Best Citation Awards

TUCSON — Hot and dry air, perfused with a scent reminiscent of a warmed hair straightener, stuffed a hangar-sized room beneath the football stadium at the University of Arizona. The space, part of the Richard F. Caris Mirror Lab, was dominated by a gyrating, carousel-sized furnace, fire truck red and shaped like a flying saucer. The swirling cocoon of a colossal light collector. “It’s making 4.9 revolutions per minute,” says astronomer Buell Januzzi of the University of Arizona, raising his voice over the lab’s droning ventilation system. About half past noon on October 7, after about a week of gradual warming, the temperature inside the rotating machine had finally peaked at 1165° Celsius. In the heart of that inferno, nearly 17,500 kilograms of borosilicate glass — roughly four semitruck loads — had melted into a crystal clear fluid. If all goes to plan, the molten material will anneal to form the body of an enormous mirror — one as tall as a two-story house, if stood on edge. The

Mars has a heavy heart after all. The Red Planet has a dense core of liquid iron surrounded by a relatively thin layer of molten rock, researchers report. The finding resolves a recent conundrum that came about when seismic measurements on Mars seemed to suggest that the planet had a surprisingly large, light core rich in low-density elements ( SN: 4/24/23 ). The new view, described in two studies in the Oct. 26 Nature , shows the planet is made of materials common in the solar system at the time Mars formed. A lighter core would have required a mix of elements that wouldn’t have matched the proportions in the dust and debris that eventually became the solar system. The researchers deduced the structure of Mars’ interior by studying seismic waves detected with NASA’s InSight lander ( SN: 2/24/20 ). It measured Marsquakes and reverberations from meteorite impacts on the planet for a little over four years. Seismic waves (blue line in this illustration) that bounced off the outer

Four decades ago, warm waters from an El Niño event killed off nearly all the corals surrounding the Galápagos. Most coral reefs never recovered ( SN: 1/9/15 ). But in recent months, researchers have discovered vast landscapes of thriving corals in deeper waters surrounding the equatorial islands. In April, scientists documented the first pristine deep coral reef found in the region, dubbed Cacho De Coral, which sits atop the ridge of an underwater volcano and stretches about 250 meters. On October 26, a second team announced the discovery of an even bigger reef, this one more than 800 meters long, spanning the length of eight football fields.   With coral reefs around the globe in peril due to climate change, the finds are a small piece of good news ( SN: 8/9/23 ). These newfound reefs within the Galápagos Islands Marine Reserve have so far been protected from human influence and the direct impacts of warming waters. Brittle stars and shrimps are among the creatures living in a

From our nose to our lungs to our guts, the human body is home to a diverse range of microorganisms. Such rich microbial ecosystems are prime hunting grounds for viruses that infect and kill bacteria. But how these bacteria-killing viruses interact with human cells has remained mysterious. Past research has shown that human cells can slurp up bacteria-killing viruses when a cell ingests a large amount of the fluid surrounding it. Microbiologist Jeremy Barr wanted to know if the ingested viruses have any effect on the cell’s immune response. To his surprise, Barr instead found that mammalian cancer cells grown in the lab use the viruses as a food source . The results, published in the Oct. 26 PLOS Biology , show that it’s possible for mammalian cells to use bacteria-killing viruses as fuel — meaning normal, noncancerous cells could do it too, though this remains to be seen. This nascent line of work upends traditional biological dogma, says Barr of Monash University in Melbourne, Aus

Female chimps living in an East African forest experience menopause and then survive years, even decades, after becoming biologically unable to reproduce. The apes are the first known examples of wild, nonhuman primates to go through the fertility-squelching hormonal changes and live well beyond their reproductive years. The finding raises new questions about how menopause evolved , UCLA evolutionary anthropologist Brian Wood and colleagues conclude in the Oct. 27 Science . Until now, females who experience menopause and keep living for years have been documented only in humans and five whale species. It’s unclear what evolutionary benefit exists to explain such longevity past the point of being able to give birth and pass on one’s genes. Although evolutionary explanations for menopause remain debatable, the new finding reflects an especially close genetic relationship between humans and chimps, Wood says. “Both [species] are more predisposed to post-reproductive survival than othe

