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Hunter-gatherers who built and worshiped at one of the oldest known ritual centers in the world carved up human skulls in a style all their own.

At Turkey’s Göbekli Tepe site — where human activity dates to between around 11,600 and 10,000 years ago — people cut deep grooves in three human skulls and drilled a hole in at least one of them, say archaeologist Julia Gresky of the German Archaeological Institute in Berlin and colleagues. Ancient hunter-gatherers there practiced a previously unknown version of a “skull cult,” in which human skulls were ritually modified after death and then deposited together, Gresky’s team reports online June 28 in Science Advances.

Collections of human skulls modified in other ways have been found at several sites from around the same time. For instance, deliberately broken faces on skulls were unearthed at a Syrian settlement and may represent a form of punishment after death.

Seven excavated skull fragments enabled Gresky’s group to reconstruct the Göbekli Tepe skulls. These skulls of the recently deceased were carved for use in ceremonies to worship them as ancestors, the researchers propose. It’s also possible that the skull incisions marked deceased individuals who had been especially revered or reviled while alive.

A cord inserted through the hole drilled in one skull may have suspended that skull for display. Grooves probably ran from front to back on the skulls and possibly stabilized cords that held decorations of some kind.

Microscopic study of skull pieces from Göbekli Tepe indicates that grooves were cut with stone tools. A lack of healed bone on the edges of incisions suggests skull carving occurred shortly after death.

In July of 1972, NASA launched the first Landsat satellite into orbit around Earth. Since then, the spacecraft and its successors have transformed our understanding of Antarctica (and the rest of the planet, too). In the first year following the launch, Landsat’s images of the faraway continent showed “uncharted mountain ranges, vast ice movements and errors in maps as little as two years old,” according to an article published in Science News. William MacDonald of the U.S. Geological Survey, who had spent eight years mapping a part of West Antarctica, was “shocked” to learn of previously unknown peaks just 100 miles from McMurdo Station.

Landsat’s images weren’t the first overhead shots of Antarctica, but to this day the program provides researchers a reliable and repeating view of hard-to-reach corners of the planet. It was Landsat images that in November of 2014 first alerted scientists to a growing crack in the Larsen C ice shelf that, after lengthening by about 20 kilometers in less than nine months, threatened to break off a Delaware-sized chunk of the shelf. With thermal imagery from Landsat 8 along with data from the European Space Agency’s Sentinel-1 satellites, scientists sitting half a world away tracked the Larsen C crack to its final break, as described by Ashley Yeager.
While satellites are scientists’ eyes in the skies, seismic sensors serve as ears to the ground. Alexandra Witze describes the work of scientists who are using seismic sensors to monitor nuclear weapons activity in a part of the planet where access to information is limited: North Korea. Five nuclear weapons tests have been confirmed in the country since 2006, all at an underground test site in Mount Mantap. By tracking seismic waves produced by such explosions, and comparing these rumbles with each other and with those produced by natural earthquakes and in experimental tests, researchers around the world gain valuable clues to where the hidden explosions are happening and, importantly, how powerful they are. A North Korea weapons test last year was detected as far away as Bolivia.

The art of eavesdropping certainly has its rewards. There are plenty more examples. Rachel Ehrenberg writes about how snooping scientists might listen in on kelp to predict ecosystem health. And Emily Conover reports on a newly discovered, relatively itty-bitty star some 600 light-years away. Astronomers spied on the star by watching it pass in front of a larger star, dimming the larger star’s light.

Sometimes astronomers get lucky and distant phenomena are much more straightforward to study. That will be the case later this month when a total solar eclipse passes across North America from Oregon to South Carolina. People will be monitoring the August 21 eclipse in all sorts of ways, including via a livestream from balloons at the edge of the atmosphere, as Lisa Grossman describes in “Watch the moon’s shadow race across the Earth from balloons.” Grossman will be reporting on the eclipse on the ground with scientists in Wyoming. You’ll find her stories — along with many others about the ways scientists watch, listen and learn — at www.lssfzb.com

Six years after the Fukushima nuclear reactor disaster in Japan, radioactive material is leaching into the Pacific Ocean from an unexpected place. Some of the highest levels of radioactive cesium-137, a major by-product of nuclear power generation, are now found in the somewhat salty groundwater beneath sand beaches tens of kilometers away, a new study shows.

