OXON HILL, Md. — Astronomers may soon know for sure if Europa is spouting off. After finding signs that Jupiter’s icy moon emits repeating plumes of water near its southern pole, astronomers using the Hubble Space Telescope hope to detect more evidence of the geysers.
“The statistical significance is starting to look pretty good,” astronomer William Sparks of the Space Telescope Science Institute in Baltimore says. He presented preliminary results on the hunt for the plumes at a meeting of the American Astronomical Society on January 9. Sparks’ team started observing Europa on January 5, hoping to catch it passing in front of Jupiter 30 times before September. Hubble can detect active plumes silhouetted against background light from Jupiter. If the plume repeats as often as it seems to, “it’s essentially a certainty we’ll see it again if it’s real,” Sparks said.
Europa probably hosts a vast saltwater ocean buried under a thick icy shell. In 2012, astronomers using Hubble spotted high concentrations of hydrogen and oxygen over Europa’s southern hemisphere — signs that Europa was spitting water into space (SN: 1/25/14, p. 6). Later efforts to find those signs using the same technique yielded nothing.
But using Jupiter as a backdrop for the plumes, Sparks and his colleagues spotted several eruptions (SN Online: 9/26/16) — once in March 2014, again in February 2016 and possibly also in March 2017, Sparks said.
Story continues below images Maps of Europa’s heat and ionosphere made by the Galileo spacecraft in the 1990s show the plumes’ location was warmer than the surrounding ice. It also had an unusually high concentration of charged particles, perhaps the result of water splitting into hydrogen and oxygen. Both observations support the idea that some ocean is escaping at that spot.
“If it’s a coincidence, it’s a hell of a coincidence,” Sparks says.
Hunter-gatherers and farming villagers don’t write parenting handbooks, much less read them. But parents in WEIRD societies — Western, educated, industrialized, rich and democratic — can still learn a few childrearing lessons from their counterparts in small-scale societies.
It’s not that Western parents and kids are somehow deficient. But we live in a culture that holds historically unprecedented expectations about how to raise children. Examples: Each child is a unique individual who must be allowed to make decisions independently; children are precious and innocent, so their needs are more important than those of adults; and kids need to be protected from themselves by constant adult supervision. When compared to family life in foraging and farming cultures, and in WEIRD societies only a few decades ago, there is nothing “normal” about parenting convictions such as these.
“Childhood, as we now know it, is a thoroughly modern invention,” says anthropologist David Lancy of Utah State University in Logan. He has studied traditional societies for more than 40 years.
In his book Raising Children: Surprising Insights from Other Cultures, Lancy examines what’s known about bringing up kids in hunter-gatherer groups and farming villages. Among the highlights:
Babies are usually regarded as nonpeople, requiring swaddling and other special procedures over months or years to become a human being. Children are typically the lowest-ranking community members. Because kids can’t feed and protect themselves, they accumulate a moral debt to their elders that takes years of hard work to repay. If that sounds harsh to WEIRD ears, withhold judgment before considering these child-rearing themes from traditional cultures.
Allow for make-believe about real life Hunter-gatherer and village kids intently observe and imitate adults (SN: 2/17/18, p. 22). Playtime often consists of youngsters of various ages acting out and even parodying adult behaviors. Virtually everything, from relations between the sexes to religious practices, is fair game. Kids scavenge for props, assign each other roles and decide what the cast of characters will say.
Western children would benefit from many more chances to play in unsupervised, mixed-age groups, Lancy says.
Let kids play collaborative games A big advantage of play groups of kids of all ages is that they become settings for games in which kids negotiate the rules. Until recently, these types of games, such as marbles, hopscotch and jump rope, were common among U.S. children.
Not anymore, at least not in neighborhoods dominated by adult-supervised play dates and sports teams. Sure, tempers can flare as village youngsters hash out rules for marbles or jacks. But negotiations rarely go off the rails. Older kids handicap themselves so that younger children can sometimes win a game. Concessions are made even for toddlers.
The point is to maintain good enough relations to keep adults from intruding. In modern societies, Lancy suspects, bullying flourishes when kids don’t learn early on how to play collaboratively.
Put young children to work In most non-WEIRD societies, miniature and cast-off tools and utensils, including knives, are the toys of choice for kids of all ages. Play represents a way to prepare for adult duties and, when possible, work alongside adults as helpers.
Western parents can find ways for preschoolers to help out around the house, but it demands flexibility and patience. Lancy suggests making allowances for a 3-year-old who mixes up socks when sorting the laundry. Maybe paper plates are needed until a kitchen helper becomes less apt to drop them.
