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A new archaeology for the Anthropocene era - Phys.org
Indiana Jones and Lara Croft have a lot to answer for. Public perceptions of archaeology are often thoroughly outdated, and these characterisations do little to help. Archaeology as practiced today bears virtually no resemblance to the tomb raiding portrayed …
Indiana Jones and Lara Croft have a lot to answer for. Public perceptions of archaeology are often thoroughly outdated, and these characterisations do little to help. Archaeology as practiced today bears virtually no resemblance to the tomb raiding portrayed in movies and video games. Indeed, it bears little resemblance to even more scholarly depictions of the discipline in the entertainment sphere. A paper published today in Nature Ecology and Evolution aims to give pause to an audience that has been largely prepared to take such out-of-touch depictions at face value. It reveals an archaeology practiced by scientists in white lab coats, using multi-million-euro instrumentation and state-of-the-art computers. It also reveals an archaeology poised to contribute in major ways to addressing such thoroughly modern challenges as biodiversity conservation, food security and climate change. "Archaeology today is a dramatically different discipline to what it was a century ago," observes Nicole Boivin, lead author of the study and Director of the Institute's Department of Archaeology. "While the tomb raiding we see portrayed in movies is over the top, the archaeology of the past was probably closer to this than to present-day archaeology. Much archaeology today is in contrast highly scientific in orientation, and aimed at addressing modern-day issues." Examining the research contributions of the field over the past few decades, the authors reach a clear conclusionarchaeology today has a great deal to contribute to addressing the challenges of the modern era. "Humans in the present era have become one of the great forces shaping nature," says Alison Crowther, coauthor and researcher at both the University of Queensland and the MPI Science of Human History. "When we say we have entered a new, human-dominated geological era, the Anthropocene, we acknowledge that role." How can archaeology, a discipline focused on the past, hope to address the challenges we face in the Anthropocene? "It is clear that the past offers a vast repertoire of cultural knowledge that we cannot ignore," says Professor Boivin. The two researchers show the many ways that data about the past can serve the future. By analyzing what worked and didn't work in the pasteffectively offering long-term experiments in human societyarchaeologists gain insight into the factors that support sustainability and resilience, and the factors that work against them. They also highlight ancient solutions to modern problems. "We show how researchers have improved the modern world by drawing upon information about the ways people in the past enriched soils, prevented destructive fires, created greener cities and transported water without fossil fuels," says Dr. Crowther. People also continue to use, and adapt, ancient technologies and infrastructure, including terrace and irrigation systems that are in some cases centuries or even millennia old. But the researchers are keen to highlight the continued importance of technological and social solutions to climate change and the other challenges of the Anthropocene. "It's not about glorifying the past, or vilifying progress," says Professor Boivin. "Instead, it's about bringing together the best of the past, present and future to steer a responsible and constructive course for humanity." More information: Mobilizing the past to shape a better Anthropocene, Nature Ecology and Evolution (2021). DOI: 10.1038/s41559-020-01361-4 , www.nature.com/articles/s41559-020-01361-4 Citation: A new archaeology for the Anthropocene era (2021, January 18) retrieved 18 January 2021 from https://phys.org/news/2021-01-archaeology-anthropocene-era.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
Mistaken identity: A presumed supernova is actually something much rarer - Phys.org
In a case of comic mistaken identity, an international team of astronomers revealed that what they once thought was a supernova is actually periodic flaring from a galaxy where a supermassive black hole gives off bursts of energy every 114 days as it tears of…
In a case of comic mistaken identity, an international team of astronomers revealed that what they once thought was a supernova is actually periodic flaring from a galaxy where a supermassive black hole gives off bursts of energy every 114 days as it tears off chunks of an orbiting star. Six years after its initial discoveryreported in The Astronomer's Telegram by Carnegie's Thomas Holoienthe researchers, led by Anna Payne of University of Hawai'i at Mnoa, can now say that the phenomenon they observed, called ASASSN-14ko, is a periodically recurring flare from the center of a galaxy more than 570 million light-years away in the southern constellation Pictor. Their findingsbased on 20 instances of regular outburstswill be published in the Astrophysical Journal and presented by Payne at the American Astronomical Society's annual meeting. Active galaxies, such as the host of ASASSN-14ko, have unusually bright and variable centers. These objects produce much more energy than the combined contribution of all their stars. Astrophysicists think this is due to gravitational and frictional forces heating up a swirling disk of gas and dust that accumulates around the central supermassive black hole. The black hole slowly consumes the material, which creates low-level, random changes in the light emitted by the disk. This is the first unambiguous example of such clockwork behavior from an active galaxy. Periodically recurring flares, such as those from ASASSN-14ko, could be evidence of observationally elusive cosmic phenomena that have been previously predicted by theorists. "Knowing the schedule of this extragalactic Old Faithful allows us to coordinate and study it in more detail," Payne said. ASASSN-14ko was first detected by the All-Sky Automated Survey for Supernovae (ASAS-SN), a global network of 20 robotic telescopes headquartered at The Ohio State University (OSU) in Columbus. When Payne examined all the ASAS-SN data on the phenomenon, she noticed a series of 17 regularly spaced flares. Based on this discovery, the astronomers predicted that the galaxy would experience another burst on May 17 of last year and coordinated ground- and space-based facilities to make observations. They have since successfully predicted and witnessed flares on September 7 and December 26. "ASAS-SN is designed to probe the physics of our universe by looking for transient and variable events." Holoien said. "It's exciting that the luminous object we originally thought was a violent supernova explosionwhich would be interesting in its own right, but more commonplaceturned out to be a long-sought-after cosmic event." So, what causes the repeated flares? The team considered several possible explanations, but think the most likely is what's called a partial tidal disruption event. Tidal disruption events, or TDEs, occur when a star gets too close to a supermassive black hole, which tears it to shreds. Some of its material gets flung out into space and the rest falls back onto the black hole, forming a disk of hot, bright gas as it is consumed. In this instance, instead of a star being obliterated by interaction with the black hole, it would be slowly stripped during each orbit. The flares occur when the lost materialequal to three times the mass of Jupiter at each passfalls in towards the black hole. The astronomers are unsure how long the flares will persist. The star can't lose mass forever, and while scientists can estimate the amount of mass it loses during each orbit, they don't know how much it had originally. "We plan to keep predicting and observing these bursts or as long as we can," said second author Benjamin Shappee, also of UH Mnoa (and a Carnegie alumnus). "This rare find could reveal new details about black hole physics." More information: ASASSN-14ko is a Periodic Nuclear Transient in ESO 253G003. arXiv:2009.03321 [astro-ph.HE] arxiv.org/abs/2009.03321 Citation: Mistaken identity: A presumed supernova is actually something much rarer (2021, January 13) retrieved 13 January 2021 from https://phys.org/news/2021-01-mistaken-identity-presumed-supernova-rarer.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
'Galaxy-sized' observatory sees potential hints of gravitational waves - Phys.org
Scientists have used a "galaxy-sized" space observatory to find possible hints of a unique signal from gravitational waves, or the powerful ripples that course through the universe and warp the fabric of space and time itself.