Putting the squeeze on light improves gravitational wave observatories. An upgrade to one such observatory, LIGO, that comes from exploiting a quantum rule known as the Heisenberg uncertainty principle makes it easier to spot spacetime ripples that arise from some of the cosmos’s most violent events. As a result, LIGO should detect up to 65 percent more collisions between massive objects like black holes and neutron stars than it would without the upgrade, researchers report in an upcoming issue of Physical Review X . To look for gravitational waves, LIGO researchers rely on laser light that moves in a detector between mirrors placed four kilometers apart. But light is subject to a version of the Heisenberg uncertainty principle that ensures the more you know about the intensity of a light signal, the less you know about its frequency. That limits how well researchers can spot gravitational waves. In 2019, LIGO scientists turned to quantum “squeezing,” which, in effect, reduced u

Many feathered dinosaurs couldn’t fly — at least, not like birds do today. But the reptiles’ feathers may have been more birdlike than scientists thought. In 2019, fossil analyses found that feathers from a flightless dinosaur mostly contained a different, more flexible form of the keratin protein that makes up modern bird beaks, scales and feathers. Researchers suggested then that feathers had evolved molecularly over time to become stiffer as birds — the last living dinosaurs — took to the skies ( SN: 7/31/14 ). Yet fossilization can change feather proteins , making one keratin protein resemble another, researchers report in the October Nature Ecology & Evolution .  The team also presented their findings on October 19 at the Society for Vertebrate Paleontology’s annual meeting in Cincinnati. The study raises the possibility that dinosaur feathers may have mainly contained the beta-keratin proteins found in bird feathers. While such a finding would not imply all feathered din

Berkley Walker didn’t plan on becoming a scientist; he wanted to be an entrepreneur. And he got started early on that goal: In high school in Portland, Ore., he started a granola bar company, which helped pay for his bachelor’s degree in microbiology. After college, Walker went to work as a product manager at an instrumentation company in Washington state, planning to go to business school and then into biotech. But a class on environmental biophysics at nearby Washington State University in 2009 changed his trajectory.   The course was about using mathematics to model physical systems in nature. “Working that math out to understand how energy and matter exchange within the environment,” Walker says — that was all it took. He decided to pursue a career as a plant scientist. “I wanted to have some kind of usefulness to the world,” Walker says. “Feeding people is where I settled.” Amazing but inefficient plants Today, at Michigan State University, Walker wants to understand the in

Neglected dangers of thermal pollution — Science News , October 20, 1973 Most urban dwellers have experienced the swelter of a summer night in the city, but higher temperatures in the atmosphere over such “heat islands” may have more insidious effects, which urban planners seldom consider.… Urban-rural temperature differences can be as high as 18 degrees [Fahrenheit]. Update Today, excess heat from pavement and buildings cause U.S. cities to run half a degree to 4 degrees Celsius (1 to 7 degrees F) higher on average than outlying areas. This heat island effect is expected to worsen as a side effect of climate change . Because urban areas are expanding, that means their growing populations are at risk for heat-related illness or death , scientists reported in 2019 in Environmental Research Letters . To stay cool, some cities are switching to roofs and surfaces that reflect a lot of sunlight and heat . Adding trees helps too: Trees provide shade and emit water vapor that lowers

Half a century ago, the first genetically modified organism ushered in a new era of biological innovation. To mark this anniversary, here are eight milestone GMOs. Many have had, or are poised to have, a dramatic impact on our lives. 1. Escherichia coli These E. coli are engineered to produce human insulin. Volker Steger/Science Source In November 1973, geneticist Stanley Cohen and colleagues reported that they had built a plasmid, a ring of DNA, that carried a gene from another organism into an E. coli cell — the birth of genetic engineering ( SN: 6/1/74 ). The team later showed that such modified cells could produce the protein associated with a foreign gene. E. coli has since been modified to mass-produce therapeutic drugs , break down plastics and more. “The most important GMO is the microbes that are used to make insulin ,” says geneticist Matthew Cobb of the University of Manchester in England. In 1978, facing problems with insulin derived from pigs and cows, scientist

