A team of scientists may have given hydrogen a squeeze strong enough to turn it into a metal. But critics vigorously dispute the claim.

Researchers from Harvard University report that under extremely high pressures hydrogen became reflective — one of the key properties of a metal. The feat required compressing hydrogen to 4.9 million times atmospheric pressure, the scientists report online January 26 in Science.

If correct, the result would be the culmination of a decades-long search for a material that could have unusual properties such as superconductivity — the ability to conduct electricity without resistance.
But physicist Eugene Gregoryanz of the University of Edinburgh, who works on similar experiments, decries the study’s publication as a failure of the journal’s review process. Given the evidence presented in the paper, Gregoryanz is skeptical that the claimed pressures were actually reached and notes that the researchers presented results from only one experiment. “How is it possible to do only one experiment and claim such a big thing?” he says.

Physicist Alexander Goncharov of the Carnegie Institution for Science in Washington, D.C., also takes issue with the researchers’ conclusions. “It’s not shown whether they have hydrogen at all at high pressure,” Goncharov says.

Not everyone is so skeptical. “I think there’s a good chance that it’s correct,” says theoretical physicist David Ceperley of the University of Illinois at Urbana-Champaign. The pressure at which the hydrogen became reflective is about where theoretical physicists have calculated that a metal should form, Ceperley says.

Theorists’ calculations also indicate that metallic hydrogen could be a high-temperature superconductor (SN: 8/20/16, p. 18). Most superconductors work only in extreme cold, but metallic hydrogen might function even at room temperature — higher than any other known superconductor. If so, its discovery would raise hopes that superconducting metallic hydrogen could be used in power lines, making transmission of electricity vastly more efficient.

To put the pressure on hydrogen, scientists capture it as a gas between the tips of two diamonds and squeeze them together. It’s no easy task. “The problem in making metallic hydrogen has been that the predicted pressures have been very high,” says physicist Isaac Silvera of Harvard University, a coauthor of the study. “Diamonds always break before you can obtain those pressures.”
To stave off breakage, the scientists smoothed the surface of the diamonds to remove any defects and covered the gems in a thin layer of aluminum oxide to prevent hydrogen from diffusing inside and creating cracks. The researchers also cooled the setup to temperatures of 83 kelvins (−190° Celsius) or below. As the scientists ratcheted up the pressure, the hydrogen first turned black, indicating a possible semiconducting phase, then became reflective, indicating a metal. The metallic hydrogen could be either a solid or a liquid, Silvera says.

But such experiments are tricky — only a few teams of researchers in the world are capable of performing them. One of the pitfalls can be that the hydrogen escapes from the chamber without the scientists realizing it. However, Silvera says, “We’re sure we have hydrogen in there.”

Some previous metallic hydrogen experiments have monitored hydrogen as the pressure is ramped up to help ensure that the hydrogen hasn’t escaped and to study its evolution. To do so, scientists use a technique called Raman spectroscopy, which involves shining a laser through the diamonds and observing the scattered light. But at pressures this high, lasers could cause the diamonds to break, Silvera says. So the researchers used lasers only after the sample had reached the metallic state.

Silvera’s group is not the first to announce the discovery of metallic hydrogen. Earlier claims of finding the metal have been overturned (SN: 12/17/11, p. 9). “It’s not the last word,” says Ceperley. “It should encourage all the other groups to come out and try to reproduce it.”

A roughly 540-million-year-old creature that may have once skimmed shorelines was a real oddball.

Dozens of peculiar, roundish fossils discovered in what is now South China represent the earliest known deuterostomes, a gigantic category of creatures that includes everything from humans to sea cucumbers.

No bigger than a pinhead, the fossils have wrinkly, baglike bodies and gaping mouths that are pleated around the edges like an accordion, researchers report January 30 in Nature. Unlike most other deuterostomes, the animals don’t seem to have an anus. Instead, the ancient oddities, named Saccorhytus coronarius, may have leaked waste (and other bodily fluids like mucus and sex cells) out of tiny holes lining their sides. These holes may have later evolved into gill slits.

A tough, flexible skin would have protected Saccorhytus as it wriggled through grains of dirt, the authors suggest. The find supports previous suggestions that the earliest deuterostomes were actually a kind of water-dwelling worm.

Are you feeling the pressure of Valentine’s Day and in need of advice on how to find someone special? The animal world has some advice for you.

