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This Early Human 'Eden' Was So Lush, Even Migratory Animals Didn't Bother to Move - ScienceAlert
New research details the hidden ecosystem that once acted as an Eden-like sanctuary for animal life, including early humans, at the southern tip of South Africa.
New research details the hidden ecosystem that once acted as an Eden-like sanctuary for animal life, including early humans, at the southern tip of South Africa. The Palaeo-Agulhas Plain (PAP), now submerged by ocean waters off the South African coast, could have provided a rich habitat for all kinds of animals during glacial periods, when coastal waters receded, exposing a shallow continental shelf at the southern tip of the African continent. These days, researchers study the landscape and the ancient evidence it reveals about early humans through cave sites such as those at Pinnacle Point, near Mossel Bay. Today, those crags are coastal caves, but in times long past the same sites would have looked out over vast plains inundated with rivers. "During glacial cycles, the coastal shelf was exposed," explains anthropologist Jamie Hodgkins from the University of Colorado Denver. "There would have been a huge amount of land in front of the cave sites. We thought it was likely that humans and carnivores were hunting animals as they migrated east and west over the exposed [shelf]." Artist rendering of the Palaeo-Agulhas Plain during the Pleistocene. (CU Denver) To test that hypothesis, Hodgkins and her team analysed the teeth of ancient herbivorous antelopes who lived at the site approximately 150,000 years ago, looking for signs of carbon and oxygen isotopes preserved in the tooth enamel, which can be used as an indicator of the travelling patterns of the animals. Scientists already knew that seasonal rainfall influences the types of plants that grow in the eastern and western zones of the region; the presence of these plants in the animals' diet could be traced through analysing molecular isotopes such as carbon-13 and oxygen-18, the latter of which shows up differently in summer and winter rainfall. Hypothetically, then, varying isotope ratios found in the animals' tooth enamel (via the isotopic signature called 13C) could indicate the migratory expanse of the antelopes, moving between regions as the seasons changed. But that's not what the researchers found. Comparing the teeth from 39 specimens of ungulates (hoofed animals), including hartebeest, wildebeest, and springbok, the researchers found that the isotope signature, for the most part, didn't vary between migratory animals and non-migratory animals such as the common reedbuck, which served in the study as a control group. "Overall, the 13C results do not support an ecosystem model in which most herbivores were undergoing long distance point-to-point migrations that would be consistent with an east and west migration system along the PAP," the researchers write in their paper. That finding parallels a similar discovery made in a previous study, leading Hodgkins and team to conclude that the conditions in the exposed, coastal PAP region could have been so flourishing, that even migratory animals opted to stay put. Study first author Jamie Hodgkins in South Africa. (CU Denver) "They weren't struggling at Pinnacle Point," Hodgkins says. "We now know that powerful river systems supplied the expanded coast, thus animals didn't have to be migratory. It was a great location, resource-wise." This coastal shelter wasn't just bountiful for creatures on hoofs, either. The same hospitable conditions would have likely attracted a diverse array of animal life, making the terrain a rich hunting ground for early humans in the Pleistocene, regardless of how glacial cycles may have determined the shoreline over the eons. "During interglacials when the coast moved closer to the caves humans had shellfish and other marine resources, and when the coast expanded in glacial times hunters had access to a rich, terrestrial environment," Hodgkins says. "Hunters wouldn't need to be as mobile with all of these herbivores wandering around." Related research from some of the same team has previously found evidence to suggest humans thrived in this area even during the eruption of the Mount Toba supervolcano about 74,000 years ago. Such an achievement might not have been possible without the generous resources afforded by this coastal haven, enabling humans to overcome even the terrible hardships of a volcanic winter. While there's still a lot we don't fully understand about the Palaeo-Agulhas Plain and the ancient conditions that prevailed in this long-gone landscape, we're learning more than ever at the moment. Hodgkins' study is part of a new collection that brings together 22 research papers on this ancient Eden, helping us comprehend just how important this vast prehistoric ecosystem was in sheltering and enabling life during the Pleistocene. "The Palaeo-Agulhas Plain, when exposed, was a 'Serengeti of the South' positioned next to some of the richest coastlines in the world," says lead researcher on the project, archaeologist Curtis Marean from Arizona State University. "This unique confluence of food from the land and sea cultivated the complex cultures revealed by the archaeology and provided safe harbour for humans during the glacial cycles that revealed that plain and made much of the rest of the world unwelcoming to human life." The findings are reported in Quaternary Science Reviews.