In May, a star in the Pinwheel galaxy exploded in just the right place at nearly the right time for astronomers to unravel details of its death. It was the closest supernova to go off in the last five years. Astronomers have long been fascinated with these stellar explosions, which signal the end of life for the universe’s biggest stars. Not only are they dramatic — a supernova can shine 5 billion times as bright as our sun — but the explosions seed the universe with gold, silver, zinc and other elements forged only in a dying star’s last moments. And this supernova — designated SN 2023ixf — was perfectly placed for astronomers to capture it relatively soon after it went off. Because researchers can’t predict when a star will die, they typically wouldn’t have lots of images of a supernova from shortly after it happened, says Edo Berger, an astronomer at Harvard University. But thanks to the supernova’s position in a nearby galaxy that’s popular with stargazers, scientists were able

Life near deep-sea hydrothermal vents can be pretty metal — literally. In addition to crushing pressures, total darkness and scorching temperatures, poisonous plumes belch from beneath the Earth’s surface. Exhaust from these underwater chimneys contains particles of heavy metals like iron and manganese, which become toxic at high concentrations. But many animals cozy up next to these vents and form thriving communities, seemingly able to withstand the dangerous metals around them. Now, researchers have a hint of how one creature survives this hard-core environment. The sea anemone Alvinactis idsseensis has a surprising abundance of genes geared toward producing proteins that move metals into a cellular area where they can’t cause harm, researchers report October 20 in Science Advances . Many organisms have a few of these MTP genes for normal metal metabolism. For instance, a related sea anemone that lives in shallow waters has one MTP gene. In comparison, A. idsseensis has 13 MT

From 2018 to 2021, an estimated 10 billion snow crabs disappeared from the eastern Bering Sea off the coast of Alaska, with the population plummeting to record lows in 2021. Researchers had only speculated as to what happened to the missing crabs. Now, a study in the Oct. 20 Science finds that a marine heat wave probably spurred a mass die-off , in part by causing crabs to starve. “It’s a fishery disaster in the truest sense of the word,” says Cody Szuwalski, a fishery biologist at the U.S. National Oceanic and Atmospheric Administration’s Alaska Fisheries Science Center in Seattle. On average, snow crabs bring in about $150 million of annual revenue for Alaskan fisheries. In the 2021-2022 crabbing season, that revenue fell to around $24 million. With marine heat waves becoming more common because of human-caused climate change, the future of such fisheries and arctic marine ecosystems, more broadly, is uncertain, researchers say ( SN: 7/13/23 ) . The new research can help fishery

Last Saturday’s “ring of fire” eclipse, which blocked out 98 percent of the sun’s surface, was a rare and spectacular sight for those who got to view it. But the total solar eclipse in 2024 is going to be a particularly special event. On April 8, when the eclipse will cross the United States, the sun will be nearing its most active phase. Solar maximum, as it’s known when the sun acts up every 11 years, features more sunspots, increased light and radiation, and frequent blasts of charged particles from the sun’s surface in solar storms that threaten satellites and may even disrupt communications and power grids on Earth ( SN: 2/26/21 ). Being on the brink of a solar maximum also means it’s a great time for an eclipse. The combination of high solar activity and a total eclipse provides a rare view of the outer edges of the sun at a time when researchers have more scientific instruments to study our star than ever before, says astrophysicist Kelly Korreck of NASA Headquarters in Wash

There are at least three certainties in life: death, taxes and the periodic emergence of millions of cicadas. But one big cicada uncertainty has finally been put to rest — the question of whether the adult insects eat. Periodical cicadas ( Magicicada spp.) live in various broods across the eastern United States. Every 13 or 17 years, depending on the brood, adult cicadas emerge from the ground en masse and embark on a four-to-six-week saga of mating and laying eggs on young trees before dying. When the baby cicadas hatch, they fall to the ground, burrow into the earth and feed on plant roots until they’re ready for the next emergence. But there’s long been a popularly accepted idea that once adults emerge, they don’t eat. That perception might stem from cicadas’ lack of obvious chewing mouthparts, like those possessed by very hungry caterpillars, says James Hepler, a research entomologist at the U.S. Arid Land Agricultural Research Center, part of the U.S. Department of Agriculture,