Make sure you look nice.
There’s no need to go for an entire makeover, but looking your best is usually a good idea when on the search for a partner. Male black-and-white snub-nosed monkeys appear to have taken a lesson from Revlon — they go for the rouge-lipped look during the mating season. Those with bright, red lips tend to be surrounded by females.
Learn to dance …
As anyone who has ever watched John Travolta in Saturday Night Fever knows, having the right dance moves can make finding a mate easier. For some animals, it’s essential. That’s true for male peacock spiders, which raise colorful flaps on their behinds and wave them while lifting their third legs in an adorable dance aimed at luring a mate. And if a guy doesn’t have the best moves or try hard enough, females don’t just reject him — they get aggressive.

… and how to flirt.
Even if you’re an expert dancer, you’ll probably need to do at least a little flirting. It may be a bit more subtle than torrent frogs, though, who turn flirting into a big production. A male frog will get a female’s attention by first calling out and puffing up his vocal sacs. Then he’ll shake his hands and feet and wiggle his toes. If he’s successful, the female will let him know with a special call.

Attend a party.
The best place to put all of this on display is, of course, a party! And there are parties everywhere, even at the bottom of the ocean. Scientists exploring a seamount off the Pacific coast of Panama in 2015 found an enormous party of small, red crabs swarming all over each other. Such large aggregations are common among crab species and may be linked to reproduction.

Practice, practice, practice.
Once you’ve landed a partner, you might want to serenade him or her with the perfect love song. But first you’ll need to practice, just like great reed warblers (probably) do. Males spend their entire winter vacation singing the songs they seem to use to woo the ladies come spring. All that singing cuts into time the guys could spend foraging for food or resting, but that practice might pay off because female warblers prefer males that sing more complex tunes.

Keep an eye on the competition.
You may not be the only one interested in your partner, so make like a peacock and check out your competition. Peacocks fan out their feathers to lure the ladies, but females only pay attention to what’s happening at the bottom of the show, studies have revealed. Males do likewise, keeping their gaze tuned to the bottom of the competition’s display.

Bring a gift.
You probably don’t need to worry that your partner will go cannibal, but that doesn’t mean you can’t take a hint from a species where that does happen. When approaching a female, male nursery spiders are smart to bring a gift of a big dead insect wrapped up in silk. The gift will not only keep the female busy while the male mates with her, but it can also double as a shield if she sees him as a potential meal rather than a mate.

Three high-energy neutrinos have been spotted traveling in tandem.

The IceCube Neutrino Observatory in Antarctica detected the trio of lilliputian particles on February 17, 2016. This is the first time the experiment has seen a triplet of neutrinos that all seemed to come from the same place in the sky and within 100 seconds of one another. Researchers report the find February 20 on arXiv.org.

Physicists still don’t know where high-energy neutrinos are born. The three neutrinos’ proximity in time and space suggests the particles came from the same source, such as a flaring galaxy or an exploding star. But the scientists couldn’t rule out the possibility of a fluke — the triplet could simply have been the result of accidental alignment between unassociated neutrinos.

Eight different telescopes followed up on the neutrino triplet, checking for some sign of the particles’ origins. The telescopes, which searched for gamma rays, X-rays and other wavelengths of light, found nothing clearly associated with the particles. But scientists were able to rule out some possible explanations, like a nearby stellar explosion caused by the collapse of a dying star.

Here’s one good reason why people often take medications and use health products that don’t live up to expectations or just don’t work — digital word of mouth.

The reviews can be glowing. Take this scuttlebutt about a cholesterol treatment: “I have been using this product for 2 years. Within the first 3 – 4 months my cholesterol was down 30 points. Just got cholesterol tested last week: down from 245 to 196.”

That’s incredible. It might even be true. But the big picture is alarming: Patients’ online reviews of three over-the-counter drugs — two for lowering cholesterol and one for losing weight — greatly exaggerate how well these substances actually work for most people, says psychologist Mícheál de Barra of the University of Aberdeen in Scotland. Online reviewers portray these medications as working three to six times better than they do in clinical trials that randomly assign drugs or placebos to broad samples of volunteers, he says.

“To learn what works in medicine, you need systematically collected data, usually randomized clinical trials,” de Barra says. “It’s very risky to rely on observations and word of mouth, whether it’s electronic or in person.”

Online reviewers probably aren’t lying, at least not in most cases. Neither are online review readers unrealistically optimistic about health treatments. The problem is that people who benefit most from a medication are especially apt to post their experiences online. Review readers get bamboozled by a wave of positive recommendations that don’t accurately represent how a drug works, or doesn’t work, for people in general.

The duping doesn’t end there. Direct word of mouth about medical treatments, as well as glowing testimonials about health products in advertisements, also traffic in positively skewed information.