Still, carefully selected jobs for 3- and 4-year-olds promote a sense of obligation and sympathy toward others, Lancy says. Western kids given chances to help adults early on may, like their non-WEIRD peers, willingly perform chores at later ages, he predicts.
Whether children live in city apartments or forest huts, having the freedom to explore and play with no adults around proves an antidote to boredom. Lancy recalls how boredom-busting works from his own early childhood in rural Pennsylvania during the 1950s. His family lived in a house bordering a river. Lancy would sit on the river bank for up to an hour at a time. His mother liked to tell visitors a story that, when asked what he had been doing, the boy replied “watching the ‘flections.”
If you’ve ever felt the urge to tap along to music, this research may strike a chord.
Recognizing rhythms doesn’t involve just parts of the brain that process sound — it also relies on a brain region involved with movement, researchers report online January 18 in the Journal of Cognitive Neuroscience. When an area of the brain that plans movement was disabled temporarily, people struggled to detect changes in rhythms.
The study is the first to connect humans’ ability to detect rhythms to the posterior parietal cortex, a brain region associated with planning body movements as well as higher-level functions such as paying attention and perceiving three dimensions. “When you’re listening to a rhythm, you’re making predictions about how long the time interval is between the beats and where those sounds will fall,” says coauthor Jessica Ross, a neuroscience graduate student at the University of California, Merced. These predictions are part of a system scientists call relative timing, which helps the brain process repetitive sounds, like a musical rhythm.
“Music is basically sounds that have a structure in time,” says Sundeep Teki, a neuroscientist at the University of Oxford who was not involved with the study. Studies like this, which investigate where relative timing takes place in the brain, could be crucial to understanding how the brain deciphers music, he says.
Researchers found hints of the relative timing system in the 1980s, when observing that Parkinson’s patients with damaged areas of the brain that control motion also had trouble detecting rhythms. But it wasn’t clear that those regions were causing patients’ difficulty with timing — Parkinson’s disease can wreak havoc on many areas of the brain. Ross and her colleagues applied magnetic pulses to two different areas of the brain in 25 healthy adults. Those areas — the posterior parietal cortex and the supplementary motor area, which controls movement — were then unable to function properly for about an hour.
Suppressing activity in the supplementary motor area caused no significant change in participants’ ability to follow a beat. But when the posterior parietal cortex was suppressed, all of the adults had trouble keeping rhythm. For example, when listening to music overlaid with beeps that were on the beat as well as off the beat, participants frequently failed to differentiate between the two. This finding suggests the posterior parietal cortex is necessary for relative timing, the researchers say.
The brain has another timing system that was unaffected by the suppression of activity in either brain region: discrete timing, which keeps track of duration. Participants could distinguish between two notes held for different amounts of time. Ross says this suggests that discrete timing is governed by other parts of the brain. Adults also had no trouble differentiating fast and slow tempos, despite tempo’s connection to rhythm, which might imply the existence of a third timing system, Ross says.
Research into how the brain processes time, sound and movement has implications for understanding how humans listen to music and speech, as well as for treating diseases like Parkinson’s.
Still, many questions about the brain’s timing mechanisms remain (SN: 07/25/15, p. 20): What are the evolutionary origins of different timing mechanisms? How do they work in conjunction to create musical perception? And why do most other animals seem to lack a relative timing system?
Scientists are confident that they will have answers — all in good time.
Fishing has left a hefty footprint on Earth. Oceans cover more than two-thirds of the planet’s surface, and industrial fishing occurred across 55 percent of that ocean area in 2016, researchers report in the Feb. 23 Science. In comparison, only 34 percent of Earth’s land area is used for agriculture or grazing.
Previous efforts to quantify global fishing have relied on a hodgepodge of scant data culled from electronic monitoring systems on some vessels, logbooks and onboard observers. But over the last 15 years, most commercial-scale ships have been outfitted with automatic identification system (AIS) transceivers, a tracking system meant to help ships avoid collisions. In the new study, the researchers examined 22 billion AIS positions from 2012 through 2016. Using a computer trained with a type of machine learning, the team then identified more than 70,000 fishing vessels and tracked their activity.
Much of the fishing was concentrated in countries’ exclusive economic zones — ocean regions within about 370 kilometers of a nation’s coastline — and in certain hot spots farther out in the open ocean, the team found. Such hot spots included the northeastern Atlantic Ocean and the nutrient-rich upwelling regions off the coasts of South America and West Africa.
