For the millions of people who have taken up the sport of rock climbing, a cliff face is a challenge, a vertical puzzle solved only with the proper placement of hands and feet. Look closely, though, and those crevices and cracks that provide hand- and footholds also provide homes for a variety of plants, invertebrates and other easily overlooked species.

People who participate in outdoor sports like rock climbing may not think about the environmental impact of what they’re doing. After all, how big of an impact can one person really have on a rock? But there is a potential for harm, notes ecologist Andrea Holzschuh of the University of Würzburg in Germany. Finding evidence of that harm, though, is a challenge — the features that make some cliffs fun to climb, or not, also make for complicated research.

Holzschuh became interested in the effects that climbers are having on the environment in part because she is a climber herself, partial to tackling rocks in the Frankenjura region of Germany, which is noted for having some of the best climbing in Europe. The plants, animals and other species that make the cliffs their home, she notes, are often specialists that have found ways to adapt and even thrive in the extreme conditions found on the rock face. They may be rare or completely absent from nearby spots, and they often are slow-growing and their numbers grow only in spurts.

And then come the climbers, who may trample what grows at the bottom of a cliff, dig out whatever is growing in a crevice to gain a better handhold, spread species not native to the area or taint the rock face with chalk, altering pH or nutrient conditions for whatever is growing there. Rock climbing isn’t quite as impact-free as some might assume.

But scientists haven’t really been able to adequately assess that impact. Holzschuh went looking for research on this topic and found only 22 studies that tested how rock climbing might affect plants or animals. She tossed out six of those studies because they failed to make comparisons with unclimbed areas or had other major design problems that made it impossible to tease out effects. The remaining 16 studies found a variety of impacts on organisms ranging from lichens to snails to cedar trees. Holzschuh’s review appears in the December Biological Conservation.

But what the review really highlights is just how difficult it is to study rock climbing’s potential impacts. Holzschuh says a big challenge is in finding appropriate unclimbed cliff faces to compare to those that rock climbers frequent — ones that share traits such as slope and how much sunlight the face gets. “Often, all cliffs in a regions that are attractive for climbers are climbed and only cliffs that do not resemble the climbed cliffs in all abiotic traits remain unclimbed,” she notes. “Then no reliable study can be conducted.”

And then, of course, there’s the inaccessibility of many cliffs and the difficulty in studying even the accessible ones. “How many people have these skills and the flexibility to work on these projects?” says Michael Tessler of the American Museum of Natural History and Fordham University. Plus, he notes that a subset of rock climbing called bouldering — in which climbers tackle boulders or short cliff faces measuring less than 3.5 meters high, without using safety ropes — is especially popular with younger people. “Professors inherently aren’t always young,” he notes.
Tessler and colleague Theresa Clark of the University of Nevada, Las Vegas published the first ever analysis attempting to quantify the impact of bouldering on the environment. This type of climbing has similar potential for ecosystem damage as roped rock climbing, they note, plus a couple of additional ones: Boulderers often clear the ground below of rocks and logs so that they can place crash pads in case of falls, and they may be more likely to trample anything at the top of a boulder or cliff, rather than coming directly down.

Tessler and Clark tried to measure the impact of climbers at bouldering routes in the Shawangunk Ridge, a popular climbing site in New York where Tessler climbs. They compared transects in climbed boulder routes with transects along nearby unclimbed sections of rock and found differences in lichen, moss and woody plants. None of this added up to a major threat, but conservation managers might want to monitor these activities in remote sites and shut down certain routes that are proving too popular — and potentially too harmful to whatever is growing there, Tessler and Clark suggest in the December Biological Conservation.

While we still can’t really say how much impact climbers might be having on the rocky environments they climb, there is a definite need for more scientists to strap on their climbing shoes and tackle the questions of climbing’s impact. (Try it! It’s lots of fun!) But climbers, too, can do their part, Holzschuh and Tessler say.

“I think climbers can easily minimize their impact on the cliff vegetation if they do not willingly remove vegetation from the cliff to ‘clean’ hand- and footholds in the climbing route. Climbers should not access the cliff plateau [and should] leave this cliff part completely undisturbed,” Holzschuh says. “At the cliff base, bags and gear should be laid down within a small area to reduce the effects of trampling.”

Tessler also has advice. “Boulderers should be aware that even infrequent climbing leaves some impression on rock-associated vegetation,” he says. “They should remove as little vegetation and soil when climbing and establishing climbs. Also, if a climb is wet, dirty or covered in vegetation, maybe go to another one. This is an easy way to ensure that some rock faces can stay more natural.”

And if climbing is restricted because, say, rare birds are breeding there, rock climbers should obey the restriction and go climb somewhere else, Holzschuh says. There are plenty of other cliffs to be conquered.

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.

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.