Bumblebees Bite Plants to Make Them Bloom, Scientists Find - ScienceAlert
When you wake up hungry and there's nothing to eat, the most sensible thing to do is acquire snacks. In this, bumblebees are no different from humans. If they wake early from hibernation to find a scarcity of pollen, the insects have a cunning way to
When you wake up hungry and there's nothing to eat, the most sensible thing to do is acquire snacks. In this, bumblebees are no different from humans. If they wake early from hibernation to find a scarcity of pollen, the insects have a cunning way to force plants to flower. Using their mandibles and proboscises, bumblebees (Bombus terrestris) chew holes in plant leaves, causing them to bloom weeks earlier than they usually would, in turn supplying the bees with food. It could be providing the fuzzy little insects with a valuable survival tool when warmer temperatures due to climate change wake them from hibernation early - that is, before plants usually start flowering. Researchers at ETH Zürich first noticed the peculiar behaviour in a greenhouse they had set up to study how bees respond to plant smells, Science Magazine reported. "Initial behavioural observations with four plant species revealed that bumblebee workers use their proboscises and mandibles to cut distinctively shaped holes in plant leaves, with each damage event taking only a few seconds," the researchers wrote in their paper. "However, we saw no clear evidence that bees were actively feeding on leaves or transporting leaf material back to the hive." Previous research had found that abiotically inducing stress in plants could accelerate the flowering timeline. So, the researchers hypothesised that if the bees were not eating the leaves or using them for nests, perhaps the plant-munching was for another reason - using this plant stress response to get aboard the pollen train sooner. To test this idea, the team put mesh cages over black mustard (Brassica nigra) and tomato plants (Solanum lycopersicum) that weren't due to flower, and released hungry, pollen-deprived bumblebees inside. As a control, more plants of each kind were set up in a greenhouse without bumblebees; in another group of each plant, the researchers themselves cut holes in the leaves in the same-half-moon shapes they'd seen the bumblebees cut. Then, they watched and waited. (Pashalidou et al., Science, 2020) The results were jaw-dropping. Black mustard plants chewed by bumblebees flowered on average 16 days earlier than the unchewed controls. The tomato plants were even more striking - they flowered up to 30 days earlier. The team also found that bumblebees deprived of pollen conducted significantly more damage to non-flowering plants than the bees with sufficient food, suggesting that hunger drives the rate at which bumblebees damage plants. They even saw two other species of bumblebee - the red-tailed bumblebee (B. lapidarius) and white-tailed bumblebee (B. lucorum) damaging plants in the same manner, confirming that the behaviour is not exclusive to commercial bumblebee hives. Where it gets really interesting though, is when it comes to the plants the researchers cut up to mimic bumblebee damage. They flowered earlier than the undamaged controls, but not nearly as early as the plants chewed by bees. The human-damaged mustard plants only flowered eight days earlier, and the tomato plants just five. Why this is the case is not yet known. It's possible that the bees release a chemical that triggers a stronger response in the plants, but more research will be needed to figure this out for sure. The results do suggest that bumblebees have access to an adaptive survival tool that could prove vital as the climate continues to warm. It's possible that the plants have adapted to respond to this bee-haviour, too - if the bumblebees die from lack of food, pollination could be greatly reduced, so it benefits the plants to flower when their pollinators need them to. In turn, this could mean these organisms are just a little bit more resistant to a changing climate than we thought, which is encouraging in the face of the growing climate crisis. "The demonstration that bee-inflicted leaf damage can have strong effects on time to flowering may have important ecological implications, including for the resilience of plant-pollinator interactions to increases in phenological asymmetry caused by anthropogenic environmental changes," the researchers wrote. The research has been published in Science.