Scientists tested for radioactivity at eight different beaches within 100 kilometers of the plant, which experienced three reactor meltdowns when an earthquake and tsunami on March 11, 2011, knocked out its power. Oceans, rivers and fresh groundwater sources are typically monitored for radioactivity following a nuclear accident, but several years following the disaster, those weren’t the most contaminated water sources. Instead, brackish groundwater underneath the beaches has accumulated the second highest levels of the radioactive element (surpassed only by the groundwater directly beneath the reactor), researchers report October 2 in the Proceedings of the National Academy of Sciences.

In the wake of the 2011 accident, seawater tainted with high levels of cesium-137 probably traveled along the coast and lapped against these beaches, proposes study coauthor Virginie Sanial, who did the work while at Woods Hole Oceanographic Institution in Massachusetts. Some cesium stuck to the sand and, over time, percolated down to the brackish groundwater beneath. Now, the radioactive material is steadily making its way back into the ocean. The groundwater is releasing the cesium into the coastal ocean at a rate that’s on par with the leakage of cesium into the ocean from the reactor site itself, Sanial’s team estimates.

Since this water isn’t a source of drinking water and is underground, the contamination isn’t an immediate public health threat, says Sanial, now a geochemist at the University of Southern Mississippi in Hattiesburg. But with about half of the world’s nuclear power plants located on coastlines, such areas are potentially important contamination reservoirs and release sites to monitor after future accidents.

THE WOODLANDS, Texas — A new map of flat, light-colored streaks and splotches on the moon links the features to a few large impacts that spread debris all over the surface. The finding suggests that some of the moon’s history might need rethinking.

Planetary scientist Heather Meyer, now at the Lunar and Planetary Institute in Houston, used data from NASA’s Lunar Reconnaissance Orbiter to make the map, the most detailed global look at these light plains yet. Previous maps had been patched together from different sets of observations, which made it hard to be sure that features that looked like plains actually were.
Astronomers originally assumed that the light plains were ancient lava flows from volcanoes. But rocks brought back from one of these plains by Apollo 16 astronauts in 1972 did not have volcanic compositions. That finding led some scientists to suspect the plains, which cover about 9.5 percent of the lunar surface, came from giant impacts.

Meyer’s map supports the impact idea. Most of the plains, which are visible across the whole moon, seem to originate from debris spewed from the Orientale basin, a 930-kilometer-wide bowl in the moon’s southern hemisphere that formed about 3.8 billion years ago.
“It looks like there’s just a giant splat mark,” Meyer says. About 70 percent of the lunar plains come from either Orientale or one other similar basin, she reported March 22 at the Lunar and Planetary Science Conference. “What this is telling us,” she says, “is these large basins modified the entire lunar surface at some point.”
The map also shows that some small impact craters up to 2,000 kilometers from Orientale have been filled in with plains material. That’s potentially problematic, because planetary scientists use the number of small impact craters to estimate the age of the lunar surface. If small craters have been erased by an impact half a moon away, that could mean some of the surface is older than it looks, potentially changing scientists’ interpretations of the moon’s history (SN: 6/11/16, p. 10).

China’s first space station, Tiangong-1, is expected to fall to Earth sometime between March 31 and April 1. No fooling.