A new species of worm-snail is rather snotty. Thylacodes vandyensis shoots out strands of mucus that tangle together, building a spiderweb-like trap for plankton and other floating snacks, researchers report April 5 in PeerJ.

Other worm-snails use this hunting technique, but T. vandyensis stands out because of the “copious amounts of mucus” it ejects, says coauthor Rüdiger Bieler. This goo net, which can stretch up to 5 centimeters across, exits the animal’s tentacles at, of course, “a snail’s pace,” jokes Bieler, a curator at the Field Museum of Natural History in Chicago.

Like other worm-snails, T. vandyensis permanently glue themselves to spots. Bieler found T. vandyensis, which typically grow half as tall as a pinkie finger, on the hull of a sunken ship in the Florida Keys. But they don’t belong there: DNA analysis shows that this invasive species’ closest relatives are in the Pacific Ocean. The worm-snail may have made its way to the Atlantic as a stowaway on a ship.

Egyptian mummies are back in style at the summer box office — and in genetics labs. A study of genetic blueprints from 90 mummies repairs the frayed reputation of sarcophagus occupants as sources of ancient DNA. And it reveals evidence of a hookup history with foreigners from the east.

An Egyptian mummy served up the first ancient human DNA sample in 1985 (SN: 4/27/85, p. 262). But both chemicals used in mummification and Egypt’s steamy climate can degrade DNA, and scientists weren’t sure if mummies could supply samples free of modern contamination.

Carefully screening for quality and using the latest in sequencing tech, Verena Schuenemann of the University of Tübingen in Germany and her colleagues extracted and analyzed mitochondrial DNA, which passes from mom to child. They worked primarily with samples from teeth and bones, rather than from soft tissue. Three mummies yielded readable samples of DNA from cell nuclei, which includes DNA from both parents. The mummies ranged in age of origin from 1388 B.C. to A.D. 426.

The analysis reveals genetic ties to the Middle East and Greece — not a huge surprise since Egypt was a center of travel and trade at that time. The conspicuous absence of genetic connections to sub-Saharan Africa seen in modern Egyptians points to a later influx of foreigners from that region, the researchers write May 30 in Nature Communications.

Imagine for a moment that you lived on another planet. Not Tatooine, Trantor or another fictional orb, but a real-deal planet circling a star somewhere in our real-deal galaxy. What would your world look like? Would there be a rocky surface? An atmosphere? How long would a day last? How about a year? What special physiology might you need to survive there? There’s no single scenario, of course. Starting with some basic facts, you can speculate in all sorts of surprising directions. That’s the fun of the exercise.

Over the last quarter century or so, astronomers have confirmed more than 3,600 exoplanets — that’s 3,600-plus worlds in addition to the planets, moons and other heavenly bodies known in our own solar system. People have long imagined what it would be like to live on Mars, and bold thinkers have dared to envision an existence on, say, Jupiter (see “Juno spacecraft reveals a more complex Jupiter“). Today there are many more possibilities, including planets orbiting dim red stars very different from our sun. In “Life might have a shot on planets orbiting dim red stars,” Christopher Crockett describes the hurdles life might face in evolving and surviving near these cool stars. On planets orbiting Proxima Centauri, TRAPPIST-1 and other M dwarfs, water could be extremely sparse, energetic flares might regularly singe the surface and you might live always in sun or forever in darkness.
Reading about these worlds, I’d say, is better than fiction — as is a lot of what Science News covers. You don’t need a novel or a movie to escape into what feels like another reality. Just flip through these pages. The stories will take you to other worlds, as well as inner, hidden ones. Former Science News intern Elizabeth S. Eaton writes about the bacteria that infect our bodies and the problem of antibiotic resistance. Picturing these invisible, single-celled organisms wreaking havoc in the body, unchecked by our best medicines, gives me goose bumps. Eaton’s story is about the battle that would ensue if predatory bacteria are sent in to hunt down and kill these bad guys, as some researchers have proposed. One researcher likens the bacteria to the antagonists in the Alien films. There’s true cinematic potential.

And it doesn’t end there. Bruce Bower takes readers into the past, to the roots of the human evolutionary tree. Most scientists think Africa was the birthplace of hominids, but new research suggests it could have been Europe. And Susan Milius offers an opportunity to consider what it might be like to live in another type of body — a flamingo’s. The birds have an off-kilter shape, with ankles where we’d expect knees. For flamingos, Milius reports, standing on one leg might be more stable than standing on two. After reading the story, I couldn’t help but attempt to balance on just my right foot, in hopes of getting a handle on human-flamingo differences. (It was an unsuccessful 20 seconds. Thank goodness my office door was closed.)

Every issue of Science News includes similar inspiration. There’s serious stuff to be sure, but there are plenty of chances to ponder the strangeness of reality — and to stretch it. After thinking about living on Proxima b or being a wading bird, consider being a wading bird on Proxima b. For fuel to help your imagination run, you’ve come to the right place.

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.