Astronomers May Have Spotted a Tiny Moon in The Outer Solar System - ScienceAlert
In the far reaches of the Solar System, past the orbit of Neptune, things start getting trickier and trickier to see. Directly imaging small objects out in the darkness of the Kuiper Belt - where Pluto resides - is really difficult, which makes a rec
In the far reaches of the Solar System, past the orbit of Neptune, things start getting trickier and trickier to see. Directly imaging small objects out in the darkness of the Kuiper Belt - where Pluto resides - is really difficult, which makes a recent discovery all the more exciting. If you know where something is, you can observe it by waiting for it to pass in front of distant stars. This is called occultation, and astronomers use it to study all sorts of trans-Neptunian objects. But when astronomers used occultation in 2018 to study one such object they've been watching for nearly two decades, they found something really unexpected - a chonk of a moon, relative to the body it is orbiting. A study describing their findings has now been accepted into Astronomy & Astrophysics. The object caught sporting this moon is probable dwarf planet (84522) 2002 TC302. It was first discovered in 2002, after which it was also identified in earlier observations. Between 2000 and 2018, astronomers collected at least 126 observations of the object across a variety of wavelengths (including the Hubble Space Telescope); using this information, they calculated the potential dwarf planet's orbit, size, and colour. They found that it's around 584 kilometres (363 miles) in diameter, and with an orbital period of 417 years - in a 2:5 orbital resonance with Neptune. That's pretty awesome. It means 2002 TC302 almost meets the requirements for a dwarf planet - it's in orbit around the Sun (but not another planet); it hasn't cleared its orbital neighbourhood; and it must have enough mass to achieve hydrostatic equilibrium, or a round shape. But we're not quite sure. When predictions of its orbit pointed to an occultation event on 28 January 2018, observatories around Europe pointed their eyes at 2002 TC302's neighbourhood to try and figure out its physical properties, such as size and shape. Telescopes in Italy, France, Slovenia and Switzerland made 12 positive detections of the occultation event, as well as four negative detections. This produced the best observation of a trans-Neptunian object we've obtained to date, the researchers said. Adding these together allowed the researchers to obtain a new, more accurate measurement of the object's diameter: 500 kilometres (311 miles). So, how to account for the missing 84 kilometres calculated from the other observations? Well, there's a really interesting answer to that. If 2002 TC302 had a moon around 200 kilometres (124 miles) in diameter, and just 2,000 kilometres (1,243 miles) from the probable dwarf planet, it could produce the signal that other astronomers interpreted as a slightly larger 2002 TC302. This is crazy close. The Moon, for context, is 384,400 kilometres (238,900 miles) from Earth (on average). At such a close proximity, 2002 TC302's satellite would be extremely hard to image - not even the Hubble Space Telescope images taken in 2005 would be able to resolve it individually. If the potential dwarf planet really has a satellite, that can help us learn things about the early Solar System. Stuff in the Kuiper Belt has changed very little since the Solar System formed, and as such, these objects are considered time capsules. Two objects extremely close together could help us to better understand close interactions when the Solar System was forming. Since the planets are thought to have formed via accretion - more and more stuff sticking together - this could be an important clue as to how smaller bodies grow. An object of similar interest is Arrokoth, the weird snowman-shaped rock visited by the New Horizons probe in 2015. The data provided by that flyby showed us that planetary accretion may be a more gentle process than we thought. 2002 TC302 is a lot bigger than Arrokoth, but it could be at a later stage of the process - which would be really useful in piecing together the stages in which it happens. At any rate, it's clear that we should probably look at it a bit more and try to figure out what its deal is. Exciting! The research has been accepted into Astronomy & Astrophysics, and is available on arXiv.
