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When the Aug. 21 solar eclipse unveils the sun’s normally dim atmosphere, the corona will look like an intricate, orderly network of loops, fans and streamers. These features trace the corona’s magnetic field, which guides coronal plasma to take on the shape of tubes and sheets.

These wispy coronal structures arise from the magnetic field on the sun’s visible surface, or its photosphere. Unlike the corona, the photosphere’s magnetism is a complete mess.
“It’s not a static surface like the ground, it’s more like an ocean,” says solar physicist Amir Caspi of the Southwest Research Institute in Boulder, Colo. “And not just an ocean. It’s like a boiling ocean.”

Because the corona’s loops and streamers all originate in the turbulent photosphere, their roots should get twisted and turned around.

“And yet these structures in the corona are not tangled and snarled and matted like kelp or seaweed in the ocean,” Caspi says. “They seem to still be these organized, smooth loops. Nobody understands why.”

To unknot the photosphere’s tangled mats, the corona must release some of the energy stored there, Caspi says. So during the eclipse, he and his colleagues will be looking for the release valves that set the corona free.
One possibility is that wave motion in the corona’s magnetic field lines helps untie the snarls. Magnetic waves in plasma, called Alfvén waves, are thought to ripple through the sun’s magnetic field lines like vibrations in a guitar string. Researchers have directly observed Alfvén waves in the lower corona, within about half a solar radius of the surface (SN: 4/11/09, p. 12), but not farther out where similar waves with higher amplitudes would travel. Those close-in waves were too weak to explain the corona’s features, but perhaps more distant waves could shake things up enough.
Another option is that little hypothetical spurts of magnetic energy could help release the tangles. These nanoflares and nanojets would be like solar flares but with a billionth of the energy. By going off all the time, nanoflares and nanojets could collectively release enough energy to give the corona some structure, simulations have shown.

“Both are symptoms of tiny rearrangements of the magnetic field — magnetic reconnection,” says solar physicist Craig DeForest, also at the Southwest Research Institute. Solar flares and bigger outbursts called coronal mass ejections are also signs of magnetic reconnection, but they’re not frequent enough to account for the corona’s smoothness. “Nanojets and/or nanoflares in the middle corona would be a smoking gun that would explain why the corona is so organized,” DeForest says.

No one has actually seen any nanoflares or nanojets. Theories suggest that they’re too small and quick to see individually — but they should be visible as a cacophony of little pops when the solar eclipse reveals the lower corona.

The shaking from Alfvén waves and the flickers of nanoflares could not only loosen up the tangled skein of magnetism, but also transfer heat high up into the corona. Caspi, DeForest and their colleagues hope to see both effects on August 21, when they fly a pair of telescopes on twin NASA WB-57 high-altitude research jets along the path of the eclipse (SN Online: 8/14/17).

“We’re taking high-speed movies of the sun and analyzing them for things that look like waves,” Caspi says. “We’re just overall looking at the structure of the corona.”

Voices carry so much information. Joy and anger, desires, comfort, vocabulary lessons. As babies learn about their world, the voice of their mother is a particularly powerful tool. One way mothers wield that tool is by speaking in the often ridiculous, occasionally condescending baby talk.

Also called “motherese,” this is a high-pitched, exaggerated language full of short, slow phrases and big vocal swoops. And when confronted with a tiny human, pretty much everybody — not just mothers, fathers and grandparents — instinctively does it.

Now, a study has turned up another way mothers modulate their voice during baby talk. Instead of focusing on changes such as pitch and rhythm, the researchers focused on timbre, the “color” or quality of a sound.

Timbre is a little bit nebulous, kind of a “know it when you hear it” sort of thing. For instance, the timbre of a reedy clarinet differs from a bombastic trumpet, even when both instruments are hitting the same note. The same is true for voices: When you hear the song “Hurt,” you don’t need to check whether it’s Nine Inch Nails’ Trent Reznor or Johnny Cash singing it. The vocal fingerprints make it obvious.
It turns out that timbre isn’t set in stone. People — mothers, in particular — change their timbre, depending on whether they’re talking to their baby or to an adult, scientists report online October 12 in Current Biology.