Scientists have used a "galaxy-sized" space observatory to find possible hints of a unique signal from gravitational waves, or the powerful ripples that course through the universe and warp the fabric of space and time itself. The new findings, which appeared recently in The Astrophysical Journal Letters, hail from a U.S. and Canadian project called the North American Nanohertz Observatory for Gravitational Waves (NANOGrav). For over 13 years, NANOGrav researchers have pored over the light streaming from dozens of pulsars spread throughout the Milky Way Galaxy to try to detect a "gravitational wave background." That's what scientists call the steady flux of gravitational radiation that, according to theory, washes over Earth on a constant basis. The team hasn't yet pinpointed that target, but it's getting closer than ever before, said Joseph Simon, an astrophysicist at the University of Colorado Boulder and lead author of the new paper. "We've found a strong signal in our dataset," said Simon, a postdoctoral researcher in the Department of Astrophysical and Planetary Sciences. "But we can't say yet that this is the gravitational wave background." In 2017, scientists on an experiment called the Laser Interferometer Gravitational-Wave Observatory (LIGO) won the Nobel Prize in Physics for the first-ever direct detection of gravitational waves. Those waves were created when two black holes slammed into each other roughly 130 million lightyears from Earth, generating a cosmic shock that spread to our own solar system. That event was the equivalent of a cymbal crasha violent and short-lived blast. The gravitational waves that Simon and his colleagues are looking for, in contrast, are more like the steady hum of conversation at a crowded cocktail party. Detecting that background noise would be a major scientific achievement, opening a new window to the workings of the universe, he added. These waves, for example, could give scientists new tools for studying how the supermassive black holes at the centers of many galaxies merge over time. "These enticing first hints of a gravitational wave background suggest that supermassive black holes likely do merge and that we are bobbing in a sea of gravitational waves rippling from supermassive black hole mergers in galaxies across the universe," said Julie Comerford, an associate professor of astrophysical and planetary science at CU Boulder and NANOGrav team member. Simon will present his team's results at a virtual press conference on Monday at the 237th meeting of the American Astronomical Society. Galactic lighthouses Through their work on NANOGrav, Simon and Comerford are part of a high stakes, albeit collaborative, international race to find the gravitational wave background. Their project joins two others out of Europe and Australia to make up a network called the International Pulsar Timing Array. Simon said that, at least according to theory, merging galaxies and other cosmological events produce a steady churn of gravitational waves. They're humungousa single wave, Simon said, can take years or even longer to pass Earth by. For that reason, no other existing experiments can detect them directly. "Other observatories search for gravitational waves that are on the order of seconds," Simon said. "We're looking for waves that are on the order of years or decades." He and his colleagues had to get creative. The NANOGrav team uses telescopes on the ground not to look for gravitational waves but to observe pulsars. These collapsed stars are the lighthouses of the galaxy. They spin at incredibly fast speeds, sending streams of radiation hurtling toward Earth in a blinking pattern that remains mostly unchanged over the eons. Simon explained that gravitational waves alter the steady pattern of light coming from pulsars, tugging or squeezing the relative distances that these rays travel through space. Scientists, in other words, might be able to spot the gravitational wave background simply by monitoring pulsars for correlated changes in the timing of when they arrive at Earth. "These pulsars are spinning about as fast as your kitchen blender," he said. "And we're looking at deviations in their timing of just a few hundred nanoseconds." Something there To find that subtle signal, the NANOGrav team strives to observe as many pulsars as possible for as long as possible. To date, the group has observed 45 pulsars for at least three years and, in some cases, for well over a decade. The hard work seems to be paying off. In their latest study, Simon and his colleagues report that they've detected a distinct signal in their data: Some common process seems to be affecting the light coming from many of the pulsars. "We walked through each of the pulsars one by one. I think we were all expecting to find a few that were the screwy ones throwing off our data," Simon said. "But then we got through them all, and we said, 'Oh my God, there's actually something here.'" The researchers still can't say for sure what's causing that signal. They'll need to add more pulsars to their dataset and observe them for longer periods to determine if it's actually the gravitational wave background at work. "Being able to detect the gravitational wave background will be a huge step but that's really only step one," he said. "Step two is pinpointing what causes those waves and discovering what they can tell us about the universe." More information:Astrophysical Journal Letters (2021). DOI: 10.3847/2041-8213/abd401 Citation: 'Galaxy-sized' observatory sees potential hints of gravitational waves (2021, January 11) retrieved 11 January 2021 from https://phys.org/news/2021-01-galaxy-sized-observatory-potential-hints-gravitational.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
NIST publishes a beginner's guide to DNA origami - Phys.org
In a technique known as DNA origami, researchers fold long strands of DNA over and over again to construct a variety of tiny 3-D structures, including miniature biosensors and drug-delivery containers. Pioneered at the California Institute of Technology in 20…
In a technique known as DNA origami, researchers fold long strands of DNA over and over again to construct a variety of tiny 3-D structures, including miniature biosensors and drug-delivery containers. Pioneered at the California Institute of Technology in 2006, DNA origami has attracted hundreds of new researchers over the past decade, eager to build receptacles and sensors that could detect and treat disease in the human body, assess the environmental impact of pollutants, and assist in a host of other biological applications. Although the principles of DNA origami are straightforward, the technique's tools and methods for designing new structures are not always easy to grasp and have not been well documented. In addition, scientists new to the method have had no single reference they could turn to for the most efficient way of building DNA structures and how to avoid pitfalls that could waste months or even years of research. That's why Jacob Majikes and Alex Liddle, researchers at the National Institute of Standards and Technology (NIST) who have studied DNA origami for years, have compiled the first detailed tutorial on the technique. Their comprehensive report provides a step-by-step guide to designing DNA origami nanostructures, using state-of-the-art tools. Majikes and Liddle described their work in the Jan .8 issue of the Journal of Research of the National Institute of