설명 불가능한 지구의 숨겨진 삼중 대칭 발견

Welcome back to the Abstract! Here are the studies this week that balanced it out, performed evasive maneuvers, decorated a love shack, and bred inside bones. First, scientists discover a new “triple symmetry” on Earth that nobody can explain. Then: female dolphins keep tabs on coercive males, bowerbirds turn urban trash into urbane treasure, and the housing opportunities provided by dead dinos. As always, for more of my work, check out my book First Contact: The Story of Our Obsession with Aliens , or subscribe to my personal newsletter the BeX Files . Triple symmetry all across the sky Zhang, Jianhao et al. “Earth’s east–west albedo symmetry.” Nature. Scientists have discovered an unexplained “triple symmetry” in Earth’s albedo, meaning its ability to reflect sunlight. The finding deepens the mystery of Earth’s oddly-balanced brightness contrasts, which has been well documented in the near-perfectly matched albedos of the northern and southern hemispheres, despite the very different geographies of these two halves of the planet. Researchers led by Jianhao Zhang of the University of Colorado Boulder now report the existence of “a unique and persistent east-west (E-W) albedo symmetry: the 27° E meridian divides the planet into an Eastern Hemisphere and a Western Hemisphere that reflect nearly identical amounts of sunlight,” according to the team’s study. The hemispheres bisected by the 27° E meridian line have nearly-identical amounts of ice-free ocean, cloud cover, as well as planetary albedo, distinguishing this phenomenon as a “triple symmetry” that is distinct from the equatorially divided north-south symmetry, which only has matching albedos. Zhang and his colleagues discovered the triple symmetry by examining 25 years of data (2001–2025) captured by NASA's Clouds and the Earth's Radiant Energy System (CERES) program. The satellite-mounted instruments measure the amount of solar energy Earth reflects back into space. The east-west symmetry persisted over this dataset, with its greatest variations linked to the El Niño-Southern Oscillation (ENSO). For this reason, the team emphasized that the symmetry is essential to accurate projections on a rapidly warming world. Currently, “all models fail to capture…the triple-symmetry feature,” a problem that may be ”contributing to the persistent uncertainty in climate projections,” according to the study. As for what causes this symmetry, nobody knows. It could be just a strange coincidence, or even weirder, an unknown process of planetary equilibrium. As we reported last year , the north-south albedo symmetry may be fading as both hemispheres get darker, with more pronounced effects in the North, so scientists are leaning toward the weird coincidence hypothesis. “We cannot yet rule out the possibility that these hemispheric symmetries are simply coincidental features of the present climate state,” the team said in the study. “The importance of the E–W symmetry discovery, however, is beyond the identification of another ‘sweet spot’ of the Earth system.” “It offers a powerful…constraint on state-of-the-art [Earth system models] and, more broadly, on our fundamental understanding of the Earth climate system,” the researchers concluded. In other news… Bottlenose bullies get bad reputations Bouchard, Alice et al. “Female dolphins use individual vocal labels to track coercive males.” Proceedings of the National Academy of Sciences. Female dolphins avoid sexually coercive males by keeping track of their signature whistles, according to scientists who observed how wild female Indo-Pacific bottlenose dolphins reacted to recorded playbacks of male vocalizations in the waters of Shark Bay, Australia. To secure mating opportunities, coercive males “will bite, hit, or charge the female, chase her…and produce threat vocalizations termed pops—all to intimidate the female and control her movements,” said researchers led by Alice Bouchard of the University of Bristol. “Indeed, pops are only produced by males” and act “as an agonistic ‘come-hither’ signal, inducing the female to stay close to the popping male.” Who could have guessed the term “popping male” could be so ominous? No wonder female dolphins keep them at fin’s length. Along those lines, the team found that females showed aversive responses to the recorded whistles of males known to have been coercive in the past. Females appear to use “individual vocal labels to guide reproductive decision-making based on their experience of individual male behavior,” according to the study. Call it a whistle campaign. Look at this stuff, isn’t it neat? This is how I reproductively compete Evans, Caitlin F. and Kelley, Laura A. “Urbanization alters courtship signals in male great bowerbirds.” Royal Society Open Science. For every popping dolphin in the seas, there is a lover bird in the trees. For the male great bowerbird ( Chlamydera nuchalis) , the key to attracting females isn’t biting or coercion, but the construction of elaborate shelters called bowers decorated with carefully selected trinkets for the enjoyment of potential mates. Scientists have now discovered that urban bowerbirds may have an edge in their game compared to their rural counterparts, thanks to the dazzling decor options that can be upcycled from their city environments. The team catalogued nearly 4,000 decorations collected by Australian bowerbirds at Dreghorn Cattle Station, the rural site, and their urban counterparts in, literally, Townsville (the children’s book writes itself). The results suggest that "urban males may represent an adaptive change to a more attractive display, and that rural males are restricted in their displays by the materials available in their environment.” “The two most common decorations in rural areas were green glass and green leaves/seeds, and in urban areas the two most common decorations were green glass and red wire,” said authors Caitlin F. Evans and Laura A. Kelley of the University of Exeter, “Decorations on urban bowers were over 10 times more likely to be anthropogenic…than decorations on rural bowers.” While the city birds may have an easier time finding flashy ornaments, the use of plastics and other human-generated trash have posed dangers, such as entanglement or ingestion, for other species, though it has not been confirmed in bowerbirds. Glass shards and scarlet wires may make for beautiful displays, but never discount the risk of fatal attraction. I’m so hungry, I could eat a titanosaur Belaústegui, Zain et al. “The fossil record of insect bone bioerosion: Insights from titanosaur remains at Lo Hueco (Late Cretaceous, Spain) and implications for continental ichnofacies.” Earth-Science Reviews. We’ll end, as all things should, with a 30,000-pound feast. Titanosaurs, the largest family of animals ever to walk on land, were so enormous as adults that predators basically left them alone (though they made for easy pickings as youngsters). But once these dinosaurs shuffled off their metric-ton mortal coils, their corpses were devoured by scavengers—including small insects that bore into their bones, leaving permanent structures in their fossilized remains, known as “ichnofacies.” In a new study, paleontologists mapped out the pits, holes, burrows, and trails etched into Cretaceous titanosaur bones deposited in the exquisitely well-preserved Lo Hueco site in Cuenca, Spain. In particular, the results revealed idiosyncratic pupation chambers likely dug out by flesh-eating Cubiculum beetles to deposit larvae. The structures suggest that the dead dinos were exposed to open air for weeks on ancient floodplains as beetles were born and bred in their bones. “Given the size of the titanosaurs…it is likely that at least part of their carcasses remained dry for long periods of time (several days and even months), and hence, to constitute a perfect scenario for insect colonization,” said researchers led by Zain Belaústegui of the University of Barcelona. “The large size of t