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<p>These two genes are all it takes to determine the sex of a kiwifruit.</p>

How kiwi plants’ Shy Girls and Friendly Boys helped them evolve separate sexes

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<p>Researchers are using fluid dynamics to try to improve the study of crime scene blood spatter.</p>

There will be blood, and physics, too: The messy science of bloodstain pattern analysis

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<p>The trifecta, discovered by NASA’s TESS, includes a “super-Earth” and two “sub-Neptunes” in a system called TOI-270.</p>

A new trio of exoplanets could offer clues to how midsized planets form

Koch Foundation

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<p>NOVA Next is NOVA’s award-winning digital publication that provides answers from the cutting edge of science and technology.</p>

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      <div class="rich-text"><p>In the fall of 1995, a team of researchers clipped 10 leaves from a potato plant, nestled them into beds of moistened soil, and <a href="http://bigidea.nianet.org/wp-content/uploads/2018/07/Chapter-Potatoes-for-Life-Support-in-Space-Wheeler-2009.pdf">shot half of them into space</a>.</p><p>The mission, conducted aboard the Space Shuttle Columbia, was a gamble, to say the least. Decades of research had already hinted that plants could, in fact, flourish outside of Earth’s atmosphere. These weren’t even the first spuds to ride a rocket—that had happened some 25 prior, when a team of Russian scientists loaded three taters onto a spacecraft and bid them adieu. But the prospect of getting a cut stem to yield an edible tuber in the vastness of space was far from a guarantee.</p></div>
  

  
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      <div class="rich-text"><p>Within a couple weeks, the stems of the five cuttings that had remained here on Earth had swollen into gumball-sized potatoes. And, orbiting a few hundred miles off the surface of Earth, their weightless counterparts did the same.</p><p>The extraterrestrial taters would eventually make their way back to Earth, where a battery of tests would reveal that they tubers were alarmingly… <i>normal.</i> In fact, they were nearly indistinguishable from their grounded brethren in most respects. Even without gravity, the spuds had fared just fine.</p>
            <figure class="richtext-image full-width"><img alt="Chapter Potatoes for Life Support in Space Wheeler 2009.jpg" class="richtext-image full-width" height="427" width="800"
            src="/wgbh/nova/media/images/Chapter_Potatoes_for_Life_Support_in_Space_Whe.width-800.jpg"/><figcaption><p>Potato tubers (each around a half-inch in diameter), half of which formed from leaf cuttings that spent 16 days in space in 1995. Image Credit: Raymond Wheeler, Advances in Potato Chemistry and Technology, 2009</p><div class="credit"><p></p></div></figcaption>
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            <p>It turns out the same is true of most of the crops researchers have launched into the cosmos. Despite eons of evolution here on our home planet, Earth’s plant life is <a href="https://www.degruyter.com/downloadpdf/j/opag.2017.2.issue-1/opag-2017-0002/opag-2017-0002.pdf">surprisingly amenable to space travel</a>—especially when given a little extra TLC from their human caretakers.</p><p>On the whole, plants on and off planet “look pretty much the same, if you don’t look too closely,” says <a href="http://ufspaceplants.org/about-us/">Anna-Lisa Paul</a>, who studies the biology of plants in microgravity at the University of Florida.</p><p>That’s very good news for the cosmic jetsetters among us. Though the menu of spaceflight has expanded tremendously in recent years, astronauts still rely mostly on packaged food. That’s a pretty monotonous diet—and a lot of baggage to carry aboard a spacecraft. If we humans are to truly go the distance vis-à-vis space travel, we’re going to need more sustainable sustenance, says <a href="https://www.nalfl.com/?page_id=6755">Gioia Massa</a>, a plant scientist at NASA’s Kennedy Space Center.</p></div>
  