Surprisingly, just five countries — China, Spain, Taiwan, Japan and South Korea — accounted for nearly 85 percent of fishing efforts on the high seas, the regions outside of any country’s exclusive economic zone.
Tracking the fishing footprint in space and time, the researchers note, can help guide marine environmental protections and international conservation efforts for fish. That may be particularly important in a time of rapid change due to rising ocean temperatures and increasing human activity on the high seas.
THE WOODLANDS, Texas — Mars’ missing magnetic field may have drowned in the planet’s core.
An excess of hydrogen, split off from water molecules and stored in the Martian mantle, could have shut down convection, switching the magnetic field off forever, planetary scientist Joseph O’Rourke proposed March 21 at the Lunar and Planetary Science Conference.
Planetary scientists think magnetic fields are produced by the churning of a planet’s molten iron core. Convection relies on denser materials sinking into the core, and lighter stuff rising to the surface. The movement of iron, which can carry a charge, generates a strong magnetic field that can protect a planet’s atmosphere from being ravaged by solar wind (SN Online: 8/18/17). But if lighter material, like hydrogen, settles close to the iron core, it could block dense material from sinking deep enough to keep convection going, said O’Rourke, of Arizona State University in Tempe.
“Too much hydrogen and you can shut down convection entirely,” he said. “Hydrogen is a heartless killer.”
O’Rourke and his ASU colleague S.-H. Dan Shim suggested the hydrogen could come from water locked up in Martian minerals. Near the hot core, water would split into hydrogen and oxygen. The oxygen would form compounds with other elements and stay high in the mantle, but the hydrogen could sit atop the core and effectively suffocate the dynamo. The question is whether Mars’ minerals would have had what it took to deliver the hydrogen at the right time. Mars’ crust is rich in the mineral olivine, which does not bond well with water and so is relatively dry.
In the planet’s interior, pressure forces olivine to transform into the minerals wadsleyite and ringwoodite, which hold more water. Deeper still, the mineral turns into bridgmanite and becomes dry again. For a time, that bridgmanite layer could act as a buffer against water, allowing the core to keep convecting. But as the mantle cooled, the bridgmanite layer would shrink and eventually disappear, O’Rourke’s study suggests.
Whether Mars’ interior ever had that saving layer of bridgmanite depends on how big its core is — a property that may be tested by NASA’s InSight Mars lander, launching on May 5, O’Rourke said. Mars did have a magnetic field more than 4 billion years ago. Scientists have struggled to explain how it vanished, leaving the planet vulnerable to solar winds, which probably stripped away its atmosphere and surface water (SN: 12/12/15, p. 31).
If hydrogen shut down the planet’s generator, it would have had to act fast. Previous observations suggest the magnetic field disappeared relatively rapidly, over 100 million years.
Another theory by James Roberts of the Johns Hopkins Applied Physics Lab in Laurel, Md., suggests a large impact could have shut down the dynamo by heating the outermost core, which would have kept it from sinking.
“It’s actually a similar idea to O’Rourke’s,” Roberts says. It may take many more sophisticated Mars missions to figure out what really happened.
Honeybee royal jelly is food meant to be eaten on the ceiling. And it might also be glue that keeps a royal baby in an upside-down cradle.
These bees raise their queens in cells that can stay open at the bottom for days. A big blob of royal jelly, abundantly resupplied by worker bees, surrounds the larva at the ceiling. Before the food is deposited in the cell, it receives a last-minute jolt of acidity that triggers its proteins to thicken into goo, says Anja Buttstedt, a protein biochemist at Technische Universität Dresden in Germany. Basic larva-gripping tests suggest the jelly’s protein chemistry helps keep future queens from dropping out of their cells, Buttstedt and colleagues propose March 15 in Current Biology. Suspecting the stickiness of royal jelly might serve some function, researchers tweaked its acidity. They then filled small cups with royal jelly with different pH levels and gently turned the cups upside down. At a natural royal jelly acidity of about pH 4.0, all 10 larvae dangled from their gooey blobs upside down overnight. But in jelly boosted to pH 4.8 (and thinned in the process), four of the 10 larvae dropped from the cups. At pH 5.9, all of them dropped.