Most of the 10.4-meter-long station will burn up as it zooms through Earth’s atmosphere. But some parts will survive and reach the ground, according to the European Space Agency’s Space Debris Office. No one can be sure where or when those pieces will hit. Even within hours of the station reaching the atmosphere, the final hit zone predictions will cover thousands of kilometers. ESA predicts that any latitude between 42.8° N (so as far north as Chicago) and 42.8° S (down to Tasmania) is fair game. The geometry of the station’s orbit means that the edges of that zone are more likely to be hit than the equator.
Much of that area is oceans or uninhabited. “The personal probability of being hit by a piece of debris from Tiangong-1 is actually 10 million times smaller than the yearly chance of being hit by lightning,” according to ESA. (If you’re wondering, the annual chance of getting zapped in the United States is 1 in 1,083,000.)
Launched in 2011, Tiangong-1 — which means Heavenly Palace — was visited twice by Chinese astronauts, in 2012 and in 2013. The craft was supposed to last only two years, and China put it into sleep mode after the second visit to prepare to steer it back to Earth for a controlled reentry. But in March 2016, the Chinese space agency announced that they had lost contact with the craft and expected it to reenter the atmosphere sometime in 2017
Reentry is unlikely to be dangerous, but it will look cool. The disintegrating space station will blaze through the sky like a fireball. ESA and the Chinese space agency are running daily updates on the station’s location, so check back to see if it will be visible where you are.

PHOENIX — A new, breathable material that can also block biological or chemical threats could offer comfortable protection for people working in contaminated environments or dangerous military zones.

The bottom layer of the material, described April 3 at the Materials Research Society spring meeting, features carbon nanotube pores embedded within a flexible synthetic polymer film. These pores are just a few nanometers across — too small for bacterial or viral cells to squeeze through, but wide enough for sweat to escape.
The top layer offers further protection. It is made of another, spongy polymer that normally allows water and other molecules to pass through. But when the polymer comes into contact with G-series nerve agents — the family of toxic chemicals that includes sarin gas — it flattens into a dense sheet that seals over the carbon nanopores underneath. The polymer can be restored to its original state by soaking it in a high-pH chemical broth.

Both layers together are still less than half the thickness of a sheet of paper, and could be laid over fabrics without putting the wearer at risk of overheating. That’s an improvement over the typical protective gear that’s permanently sealed against contaminants, said study coauthor Francesco Fornasiero, a chemical engineer at Lawrence Livermore National Laboratory in California.

In early testing, the material completely blocked out dengue virus cells, as well as 90 percent of the chemical diethyl chlorophosphate, used as a stand-in for toxic nerve agents. The researchers are working to make the material even more impervious to dangerous chemicals, Fornasiero said.

About 50 million years ago, a monitor lizard in what is now Wyoming perceived the world through four eyes. Saniwa ensidens is the only known jawed vertebrate to have had two eyelike photosensory structures at the top of the head, in addition to the organs we commonly think of as eyes, researchers report April 2 in Current Biology.

The structures are called the pineal and parapineal organs. Among animals alive today, only the jawless fish called a lamprey has both structures. But many modern reptiles have a so-called third eye, the pineal organ.
The researchers examined fossils collected 150 years ago by Yale University students. Scans of the fossils using a technique called X-ray computed tomography revealed spaces in the skull for both the third and fourth eye.

What the ancient lizard did with these organs isn’t known, but some modern vertebrates use the amplified photosensitivity they glean from the pineal glands to navigate. S. ensidens may have been able to perceive polarized light and use the angle of the sun like a compass, as some modern lizards do. Or it may have navigated using Earth’s magnetic field, much like some amphibians and migratory birds.

There’s a great future in plastics.

A new kind of plastic can, when exposed to the right chemicals, break down into the same basic building blocks that it came from and be rebuilt again and again. The recyclable material is more durable than previous attempts to create reusable plastics, researchers report inthe April 27 Science.