This Eerie Neon Glow Coming From Bleached Coral Could Actually Be Good News - ScienceAlert
Ocean heatwaves cause vast coral bleaching events almost every year due to climate change, threatening reefs around the world. The high water temperatures stress reef building corals, causing them to eject the photosynthetic algae that reside in thei
Ocean heatwaves cause vast coral bleaching events almost every year due to climate change, threatening reefs around the world. The high water temperatures stress reef building corals, causing them to eject the photosynthetic algae that reside in their tissue. Losing these brownish-coloured plant cells lets the coral's white limestone skeleton shine through, turning reefs ghostly white. But when some corals bleach, they undergo a mysterious transformation that has confounded scientists. Rather than turning white, these corals emit a range of different neon colours. Colorful bleaching, as it's known, was covered in the documentary Chasing Coral, which showed a whole reef turning fluorescent. The underwater photographer who documented the event said: It was as if the corals were screaming for attention in vivid colour, trying to protect themselves from ocean heatwaves. We'd witnessed the ultimate warning that the ocean is in trouble. In new research, we've finally uncovered why corals do this. Neon purple bleached coral, New Caledonia, 2016. (Richard Vevers/The Ocean Agency) Solving a coral conundrum We knew that the appearance of unusually fluorescent corals was linked to bleaching. But why didn't all corals suddenly become more colourful? And why did they only seem to appear during certain bleaching events? Things got even stranger when we tried to expose corals in the laboratory to experimental heat stress. In our first trials, instead of becoming more colourful, they just bleached white. But after conducting more lab experiments with the help of our students Elena Bollati and Rachel Alderdice, we found an answer. (Cecilia D'Angelo & Jörg Wiedenmann / University of Southampton) In healthy corals, much of the sunlight is absorbed by the photosynthetic pigments of the algae. When corals lose their algae due to stress, the excess light travels back and forth inside the coral tissue, reflected by the white skeleton. The algae inside coral can recover after bleaching, once conditions return to normal. But when the coral interior is lit up brightly like this, it can be very stressful for the algae, potentially delaying or even preventing their return. If the coral cells can still carry out at least some of their normal functions during bleaching, the increased internal light levels boost the production of colourful pigments which protect the coral from light damage, forming a kind of sunscreen layer that allows algae to return. As the recovering algae start absorbing light for photosynthesis again, light levels inside the coral drop, and so the coral stops producing as much of these colourful pigments. But it's not just heat stress that can cause colourful bleaching. Corals and their algae are very sensitive to changes in nutrient levels in their environment. When there's too little phosphorous or too much nitrogen in the water something that can happen when fertiliser runs off from farmland into the ocean strong colourful bleaching can occur. (Jörg Wiedenmann/Elena Bollati/Cecilia D'Angelo/University of Southampton/Ryan Goehrung/University of Washington) A brighter future for reefs Using satellite data, we reconstructed the temperature profiles for known colourful bleaching events. We saw that they tend to occur after brief or mild episodes of heat stress. When corals are exposed to severe or prolonged temperature extremes, they tend to bleach white. That's why we only see bright neon colours in particular bleaching episodes, when conditions are just right. Different members of the coral community can display different colours during these events, while some species don't produce these colourful protective pigments at all. But even within coral species, there can be different colour variants that result from differences in their genetic makeup. These variants have evolved to give species different strategies to deal with light, depending on where they grow on the reef. For corals in shallower water it's beneficial to invest a lot of energy in producing the colourful sunscreen. (Darren Coker / JCU Townsville) At greater depths or in shaded areas where light stress is lower, corals that produce less of the protective pigment are better off as they can save their energy for other useful purposes. Even so, these different variants often occur side-by-side, which is why some corals bleach colourful while their neighbours turn white. The good news is that colourful bleached reefs seem more likely to recover than corals that bleach white, since they tend to appear when heat stress isn't so severe and the colourful pigments themselves offer protection. Reports suggest that colourful bleaching occurred on some parts of the Great Barrier Reef in March and April 2020, so some patches of the world's largest reef system may have better prospects for recovery after the recent bleaching. Now that we know that nutrient levels can affect colourful bleaching too, we can more easily pinpoint cases where heat stress might have been aggravated by poor water quality. This can be managed locally, whereas the ocean heat waves caused by climate change will need global leadership. Together, these actions can secure a future for coral reefs. Jörg Wiedenmann, Head of the Coral Reef Laboratory, University of Southampton and Cecilia D'Angelo, Senior Research Fellow, Coral Reef Laboratory, University of Southampton. This article is republished from The Conversation under a Creative Commons license. Read the original article.
Astronomers Have Just Detected a New Kind of Asteroid - ScienceAlert
We tend to think of asteroids and comets as pretty strictly delineated categories.
