for as long a time as possible,” says Miriam Laufer, a pediatric infectious disease doctor and director of the Malaria Research Program at the University of Maryland School of Medicine in Baltimore.

Ideally, Laufer says, that would be a highly effective vaccine that provides years and years of protection. A new malaria vaccine has recently become available, but it is only modestly protective against the disease, and that protection wanes rapidly (SN: 12/22/21). The vaccine requires four shots.

Monoclonal antibodies could provide an option that requires only one shot, once a year. It will take more research to see how well the antibodies work against malaria outside of the laboratory and how cost-effective the shot is.

The monoclonal antibodies shot wouldn’t exclude the need for other prevention strategies, says Laufer, who was not involved in the new study. But it could be “one of the easier interventions in terms of minimal contact with the health care system, with good benefit.”

What’s appealing, she says, “is the possibility that you could give kids, even the youngest kids, an injection [of] premade antibodies that could last for six months or longer and protect them throughout the rainy season.” That once-a-season shot would be helpful in countries in West Africa, where malaria transmission only occurs during the rainy season.

Malaria sickened an estimated 241 million people and killed 627,000 worldwide in 2020. Most of those deaths occurred in sub-Saharan Africa in children younger than 5. These littlest kids haven’t had the chance to develop immunity to the disease and are more susceptible to dying if severe malaria develops.

Reducing the spread of malaria includes measures to control mosquitoes, such as using insecticide-treated nets over beds or spraying to kill mosquitoes indoors, as well as preventing infections, such as taking antimalarial drugs at regular intervals. In October 2021, the World Health Organization also recommended the new vaccine, which in clinical trials reduced cases of malaria and severe malaria by 36 percent after four years of follow-up.

Monoclonal antibodies are a laboratory-made version of antibodies, the proteins that the immune system produces in response to a vaccine or natural infection. Monoclonal means that it contains clones, or copies, of one particular antibody.

The antibody evaluated in the clinical trial attaches to a protein on the surface of sporozoites — the form of the malaria parasite that enters the body after an infected mosquito bites — and stops the parasites from infecting the liver.

The new monoclonal antibody has improvements over an earlier version developed by the same research team. The new version binds more strongly to the targeted malaria parasite protein. It also has a tweak that keeps it from degrading too quickly in the body. This boosts its half-life in the blood (the time it takes for half of the medicine to degrade) to 56 days, almost three times that of its predecessor.

Two clinical trials are planned to assess how well the medicine protects children in places where malaria is spreading. One trial in Mali, where malaria transmission is seasonal, will study the shot’s efficacy over seven months. Another trial in Kenya, among the countries in East Africa where malaria spreads year-round, will assess how well the shot works while following the children for a year. Those studies will also help to determine the best dose for children.

Scientists turned dead spiders into robots

Scientists have literally reanimated dead spiders to do their bidding.

In a new field dubbed “necrobotics,” researchers converted the corpses of wolf spiders into grippers that can manipulate objects. All the team had to do was stab a syringe into a dead spider’s back and superglue it in place. Pushing fluid in and out of the cadaver made its legs clench open and shut, the researchers report July 25 in Advanced Science.

The idea was born from a simple question, explains Faye Yap, a mechanical engineer at Rice University in Houston. Why do spiders curl up when they die?
The answer: Spiders are hydraulic machines (SN: 4/25/22). They control how much their legs extend by forcing blood into them. A dead spider no longer has that blood pressure, so its legs curl up.

“We were just thinking that was so cool,” Yap says. “We wanted to leverage it.”

Her team first tried putting dead wolf spiders in a double boiler, hoping that the wet heat would make the spiders expand and push their legs outward. That didn’t work. But when the researchers injected fluid straight into a spider corpse, they found that they could control its grip well enough to pull wires from a circuit board and pick up other dead spiders. Only after hundreds of uses did the necrobots start to become dehydrated and show signs of wear.
In the future, the researchers will coat spiders with a sealant to hold off that decline. But the next big step is to control the spiders’ legs individually, Yap says, and in the process, figure out more about how spiders work. Then her team could translate their understanding into better designs for other robots.

“That would be very, very interesting,” says Rashid Bashir, a bioengineer at the University of Illinois Urbana-Champaign who wasn’t involved in the new study. A spider corpse itself would probably have problems as a robot, he says, because it won’t perform consistently like “hard robots” and its body will break down over time. But spiders can definitely offer lessons to engineers (SN: 4/2/19). “There’s a lot to be learned from biology and nature,” Bashir says.

Despite the whole reanimating dead spiders thing, Yap is no mad scientist. She wonders whether it’s okay to play Frankenstein, even with spiders. “No one really talks about the ethics” when it comes to this sort of research, she says.