  
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      <div class="rich-text"><p>As such, there’s <a href="http://bigidea.nianet.org/wp-content/uploads/2018/07/Chapter-Potatoes-for-Life-Support-in-Space-Wheeler-2009.pdf">a decent argument for sending spuds into space</a>. These tubers teem with several vitamins and minerals, and pack a decent amount of protein for a starch. They also boast a high harvest index, or the fraction of their mass that’s edible, says <a href="https://www.nasa.gov/feature/nasa-plant-researchers-explore-question-of-deep-space-food-crops">Raymond Wheeler</a>, a plant physiologist and potato expert at NASA. “You can get about 80 percent of a [potato’s mass] to tuberize,” he says. “They’re a good, nutritious crop.”</p><p>There’s a catch, though: Raw potatoes aren’t terribly palatable—and there aren’t ovens and deep fryers in space.</p><p>In fact, any crop that needs to be cooked before it’s eaten presents an additional hurdle for hungry astronauts. And so, aboard the International Space Station (ISS), researchers like Massa focus on roughage that can simply be plucked from its stem.</p><p>One of their ongoing experiments, <a href="https://www.nasa.gov/content/growing-plants-in-space">Veggie</a>—which Massa has been involved in since 2014—is a suitcase-sized space garden that can support about six plants at a time, supported on porous pillows of fertilized clay. Instead of soaking up sunlight, the sprouts spend their days beneath LEDs, bathed in a soft magenta glow (a mix of the red and blue wavelengths that plants like best).</p><p>Already, the team has gotten several kinds of salad greens to sprout, and in the summer of 2015, red romaine lettuce became the <a href="https://www.nasa.gov/mission_pages/station/research/news/meals_ready_to_eat">first plant</a> to be grown, harvested, and eaten in space.</p><p>But when things get extraterrestrial, even fast-growing greens come with challenges. “Growing a large plant is a huge undertaking in microgravity,” says <a href="http://ufspaceplants.org/about-us/">Robert Ferl</a>, a plant biologist at the University of Florida and Paul’s collaborator. “When you really want to control its water, nutrition, carbon dioxide, and everything else, it becomes a monumental engineering task.”</p><p>In the absence of gravity, fluids like water and air have trouble flowing, clumping instead into stubborn bubbles. Fans are a pretty straightforward fix for the airflow issues, but keeping plants hydrated is a bit more of a logistical headache.</p><p>With Veggie, caretakers dispense liquid to plants with a syringe, a process that still requires manual labor. In a companion experiment called the Advanced Plant Habitat—a mostly self-sufficient growth chamber that continually monitors temperature, light, moisture, and oxy­gen levels—scientists are tinkering with ways to automate this process entirely.</p>
            <figure class="richtext-image full-width"><img alt="36731018021_f48f1c6597_o.jpg" class="richtext-image full-width" height="533" width="800"
            src="/wgbh/nova/media/images/36731018021_f48f1c6597_o.width-800.jpg"/><figcaption><p>A scientist administers water and nutrients to plants in the Veggie hardware in NASA Kennedy Space Center&#x27;s ISS environment simulator chamber. Image Credit: NASA/Cory Huston</p><div class="credit"><p></p></div></figcaption>
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            <p>“The ultimate goal would be to minimize astronaut labor,” says <a href="http://naes.unr.edu/directory_details.aspx?hIj7_GDp0x45=836">Won-Gyu Choi</a>, a plant biologist at the University of Nevada, Reno.</p><p>Even with all this coddling, though, plants aren’t fooled: They’re still very much aware that they’re in space, Paul says. In response to low gravity, plants initiate a whole set of changes at the level of gene expression—many of which scientists like Paul, Ferl, and Choi are still puzzling through back here on Earth.</p><p>Awareness isn’t necessarily a bad thing, though. Plants’ exquisite sensitivity to their surroundings tells them how best to adapt—and flexibility is key when you’re tethered to the ground. Unlike us, plants can’t uproot and move into more accommodating territory when times get tough, Massa says.</p><p>In space, there’s no gravity to guide roots as they spread away from seeds in search of water and nutrients. So the plants make do with other cues, turning on a set of sun-sensitive genes that instructs roots to snake away from strong light. A few years ago, a team of researchers led by Paul and Ferl was astounded to see that this reprogramming was enough to allow plants aboard the ISS to <a href="https://bmcplantbiol.biomedcentral.com/articles/10.1186/1471-2229-12-232">unfurl their roots</a> into a pattern similar to those seen on Earth.</p><p>It’s unclear whether this light-driven strategy will work in more foreign locales, like the Moon or Mars, which both have more gravity than an orbiting spacecraft. Earlier this year, cotton seeds aboard <a href="https://www.pbs.org/wgbh/nova/article/change-4-mantle-moon/">China’s Chang’e 4 lunar lander</a> became the first to germinate on the Moon, sprouting small green shoots inside a tiny biosphere within the probe, but no one was around to keep tabs on the plants’ growth. Scientists also don’t know whether the lunar or Martian soil—a rocky, ash-like material called regolith that lacks many nutrients—will ever be hospitable to plant life, Massa says.</p>
            <figure class="richtext-image full-width"><img alt="KSC-04pd1307_orig.jpg" class="richtext-image full-width" height="531" width="800"
            src="/wgbh/nova/media/images/KSC-04pd1307_orig.width-800.jpg"/><figcaption><p>NASA plant biologist Raymond Wheeler checking radishes in a plant growth chamber at Kennedy Space Center, where researchers are studying different growth techniques that may someday be applied in space. Image Credit: NASA</p><div class="credit"><p></p></div></figcaption>
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            <p>There are also a few lingering uncertainties in the arena of food safety. <a href="https://www.pbs.org/wgbh/nova/article/bacteria-on-the-international-space-station/">Where humans go, so too do their microbes</a>—friend and foe alike. Though many plants depend on bacteria, they can also harbor agents of disease, and researchers still aren’t sure how the dynamics of illness and immunity play out in space. “Microorganisms are likely going to have a huge role in any space agriculture system...but food safety is also one of our biggest concerns,” Massa says.</p><p>Still, researchers believe the potential benefits of astrobotany far outweigh the costs. In addition to their nutritional perks, plants provide oxygen, as well as a sink for human waste. Some event manufacture antioxidants that could safeguard astronauts against the perils of UV radiation, which abounds in space.</p><p>Green stuff is also good for mental health—especially so far from sea level, Choi says. Homesick space travelers may find gardening psychologically soothing, or take comfort in simply being around familiar leaves and blooms.</p><p>Looking ahead, the highest priority plants remain those that have a high harvest index and grow quickly and robustly, Massa says. Ideal crops will also be chock full of key nutrients that are tough to package, like potassium. Flavor can’t be neglected either: “If it doesn’t taste good, no one will eat it, no matter how nutritious it is,” she says.</p><p>Cabbage, kale, and lettuce are among the crops that have already sprouted successfully in space. Massa hopes to add some fruiting plants, like peppers, to the ISS within the next year—ingredients that could spice things up at mealtime.</p><p>Choi’s plant passion <i>du jour</i> is tomatoes, which, in addition to their appealing taste, pack in an impressive number of vitamins and antioxidants, he says. A few genetic tweaks could enhance their nutritional value, he says, or make the entire tomato plant edible, even when the fruits are still green.</p>
            <figure class="richtext-image full-width"><img alt="mars_food_production_bisected.jpg.jpeg" class="richtext-image full-width" height="450" width="800"
            src="/wgbh/nova/media/images/mars_food_production_bisected.jpg.width-800.jpg"/><figcaption><p>An artist&#x27;s impression of a potential food production unit on Mars. Image Credit: NASA</p><div class="credit"><p></p></div></figcaption>
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            <p>These top tier crops all have something in common: They can be consumed straight off the stem or vine—which, unfortunately, isn’t true of many tubers, like potatoes.</p><p>So, is there still a future for these second-string spuds? “I hope so,” Wheeler says. Potatoes still have a lot going for them nutritionally. And when ovens and other appliances make their way into space, potatoes will still have a leg up on other staple crops like wheat or soybeans, which often require additional processing before they can be cooked.</p><p>Fresh, supplemental crops like lettuce will do well aboard the ISS, Wheeler says. But farther from Earth, humans will need more autonomy. When it comes to lunar or Martian agriculture, “that’s the stage where more stable, agronomic crops [that supply more energy] can be considered,” he says. “I’m hoping we get to that point.”</p><p>There’s no telling what that future will bring. But for now, even in the vastness of space, it would seem that everything’s coming up Russets.</p></div>
  