Standards and Technology. "We wanted to take all the tools that people have developed and put them all in one place, and to explain things that you can't say in a traditional journal article," said Majikes. "Review papers might tell you everything that everyone's done, but they don't tell you how the people did it. " DNA origami relies on the ability of complementary base pairs of the DNA molecule to bind to each other. Among DNA's four basesadenine (A), cytosine (C), guanine (G) and thymine (T)A binds with T and G with C. This means that a specific sequence of As, Ts, Cs and Gs will find and bind to its complement. The binding enables short strands of DNA to act as "staples," keeping sections of long strands folded or joining separate strands. A typical origami design may require 250 staples. In this way, the DNA can self-assemble into a variety of shapes, forming a nanoscale framework to which an assortment of nanoparticlesmany useful in medical treatment, biological research and environmental monitoringcan attach. The challenges in using DNA origami are twofold, said Majikes. First, researchers are fabricating 3-D structures using a foreign languagethe base pairs A, G, T and C. In addition, they're using those base-pair staples to twist and untwist the familiar double helix of DNA molecules so that the strands bend into specific shapes. That can be difficult to design and visualize. Majikes and Liddle urge researchers to strengthen their design intuition by building 3-D mock-ups, such as sculptures made with bar magnets, before they start fabrication. These models, which can reveal which aspects of the folding process are critical and which ones are less important, should then be "flattened" into 2-D to be compatible with computer-aided design tools for DNA origami, which typically use two-dimensional representations. DNA folding can be accomplished in a variety of ways, some less efficient than others, noted Majikes. Some strategies, in fact, may be doomed to failure. "Pointing out things like 'You could do this, but it's not a good idea'that type of perspective isn't in a traditional journal article, but because NIST is focused on driving the state of technology in the nation, we're able to publish this work in the NIST journal," Majikes said. "I don't think there's anywhere else that would have given us the leeway and the time and the person hours to put all this together." Liddle and Majikes plan to follow up their work with several additional manuscripts detailing how to successfully fabricate nanoscale devices with DNA. More information: Jacob M. Majikes et al, DNA Origami Design: A How-To Tutorial, Journal of Research of the National Institute of Standards and Technology (2021). DOI: 10.6028/jres.126.001 Citation: NIST publishes a beginner's guide to DNA origami (2021, January 9) retrieved 9 January 2021 from https://phys.org/news/2021-01-nist-publishes-beginner-dna-origami.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
Fast transport in carbon nanotube membranes could advance human health - Phys.org
Lawrence Livermore National Laboratory (LLNL) researchers have discovered that carbon nanotube membrane pores could enable ultra-rapid dialysis processes that would greatly reduce treatment time for hemodialysis patients.
Lawrence Livermore National Laboratory (LLNL) researchers have discovered that carbon nanotube membrane pores could enable ultra-rapid dialysis processes that would greatly reduce treatment time for hemodialysis patients. The ability to separate molecular constituents in complex solutions is crucial to many biological and man-made processes. One way is via the application of a concentration gradient across a porous membrane. This drives ions or molecules smaller than the pore diameters from one side of the membrane to the other while blocking anything that is too large to fit through the pores. In nature, biological membranes such as those in the kidney or liver can perform complex filtrations while still maintaining high throughput. Synthetic membranes, however, often struggle with a well-known trade-off between selectivity and permeability. The same material properties that dictate what can and cannot pass through the membrane inevitably reduce the rate at which filtration can occur. In a surprising discovery published in the journal Advanced Science, LLNL researchers found that carbon nanotube pores (graphite cylinders with diameters thousands of times smaller than a human hair) might provide a solution to the permeability vs. selectivity tradeoff. When using a concentration gradient as a driving force, small ions, such as potassium, chloride and sodium, were found to diffuse through these tiny pores more than an order of magnitude faster than when moving in bulk solution. "This result was unexpected because the general consensus in the literature is that diffusion rates in pores of this diameter should be equal to, or below what we see in bulk," said Steven Buchsbaum, lead author of the paper. "Our finding enriches the number of exciting and often poorly understood nanofluidic phenomena recently discovered in a-few-nanometer confinement," added Francesco Fornasiero, the principal investigator on the project. The team believes this work has significant implications in several technology areas. Membranes employing carbon nanotubes as transport channels could enable ultra-rapid hemodialysis processes that would greatly reduce treatment time. Similarly, cost and time for purifying proteins and other biomolecules as well as recovering valuable products from electrolyte solutions could be drastically reduced. Enhanced ion transport in small graphitic pores could enable supercapacitors with high power density even at pore sizes closely approaching those of the ions. To perform these studies the team leveraged previously developed membranes that allow for transport to occur only through the hollow interior of aligned carbon nanotubes with a few nanometer diameters. Using a custom diffusion cell, a concentration gradient was applied across these membranes and the transport rate of various salts and water was measured. "We have developed rigorous control tests to make sure there was no other possible explanation of the recorded large ion fluxes, such as transport occurring through leaks or defects in our membranes," Buchsbaum said. To better understand why this behavior occurs, the team enlisted the help of several LLNL experts. Anh Pham and Ed Lau used computational simulations and April Sawvel used nuclear magnetic resonance spectroscopy to study the movement of ions inside carbon nanotubes. Several possible explanations have been successfully ruled out, making the picture clearer. However, a complete, quantitative understanding of the observed transport rates is still being developed. More information: Steven F. Buchsbaum et al. Fast Permeation of Small Ions in Carbon Nanotubes, Advanced Science (2020). DOI: 10.1002/advs.202001802 Citation: Fast transport in carbon nanotube membranes could advance human health (2021, January 8) retrieved 8 January 2021 from https://phys.org/news/2021-01-fast-carbon-nanotube-membranes-advance.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
New microscopy technique images live cells with 7 times greater sensitivity - Phys.org
Experts in optical physics have developed a new way to see inside living cells in greater detail using existing microscopy technology and without needing to add stains or fluorescent dyes.