In some cases, science does, too. Researchers have recently raised alarms about the “file-drawer problem,” in which studies that find no statistical effects are not published (SN: 5/19/12, p. 26). Published studies reporting positive effects then look unjustifiably bulletproof.

Clinical trials can tilt results in other ways as well. Authors of published trials often fail to preregister details of what they plan to study and how they’ll measure it, enabling data manipulation, selective reporting of results and self-serving interpretations of findings. Clinical trials report patients’ “average” responses to, say, an anticholesterol drug, but do a poor job of predicting which individuals will benefit from that treatment. “Published evidence from randomized trials is already an amalgam of evidence-based medicine and hearsay,” notes Stanford University epidemiologist John Ioannidis.
Online reviews are just old-fashioned word of mouth with a global bullhorn. But they offer one way to quantify the positive bias inherent in so much communication about medical treatments. Patients’ medication reviews that include numerical information, such as cholesterol levels before and after taking an anticholesterol drug, represent what Ioannidis calls “evidence-based hearsay.” Even if patients’ reviews rate treatments with a star system rather than including quantified measures of some kind, those opinions become powerful hearsay evidence for other patients, Ioannidis suspects.

De Barra evaluated 908 online reviews of two cholesterol reduction products, Benecol caramel smart chews and CholestOff, written on or before March 18, 2015. He also assessed 767 reviews of a weight-loss drug, Alli (orlistat), written on or before February 28, 2015.

Benecol reviewers reported a not-too-shabby average cholesterol decline of 45 milligrams per deciliter, versus a small average decline of 14 milligrams per deciliter in nine clinical trials. Respective numbers for CholestOff were 31 milligrams per deciliter and 13 milligrams per deciliter. Alli reviewers reported an average weight loss of about 10 kilograms after taking the drug for three months, versus an average of about two or three kilograms in two clinical trials. That disparity widened slightly after taking Alli for seven months.

Each drug garnered mainly positive reviews, some reporting effects far larger than the average, peppered with a few pans, De Barra reports in the March Social Science & Medicine.

What’s particularly concerning is that these three medications displayed small or negligible effects in clinical trials that probably already inflated how well the drugs work, Ioannidis says. So people searching for help in lowering cholesterol or shedding pounds may instead be getting a massive dose of disappointment from online reviews.

Online reviews can also exaggerate a treatment’s worst effects, whether real or alleged. Evidence-based hearsay may be particularly catchy online and in person when it’s frightening, de Barra suspects.

The anti-vaccination movement provides a potent example, due in part to the success of vaccines. When people face no immediate threat from measles or other infectious diseases, anti-vaccine stories may go viral, so to speak, thanks to misapplied but deeply felt intuitions. Two cognitive scientists, Helena Miton of Central European University in Budapest and Hugo Mercier of the Cognitive Sciences Institute in Bron, France, proposed this scenario in the November 2015 Trends in Cognitive Sciences.

However medical treatments acquire halos or horns, only well-conducted, transparent clinical trials can identify effective medical treatments, such as childhood vaccinations, and their potential side effects, Ioannidis says. But an ominous research trend is gathering steam, he warns. Researchers, professional societies, funders and lobbyists increasingly push to replace clinical trials of randomly selected volunteers with studies of interventions for select samples of people who eat certain foods, take certain drugs or behave in certain ways. The latter investigations may inflate a treatment’s effects even more than online patient reviews do, Ioannidis asserts.

Perhaps a new wave of studies showing how evidence-based hearsay misrepresents many medications will be just what the doctor ordered to resuscitate evidence-based medicine, he muses.

Remnants of a royal palace in southern Mexico, dating to between around 2,300 and 2,100 years ago, come from what must have been one of the Americas’ earliest large, centralized governments, researchers say.

Excavations completed in 2014 at El Palenque uncovered a palace with separate areas where a ruler conducted affairs of state and lived with his family, say archaeologists Elsa Redmond and Charles Spencer, both of the American Museum of Natural History in New York City. Only a ruler of a bureaucratic state could have directed construction of this all-purpose seat of power, the investigators conclude the week of March 27 in Proceedings of the National Academy of Sciences.

The royal palace, the oldest such structure in the Valley of Oaxaca, covered as many as 2,790 square meters, roughly half the floor area of the White House. A central staircase connected to an inner courtyard that probably served as a place for the ruler and his advisors to reach decisions, hold feasts and — based on human skull fragments found there — perform ritual sacrifices, the scientists suggest. A system of paved surfaces, drains and other features for collecting rainwater runs throughout the palace, a sign that the entire royal structure was built according to a design, the researchers say.