  
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<p>With the right kind of care, plenty of plants actually do just fine in microgravity.</p>

The weird and wonderful world growing spuds (and other crops) in space





  
      <div class="rich-text"><p>In October of 2018, Hurricane Michael was kicking into high gear. But while Florida residents busily stockpiled non-perishables and shuttered their homes, <a href="https://labs.eemb.ucsb.edu/pruitt/jonathan/">Jonathan Pruitt</a> was steering his rented Nissan Titan straight into the path of the storm.</p><p>Armed with antifreeze, shovels, and a rock solid auto insurance policy, the University of California, Santa Barbara evolutionary ecologist had one clear mission: to figure out whether aggressive <i>Anelosimus studiosus </i>spiders might have a leg up—or eight—on their more bashful brethren in the wake of a tropical cyclone.</p></div>
  

  
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      <div class="rich-text"><p>It was a weird area of exploration—and a difficult one. After all, natural disasters don’t exactly play by the rules of experimental design. But Pruitt’s spider storm-chasing would eventually pay off: As he and his colleagues <a href="https://www.nature.com/articles/s41559-019-0951-x">report today</a> in the journal <i>Nature Ecology &amp; Evolution</i>, arachnids with an attitude seem better equipped to navigate a post-hurricane world.</p><p>It’s still unclear exactly how aggression behooves storm-battered spiders. But as climate change continues to <a href="https://www.gfdl.noaa.gov/global-warming-and-hurricanes/">alter the frequency and intensity</a> of tropical cyclones, the study’s findings highlight the unexpected ways in which environment impacts the behavior—and ultimately, the wellbeing—of species of all kinds.</p><p>“This study points to yet another one of the indirect ways in which climate change will affect species persistence,” says <a href="https://mcchelini.weebly.com/">Marie-Claire Chelini</a>, a behavioral ecologist at Duke University who was not involved in the study. </p>
            <figure class="richtext-image full-width"><img alt="10616550_10103086047727461_5755952118747864245_n.jpg" class="richtext-image full-width" height="600" width="800"
            src="/wgbh/nova/media/images/10616550_10103086047727461_5755952118747864245.width-800.jpg"/><figcaption><p>In <i>Anelosimus studiosus</i> colonies, “females are the movers and shakers,” says study author Jonathan Pruitt. “Males just wander around trying to find virgin females to inseminate. Then they die.” Image Credit: Courtesy of Jonathan Pruitt, University of California, Santa Barbara</p><div class="credit"><p></p></div></figcaption>
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            <p>Some children get their eyes from their mothers; others acquire their father’s winning smile. <i>A. studiosus</i> offspring, however, inherit a more unusual heirloom: their parents’ personalities. In this species, spiders segregate into two camps—docile and aggressive—and the trait appears to pass from generation to generation. And, because <i>A. studiosus </i>often lives in large, female-dominated colonies, groups of these spiders can collectively skew toward one disposition or the other.</p><p>Years of research have shown that more combative spiders are better at most spidery things—building webs, catching prey, defending their colonies against invaders. Conversely, their docile relatives are shy, sluggish couch potatoes, difficult to rouse from their silken perches even when tempted with a freshly snared insect. “I’m often shocked that the docile ones accomplish anything,” Pruitt says.</p></div>
  