Experts in optical physics have developed a new way to see inside living cells in greater detail using existing microscopy technology and without needing to add stains or fluorescent dyes. Since individual cells are almost translucent, microscope cameras must detect extremely subtle differences in the light passing through parts of the cell. Those differences are known as the phase of the light. Camera image sensors are limited by what amount of light phase difference they can detect, referred to as dynamic range. "To see greater detail using the same image sensor, we must expand the dynamic range so that we can detect smaller phase changes of light," said Associate Professor Takuro Ideguchi from the University of Tokyo Institute for Photon Science and Technology. The research team developed a technique to take two exposures to measure large and small changes in light phase separately and then seamlessly connect them to create a highly detailed final image. They named their method adaptive dynamic range shift quantitative phase imaging (ADRIFT-QPI) and recently published their results in Light: Science & Applications. "Our ADRIFT-QPI method needs no special laser, no special microscope or image sensors; we can use live cells, we don't need any stains or fluorescence, and there is very little chance of phototoxicity," said Ideguchi. Phototoxicity refers to killing cells with light, which can become a problem with some other imaging techniques, such as fluorescence imaging. Quantitative phase imaging sends a pulse of a flat sheet of light towards the cell, then measures the phase shift of the light waves after they pass through the cell. Computer analysis then reconstructs an image of the major structures inside the cell. Ideguchi and his collaborators have previously pioneered other methods to enhance quantitative phase microscopy. Quantitative phase imaging is a powerful tool for examining individual cells because it allows researchers to make detailed measurements, like tracking the growth rate of a cell based on the shift in light waves. However, the quantitative aspect of the technique has low sensitivity because of the low saturation capacity of the image sensor, so tracking nanosized particles in and around cells is not possible with a conventional approach. The new ADRIFT-QPI method has overcome the dynamic range limitation of quantitative phase imaging. During ADRIFT-QPI, the camera takes two exposures and produces a final image that has seven times greater sensitivity than traditional quantitative phase microscopy images. The first exposure is produced with conventional quantitative phase imaginga flat sheet of light is pulsed towards the sample and the phase shifts of the light are measured after it passes through the sample. A computer image analysis program develops an image of the sample based on the first exposure then rapidly designs a sculpted wavefront of light that mirrors that image of the sample. A separate component called a wavefront shaping device then generates this "sculpture of light" with higher intensity light for stronger illumination and pulses it towards the sample for a second exposure. If the first exposure produced an image that was a perfect representation of the sample, the custom-sculpted light waves of the second exposure would enter the sample at different phases, pass through the sample, then emerge as a flat sheet of light, causing the camera to see nothing but a dark image. "This is the interesting thing: We kind of erase the sample's image. We want to see almost nothing. We cancel out the large structures so that we can see the smaller ones in great detail," Ideguchi explained. In reality, the first exposure is imperfect, so the sculptured light waves emerge with subtle phase deviations. The second exposure reveals tiny light phase differences that were "washed out" by larger differences in the first exposure. These remaining tiny light phase difference can be measured with increased sensitivity due to the stronger illumination used in the second exposure. Additional computer analysis reconstructs a final image of the sample with an expanded dynamic range from the two measurement results. In proof-of-concept demonstrations, researchers estimate the ADRIFT-QPI produces images with seven times greater sensitivity than conventional quantitative phase imaging. Ideguchi says that the true benefit of ADRIFT-QPI is its ability to see tiny particles in context of the whole living cell without needing any labels or stains. "For example, small signals from nanoscale particles like viruses or particles moving around inside and outside a cell could be detected, which allows for simultaneous observation of their behavior and the cell's state," said Ideguchi. More information: Keiichiro Toda et al, Adaptive dynamic range shift (ADRIFT) quantitative phase imaging, Light: Science & Applications (2021). DOI: 10.1038/s41377-020-00435-z Citation: New microscopy technique images live cells with 7 times greater sensitivity (2021, January 4) retrieved 4 January 2021 from https://phys.org/news/2021-01-microscopy-technique-images-cells-greater.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
Japan's capsule with asteroid samples retrieved in Australia - Phys.org
A Japanese capsule carrying the world's first asteroid subsurface samples shot across the night atmosphere early Sunday before landing in the remote Australian Outback, completing a mission to provide clues to the origin of the solar system and life on Earth.