Honeybees build several forms of royally oversized cells for raising a queen. Those for queens who will swarm with their workers to a new home hang from the rim of an array of regular cells. A hole stays open at the bottom of the cell until the larva nears pupation from her fat grub shape into a queen with wings. That hole at the bottom is big enough for a royal larva to fall through, confirms insect physiologist Steven Cook at the honeybee research lab in Beltsville, Md., run by the U.S. Department of Agriculture’s Agricultural Research Service.
Buttstedt and colleagues propose that the stickiness of royal jelly may be what keeps the larva in place. The team worked out how the jelly’s proteins change as it is made, and how those changes affect its consistency.
Royal jelly is secreted as a brew of proteins from the glands above a worker bee’s brain. At that point, it has a neutral pH, around 7, like water’s. The worker bee then adds fatty acids from glands in her mouthparts, which take the pH to around 4. “It has a quite sour smell,” Buttstedt says. As for taste? “Really weird.” A steady diet of this jelly is what turns a larvae into a queen instead of a worker.
At pH 4, the jelly’s most common protein, MRJP1, goes complicated. When the protein leaves the glands above the brain, it’s clustered in groups of four along with smaller proteins called apisimins, the team found. When the acidity shifts, the MRJP1 foursomes and the apisimins hook together in slender fibers and get gluey.
“The most puzzling question,” Buttstedt says, is “why build upside-down queen cells in the first place?”
Delusional infestation de-LU-zhen-al in-fes-TAY-shun n. A deep conviction that one’s skin is contaminated with insects or other objects despite a lack of medical evidence.
She was certain her skin was infested: Insects were jumping off; fibers were poking out. Fearful her condition could spread to others, the 50-year-old patient told doctors at the Mayo Clinic in Rochester, Minn., that she was avoiding contact with her children and friends.
The patient had delusional infestation, explains Mayo Clinic dermatologist Mark Davis. Sufferers have an unshaking belief that pathogens or inanimate objects pollute their skin despite no medical evidence. Davis and colleagues report online April 4 in JAMA Dermatology that the disorder is not as rare as previously assumed. In the first population-based study of the disorder’s prevalence, the researchers identified 35 cases from 1976 to 2010 reported in Minnesota’s Olmsted County. Based on the findings, the authors estimate 27 out of every 100,000 people in the United States have delusional infestation. Due to the county’s lack of diversity — the population of about 150,000 is predominantly white — the researchers used only the nationwide white population to estimate prevalence, so the result may not be representative of other populations.
Delusional infestation has been recognized for decades, albeit under different names. Patients insist they’ve been overtaken with creatures, such as insects, worms or parasites, or inanimate materials like fibers — or both. “It’s like aliens have infested their skin,” Davis says. Some present bagged samples of the claimed culprits, which turn out to be such debris as sand, dander or, as in the case of the 50-year-old woman, bits of skin and scabs. When lab tests confirm no infestation, patients often seek another opinion rather than accept the findings. Some attempt risky self-treatments, such as bathing in kerosene or bleach, or tweezing or cutting the skin.
Schizophrenia, dementia or other psychiatric illnesses can trigger delusional infestation. So can such drugs as amphetamines or cocaine. But when no other illness is involved, patients often reject the notion that the issue is psychiatric and tend to refuse the antipsychotic medications that can help, Davis says.
As for the 50-year-old patient, upset with the doctors’ diagnosis, she no longer comes to the Mayo Clinic.
Scientists playing peekaboo with dark matter have entered a new stage of the game.
For the first time, physicists are snooping on some of the likeliest hiding places for hypothetical subatomic particles called axions, which could make up dark matter. So far, no traces of the particles have been found, scientists with the Axion Dark Matter Experiment, ADMX, report April 9 in Physical Review Letters. But the researchers have now shown that their equipment is sensitive enough to begin searching in earnest.
An ethereal substance that makes up much of the matter in the universe, dark matter is necessary to explain the motions of stars within galaxies, among other observations. Scientists don’t know what dark matter is, but axions, extremely lightweight particles that may permeate the cosmos, are one of the major contenders.
Most past searches for dark matter particles have focused on a different candidate particle, known as a weakly interacting massive particle, or WIMP. But those efforts have so far come up empty (SN: 11/12/16, p. 14). Now, the spotlight is on the underdog axions. “We have to make sure we are considering all the possibilities,” says theoretical physicist Matthew Buckley of Rutgers University in Piscataway, N.J., who was not involved with the new result. Axions, he says, are a plausible candidate for dark matter.