  
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      <div class="rich-text"><p>But hostility, too, comes at a cost: For all their gumption, aggressive spiders are loose cannons, prone to infighting and even slaughtering their young. Despite being pushovers in most other respects, docile spiders are the colonies’ parents and peacekeepers, every bit as necessary as their hot-blooded groupmates.</p><p>This delicate balance made Pruitt wonder how aggressive colonies would fare in the aftermath of a natural disaster like a tropical cyclone. Food scarcity might favor go-getters that excel at scrounging up meals—or it could trigger violence, causing more bellicose groups to self-destruct.</p><p>To tease out the two possibilities, Pruitt and his dog Winifred Sanderson packed their bags and headed to the Southeast. Each time a hurricane loomed, the pair would leave their inland post to pick out spider colonies on and off the storm’s predicted path. </p><p>First, Pruitt would count the spiders. Then he’d administer a personality test, touching the tip of an electric toothbrush to a square of paper fixed to the center of a cobweb. The shudder of silk—which mimics thrashing prey—sends aggressive spiders into a frenzy, Pruitt says. Their docile counterparts, however, are far slower to react, sometimes ignoring the vibrations entirely.</p><p>After marking dozens of colonies with identifying tape, Pruitt would hunker down inland and wait for the storm to take its course. Two days after the cyclone cleared, he and Winifred Sanderson returned to tabulate survivors. </p><p>Collectively, three of 2018’s tropical cyclones—Subtropical Storm Alberto, Hurricane Florence, and Hurricane Michael—felled docile and aggressive spiders indiscriminately, with just 75 percent of colonies making it through.</p><p>But when the researchers checked in on the spiders in the months following, they discovered that many of the docile colonies in cyclone-disrupted zones had begun to falter. Only a handful of egg sacs clung to their nests; fewer of their spiderlings lived to see the start of winter. More aggressive colonies in these spots, however, were reproducing just fine.</p>
            <figure class="richtext-image full-width"><img alt="2014 August 024 (2).jpg" class="richtext-image full-width" height="600" width="800"
            src="/wgbh/nova/media/images/2014_August_024_2.width-800.jpg"/><figcaption><p>An <i>Anelosimus studiosus</i> web, home to dozens of female spiders that segregate into two personality types. Image Credit: Courtesy of Jonathan Pruitt, University of California, Santa Barbara</p><div class="credit"><p></p></div></figcaption>
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            <p>The study’s results didn’t offer an explanation for <i>why</i> storms favor the belligerent, but considering aggressive spiders’ aptitude for hunting and territory defense, it’s not hard to speculate, Pruitt says. When the going gets tough, the tough get going—and in the case of spiders, aggression may beget resilience.</p><p>Another set of data seemed to back this up: When Pruitt and his team surveyed a larger swath of the American Southeast, they found that the more tropical cyclones a region had suffered in the past century, the more hot to trot its spiders were.</p><p>“We often think about evolution occurring bit by bit, on a slower pace than a cyclone can initiate,” says <a href="https://www.fowlerfinnlab.com/">Kasey Fowler-Finn</a>, an evolutionary biologist at St. Louis University who was not involved in the study. “But the fact that big weather events like cyclones can cause shifts in selection that can be picked up over the course of 100 years is pretty exciting.”</p><p>That doesn’t necessarily mean the future will be dominated by angry, cyclone-ravaged spiders. In areas the cyclones had bypassed, it was the meeker spiders who won out—possibly because pacifist colonies could afford to invest their energy in parenting instead of warfare, points out <a href="https://nature.berkeley.edu/eliaslab/People.html">Trinity Walls</a>, who studies spider behavior at the University of California, Berkeley but was not involved in the study. “There’s costs and benefits to both ends of the spectrum of personality,” she says.</p>
            <figure class="richtext-image full-width"><img alt="036.JPG" class="richtext-image full-width" height="600" width="800"
            src="/wgbh/nova/media/images/036.width-800.jpg"/><figcaption><p>Study author Jonathan Pruitt prepares to touch a vibrator to a piece of paper positioned at the center of an <i>Anelosimus studiosus</i> cobweb. The fluttering paper mimics the thrashing of snared prey. (In the study, an Oral B toothbrush performed a similar function.) Image Credit: Courtesy of Jonathan Pruitt, University of California, Santa Barbara</p><div class="credit"><p></p></div></figcaption>
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            <p>Still, the findings underscore the myriad ways in which extreme events affect animals, all the way down to the minutiae of personality, Chelini says. Harsh environments have a way of weeding out individuals and populations that fail to go the extra mile for food or mates. Impediments to those evolutionary chores might be physical or behavioral, but they’re impediments all the same.</p><p>Now more than ever, these relationships are especially important to understand, Chelini says. Under the influence of climate change, tropical cyclones are expected to become <a href="https://www.c2es.org/content/hurricanes-and-climate-change/">more common and severe in certain parts of the world</a>. “Human activity is making the climate change <a href="https://www.pbs.org/wgbh/nova/article/animal-adaptation-climate-change/">much faster than species can adapt and evolve</a>,” she says. “We will lose biodiversity through not just the direct, better understood ways [like habitat loss], but also to all of these less direct mechanisms that we are just beginning to understand.”</p><p>Climate change won’t have uniform effects on all species, however. And for Pruitt’s eight-legged study subjects, there could still be a silver lining. Spiders have been scuttling the Earth for at least a few hundred million years, he says. Regardless of what’s in store for the rest of us, arachnids will probably be around for generations to come. </p><p>“Spiders are incredibly tolerant little cysts of life,” he says. “Even if Earth changes, they’ll find a way to navigate it.”</p></div>
  

  
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<p>For <i>Anelosimus studiosus</i> spiders, the storm survival checklist apparently includes a combative personality.</p>

Hurricanes give aggressive spiders a leg up on their docile kin





  
      <div class="rich-text"><p>A new molecule can now officially join the ranks of Club Carbon.</p><p>The chemical debutante is cyclo[18]carbon, a ring of 18 carbon atoms that’s finally been created, imaged, and analyzed in a <a href="https://science.sciencemag.org/content/early/2019/08/14/science.aay1914">report</a> published today in the journal <i>Science. </i>The findings help settle decades of debate on the structure and properties of the molecule, which some researchers doubted could even be stably made in the lab.</p></div>
  

  
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      <div class="rich-text"><p>Carbon is well-known for its versatility. Even without input from other elements, atoms of carbon can link up to create a diverse set of compounds, ranging from hard, clear diamonds to malleable black graphite. Without much prompting, carbon can come together in thin, flat sheets, or intricate, three-dimensional crystals; it can arrange itself into meticulously structured lattices, or slouch into amorphous blobs.</p>
            <figure class="richtext-image full-width"><img alt="kaiser4HR 1.jpg" class="richtext-image full-width" height="424" width="800"
            src="/wgbh/nova/media/images/kaiser4HR_1.width-800.jpg"/><figcaption><p>A model of cyclo[18]carbon&#x27;s molecular structure. Image Credit: IBM Research.</p><div class="credit"><p></p></div></figcaption>
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            <p>But one structure eluded scientists for decades: an elegant ring of carbons, unsupported by any other stabilizing element. Previous attempts to generate so-called cyclocarbons in the lab had resulted in volatile gas, too ephemeral to study in any rigorous way.</p></div>
  