Scientists need to figure out the morality of this sort of bioengineering before they get too good at it, Bashir agrees. The question is, he says, “how far do you go?”

The Windchime experiment could use gravity to hunt for dark matter ‘wind’

The secret to directly detecting dark matter might be blowin’ in the wind.

The mysterious substance continues to elude scientists even though it outweighs visible matter in the universe by about 8 to 1. All laboratory attempts to directly detect dark matter — seen only indirectly by the effect its gravity has on the motions of stars and galaxies — have gone unfulfilled.

Those attempts have relied on the hope that dark matter has at least some other interaction with ordinary matter in addition to gravity (SN: 10/25/16). But a proposed experiment called Windchime, though decades from being realized, will try something new: It will search for dark matter using the only force it is guaranteed to feel — gravity.
“The core idea is extremely simple,” says theoretical physicist Daniel Carney, who described the scheme in May at a meeting of the American Physical Society’s Division of Atomic Molecular and Optical Physics in Orlando, Fla. Like a wind chime on a porch rattling in a breeze, the Windchime detector would try to sense a dark matter “wind” blowing past Earth as the solar system whips around the galaxy.

If the Milky Way is mostly a cloud of dark matter, as astronomical measurements suggest, then we should be sailing through it at about 200 kilometers per second. This creates a dark matter wind, for the same reason you feel a wind when you stick your hand out the window of a moving car.

The Windchime detector is based on the notion that a collection of pendulums will swing in a breeze. In the case of backyard wind chimes, it might be metal rods or dangling bells that jingle in moving air. For the dark matter detector, the pendulums are arrays of minute, ultrasensitive detectors that will be jostled by the gravitational forces they feel from passing bits of dark matter. Instead of air molecules bouncing off metal chimes, the gravitational attraction of the particles that make up the dark matter wind would cause distinctive ripples as it blows through a billion or so sensors in a box measuring about a meter per side.
While it may seem logical to search for dark matter using gravity, no one has tried it in the nearly 40 years that scientists have been pursuing dark matter in the lab. That’s because gravity is, comparatively, a very weak force and difficult to isolate in experiments.

“You’re looking for dark matter to [cause] a gravitational signal in the sensor,” says Carney, of Lawrence Berkeley National Laboratory in California. “And you just ask . . . could I possibly see this gravitational signal? When you first make the estimate, the answer is no. It’s actually going to be infeasibly difficult.”

That didn’t stop Carney and a small group of colleagues from exploring the idea anyway in 2020. “Thirty years ago, this would have been totally nuts to propose,” he says. “It’s still kind of nuts, but it’s like borderline insanity.”

The Windchime Project collaboration has since grown to include 20 physicists. They have a prototype Windchime built of commercial accelerometers and are using it to develop the software and analysis that will lead to the final version of the detector, but it’s a far cry from the ultimate design. Carney estimates that it could take another few decades to develop sensors good enough to measure gravity even from heavy dark matter.

Carney bases the timeline on the development of the Laser Interferometer Gravitational-Wave Observatory, or LIGO, which was designed to look for gravitational ripples coming from black holes colliding (SN: 2/11/16). When LIGO was first conceived, he says, it was clear that the technology would need to be improved by a hundred million times. Decades of development resulted in an observatory that views the sky in gravitational waves. With Windchime, “we’re in the exact same boat,” he says.

Even in its final form, Windchime will be sensitive only to dark matter bits that are roughly the mass of a fine speck of dust. That’s enormous on the spectrum of known particles — more than a million trillion times the mass of a proton.

“There is a variety of very interesting dark matter candidates at [that scale] that are definitely worth looking for … including primordial black holes from the early universe,” says Katherine Freese, a physicist at the University of Michigan in Ann Arbor who is not part of the Windchime collaboration. Black holes slowly evaporate, leaking mass back into space, she notes, which could leave many relics formed shortly after the Big Bang at the mass Windchime could detect.

But if it never detects anything at all, the experiment still stands out from other dark matter detection schemes, says Dan Hooper, a physicist at Fermilab in Batavia, Ill., also not affiliated with the project. That’s because it would be the first experiment that could entirely rule out some types of dark matter.

Even if the experiment turns up nothing, Hooper says, “the amazing thing about [Windchime] … is that, independent of anything else you know about dark matter particles, they aren’t in this mass range.” With existing experiments, a failure to detect anything could instead be due to flawed guesses about the forces that affect dark matter (SN: 7/7/22).

Windchime will be the only experiment yet imagined where seeing nothing would definitively tell researchers what dark matter isn’t. With a little luck, though, it could uncover a wind of tiny black holes, or even more exotic dark matter bits, blowing past as we careen around the Milky Way.