Designing plastics that can be easily reused is one line of attack against the global plastic waste problem. Only about 10 percent of plastic ever made gets recycled, according to a 2017 study in Science Advances. But the material is so cheap and useful that hundreds of millions of tons of it keeps getting churned out each year.
A major impediment to plastic recycling is that most plastics degrade into molecules that aren’t immediately useful. Transforming those molecules back into plastic or into some other product requires many chemical reactions, which makes the recycling process less efficient. And while biodegradable plastics have become popular in recent years, they break down only if the right microbes are present. More often than not, these plastics end up lingering in landfills or floating in the ocean. Creating plastics that could be broken down into their building blocks and reused without additional processing and purifying could help reduce the pollution buildup.

But designing such a plastic polymer is a balancing act, says Michael Shaver, a polymer chemist at the University of Edinburgh who wasn’t part of the study. Polymers are long chains of small molecules, called monomers, that link together like beads on a string. Monomers that need extreme temperatures or too much chemical coaxing to join up into polymers might not be practical building blocks. And resulting polymers need to be stable up to a high enough temperature that, say, pouring hot coffee into a cup made of them won’t destabilize the chains and make the plastic melt into a sticky puddle.
Polymer chemist Jianbo Zhu and his colleagues at Colorado State University in Fort Collins set out to solve this challenge. The team had had some luck in the past creating a polymer that could be broken down into its starting molecules. But the resulting plastics created by their lab and others on the same track were too soft and temperature-sensitive to have much practical use.
This time, Zhu and his colleagues modified one of their previous creations, a small ringed molecule, by adding another ring in a way that braced the molecule into a particular conformation. That rigidity helped the monomers quickly link together at room temperature into polymer chains that are heat-stable.
Then, when exposed to certain mild chemicals or high enough heat, the polymers degraded back into monomers. The researchers were able to repeat this cycle several times, showing that, in theory, the polymer could be infinitely recyclable.

While each monomer is locked into a particular conformation, not all of them have the same shape even though they’re made from the same chemical recipe. Mixing two different conformations of monomers created an even stronger plastic, says Zhu.

“This is probably the best system out there,” Shaver says.

Still, it’s not perfect yet: Zhu and his colleagues plan to tinker with the monomer design more in the future to make the resulting plastic a bit less brittle. Eventually, they hope to commercialize the product.

As opioid-related deaths rise in the United States, so has the role of synthetic opioids — primarily illicit fentanyl, mixed into heroin or made into counterfeit pills (SN Online: 3/29/18). In 2016, synthetics surged past prescription opioids and were involved in 19,413 deaths, compared with 17,087 deaths involving prescription opioids, researchers report May 1 in JAMA. The study is based on data from the National Vital Statistic System’s record of all U.S. deaths.

“Synthetic opioids are much deadlier than prescription opioids,” says emergency physician Leana Wen, Health Commissioner of Baltimore, who was not involved in the study. Fentanyl, for example, is about 50 to 100 times more potent than morphine. The illicit origins of many synthetic opioids make the public health response more difficult, she says. “We can track prescriptions; it’s much harder to track illegally trafficked drugs.”

Clearwing moths may not look all that dangerous, despite having largely see-through wings like bees and wasps. But some fly like fierce insects best left well alone.

Four clearwing species from Southeast Asian rainforests aren’t perfect mimics of local bees and wasps. Yet the resemblance looked much stronger when entomologist Marta Skowron Volponi of the University of Gdansk in Poland and her husband, nature filmmaker Paolo Volponi, spent days at a time poised with a video camera on riverbanks to capture the flight patterns. Four clearwing species occasionally showed up, including a shaggy Aschistophleps that turned out to be a species new to science.

That newly named A. argentifasciata and two other species flew in slow, zigzaggy paths that resembled the meanderings of local stingless bees. (This kind of bee is not great for snacking birds because it bites fiercely.) Another clearwing moth flew distinctly faster with broader turning sweeps instead of zigzags, much like a wasp.

Behaving like something that stings or bites may be an advantage for moths that forgo the cover of night and fly in daylight with its abundance of hungry birds and other predators that hunt by sight. Even imperfect body mimics get convincing in the air, Skowron Volponi and her colleagues report May 2 in Biology Letters.