  
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      <div class="rich-text"><p>The recent breakthrough, however, shows that a cyclocarbon can be generated by pruning carbon and oxygen atoms off a more complex molecule at extremely cold temperatures with a technique called atomic force microscopy. Starting with a molecule made up of 24 carbons linked to six oxygens, researchers at IBM Research and Oxford University were able to generate a final structure of 18 carbons—the smallest possible ring of carbons predicted to be stable by theoretical models. Imaging and further analysis also revealed that the atoms in the cyclocarbon were joined together by alternating single and triple bonds, rather than a uniform chain of double bonds.</p><p>It was a harrowing process—the culmination of many months of trial and error, study author Lorel Scriven of Oxford University <a href="https://gizmodo.com/50-year-chemistry-mystery-solved-by-wild-new-carbon-rin-1837277104">told Ryan F. Mandelbaum at <i>Gizmodo</i></a>. The actual synthesis of cyclo[18]carbon was only part of the battle: To keep the unstable molecule from reacting into other forms of carbon, or creating a hybrid element with something in its surroundings, the team had to conduct their experiment on a bed of inert table salt. </p><p>But cyclo[18]carbon’s fickle nature is part of what makes it potentially powerful, too. “At some point we might be able to controllably trigger such reactions and create more complex molecular structures at will,” study author Katharina Kaiser, a physicist at IBM Research, <a href="https://www.popularmechanics.com/technology/robots/a28705498/super-material-ai-chips/">told John Wenz at <i>Popular Mechanics</i></a>. This could give chemists an unprecedented amount of control over the synthesis of carbon-based molecules.</p>
            <figure class="richtext-image full-width"><img alt="kaiser1HR.jpg" class="richtext-image full-width" height="409" width="800"
            src="/wgbh/nova/media/images/kaiser1HR.width-800.jpg"/><figcaption><p>The process by which cyclo[18]carbon was synthesized in a new study. C24O6, a molecule with 24 carbon atoms and 6 oxygen atoms, was pared down into a ring of 18 carbon atoms. Image Credit: IBM Research</p><div class="credit"><p></p></div></figcaption>
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            <p>It’s not totally clear what’s next for cyclo[18]carbon. But if it’s anything like graphene—another form of carbon that’s extremely good at conducting electricity—the new molecule could someday play a role in efficiently powering devices that require a lot of processing power, like those relying on artificial intelligence, Wenz reports.</p><p>Regardless of what the future holds, simply locking down cyclo[18]carbon is a big win for the chemistry community. </p><p>As chemist Rik Tykwinski of the University of Alberta in Edmonton, Canada, who was not involved with the research, <a href="https://www.sciencenews.org/article/chemists-have-created-and-imaged-new-form-carbon?tgt=nr">told Emily Conover at <i>Science News</i></a>, “It’s not every day that you make a new form of carbon.”</p></div>
  

  
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<p>The long-sought molecule could one day power high-energy electronics.</p>

A new form of carbon is born—on a bed of salt





  
      <div class="rich-text"><p>Even after 4.5 billion years of growing pains, Earth may still be young at heart.</p><p>Reporting today in the journal <i>Science</i>, an international team of researchers has unearthed <a href="https://science.sciencemag.org/cgi/doi/10.1126/science.aax5293">a small trove of diamonds</a> that may harbor gassy heirlooms from Earth’s early years. The helium atoms locked within these alluring crystals, which hail from beneath Brazil, hint at the existence of a subterranean reservoir of rocks and gas that could be nearly as old as the planet itself.</p></div>
  

  
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      <div class="rich-text"><p>Located at least 250 miles beneath Earth’s surface, this primordial cache can’t be accessed directly, and its true nature remains a topic of contention. But as hot rock shifts within our planet’s interior, it may deliver some of the contents of this reservoir to diamonds in the making, which in turn chauffeur the geologic goods to the surface. Understanding this rocky relay could give researchers a glimpse of Earth’s interior—and even unveil some of the conditions surrounding our planet’s cataclysmic conception.</p><p>“This is a very impressive study,” says <a href="https://eesc.columbia.edu/faculty/conny-class">Cornelia Class</a>, a geochemist at Columbia University’s Lamont-Doherty Earth Observatory who was not involved in the study. “By looking at these diamonds and their geochemical signatures...we can understand the overall evolution of Earth and its deep reservoirs.”</p>
            <figure class="richtext-image full-width"><img alt="timmerman1HR.jpg" class="richtext-image full-width" height="245" width="800"
            src="/wgbh/nova/media/images/timmerman1HR.width-800.jpg"/><figcaption><p>Diamonds from Juina, Brazil. Diamonds can trap solids, liquids, and gases in pockets within their crystal structure, preserving them over time and space. Shown here are images from an electron microscope used to visualize the minerals. Image Credit: Suzette Timmerman</p><div class="credit"><p></p></div></figcaption>
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            <p><a href="https://www.scientificamerican.com/article/evolution-of-earth/">A lot has changed</a> since the planets in our solar system first came together. In its infancy, Earth was little more than a roiling ball of magma, kept astir by volcanism and frequent collisions with other newborn space rocks. As it began to cool, our planet separated into a Russian nesting doll of concentric shells: the crust, the upper and lower mantle, and the outer and inner core. But even after its planetary pubescence, Earth continued to rejigger its internal architecture—particularly within its gooey mantle, which is home to a chaotic slew of chemical reactions.</p><p>Millennia of churning have erased almost all traces of Earth’s geological genesis. Still, many researchers have held out hope that our planet retains an echo of its molten fetal state—a sort of primordial goop that’s managed to survive the mantle’s tumultuous history.</p><p>Pinpointing this elusive reservoir isn’t easy. If it exists, it’s buried hundreds of miles beneath our planet’s surface, at depths researchers have no way to access (despite what Hollywood might want you to think, we aren’t equipped to journey to the center of the Earth).</p></div>
  