A Japanese capsule carrying the world's first asteroid subsurface samples shot across the night atmosphere early Sunday before landing in the remote Australian Outback, completing a mission to provide clues to the origin of the solar system and life on Earth. The spacecraft Hayabusa2 released the small capsule on Saturday and sent it toward Earth to deliver samples from a distant asteroid. At about 10 kilometers (6 miles) aboveground, a parachute was opened to slow its fall and beacon signals were transmitted to indicate its location in the sparsely populated area of Woomera in southern Australia. About two hours after the reentry, the Japan Aerospace Exploration Agency, or JAXA, said its helicopter search team found the capsule in the planned landing area. The retrieval of the pan-shaped capsule, about 40 centimeters (15 inches) in diameter, was completed after another two hours. "The capsule collection work at the landing site was completed," the agency said in a tweet. "We practiced a lot for today ... it ended safe." The capsule's return came weeks after NASA's OSIRIS-REx spacecraft made a successful touch-and-go grab of surface samples from the asteroid Bennu. China, meanwhile, announced last week that its lunar lander collected underground samples and sealed them within the spacecraft for return to Earth, as space developing nations compete in their missions. Thomas Zurbuchen, a Swiss-American astrophysicist and the associated administrator of NASA's Science Mission Directorate, congratulated the Japanese space agency and "the many individuals in Japan and beyond who made this possible." "Together, we'll gain a better understanding of the origins of our solar system, & the source of water & organic molecules that may have seeded life on Earth," Zurbuchen wrote on Twitter. The fireball could be seen even from the International Space Station. A Japanese astronaut, Soichi Noguchi, who is now on a six-month mission there, tweeted: "Just spotted #hayabusa2 from #ISS! Unfortunately not bright enough for handheld camera, but enjoyed watching capsule!" Hayabusa2 left the asteroid Ryugu, about 300 million kilometers (180 million miles) away, a year ago. After it released the capsule on Saturday, it set off on a new expedition to another distant asteroid. The capsule descended from 220,000 kilometers (136,700 miles) away after it was separated from Hayabusa2 in a challenging operation that required precision control. JAXA officials said they hoped to conduct a preliminary safety inspection at an Australian lab and bring the capsule back to Japan soon. Dozens of JAXA staff had been working in Woomera to prepare for the sample return. They set up satellite dishes at several locations in the target area inside the Australian Air Force test field to receive the signals. Australian National University space rock expert Trevor Ireland, who was in Woomera for the arrival of the capsule, said he expected the Ryugu samples to be similar to the meteorite that fell in Australia near Murchison in Victoria state more than 50 years ago. "The Murchison meteorite opened a window on the origin of organics on Earth because these rocks were found to contain simple amino acids as well as abundant water," Ireland said. "We will examine whether Ryugu is a potential source of organic matter and water on Earth when the solar system was forming, and whether these still remain intact on the asteroid." Scientists say they believe the samples, especially ones taken from under the asteroid's surface, contain valuable data unaffected by space radiation and other environmental factors. They are particularly interested in analyzing organic materials in the samples. JAXA hopes to find clues to how the materials are distributed in the solar system and are related to life on Earth. Makoto Yoshikawa, the Hayabusa2 project mission manager, said 0.1 gram of the dust would be enough to carry out all planned research. For Hayabusa2, it's not the end of the mission it started in 2014. It is now heading to a small asteroid called 1998KY26 on a journey slated to take 10 years one way, for possible research including finding ways to prevent meteorites from hitting Earth. So far, its mission has been fully successful. It touched down twice on Ryugu despite the asteroid's extremely rocky surface, and successfully collected data and samples during the 1½ years it spent near Ryugu after arriving there in June 2018.
- In this image made from video provided by JAXA, its project manager Yuichi Tsuda, left, and Hitoshi Kuninaka, Director General of ISAS/JAXA, pose with a Hayabusa2 model, during a press conference in Sagamihara, near Tokyo, Sunday, Dec. 6, 2020. Japanese space agency officials said Sunday they are excited about looking inside a capsule and analyzing soil samples of a distant asteroid asteroid subsurface that safely landed in the remote Australian Outback as planned. (JAXA via AP)
- In this photo provided by the Japan Aerospace Exploration Agency (JAXA), members of JAXA retrieve a capsule dropped by Hayabusa2 in Woomera, southern Australia, Sunday, Dec. 6, 2020. A Japanese capsule carrying the first samples of asteroid subsurface shot across the night atmosphere early Sunday before successfully landing in the remote Australian Outback, completing a mission to provide clues to the origin of the solar system and life on Earth. (JAXA via AP)
- Yuichi Tsuda, Hayabusa2 project manager at Japan Aerospace Exploration Agency, speaks during a press conference at JAXA's Sagamihara Campus in Sagamihara, near Tokyo Sunday, Dec. 6, 2020. Japanese space officials said Sunday they are excited about bringing home a capsule carrying soil samples from a distant asteroid and safely landed on Australian Outback and look inside and analyzing what's inside. (Masanori Takei/Kyodo News via AP)
- In this photo provided by the Japan Aerospace Exploration Agency (JAXA), Hayabusa2 project members react as they watch over the live streaming about the fireball phase of the re-entry capsule at a control room of JAXA's Sagamihara Campus in Sagamihara, near Tokyo, early Sunday, Dec. 6, 2020. A Japanese capsule carrying the first samples of asteroid subsurface shot across the night atmosphere early Sunday before successfully landing in the remote Australian Outback, completing a mission to provide clues to the origin of the solar system and life on Earth. (JAXA via AP)
- This photo provided by Japan Aerospace Exploration Agency (JAXA) shows the Japanese space capsule about to re-enter Earth with asteroid samples seen in Coober Pedy, southern Australia, on Sunday, Dec. 6, 2020. A Japanese capsule carrying the first samples of asteroid subsurface shot across the night atmosphere early Sunday before successfully landing in the remote Australian Outback, completing a mission to provide clues to the origin of the solar system and life on Earth. (JAXA via AP)
- In this photo provided by the Japan Aerospace Exploration Agency (JAXA), a capsule, center, dropped by Hayabusa2 is seen before being retrieved in Woomera, southern Australia, Sunday, Dec. 6, 2020. A Japanese capsule carrying the first samples of asteroid subsurface shot across the night atmosphere early Sunday before successfully landing in the remote Australian Outback, completing a mission to provide clues to the origin of the solar system and life on Earth. (JAXA via AP)
- In this photo provided by the Japan Aerospace Exploration Agency (JAXA), members of JAXA retrieve a capsule dropped by Hayabusa2 in Woomera, southern Australia, Sunday, Dec. 6, 2020. A Japanese capsule carrying the first samples of asteroid subsurface shot across the night atmosphere early Sunday before successfully landing in the remote Australian Outback, completing a mission to provide clues to the origin of the solar system and life on Earth. (JAXA via AP)
- This photo provided by Japan Aerospace Exploration Agency shows the Japanese space capsule about to re-enter Earth with asteroid samples on Saturday, Dec. 5, 2020. Japan's Hayabusa2 spacecraft successfully released a small capsule and sent it toward Earth to deliver samples from a distant asteroid that could provide clues to the origin of the solar system and life on our planet, the country's space agency says. (Japan Aerospace Exploration Agency (JAXA) via AP)
Australia-bound asteroid sample may reveal life's origins - Phys.org
A Japanese space mission will deliver samples collected from asteroid Ryugu in a capsule to the outback desert of Woomera in South Australia this Sunday morning.