We tend to think of asteroids and comets as pretty strictly delineated categories. Comets have long, looping orbits and are loaded up with volatile ices that sublimate, generating a dusty, misty halo and tail when the comet comes close to the Sun. Asteroids, on the other hand, are generally considered rocky, dry and inert, with orbits in the Solar System similar to those of the planets. Every now and again, though, we come across something that challenges these definitions. And a newly discovered asteroid called 2019 LD2 is truly special - an asteroid of a kind we've never seen before. It has an asteroid-like orbit, but a comet-like tail. That's rare, but not unknown - we call asteroids that exhibit comet-like characteristics (such as outgassing and sublimation) active asteroids. It's not the what, but the where that makes 2019 LD2 unique. You see, the object shares its orbit with Jupiter, in an asteroid swarm known as the Jupiter Trojans. And it's the first Jupiter Trojan astronomers have ever seen spewing out gas like a comet would. 2019 LD2 first caught astronomers' attention in early June of last year, when the University of Hawaii's Asteroid Terrestrial-impact Last Alert System (ATLAS) detected a faint new signal that appeared to be an asteroid in the Trojan group. Follow-up observations came quickly. On June 10, astronomers using ATLAS noticed what appeared to be comet-like behaviour. On June 11 and 13, astronomers using the Las Cumbres Observatory found the same features. And in July 2019, new ATLAS images were the clincher: it was faint, but it was there, a trailing comet-like tail. Further observations from that point had to be put on hold as the Jupiter Trojan swarm moved behind the Sun, where we can't see them. But they recently reemerged, and last month, astronomers took another look. There was 2019 LD2, still flaunting a tail like a fabulous cosmic bride; it was probably doing so continuously for all that time. Because of its unusual orbit, astronomers are intrigued as to what processes could be driving 2019 LD2's unique outgassing. There are thousands of asteroids in the Jupiter Trojan category, divided into two distinct groups. One group of Trojans orbits in front of Jupiter (this is where 2019 LD2 is), and the other trails behind it, in curved regions centring on the planet's Lagrangian points. These are spots where the combined gravitational forces of two larger bodies (in this case Jupiter and the Sun) create a small area of gravitational stability. The Lagrangian points generated by Earth's gravitational interactions with the Sun and Moon are actually really useful for things like space telescopes and relay satellites, but Jupiter's provide the inner Solar System with an essential service, acting as a net that prevents space rocks from flying willy-nilly and smashing into other planets. The Jupiter Trojans are thought to have been swept up around 4 billion years ago, a period when the Solar System planets are thought to have been migrating into their current position. If that's how long they have been sharing Jovian space, any ice they may have had on their surface should have sublimated long ago. But what if the ice is inside the asteroids? "We have believed for decades that Trojan asteroids should have large amounts of ice beneath their surfaces, but never had any evidence until now," said astronomer Alan Fitzsimmons of Queen's University Belfast in Ireland. "ATLAS has shown that the predictions of their icy nature may well be correct." If 2019 LD2 had recently collided with another chunk of rock, the impact could have dislodged enough material to expose this previously sealed ice, allowing it to sublimate and outgas. It's also possible that 2019 LD2 was a stray recently captured by Jupiter from farther out in the Solar System, where it's cold enough for ice to stick around. The Jupiter Trojans are pretty hard to study, but we could learn a lot from taking a closer look at this weirdo. Astronomers put in a request in December of last year to do just that using the Spitzer Space Telescope. "As this object is the first of its kind, the detection of gas will be immensely exciting as it will provide first constraints on the volatile contents of the Trojan population measured from one of its members with implications on testing Solar System evolution models involving the capture of Trojans during the instability of the gas giants," they wrote. "In either case of the volatile gases being detection or not detected, we expect the results to be high-impact as it allows us to characterise the activity mechanism of this novel object." Sadly, Spitzer was retired in January of this year. But the new April observations flag 2019 LD2 as a very strong object of interest, and we know that this is not the last we're going to hear of the strange little space rock. And hey, NASA will be launching the first spacecraft, Lucy, to visit the Jupiter Trojans next year. It'll take a few years to get there, and 2019 LD2 is not on the visitation schedule, but maybe it will be able to capture a few flyby observations as it passes through.
Scientists Reveal a Proof-of-Concept Bionic Human Eye - ScienceAlert
Researchers say they've created a proof-of-concept bionic eye that could surpass the sensitivity of a human one.