El Palenque’s palace contains no tombs. Its ancient ruler was probably buried off-site, at a ritually significant location, Redmond and Spencer say.

Animal-hair cords dating to the late 1700s contain a writing system that might generate insights into how the Inca communicated, a new study suggests.

Researchers have long wondered whether some twisted and knotted cords from the Inca Empire, which ran from 1400 to 1532, represent a kind of writing about events and people. Many scholars suspect that these textile artifacts, known as khipus, mainly recorded decimal numbers in an accounting system. Yet Spanish colonial documents say that some Inca khipus contained messages that runners carried to various destinations.
Now a new twist in this knotty mystery comes from two late 18th century khipus stored in a wooden box at San Juan de Collata, a Peruvian village located high in the Andes Mountains. A total of 95 cord combinations of different colors, animal fibers and ply directions, identified among hundreds of hanging cords on these khipus, signify specific syllables, reports Sabine Hyland. Hyland, a social anthropologist at the University of St. Andrews in Scotland, describes the khipus online April 19 in Current Anthropology.

Her findings support a story told by Collata villagers that the khipus are sacred writings of two local chiefs concerning a late 18th century rebellion against Spanish authorities.

The Collata khipus display intriguing similarities to Inca khipus, including hanging cords with nearly the same proportions of two basic ply directions, Hyland says. A better understanding of Central Andean khipus from the 1700s through the 1900s will permit a reevaluation of the earlier Inca twisted cords, she suggests.

Each Collata khipu, like surviving Inca examples, consists of a horizontal cord from which a series of cords hang. One Collata specimen contains 288 hanging cords separated into nine groups by cloth ribbons tied at intervals along the top cord. The other khipu features 199 hanging cords divided by ribbons into four groups. Knots appear only at cord ends to prevent unraveling. In contrast, proposed accounting khipus contain many knots denoting numbers.

Collata khipus’ initial hanging cords are made of bundles of colored animal hairs that represent the message’s subject matter, Hyland proposes. One khipu starts with a tuft of bright red deer hair, followed by a woven, cone-shaped bundle with metallic-colored thread. The second khipu commences with a woven, tube-shaped bundle of multicolored alpaca hair atop the remains of a red tassel.
“The Collata khipus are completely unlike accounting khipus that I have been studying for over a decade,” Hyland says. Central Andean khipus generally viewed as accounting devices were often made of cotton, and they contain two main colors, between 15 and 39 cord combinations and repetitive knot sequences.

Hyland makes an “excellent case” that these cords represent syllables and probably words as well, says anthropological archaeologist Penelope Dransart of the University of Wales Trinity Saint David in Lampeter.

So far, Hyland has translated the final three cords on one khipu as the word Alluka, the name of a family lineage in Collata. She first talked to villagers and identified the lineage chief that they claimed wrote one of the khipus. Hyland then assigned the three syllables in Alluka to the trio of ending cords, assuming that the sender’s name would appear either there or at the beginning of the message. That enabled her to decipher the final cords on the second khipu as Yakapar, the name of a family lineage in a neighboring village. Heads of these lineages wrote the corded messages, Hyland suspects.

She has not yet deciphered other cords on the two khipus.

Hyland’s insights into 18th century khipus are “profoundly significant,” but won’t help to decipher Inca twisted and knotted cords, predicts Harvard University archaeologist Gary Urton. Collata villagers probably invented a phonetic form of khipu communication after the Inca civilization’s demise, when they were exposed to Spaniards’ alphabetic writing, Urton says. Inca khipus show no signs of cord combinations that corresponded to particular speech sounds, he asserts.

Thanks to the new discoveries, though, “we have hope that at least some khipus might be understood,” says archaeologist Jeffrey Splitstoser of George Washington University in Washington, D.C. Before Hyland’s report, Splitstoser thought it likely that colored threads on khipus had arbitrary meanings assigned by their makers, making them indecipherable. He studies khipus from the Wari empire, which flourished in the Peruvian Andes from around 600 to 1000 (SN: 5/10/03, p. 302).

Officials at several museums with khipu collections have classified as forgeries a few animal-hair specimens that resemble the Collata khipus, Hyland says. Those alleged fakes deserve a closer look for signs of writing, she contends.

A newly discovered glass frog from Ecuador’s Amazon lowlands is giving researchers a window into its heart.

Hyalinobatrachium yaku has a belly so transparent that the heart, kidneys and urine bladder are clearly visible, an international team of researchers reports May 12 in ZooKeys. Researchers identified H. yaku as a new species using field observations, recordings of its distinct call and DNA analyses of museum and university specimens.