A Japanese space mission will deliver samples collected from asteroid Ryugu in a capsule to the outback desert of Woomera in South Australia this Sunday morning. A leading expert from The Australian National University (ANU) who will analyze the samples says they could provide major insights into the origin of life on Earth. The subsurface material collected from the asteroid will be dropped off by Hayabusa2. Testing will start almost immediately on the returned material. The mission aims to shed light on the nature of asteroids and the origins of planets in our solar system, as well as the origin of Earth's water, which is vital for all life. ANU space rock expert Professor Trevor Ireland, who is on the Hayabusa2 science team, is in Woomera awaiting the arrival of the asteroid sample, which he will analyze in the lab. "I anticipate that the Hayabusa2 samples of asteroid Ryugu will be very similar to the meteorite that fell in Australia near Murchison, Victoria, more than 50 years ago," Professor Ireland, from the ANU Research School of Earth Sciences, said. "The Murchison meteorite opened a window on the origin of organics on Earth because these rocks were found to contain simple amino acids as well as abundant water." Professor Ireland said his work would help answer big questions about the diamond-shaped asteroid, which is about one kilometer in diameter and in an orbit that takes it between Earth and Mars. "We will examine whether Ryugu is a potential source of organic matter and water on Earth when the solar system was forming and whether these still remain intact on the asteroid," he said. "This C-type asteroid, which is the most common kind, appears to be similar to the Murchison meteoritesrare carbonaceous chondrites packed with organic molecules and water. "We might find that missing connection on Ryugu. "We will also discover the history of this curious looking asteroid. The other rubble-pileasteroid Itokawa is quite young. Will Ryugu prove to be a lot older?" ANU astronomer Dr. Brad Tucker said technology has enabled space missions to regularly land on objects in space and return back to Earth. "With China's Chang'e 5 mission landing on the Moon and returning in late December, Osiris-Rex and future missions planned, we'll be able to get our hands dirty and learn a lot about the solar system and our own planet," Dr. Tucker, from the ANU Research School of Astronomy and Astrophysics, said. "Future space travel and exploration missions are going to be need to be able to extract resources in space. Missions like Hayabusa2 are laying the groundwork for this endeavor." Citation: Australia-bound asteroid sample may reveal life's origins (2020, December 4) retrieved 4 December 2020 from https://phys.org/news/2020-12-australia-bound-asteroid-sample-reveal-life.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
The 'smell' of coral as an indicator of reef health - Phys.org
You might not normally think about what corals smell like—or how the smell changes during heat stress. However, that is what researchers from the University of Technology Sydney (UTS), the University of Sydney and Southern Cross University set out to investig…
You might not normally think about what corals smell likeor how the smell changes during heat stress. However, that is what researchers from the University of Technology Sydney (UTS), the University of Sydney and Southern Cross University set out to investigate on the Great Barrier Reef. Every organism releases a distinct mix of volatile gases that makes up their smell and we are learning that these "smells" can tell us a lot about health. Some individual gases that make up the overall smell even have the ability to influence how an organism copes with stress, and once released from reefs, these gases can affect atmospheric processes. Despite their importance, these volatile gases have received little attention in tropical coral reefs. This study is the first to explore the overall "smell" of healthy and stressed corals, identifying a distinct chemical diversity. The research, led by Dr. Caitlin Lawson in the Climate Change Cluster at UTS, discovered that across the coral species studied on Heron Island in the southern Great Barrier Reef, the abundance and chemical diversity of their gas emissions fell significantly during heat stress experiments. The findings are published in the journal Global Change Biology. Recent mass bleaching events, driven by heat stress, have largely caused a 50 per cent loss of Great Barrier Reef corals in the past 25 years. Climate forecasts suggest some Great Barrier Reef areas may bleach again in 2021. "Our results provide the first insights into the range of gases produced by reef-building corals and highlight a diverse suite of compounds that may play potentially importantbut previously unrecognizedroles in maintaining healthy reef functioning," Dr. Lawson said. "Our results also reveal that heat stress dramatically decreases the chemical diversity, quantity and functional potential of these important compounds, which could further impact the capacity of corals to cope with increasing temperatures." Co-author Dr. Jean-Baptiste Raina said he was surprised to discover just how many different chemicals made up the "smell of these corals", when previously only a handful of compounds had been identified. He says that number is "just going to keep growing, the more we look into it and the more species we start to investigate". Further unlocking the complexity and diversity of these reef gases will allow scientists to understand just how they might be silently driving the health and resilience of deteriorating coral reefs, Dr. Lawson said. "We know that within terrestrial ecosystems, some of these compounds can help plants deal with drought conditions, for example, or heat stress or insect attack," she said. "I get really excited about the signaling that could be happening between different species of corals, or whether they have certain smells that they'll release that might attract grazing fish if there's too much algae. Is there a certain smell that indicates corals are more vulnerable? "With the increasing frequency of heatstress eventsand it is looking likely that bleaching will occur again in early 2021it is even more important that we understand coral emissions as they may prove to be a key tool in our efforts to monitor and conserve coral reefs." Senior author and leader of the Future Reefs Team at UTS, Associate Professor David Suggett says the discovery adds to the evidence that, just like humans, reefs rely on multiple forms of communication to stay healthy. "Coral reef diversity is sustained through sights and sounds, and our work shows that smells also play many critical roles," he said. "The discovery of a loss of these smells under heat stress driven by ocean warming is yet more evidence reefs will change as we know them unless we urgently tackle climate change." More information:Global Change Biology, DOI: 10.1111/gcb.15446 Citation: The 'smell' of coral as an indicator of reef health (2020, November 30) retrieved 30 November 2020 from https://phys.org/news/2020-11-coral-indicator-reef-health.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
Leaf-cutter ant first insect found with biomineral body armour - Phys.org
A well-known leaf-cutting ant grows its own body armour using biominerals, a protective power previously unknown in the insect world, scientists have discovered in research published Tuesday showing this makes the ants almost unbeatable in battle.