Researchers say they've created a proof-of-concept bionic eye that could surpass the sensitivity of a human one. "In the future, we can use this for better vision prostheses and humanoid robotics," researcher Zhiyong Fan, at the Hong Kong University of Science and Technology, told Science News. The eye, as detailed in a paper published in the prestigious journal Nature today, is in essence a three-dimensional artificial retina that features a highly dense array of extremely light-sensitive nanowires. The team, led by Fan, lined a curved aluminum oxide membrane with tiny sensors made of perovskite, a light-sensitive material that's been used in solar cells. Wires that mimic the brain's visual cortex relay the visual information gathered by these sensors to a computer for processing. The nanowires are so sensitive they could surpass the optical wavelength range of the human eye, allowing it to respond to 800 nanometer wavelengths, the threshold between visual light and infrared radiation. That means it could see things in the dark when the human eye can no longer keep up. "A human user of the artificial eye will gain night vision capability," Fan told Inverse. The researchers also claim the eye can react to changes in light faster than a human one, allowing it to adjust to changing conditions in a fraction of the time. Each square centimeter of the artificial retina can hold about 460 million nanosize sensors, dwarfing the estimated 10 million cells in the human retina. This suggests that it could surpass the visual fidelity of the human eye. Fan told Inverse that "we have not demonstrated the full potential in terms of resolution at this moment," promising that eventually "a user of our artificial eye will be able to see smaller objects and further distance." Other researchers who were not involved in the project pointed out that plenty of work still has to be done to eventually be able to connect it to the human visual system, as Scientific American reports. But some are hopeful. "I think in about 10 years, we should see some very tangible practical applications of these bionic eyes," Hongrui Jiang, an electrical engineer at the University of Wisconsin-Madison who was not involved in the research, told Scientific American. This article was originally published by Futurism. Read the original article.
Astronomers Detect a Suspiciously Shaped Galaxy Lurking in The Very Early Universe - ScienceAlert
Around 13.8 billion years ago, somehow the Universe popped into existence. But it didn't come fully equipped. At some point, the first stars formed, and the first galaxies. How and when this happened is still a mystery astronomers are trying to solve
Around 13.8 billion years ago, somehow the Universe popped into existence. But it didn't come fully equipped. At some point, the first stars formed, and the first galaxies. How and when this happened is still a mystery astronomers are trying to solve but one galaxy could have a vitally important key. It's called DLA0817g - nicknamed the Wolfe Disk - a cool, rotating, gas-rich disc galaxy with a mass of about 72 billion times that of our Sun. And the Atacama Large Millimeter/submillimeter Array has snapped it a massive 12.5 billion light-years away - when the Universe was just 10 percent of its current age. It's the earliest rotating disc galaxy astronomers have found yet, and its very existence changes our understanding of galaxy formation in the early Universe. Most of the galaxies in the early Universe are a hot mess, literally. They're all blobby, with stars flying every which way, and rather high temperatures. Astronomers have interpreted this to mean that they grew large by colliding and merging with other galaxies - a hot, messy process. "Most galaxies that we find early in the Universe look like train wrecks because they underwent consistent and often 'violent' merging," explained astronomer Marcel Neeleman of the Max Planck Institute for Astronomy in Germany. "These hot mergers make it difficult to form well-ordered, cold rotating disks like we observe in our present Universe." Under this scenario, it takes a long time for the galaxies to cool down and smooth out into the more orderly rotating disc galaxies like the Milky Way. We don't generally start seeing them until about 4 to 6 billion years after the Big Bang. This is the "hot" mode of galaxy formation. But astronomers had also predicted and simulated another way - the "cold" mode. First, you need to start with the primordial soup, an ionised quark-gluon plasma that filled the Universe before the formation of matter. To go from this homogeneous plasma to a Universe filled with stuff, astrophysicists have run simulations that suggest dark matter is responsible. We don't know what dark matter is. We can't detect it directly, but it interacts gravitationally with normal matter. It helps to hold galaxies together, and we believe that it could be crucial to galaxy formation, clumps of it pulling together gas and stars into galaxies. Supercomputer simulations have shown that a massive network of dark matter in the early Universe could have facilitated the formation of cool galaxies. If the gas was cool to start with, it could have been fed along filaments of the network into the dark matter clumps, accreting into large, cool, orderly disc galaxies. But the only way to confirm this model is through observational evidence, so the researchers went looking, using the light of even more distant galaxies, called quasars, to illuminate the way. Distant galaxies are very hard to see, but quasars are among the most luminous objects in the Universe - galaxies lit by an active supermassive black hole, the space around it blasting out radiation as it feeds. The team turned ALMA's powerful capabilities to these distant quasars, looking for signatures in their light that showed that it had passed through a gas-filled galaxy on the way. They found it. The light from one of the quasars they imaged had passed through a region rich with hydrogen - the signature of the Wolfe Disk. And there was something else. The light on one side of the disc was compressed, or blueshifted. We see this when something is moving towards us. And the light from the other side was stretched, or redshifted - moving away from us. The object was rotating. Those Doppler shifts, as they are known, then allowed the researchers to calculate the velocity of the galaxy's rotation: around 272 kilometres per second. What's even more wild is that the team believes the Wolfe Disk isn't one of a kind. "The fact that we found the Wolfe Disk using this method, tells us that it belongs to the normal population of galaxies present at early times," Neeleman said. "When our newest observations with ALMA surprisingly showed that it is rotating, we realised that early rotating disk galaxies are not as rare as we thought and that there should be a lot more of them out there." The team will continue their search for these galaxies to find out just how common cold accretion was in the early Universe. The research has been published in Nature.