  
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      <div class="rich-text"><p>One window into Earth’s interior comes from studying the chemical composition of rocks and minerals belched up from the mantle. Some samples of <a href="https://www.nature.com/articles/nature09287">lava</a>, for instance, have been found to contain <a href="https://www.nature.com/articles/nature21023">unusually high amounts of helium-3</a>—a rare isotope of helium that’s thought to be a chemical relic from the early solar system.</p><p>Many geochemists have taken this as an indication of an ancient wellspring of helium-3 lurking somewhere in the mantle. But lava data has to be taken with a grain of (ba)salt, because it’s difficult to determine the depth at which the lava’s starting material originates, says <a href="https://isotopic.wustl.edu/people/rita-parai/">Rita Parai</a>, a geochemist at Washington University in St. Louis who wasn’t involved in the study.</p><p>That’s where diamonds come in. As these minerals take shape, their near-indestructible crystal structure can trap solids, liquids, and gases from their surroundings in an exquisite state of preservation—the geologic equivalent of a cryogenic chamber. The chemicals locked within these crystalline cages can persist undisturbed for millennia, surviving even the bumpy ride diamonds take to the surface when deep-seated volcanic eruptions rustle them from their nurseries. Diamonds’ interior riches can clue researchers in to the exact conditions of their birth, as well as the approximate depths at which they were forged, making the minerals especially informative envoys from the deep.</p><p>In other words, diamonds are kind of forever—and the same can be said for whatever cargo they’re carrying.</p><p>“Diamonds are unique, powerful samples because they tell us so much about the deep Earth that we couldn’t get in any other way,” says <a href="https://www.gia.edu/gia-research-postdoctoral-karen-smit">Karen Smit</a>, a geochemist and diamond expert at the Gemological Institute of America who was not involved in the study.</p><p>To see what these tiny time capsules had to say about our planet’s innards, a group of researchers led by <a href="https://www.uni-muenster.de/Mineralogie/en/personen/index.html">Suzette Timmerman</a>, a geochemist at the University of Münster in Germany, cracked open a collection of crystals mined from Juina, Brazil. Unlike most diamonds, which form at depths around 100 to 150 miles beneath Earth’s surface, the Brazilian stash was “super-deep,” with origins in the mantle transition zone—a region 250 to 400 miles down.</p><p>The team’s original intention had been to draw on the diamonds’ powers of preservation to better understand the mixing in Earth’s mantle. The crystals’ composition showed they were a chemically diverse bunch, suggesting they’d been forged in part from a mashup of material from different depths, probably within the last 500 million years, before jetting to the surface. But Timmerman was also surprised to find the diamonds were—relatively speaking—chock full of helium-3.</p>
            <figure class="richtext-image full-width"><img alt="timmerman2HR.jpg" class="richtext-image full-width" height="600" width="800"
            src="/wgbh/nova/media/images/timmerman2HR.width-800.jpg"/><figcaption><p>A diamond from a site in Juina, Brazil, which produces an unusually large number of super-deep diamonds from 250 to 400 miles beneath Earth’s surface. Image Credit: Antony Burnham</p><div class="credit"><p></p></div></figcaption>
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            <p>This unexpected find suggested that the crystals had access to the mantle’s mythical primordial ooze—and set an upper limit for its location. “This provides a very important clue that constrains the depth of this reservoir,” Smit says. Helium-3 can only hitch a ride on a diamond that’s at its level or above, meaning it must originate from within or below the transition zone.</p><p>That’s still a lot of room to work with, though: The mantle is almost 2,000 miles thick. Gobs of primordial gunk could be bopping around the transition zone, where the super-deep diamonds was forged. Alternatively, helium-3 from deeper layers may get spiked into diamond territory by mantle plumes—upward gushes of hot material—and ensnared <i>en route</i> by crystals in the making.</p><p>It’s also unclear just how many of these reservoirs there are—or what else is in them (helium-3 probably isn’t the only ancient ingredient). But perhaps the biggest elephant in the room is how the reservoir has stayed intact all these years, given all the mixing that happens in the mantle.</p>
            <figure class="richtext-image full-width"><img alt="timmerman5HR.jpg" class="richtext-image full-width" height="600" width="800"
            src="/wgbh/nova/media/images/timmerman5HR.width-800.jpg"/><figcaption><p>Diamonds mined from Juina, Brazil. The area is known for its super-deep diamonds. Image Credit: Graham Pearson</p><div class="credit"><p></p></div></figcaption>
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            <p>That sort of deep-Earth tranquility would be hard to accomplish, but not impossible, says <a href="https://earthsci.carleton.ca/people/faculty-members/hanika-rizo">Hanika Rizo</a>, a geochemist at Carleton University in Canada who was not involved in the study. Some researchers have proposed that ancient rock reservoirs may remain above the fray by plunging <i>below</i> it: These primordial pockets may have chemical properties that make them <a href="https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2016GC006605">denser</a> than the rest of the mantle, forcing them inward toward Earth’s core like sinking stones.</p><p>This theory awaits confirmation. But none of the lingering uncertainty takes away from the study’s importance, Class says. “This is the first direct sample [of these isotopes] we have from as deep as the transition zone,” she says.</p><p>Much of the credit for that, of course, goes to the diamonds. These crystals are certainly pretty, Timmerman says. But their geological value far outshines their glimmer.</p><p>“A lot of people use them for jewels...but for scientists, they’re so much more,” she says. “It’s just so cool to hold one and know you have in your hands information about the history of the Earth.”</p></div>
  

  
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<p>Scientists studying diamonds from deep within Earth’s mantle found evidence of a reservoir of rocks and gas that may be nearly as old as the planet itself.</p>

Deep-Earth diamonds may contain gassy relics from the early solar system





  
      <div class="rich-text"><p>In its distant past, Jupiter may have been something of a planetary cannibal—and its core paid the ultimate price.</p><p>A new <a href="https://www.nature.com/articles/s41586-019-1470-2">computer simulation</a> published yesterday in the journal <i>Nature </i>suggests that some 4.5 billion years ago, a youthful Jupiter may have collided with another primordial planetary body. This violent rendezvous likely ended in Jupiter swallowing its dance partner whole—a merger that fractured Jupiter’s hard, compact core into the diffuse, borderless ball of gassy fluff it still has today.</p></div>
  

  
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      <div class="rich-text"><p>Prior to NASA’s recent Juno mission, researchers assumed that Jupiter’s core was a solid pit of rock and ice—a dense seed that was able to attract clouds of hydrogen and helium with its gravitational pull. But the spacecraft’s measurements of the gas giant’s gravitational field in 2016 painted a very different portrait, with no clear delineation between the core and its gas envelope. Jupiter’s heart, it seems, is hazy, dilute, and massive, spanning up to half the planet’s radius.</p></div>
  