A well-known leaf-cutting ant grows its own body armour using biominerals, a protective power previously unknown in the insect world, scientists have discovered in research published Tuesday showing this makes the ants almost unbeatable in battle. Biomineral armour is seen in the natural world in crustaceans like lobsters as well as in other marine animalssea urchin spines contain calcium carbonate for examplebut it has not previously been found in insects. Researchers stumbled across the discovery while investigating the relationship between the fungus-growing ant species Acromyrmex echinatior and antibiotic-producing bacteria that helps them protect their crops. They noticed that the larger worker ants, known as majors, have a "whitish, granular coating" over the surface of their bodies, according to co-author Cameron Currie, professor of Bacteriology at the University of Wisconsin-Madison. He said Hongjie Li, the lead author of the report published in Nature Communications, "became fascinated with the crystals" and discovered it was a biomineral layer that develops as the ants mature, increasing the hardness of their exoskeleton and covering nearly the entire body. While researchers do not know for certain why the ants have this unusual armour, Currie told AFP they suspect it has a lot to do with the soldier ants of another species of fungus-growing ants, Atta cephalotes. The two species will often engage in territorial "ant wars", which the researchers simulated in lab-based battles. "When the Acro majors are without their armour the Atta soldiers quickly cut them into pieces, literally," Currie said. "When they have their armour, they actually go from almost always losing the battles to almost always winning." The authors found that the benefits of a biomineralised exoskeleton go beyond giving the workers an edge in ant wars. Their studies suggest it also helps protect them against infection from the disease-causing fungus Metarhizium anisopliae, which might otherwise spread quickly through their dense colonies. Rare as sea urchin teeth Ants are believed to have started fungus subsistence farming about 60 million years ago in South America. Some 20 million years ago the practice became more "industrialised", with the emergence of leaf-cutting ant species like Acromyrmex echinatior and Atta cephalotes living in large, complex colonies and harvesting fresh vegetation that they use to grow their fungus. Acromyrmex echinatior colonies can be formed with hundreds of thousands of large and small worker ants. "The large ones do the cutting and carrying of leaves, as well as engaging in wars and battles with other ants," said Currie. "The small ones do the gardening." Atta colonies are bigger, composed of perhaps millions of ants, with up to seven different sizes of workers, including soldiers for "defence and ant wars", Currie said. The Acromyrmex echinatior armour is made from a high-magnesium calcite, researchers found. This is a rarer form of biomineralisation where the increased hardness from the magnesium is thought to help them grind up limestone. Given that the armour has only just been found on a relatively well-studied ant species, the researchers said this type of biomineral protection could be more widespread in the insect world. But Currie said this was likely to be the calcite biominerals found more commonly in marine animals like lobsters, rather than the high-magnesium calcite of the ants' armour and sea urchin teeth. "These ants are pretty special in many regards," he added. © 2020 AFP Citation: Leaf-cutter ant first insect found with biomineral body armour (2020, November 24) retrieved 24 November 2020 from https://phys.org/news/2020-11-leaf-cutter-ant-insect-biomineral-body.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
Humans and climate drove giants of Madagascar to extinction - Phys.org
Nearly all Madagascan megafauna—including the famous dodo bird, gorilla-sized lemurs, giant tortoises, and the Elephant Bird, which stood 3 meters tall and weighted close to a half ton—vanished between 1,500 and 500 years ago. Were these animals overhunted to…
Nearly all Madagascan megafaunaincluding the famous dodo bird, gorilla-sized lemurs, giant tortoises, and the Elephant Bird, which stood 3 meters tall and weighted close to a half tonvanished between 1,500 and 500 years ago. Were these animals overhunted to extinction by humans? Or did they disappear because of climate change? There are numerous hypotheses, but the exact cause of this megafauna crash remains elusive and hotly debated. The Mascarene islands east of Madagascar are of special interest because they are among the last islands on Earth to be colonized by humans. Intriguingly, the islands' megafauna crashed in just a couple of centuries following human settlement. In a recent study published by Science Advances, a team of international researchers found that it was likely a "double whammy" of heightened human activities in combination with a particularly severe spell of region-wide aridity that may have doomed the megafauna. The researchers rule out climate change as the one and only cause, and instead suggest that the impact of human colonization was a crucial contributor to the megafaunal collapse. Hanying Li, a postdoctoral scholar at the Xi'an Jiaotong University in China and the lead author of this study, pieced together a detailed history of the regional climate variations. The primary source of this new paleoclimate record came from the tiny Mascarene island of Rodrigues in the southwest Indian Ocean approximately 1600 km east of Madagascar. "[It is] an island so remote and small that one will not find it on most schoolbook atlases," says Gayatri Kathayat, one of the co-authors and an associate professor of climate science at Xi'an Jiaotong University. Analysis of Cave Deposits Li and colleagues built their climate records by analyzing the trace elements and carbon and oxygen isotopes from each incremental growth layer of stalagmites, which they collected from one of the many caves on this island. The bulk of these analyses were conducted at the Quaternary Research Group at the Institute of Geology at the University of Innsbruck, led by Prof. Christoph Spötl. Variations in the geochemical signatures provided the information needed to reconstruct the region's rainfall patterns over the last 8000 years. To analyze the stalagmites, the researchers used the stable isotope method in their lab in Innsbruck. Despite the distance between the two islands, the summer rainfall at Rodrigues and Madagascar is influenced by the same global-wide tropical rain belt that oscillates north and south with the seasons. Hai Cheng, the study's senior co-author, says, "And when this belt falters and stays further north of Rodrigues, droughts can strike the whole region from Madagascar to Rodrigues." Co-author Hubert Vonhof, scientist at Max Planck Institute of Chemistry in Mainz, Germany, says, "Li's work from Rodrigues demonstrates that the hydroclimate of the region experienced a series of drying trends throughout the last eight millennia, which were frequently punctuated by 'megadroughts' that lasted for decades." Resilient to climate stress The most recent of the drying trends in the region commenced around 1,500 years ago at a time when the archeological and proxy records