Earth's Magnetic North Is Moving From Canada to Russia, And We May Finally Know Why - ScienceAlert
Our planet wears its magnetic field like an oversized coat that just won't sit comfortably. All that sliding means the north magnetic pole is destined to move ever closer to Siberia's coastline over the coming decade.
Our planet wears its magnetic field like an oversized coat that just won't sit comfortably. All that sliding means the north magnetic pole is destined to move ever closer to Siberia's coastline over the coming decade. There's no conspiracy behind it - but the geological forces responsible have been something of a mystery. Now, we might be a little closer to understanding what's going on. Researchers from the University of Leeds in the UK and the Technical University of Denmark have analysed 20 years of satellite data, finding that a monolithic competition between two lobes of differing magnetic force near the core is likely to be behind the pole's wanderlust. When the precise position of Earth's magnetic north was located for the first time back in 1831, it was squarely in Canada's corner of the Arctic, on the Boothia Peninsula in the territory of Nunavut. Ever since, fresh sets of measurements have recorded this spot drift north by an average of around 15 kilometres (about 9 miles) every year. Advanced technology means we can now keep a careful watch on the pole's location with unprecedented accuracy. Prior to the 1970s, the north magnetic pole's position was like a drunken stagger. Since then, it's had a mission, marching in a straight line, building speed. Since the 1990s, its movement has quadrupled in speed, to a current rate of between 50 and 60 kilometres (about 30 and 37 miles) a year. In late 2017, the pole's sprint brought it within 390 kilometres (240 miles) of the geographical north pole. Tracking the magnetic north pole's drift towards Siberia (Livermoreetal., Nature Geoscience, 2020) On its current trajectory, we can expect it to be anywhere between 390 and 660 kilometres (240 and 410 miles) further along its journey in ten years, bringing it within a whisker of the northern limits of the East Siberian Sea. The rapid displacement is a concern for navigation systems that rely on pinpoint calculations of the pole's location, forcing the US National Geophysical Data Center to fast track its usual updates to the World Magnetic Model last year. What the world really needs is a solid idea of the physical mechanisms behind this displacement, allowing for accurate predictions on the planet's magnetic movements. So Earth scientists Philip Livermore and Matthew Bayliff from the University of Leeds in the UK and Christopher Finlay from the Technical University of Denmark reviewed 20 years of geomagnetic data from the ESA's Swarm mission. The pole's heading lines up neatly with two anomalies called negative magnetic fluxes, one deep beneath Canada, and the other below Siberia. "The importance of these two patches in determining the structure of the field close to the north magnetic pole has been well known for several centuries," the researchers note in their recently published report. These large lobes of magnetism grow and shrink with time, having a profound effect on the magnetic field we perceive on the surface. Between 1970 and 1999, changes to interactions between the flowing mantle and the planet's dense, spinning core caused the patch beneath Canada to elongate, reducing the corresponding magnetic field's strength to drop up top. "Now historically, the Canadian patch has been winning the war and that's why the pole has been centred over Canada," Livermore told BBC Radio 4's Today programme in a recent interview. "But in the last few decades, the Canadian patch has weakened and the Siberian patch has strengthened slightly, and that explains why the pole has suddenly accelerated away from its historical position." While this means we can expect the pole to continue racing for a little longer, it doesn't tell us precisely where it will stop, how long it will stop for, or when it might return. There is an incredible amount we don't know about the engine whirring away inside our planet's guts. Given that extensive geological records hint at significant fluctuations in its protective magnetic field, we really ought to know a lot more than we do. We're going to need more models like this if we're to have a hope of predicting just where our planet's poles will end up in the future. This research was published in Nature Geoscience.