Yaku means “water” in Kichwa, a language spoken in Ecuador and parts of Peru where H. yaku may also live. Glass frogs, like most amphibians, depend on streams. Egg clutches dangle on the underside of leaves, then hatch, and the tadpoles drop into the water below. But the frogs are threatened by pollution and habitat destruction, the researchers write. Oil extraction, which occurs in about 70 percent of Ecuador’s Amazon rainforest, and expanding mining activities are both concerns.

When faced with rushing floodwaters, fire ants are known to build two types of structures. A quickly formed raft lets the insects float to safety. And once they find a branch or tree to hold on to, the ants might form a tower up to 30 ants high, with eggs, brood and queen tucked safely inside. Neither structure requires a set of plans or a foreman ant leading the construction, though. Instead, both structures form by three simple rules:

If you have an ant or ants on top of you, don’t move.
If you’re standing on top of ants, keep moving a short distance in any direction.
If you find a space next to ants that aren’t moving, occupy that space and link up.
“When in water, these rules dictate [fire ants] to build rafts, and the same rules dictate them to build towers when they are around a stem [or] branch,” notes Sulisay Phonekeo of the Georgia Institute of Technology in Atlanta. He led the new study, published July 12 in Royal Society Open Science.

To study the fire ants’ construction capabilities, Phonekeo and his Georgia Tech colleagues collected ants from roadsides near Atlanta. While covered in protective gear, the researchers dug up ant mounds and placed them in buckets lined with talc powder so the insects couldn’t climb out. Being quick was a necessity because “once you start digging, they’ll … go on attack mode,” Phonekeo says. The researchers then slowly flooded the bucket until the ants floated out of the dirt and formed a raft that could be easily scooped out.

In the lab, the researchers placed ants in a dish with a central support, then filmed the insects as they formed a tower. The support had to be covered with Teflon, which the ants could grab onto but not climb without help. Over about 25 minutes, the ants would form a tower stretching up to 30 mm high. (The ants themselves are only 2 to 6 mm long.)
The towers looked like the Eiffel Tower or the end of a trombone, with a wide base and narrow top. And the towers weren’t static, like rafts of ants are. Instead, videos of the ant towers showed that the towers were constantly sinking and being rebuilt.

Peering into the transparent Petri dish from below revealed that the ants build tunnels in the base of a tower, which they use to exit the base before climbing back up the outside.

“The ants clear a path through the ants underneath much like clearing soil,” Phonekeo says. Ants may be using the tunnels to remove debris from inside the towers. And the constant sinking and rebuilding may give the ants a chance to rest without the weight of any compatriots on their backs, he says.

To find out what was happening inside the tower, the researchers fed half their ants a liquid laced with radioactive iodide and then filmed the insects using a camera that captured X-rays. In the film, radioactive ants appeared as dark dots, and the researchers could see that some of those dots didn’t move, but others did.

The team then turned to the three rules that fire ants follow when building a raft and realized that they also applied to towers. But there was also a fourth rule: A tower’s stability depends on the ants that have attached themselves to the rod. The top row of ants on the rod aren’t stable unless they form a complete ring. So to get a taller tower, there needs to be a full ring of ants gripping to the rod and each other.

That such simple rules could form two completely different structures is inspiring to Phonekeo. “It makes me wonder about the possibilities of living structures that these ants can build if we can design the right environment for them.”

Plate tectonics may have gotten a pretty early start in Earth’s history. Most estimates put the onset of when the large plates that make up the planet’s outer crust began shifting at around 3 billion years ago. But a new study in the Sept. 22 Science that analyzes titanium in continental rocks asserts that plate tectonics began 500 million years earlier.

Nicolas Greber, now at the University of Geneva, and colleagues suggest that previous studies got it wrong because researchers relied on chemical analyses of silicon dioxide in shales, sedimentary rocks that bear the detritus of a variety of continental rocks. These rocks’ silicon dioxide composition can give researchers an idea of when continental rocks began to diverge in makeup from oceanic rocks as a result of plate tectonics.

But weathering can wreak havoc on the chemical makeup of shales. To get around that problem, Greber’s team turned to a new tool: the ratios of two titanium isotopes, forms of the same element that have different masses. The proportion of titanium isotopes in the rocks is a useful stand-in for the difference in silicon dioxide concentration between continental and oceanic rocks, and isn’t so easily altered by weathering. Those data helped the team estimate that continental rocks — and therefore plate tectonics — were already going strong by 3.5 billion years ago.