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A question flamingo researchers get asked all the time — why the birds stand on one leg — may need rethinking. The bigger puzzle may be why flamingos bother standing on two.

Balance aids built into the birds’ basic anatomy allow for a one-legged stance that demands little muscular effort, tests find. This stance is so exquisitely stable that a bird sways less to keep itself upright when it appears to be dozing than when it’s alert with eyes open, two Atlanta neuromechanists report May 24 in Biology Letters.
“Most of us aren’t aware that we’re moving around all the time,” says Lena Ting of Emory University, who measures what’s called postural sway in standing people as well as in animals. Just keeping the human body vertical demands constant sensing and muscular correction for wavering. Even standing robots “are expending quite a bit of energy,” she says. That could have been the case for flamingos, she points out, since effort isn’t always visible.
Ting and Young-Hui Chang of the Georgia Institute of Technology tested balance in fluffy young Chilean flamingos coaxed onto a platform attached to an instrument that measures how much they sway. Keepers at Zoo Atlanta hand-rearing the test subjects let researchers visit after feeding time in hopes of catching youngsters inclined toward a nap — on one leg on a machine. “Patience,” Ting says, was the key to any success in this experiment.

As a flamingo standing on one foot shifted to preen a feather or joust with a neighbor, the instrument tracked wobbles in the foot’s center of pressure, the spot where the bird’s weight focused. When a bird tucked its head onto its pillowy back and shut its eyes, the center of pressure made smaller adjustments (within a radius of 3.2 millimeters on average, compared with 5.1 millimeters when active).
Museum bones revealed features of the skeleton that might enhance stability, but bones alone didn’t tell the researchers enough. Deceased Caribbean flamingos a zoo donated to science gave a better view. “The ‘ah-ha!’ moment was when I said, ‘Wait, let’s look at it in a vertical position,’” Ting remembers. All of a sudden, the bird specimen settled naturally into one-legged lollipop alignment.

In flamingo anatomy, the hip and the knee lie well up inside the body. What bends in the middle of the long flamingo leg is not a knee but an ankle (which explains why to human eyes a walking flamingo’s leg joint bends the wrong way). The bones themselves don’t seem to have a strict on-off locking mechanism, though Ting has observed bony crests, double sockets and other features that could facilitate stable standing.

The bird’s distribution of weight, however, looked important for one-footed balance. The flamingo’s center of gravity was close to the inner knee where bones started to form the long column to the ground, giving the precarious-looking position remarkable stability. The specimen’s body wasn’t as stable on two legs, the researchers found.
Reinhold Necker of Ruhr University in Bochum, Germany, is cautious about calling one-legged stances an energy saver. “The authors do not consider the retracted leg,” says Necker, who has studied flamingos. Keeping that leg retracted could take some energy, even if easy balancing saves some, he proposes.

The new study takes an important step toward understanding how flamingos stand on one leg, but doesn’t explain why, comments Matthew Anderson, a comparative psychologist at St. Joseph’s University in Philadelphia. He’s found that more flamingos rest one-legged when temperatures drop, so he proposes that keeping warm might have something to do with it. The persistent flamingo question still stands.

Astronomers want you in on the search for the solar system’s ninth planet.

In the online citizen science project Backyard Worlds: Planet 9, space lovers can flip through space images and search for this potential planet as well as other far-off worlds awaiting discovery.

The images, taken by NASA’s Wide-field Infrared Survey Explorer satellite, offer a peek at a vast region of uncharted territory at the far fringes of the solar system and beyond. One area of interest is a ring of icy rocks past Neptune, known as the Kuiper belt. Possible alignments among the orbits of six objects out there hint that a ninth planet exerting its gravitational influence lurks in the darkness (SN: 7/23/16, p. 9). The WISE satellite may have imaged this distant world, and astronomers just haven’t identified it yet. Dwarf planets, free-floating worlds with no solar system to call home (SN: 4/4/15, p. 22) and failed stars may also be hidden in the images.
The WISE satellite has snapped the entire sky several times, resulting in millions of images. With so many snapshots to sift through, researchers need extra eyes. At the Backyard Worlds website, success in spotting a new world requires sharp sight. You have to stare at what seems like thousands of fuzzy dots in a series of four false-color infrared images taken months to years apart and identify faint blobs that appear to move. Spot that movement and you may have found a new world.

But you can’t let blurry spots or objects moving in only a couple of the frames fool you: Image artifacts can look like convincing space objects. True detections come from slight shifts in the positions of red or whitish-blue dots. With so many dots to track, it’s best to break up an image into sections and then click through the four images section by section. This process can take hours. But think of the payoff — discovering a distant world no one has observed before.

Once you’ve marked any potential object of interest, the project’s astronomers take over. Jackie Faherty of the American Museum of Natural History in New York City and colleagues cross-reference the object’s coordinates with databases of celestial worlds. If the object does, in fact, appear to be a newbie, the team requests time on other telescopes to do follow-up. Those studies can reveal whether the object is a failed star or a planet.

So far, tens of thousands of citizen scientists have scoured images at Backyard Worlds. The team has identified five possible failed stars and had its first paper accepted for publication.

But there’s still much more to explore: The elusive Planet Nine might still be out there, disguised as a flash of dots.

Water swirling down a drain has exposed an elusive phenomenon long believed to appear in black holes.

Light waves scattering off a rotating black hole can bounce off with more energy than they came in with, by sapping some of the black hole’s rotational energy. But the effect, predicted in 1971 and known as rotational superradiance, is so weak that it would be extremely difficult to observe in a real black hole. So scientists had never seen rotational superradiance in action. Now, physicists report June 12 in Nature Physics that they’ve glimpsed the effect for the first time, in a black hole doppelgänger made with a vortex of water, similar to water swirling down a bathtub drain.
“If you take a tennis ball and you throw it against a wall, you don’t expect it to come back with more energy,” says Silke Weinfurtner of the University of Nottingham in England, who led the study. “But when you throw something at a black hole, if it’s a rotating black hole, you can actually gain energy.”

To demonstrate the effect, the scientists created a swirl of water. “The fluid has to drain in a way that looks like a black hole,” says physicist Antonin Coutant, also at Nottingham. Surface ripples reach a point of no return where they are sucked into the vortex. That’s analogous to a black hole’s event horizon, the boundary from which no light can escape. Weinfurtner, Coutant and colleagues report that water waves scattering off the vortex got a superradiant boost: They were amplified by up to 14 percent on average, depending on the frequency and direction of the waves.

For obvious reasons, researchers can’t study a real black hole in a laboratory. If they could, “we’d all be in trouble,” says physicist Sam Dolan of the University of Sheffield in England, who was not involved with the study. A water vortex is the next best thing. The result, Dolan says, “gives us more confidence that our theories about black holes are correct.”

Although rotational superradiance is a weak effect in black holes, there may be opportunities to observe it, says physicist Vítor Cardoso of Instituto Superior Técnico in Lisbon, Portugal. Superradiance affects gravitational waves as well as light waves. Ripples in spacetime stirred up by merging black holes (SN Online: 6/1/17) should be slightly amplified if those black holes are spinning. That amplification could be observed by future ultrasensitive gravitational wave detectors.

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.