began to show definitive signs of increased human presence on the island. Ashish Sinha, professor of Earth science at California State University Dominguez Hills, U.S., says, "While we cannot say with 100 percent certainty whether human activity, such as overhunting or habitat destruction, was the proverbial straw that broke the camel's back, our paleoclimate records make a strong case that the megafauna had survived through all the previous episodes of even greater aridity. This resilience to past climate swings suggests that an additional stressor contributed to the elimination of the region's megafauna." "There are still many pieces missing to fully solve the riddle of megafauna collapse. This study now provides an important multi-millennial climatic context to megafaunal extinction," says Ny Rivao Voarintsoa from KU Leuven in Belgium. The study sheds new light on the decimation of flora and fauna of Mauritius and Rodrigues: "Both islands were rapidly stripped of endemic species of vertebrates within two centuries of the initial human colonization, including the well-known flightless dodo bird from Mauritius and the saddle-backed Rodrigues giant tortoise endemic to Rodrigues," adds Aurele Anquetil André, the reserve manager and chief conservator at the Francois Leguat Giant Tortoise and Cave Reserve at Rodrigues. "The story our data tells is one of resilience and adaptability of the islands' ecosystems and fauna in enduring past episodes of severe climate swings for eonsuntil they were hit by human activities and climate change," the researchers conclude. More information: Hanying Li et al. A multimillennial climatic context for the megafaunal extinctions in Madagascar and Mascarene Islands, Science Advances (2020). DOI: 10.1126/sciadv.abb2459 Citation: Humans and climate drove giants of Madagascar to extinction (2020, October 19) retrieved 19 October 2020 from https://phys.org/news/2020-10-humans-climate-drove-giants-madagascar.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
Einstein's description of gravity just got much harder to beat - Phys.org
Einstein's theory of general relativity—the idea that gravity is matter warping spacetime—has withstood over 100 years of scrutiny and testing, including the newest test from the Event Horizon Telescope collaboration, published today in the latest issue of Ph…
Einstein's theory of general relativitythe idea that gravity is matter warping spacetimehas withstood over 100 years of scrutiny and testing, including the newest test from the Event Horizon Telescope collaboration, published today in the latest issue of Physical Review Letters. According to the findings, Einstein's theory just got 500 times harder to beat. Despite its successes, Einstein's robust theory remains mathematically irreconcilable with quantum mechanics, the scientific understanding of the subatomic world. Testing general relativity is important because the ultimate theory of the universe must encompass both gravity and quantum mechanics. "We expect a complete theory of gravity to be different from general relativity, but there are many ways one can modify it. We found that whatever the correct theory is, it can't be significantly different from general relativity when it comes to black holes. We really squeezed down the space of possible modifications," said UArizona astrophysics professor Dimitrios Psaltis, who until recently was the project scientist of the Event Horizon Telescope collaboration. Psaltis is lead author of a new paper that details the researchers' findings. "This is a brand-new way to test general relativity using supermassive black holes," said Keiichi Asada, an EHT science council member and an expert on radio observations of black holes for Academia Sinica Institute of Astronomy and Astrophysics. To perform the test, the team used the first image ever taken of the supermassive black hole at the center of nearby galaxy M87 obtained with the EHT last year. The first results had shown that the size of the black-hole shadow was consistent with the size predicted by general relativity. "At that time, we were not able to ask the opposite question: How different can a gravity theory be from general relativity and still be consistent with the shadow size?" said UArizona Steward Theory Fellow Pierre Christian. "We wondered if there was anything we could do with these observations in order to cull some of the alternatives." The team did a very broad analysis of many modifications to the theory of general relativity to identify the unique characteristic of a theory of gravity that determines the size of a black hole shadow. "In this way, we can now pinpoint whether some alternative to general relativity is in agreement with the Event Horizon Telescope observations, without worrying about any other details," said Lia Medeiros, a postdoctoral fellow at the Institute for Advanced Study who has been part of the EHT collaboration since her time as a UArizona graduate student. The team focused on the range of alternatives that had passed all the previous tests in the solar system. "Using the gauge we developed, we showed that the measured size of the black hole shadow in M87 tightens the wiggle room for modifications to Einstein's theory of general relativity by almost a factor of 500, compared to previous tests in the solar system," said UArizona astrophysics professor Feryal Özel, a senior member of the EHT collaboration. "Many ways to modify general relativity fail at this new and tighter black hole shadow test." "Black hole images provide a completely new angle for testing Einstein's theory of general relativity," said Michael Kramer, director of the Max Planck Institute for Radio Astronomy and EHT collaboration member. "Together with gravitational wave observations, this marks the beginning of a new era in black hole astrophysics," Psaltis said. Testing the theory of gravity is an ongoing quest: Are the general relativity predictions for various astrophysical objects good enough for astrophysicists to not worry about any potential differences or modifications to general relativity? "We always say general relativity passed all tests with flying colorsif I had a dime for every time I heard that," Özel said. "But it is true, when you do certain tests, you don't see that the results deviate from what general relativity predicts. What we're saying is that while all of that is correct, for the first time we have a different gauge by which we can do a test that's 500 times better, and that gauge is the shadow size of a black hole." Next, the EHT team expects higher fidelity images that will be captured by the expanded array of telescopes, which includes the Greenland Telescope, the 12-meter Telescope on Kitt Peak near Tucson, and the Northern Extended Millimeter Array Observatory in France. "When we obtain an image of the black hole at the center of our own galaxy, then we can constrain deviations from general relativity even further," Özel said. Will Einstein still be right, then? More information:Physical Review Letters (2020). dx.doi.org/10.1103/PhysRevLett.125.141104 Citation: Einstein's description of gravity just got much harder to beat (2020, October 1) retrieved 1 October 2020 from https://phys.org/news/2020-10-einstein-description-gravity-harder.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.