For the study, 12 English-speaking moms brought their babies into a Princeton lab. Researchers recorded the women talking to or reading to their 7- to 12-month old babies, and talking with an adult.
An algorithm sorted through timbre data taken from both baby- and adult-directed speech, and used this input to make a mathematical classifier. Based on snippets of speech, the classifier then could tell whether a mother was talking with an adult or with her baby. The timbre differences between baby- and adult-directed speech were obvious enough that a computer program could tell them apart.

Similar timbre shifts were obvious in other languages, too, the researchers found. These baby-directed shifts happened in 12 different women who spoke Cantonese, French, German, Hebrew, Hungarian, Polish, Russian, Mandarin or Spanish — a consistency that suggests this aspect of baby talk is universal.

Defined mathematically, these timbre shifts were consistent across women and across languages, but it’s still not clear what vocal qualities drove the change. “It likely combines several features, such as brightness, breathiness, purity or nasality,” says study coauthor Elise Piazza, a cognitive neuroscientist at Princeton University. She and her colleagues plan on studying these attributes to see whether babies pay more attention to some of them.

It’s not yet known whether babies perceive and use the timbre information from their mother. Babies recognize their mother’s voice; it’s possible they recognize their mother’s baby-directed timbre, too. Babies can tell timbre differences between musical instruments, so they can probably detect timbre differences in spoken language, Piazza says.
The work “highlights a new cue that mothers implicitly use,” Piazza says. The purpose of this cue isn’t clear yet, but the researchers suspect that the timbre change may emotionally engage babies and help them learn language.

People may not reserve timbre shifts just for babies, Piazza points out. Politicians talking to voters, middle school teachers talking to a classroom, and lovers whispering to each other may all tweak their timbre to convey … something.

Beer breweries’ trash may have been Danish painters’ treasure.

The base layer of several paintings created in Denmark in the mid-1800s contains remnants of cereal grains and brewer’s yeast, the latter being a common by-product of the beer brewing process, researchers report May 24 in Science Advances. The finding hints that artists may have used the leftovers to prime their canvases.

Records suggest that Danish house painters sometimes created glossy, decorative paint by adding beer, says Cecil Krarup Andersen, a conservator at the Royal Danish Academy in Copenhagen. But yeast and cereal grains have never been found in primer.
Andersen had been studying paintings from the Danish Golden Age, an explosion of artistic creativity in the first half of the 19th century, at the National Gallery of Denmark. Understanding these paintings’ chemical compositions is key to preserving them, she says. As part of this work, she and colleagues looked at 10 pieces by Christoffer Wilhelm Eckersberg, considered the father of Danish painting, and his protégé Christen Schiellerup Købke.

Canvas trimmings from an earlier conservation effort allowed for an in-depth analysis that wouldn’t have otherwise been possible, since the process destroys samples. In seven paintings, Saccharomyces cerevisiae proteins turned up, as well as various combinations of wheat, barley, buckwheat and rye proteins. All these proteins are involved in beer fermentation (SN: 9/19/17).

Tests of an experimental primer that the researchers whipped up using residual yeast from modern beer brewing showed that the mixture held together and provided a stable painting surface — a primary purpose of a primer. And this concoction worked much better than one made with beer.

Beer was the most common drink in 1800s Denmark, and it was akin to liquid gold. Water needed to be treated prior to consuming and the brewing process took care of that. As a result, plenty of residual yeast would have been available for artists to purchase, the researchers say.

If the beer by-product is found in paintings by other artists, Andersen says, that information can help conservators better preserve the works and better understand the artists’ lives and craftsmanship. “It’s another piece of the puzzle.”