  
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      <div class="rich-text"><p>Though there’s no time machine that can transport researchers back to the era of Jupiter’s genesis, the new model—the brainchild of a team of researchers led by Shang-Fei Liu of Sun Yat-sen University—offers a possible explanation for this puzzling observation.</p><p>The early days of the solar system were an especially tumultuous time. Space rocks ricocheted about; primitive planetary bodies crashed together and came apart. Even in its fetal state, Jupiter was the heftiest kid on the block, boasting a gravitational pull that could have easily sucked in another cosmic nugget on the rise, study author Andrea Isella, an astronomer at Rice University in Houston, <a href="https://www.sciencenews.org/article/jupiter-weird-core-may-have-resulted-early-collision">told Maria Temming at <i>Science News</i></a>. </p><p>In the researchers’ proposed scenario, this object was about 10 times as massive as Earth (for perspective, Jupiter’s mass is more than 300 times that of our home planet), and “smacked head-on” into the growing gas giant, Liu <a href="https://www.space.com/jupiter-strange-core-formed-by-collision.html">told Chelsea Gohd at <i>Space.com</i></a>.</p><p>As the ill-fated planetary embryo was absorbed into Jupiter, the pair’s cores combined, their materials mingling with heavy elements in the newly-expanded planet’s gaseous sheath. As a result, the diameter of Jupiter’s core more than doubled.</p><p>The model isn’t easy to confirm, and it’s not the only theory that’s been put forth. Other researchers have suggested that Jupiter’s dilute core has a more mundane origin: Gas may have been present in the core from the start, rather than glomming on during the planet’s adolescence, for instance.</p>
            <figure class="richtext-image full-width"><img alt="sequence.jpg" class="richtext-image full-width" height="531" width="800"
            src="/wgbh/nova/media/images/sequence.width-800.jpg"/><figcaption><p>A simulation showing Jupiter colliding with another planetary body early in its evolution. In the model, Jupiter absorbed its partner within hours of impact. Image Credit: Liu et al., Nature, 2019</p><div class="credit"><p></p></div></figcaption>
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            <p>More computer simulations could help researchers compare these competing theories, Juno mission leader Scott Bolton of the Southwest Research Institute in San Antonio, who wasn’t involved in the study, told Temming.</p><p>If the impact scenario is correct, though, it might not actually be that big of a surprise. Researchers have long been aware of the solar system’s chaotic beginnings, and few planets—if any—escaped unscathed. Even Earth’s moon might not be around if not for a calamitous collision. </p><p>What’s more, the internal structure of several planets, including Saturn, Uranus, and Neptune, remain vastly unexplored. Jupiter’s quirky core may yet be par for the course.</p></div>
  

  
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<p>A computer simulation suggests that a massive collision may have caused Jupiter’s core to shatter into a gassy, borderless cloud.</p>

Jupiter’s ravenous past might help explain its diffuse, hazy core





  
      <div class="rich-text"><p>Ebola may no longer be an incurable disease.</p><p>Two therapies tested in a clinical trial in the Democratic Republic of Congo appear to dramatically improve survival rates—so much so that both treatments will now be available to all enrolled patients, scientists announced today.</p><p>Both treatments rely on transferring antibodies that target the Ebola virus into patients, conferring swift protection. While Ebola typically carries a fatality rate of <a href="https://www.afro.who.int/health-topics/ebola-virus-disease">around 50 percent</a> (and, in the current outbreak, <a href="https://www.statnews.com/2019/08/12/for-the-first-time-clinical-trial-results-show-ebola-drugs-improve-survival-rates/">closer to 70 percent</a>), only about 10 percent of patients who began either therapy soon after falling ill succumbed to the disease.</p><p>Two other therapies in the trial, which began in November, with less impressive survival rates have been discontinued so that study participants can switch over to better options.</p></div>
  

  
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      <div class="rich-text"><p>The findings remain preliminary, and it’s unclear how the drugs will perform outside clinical trials. But the researchers behind the announcement are hopeful that this early success may pave the way to halting the ongoing epidemic in the Democratic Republic of Congo, which has killed nearly 2,000 since it <a href="https://www.cdc.gov/vhf/ebola/outbreaks/drc/2018-august.html">began last summer</a>.</p></div>
  

  
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      <div class="rich-text"><p>The treatments, called REGN-EB3 and mAb-114, both involve an injection of antibodies that latch onto the exterior of the Ebola virus. This swarming strategy blocks the virus from invading cells, while immune cells are recruited to take down the invader. A similar process underlies a third drug in the trial, ZMapp, which has until now been considered the standard of care in Ebola epidemics. But REGN-EB3 and mAb-114 both outperform their predecessor, as well as a fourth drug called remdesivir.</p><p>Across four treatment centers, half the patients taking ZMapp or remdesivir died, while REGN-EB3 and mAb-114 lowered the mortality rate to 29 and 34 percent, respectively. Deaths dwindled further for patients who received therapy soon after they began experiencing symptoms, with about 90 percent of REGN-EB3 and mAb-114 patients surviving, compared to around 65 to 75 percent of those taking the other drugs.</p><p>The results came as a complete shock, Sumathi Sivapalasingam, Regeneron’s medical lead on the REGN-EB3 project, <a href="https://www.statnews.com/2019/08/12/for-the-first-time-clinical-trial-results-show-ebola-drugs-improve-survival-rates/">told Helen Branswell at <i>STAT News</i></a>.</p><p>The trial’s findings also underscore the urgency for immediate treatment. On average, people arrive at treatment centers about four days after they fall ill, Michael Ryan from the World Health Organization <a href="https://www.theguardian.com/world/2019/aug/12/ebola-now-curable-after-trials-of-drugs-in-drc-say-scientists">told Sarah Bosely at <i>The Guardian</i></a>—a delay that not only reduces the chances of survival, but also increases the likelihood that the virus will be transmitted.</p><p>There’s no guarantee that the current numbers will hold as a new series of trials begin, now with a renewed focus on comparing the efficacy of REGN-EB3 and mAb-114. But the manufacturers of both drugs have already committed to continued production.</p>
            <figure class="richtext-image full-width"><img alt="6136_PHIL_scientists_PPE_Ebola_outbreak_1995.jpg" class="richtext-image full-width" height="521" width="800"
            src="/wgbh/nova/media/images/6136_PHIL_scientists_PPE_Ebola_outbreak_1995.width-800.jpg"/><figcaption><p>A photo from the 1995 Ebola outbreak in the Democratic Republic of Congo. Image Credit: CDC/ Ethleen Lloyd</p><div class="credit"><p></p></div></figcaption>
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            <p>It’s unclear why the two new treatments have a leg up over ZMapp, but it may have something to do with how each is formulated. While ZMapp is a slurry of a single antibody isolated from mice infected with Ebola, REGN-EB3 is a mixture of three—an immune cocktail that boosts the body’s chances of keeping the virus in check. mAb-114 also has a single antibody ingredient, but one isolated that was from a human Ebola survivor, <a href="https://www.wired.com/story/ebola-is-now-curable-heres-how-the-new-treatments-work/">reports Megan Molteni at <i>Wired</i></a>.</p><p>Having two options available also makes for an unexpected boon, providing a natural backup in case one drug or the other encounters complications, Ryan <a href="https://www.nytimes.com/2019/08/12/health/ebola-outbreak-cure.html">told Donald G. McNeil Jr. at <i>The New York Times</i></a>.</p><p>The forecast isn’t yet clear, especially for the now-unseated ZMapp. But potentially taking its place are two new therapies that may finally change the outcomes for Ebola patients.</p><p>“From now on, we will no longer say that Ebola is incurable,” Jean-Jacques Muyembe, the director general of the Institut National de Recherche Biomédicale in DRC, which oversaw the trial, told Bosely. “These advances will help save thousands of lives.”</p></div>
  