Axions would produce incredibly feeble signals, so pinning down evidence for the minuscule particles is no easy undertaking. But ADMX, located at the University of Washington in Seattle, is now up to the task, says ADMX member Aaron Chou, a physicist at Fermilab in Batavia, Ill. Previous experiments have searched for axions, but those efforts weren’t sensitive enough to have a good chance of detecting the particles.
“It’s an experimental tour de force; it’s amazing work,” says theoretical physicist Helen Quinn of SLAC National Accelerator Laboratory in Menlo Park, Calif., who was not involved with the research.
ADMX uses what is essentially a supersensitive radio, isolated from external sources of radio waves and cooled to temperatures near absolute zero (‒273.15° Celsius). Scientists use the apparatus to search for axions converting into radio waves in a strong magnetic field. If axions exist, they are expected to interact with photons, particles of light, from the magnetic field. In the process, they would produce radio waves at a frequency that depends on the axion’s mass, which is unknown. Like scanning the dial for a good oldies station, scientists will gradually change the frequency at which they search, trying to “listen in” on the axion signal.
While the new study came up empty, scientists scanned only a small range of frequencies, ruling out some possible masses for axions, from 2.66 to 2.81 microelectron volts. Those tiny masses are less than a billionth of an electron’s mass. In the future, ADMX will study other possible masses. “There’ll be a lot of excitement in the next few years,” Chou says. “A discovery could come at any time.”
Using the precise position and brightness of almost 1.7 billion stars, the Gaia spacecraft has created the most precise 3-D map of the Milky Way yet.
On April 25, the European Space Agency’s Gaia team released the spacecraft’s second batch of data, gathered from July 2014 to May 2016, used to create the map. The tally includes measurements of half a million quasars — the active black holes at the centers of distant galaxies — and 14,099 known solar system objects (mostly asteroids), observations of other nearby galaxies and the amount of dust in between Earth and 87 million stars (SN: 4/14/18, p. 27).The spacecraft also measures the distances and motions of stars by taking advantage of Earth’s motion around the sun, a technique called parallax. As Earth moves, stars appear to trace a small ellipse, whose size is related to the stars’ distance. Measuring the wavelengths of light the stars emit tells how fast they are moving toward or away from the sun. Combining Gaia’s measurements with earlier sky surveys let astronomers track stars’ motions.
Gaia launched in 2013, and released its first batch of data in September 2016 (SN: 10/15/16, p. 16). Those data included distances and motions of roughly 2 million stars; the new data up that number to 1.3 billion.
Knowing those distances will allow astronomers to decipher details about the Milky Way’s shape and history. Already the second data release suggests that the galaxy contains two distinct populations of stars that may have different origins. The stars’ chemistry and motions suggest that some could have originated in a different galaxy that the Milky Way cannibalized long ago.
“With Gaia, we can reconstruct the whole history of the Milky Way,” ESA science director Günther Hasinger said in a news conference April 25.
In Finland, 88 percent of people have a genetic variation that increases their risk for migraines. But in people of Nigerian descent, that number drops to 5 percent.
Coincidence? Maybe. But a new study suggests that, thousands of years ago, that particular genetic mutation increased in frequency in northern populations because it somehow made people better suited to handle cold temperatures. That change may have had the unfortunate consequence of raising the prevalence of these severe headaches in certain populations, researchers report May 3 in PLOS Genetics. The mutation is in a stretch of DNA that controls the behavior of TRPM8, a protein that responds to cold sensation. People with the older version of this DNA snippet seems less susceptible to migraines than people with the mutated version, previous studies have shown.
Using a global database of human genetic information, evolutionary geneticist Aida Andres and her colleagues showed a correlation between the frequency of the mutation in a given population and that population’s latitude. It’s rare in Africa, for example, but fairly common across Europe.
Differences in temperature may have led to this variation, though scientists still aren’t sure exactly how the mutation affects TRPM8. Perhaps the mutation conferred some benefit to early humans who moved north from Africa, says Andres, of University College London. The connection to migraine appears to be a side effect.
The researchers acknowledge, however, that the science of migraines isn’t so simple. One variant can’t fully explain why these headaches are more common in certain populations. Migraine risk is “very complex,” Andres says. “It’s highly heritable, but other things impact it, too.” Plus, there’s still a lot to learn about TRPM8. “We don’t even really know how the entirely normal [protein], with no mutations, contributes to migraine,” says Greg Dussor, a neurobiologist at the University of Texas at Dallas who wasn’t part of the study.
Even the link between migraine and temperature is muddy: While cold temperatures can trigger migraines in some people, heat sets others off.