  
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<p>Both treatments rely on infusing patients with antibodies that latch onto the virus and block it from invading cells.</p>

Two new Ebola drugs dramatically boost survival in a clinical trial





  
      <div class="rich-text"><p>If a meteorite streaking through Earth’s atmosphere is too thin, it’ll tumble about. Too wide and it will flutter wildly. But if it’s taken on just the right cone shape, it’ll plummet straight to the ground.</p><p>Roughly a quarter to a third of meteorites that make it to Earth converge on this “Goldilocks” cone shape and, until recently, scientists haven’t been able to explain why. New findings <a href="https://doi.org/10.1073/pnas.1815133116">published last month</a> in the journal <i>PNAS</i> show that the answer has to do with fluid mechanics, the way forces interact with liquids, gasses, and plasmas.</p></div>
  

  
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      <div class="rich-text"><p>The story starts back in 2012, with a team of researchers from the Courant Institute at New York University holding balls of clay in a water tunnel to study erosion. The team observed that “if you hold an object fixed and let it erode, it makes a cone,” says study author Leif Ristroph, a mathematician at the Courant Institute who was also part of the team that made the <a href="https://www.pnas.org/content/109/48/19606">initial observations</a>.</p><p>More specifically, he says, erosion always sculpted these cones so their tips, which pointed toward the oncoming water, formed a V with an angle of about 90 to 100 degrees. This tip angle happens to be very similar to those of cone-shaped meteorites found on Earth.</p><p>A ball of clay stuck in water may not seem to have much in common with a meteorite crashing to Earth, but the forces at work on their surfaces aren’t all that different, Ristroph says. Meteorites entering the Earth’s atmosphere encounter intense heat that melts and reshapes them in a process similar to water eroding clay.</p><p>With that in mind, the researches decided to use water to take a closer look to determine if this cone shape might be favorable for meteorite flight: They dropped solid aluminum cones into water and used a video camera to track their motion.</p></div>
  

  
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      <div class="rich-text"><p>This is where they witnessed the Goldilocks principle at work. Cones with tip angles that were too slim or too wide moved in unstable paths through the water. But cones that hit a sweet spot between 60 and 100 degrees oriented themselves so that their tips pointed down and fell straight—just as a similarly shaped meteorite would fall through air.</p><p>The reason for this stability is the way forces from the surrounding fluids—­water in the 2012 experiment, and air in the case of meteorites—act on the cones as they fall, Ristroph says. As fluid is displaced by the cones, it flows around them, only to come back together in the cones’ wakes, like the turbulent surf behind a fast-moving boat. While narrow or wide cones get pushed around by these fluid forces, Goldilocks cones are just the right shape to stay stable.</p><p>When to team looked back at their data, they realized the same angles kept popping up and theorized that these erosion and stability effects might be related, says study author Jun Zhang, a physicist and mathematician at the Courant Institute and NYU Shanghai.</p><p>Erosion leads to a cone shape, which leads to stability, which enables further erosion. “These two mechanisms reinforce each other,” says Zhang.</p><p>But there may yet be more to the story.</p><p>Meteorites aren’t just made of clay, Maitrayee Bose, an isotope cosmochemist at Arizona State University who was not involved in the study, said in an email. Meteorites can be made of harder materials, like iron and stone, which could respond very differently to erosion stresses when falling through the atmosphere, she says.</p>
            <figure class="richtext-image full-width"><img alt="Wiluna.jpg" class="richtext-image full-width" height="621" width="800"
            src="/wgbh/nova/media/images/Wiluna.width-800.jpg"/><figcaption><p>A cone-shaped meteorite found east of the Wiluna township in Western Australia. Image Credit: Jon Taylor, Flickr, Wikimedia Commons</p><div class="credit"><p></p></div></figcaption>
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            <p>And it’s not just what meteorites are made of that needs to be considered.</p><p>At supersonic speeds—like those of a falling meteorite—flight dynamics get very complicated, and surface pressure and temperatures can skyrocket, Ed White, an aerospace engineer at Texas A&amp;M University who was not involved in the study, said in an email. A water tunnel experiment may not be enough to properly capture everything that’s going on, he says.</p><p>Ristroph acknowledges these limitations as well. “We’ve sort of solved two parts of the problem individually,” he says, “but how that all works out in the full problem is not yet solved.”</p><p>Given the complexities of meteorite flight, it may be difficult to replicate every aspect of it in a lab. “We have our work cut out for us,” Ristroph says.</p></div>
  

  
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<p>Researchers eroding clay in water may have uncovered secrets of meteorites’ aerodynamic stability.</p>

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