It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Thursday, September 26, 2024
OCEANOGRAPHY
‘Invisible forest’ of algae thrives as ocean warms
University of Exeter
image:
CTD rosette – a device equipped with sensors and bottles to collect water samples and measure different properties of the ocean at various depths
An “invisible forest” of phytoplankton is thriving in part of our warming ocean, new research shows.
Phytoplankton are tiny drifting organisms that do about half of the planet’s “primary production” (forming living cells by photosynthesis).
The new study, by the University of Exeter, examined phytoplankton at the ocean surface and the “subsurface” – a distinct layer of water beneath – to see how climate variability is affecting them.
Published in the journal Nature Climate Change, the findings show these two communities are reacting differently.
Over the last decade, the total “biomass” (living material) of subsurface phytoplankton has increased in response to warming.
Meanwhile, surface phytoplankton now has less chlorophyll – making it less green – but in fact total biomass has remained stable.
Based on 33 years of data from the Bermuda Atlantic Time-series Study (BATS) in the Sargasso Sea, the findings also suggest the depth of the “surface mixed-layer” (region of turbulence at the surface of the ocean) has shallowed as the ocean rapidly warmed in the last decade.
“It’s important to understand these trends because phytoplankton are the foundation of the marine food web, and play a key role in removing carbon dioxide from the atmosphere,” said Dr Johannes Viljoen, from the Department of Earth and Environmental Science at Exeter’s Penryn Campus in Cornwall.
“Our findings reveal that deep-living phytoplankton, which thrive in low-light conditions, respond differently to ocean warming and climate variability compared to surface phytoplankton.
“We typically rely on satellite observations to monitor phytoplankton, but the subsurface is hidden from satellite view.
“Our study highlights the limitations of satellite observations, and underscores the urgent need for improved global monitoring of phytoplankton below what satellites can see.”
Co-author Dr Bob Brewin added: “Changes at the base of the food web can have cascading effects on marine life, from tiny zooplankton to large fish and marine mammals.
“So the future of phytoplankton will have major implications for biodiversity, as well as climate change.”
Dr Viljoen added: “Continued monitoring of these deep-living phytoplankton will help scientists better understand ongoing changes in the ocean that might otherwise go unnoticed.”
The research of Dr Viljoen and co-authors Dr Brewin and Dr Xuerong Sun, all from the Centre for Geography and Environmental Science, is supported by a UKRI Future Leader Fellowship awarded to Dr Brewin.
The paper is entitled: “Climate variability shifts the vertical structure of phytoplankton in the Sargasso Sea.”
CTD rosette – a device equipped with sensors and bottles to collect water samples and measure different properties of the ocean at various depths
Credit
Dr Xuerong Sun
Journal
Nature Climate Change
Article Title
Climate variability shifts the vertical structure of phytoplankton in the Sargasso Sea
Article Publication Date
25-Sep-2024
New study: Deep-sea discovery shines light on life in the twilight zone
Unexpected findings expand our understanding of the impacts of climate change, including how and where the ocean stores carbon, said co-author and University of South Florida scholar Tim Conway
A conductivity, temperature and depth (CTD) rosette used to sample water from the ocean’s twilight zone during a GEOTRACES expedition in the Pacific Ocean.
TAMPA, Fla. (Sept. 23, 2024) – The ocean’s twilight zone is deep, dark, and — according to new research — iron deficient.
No sunlight reaches this region 200 to 1,000 meters below the sea surface, where levels of iron, a key micronutrient, are so low that the growth of bacteria is restricted. To compensate, these bacteria produce molecules called siderophores, which help the bacteria scavenge trace amounts of iron from the surrounding seawater.
The paper detailing these unexpected findings from the Pacific Ocean will publish on Wednesday, Sept. 25, at 11 a.m. ET (4 p.m. London Time) in Nature, and will be viewable at that time at this link. The study could change the way scientists view microbial processes in the deep ocean and offer new insight into the ocean’s capacity to absorb carbon.
“Understanding the organisms that facilitate carbon uptake in the ocean is important for understanding the impacts of climate change,” said Tim Conway, associate professor of chemical oceanography at the USF College of Marine Science, who co-authored the recent study. “When organic matter from the surface ocean descends to the deep ocean, it acts as a biological pump that removes carbon from the atmosphere and stores it in seawater and sediments. Measuring the rates and processes that influence this pump gives us insight into how and where the ocean stores carbon.”
To conduct the study, researchers collected water samples from the upper 1,000 meters of the water column during an expedition through the eastern Pacific Ocean from Alaska to Tahiti. What they found in the samples surprised them. Not only were concentrations of siderophores high in surface waters where iron is expected to be deficient, but they were also elevated in waters between 200 and 400 meters deep, where nutrient and iron concentrations were thought to have little impact on the growth of bacteria.
“Unlike in surface waters, we did not expect to find siderophores in the ocean’s twilight zone,” said Conway. “Our study shows that iron-deficiency is high for bacteria living in this region throughout much of the east Pacific Ocean, and that the bacteria use siderophores to increase their uptake of iron. This has a knock-on effect on the biological carbon pump, because these bacteria are responsible for the breakdown of organic matter as it sinks through the twilight zone.”
The recent discovery was part of GEOTRACES, an international effort to provide high-quality data for the study of climate-driven changes in ocean biogeochemistry.
The study of siderophores is still in the early stages. Researchers involved in GEOTRACES only recently developed reliable methods to measure these molecules in water samples, and they’re still working to understand where and when microbes use siderophores to acquire iron.
Although the research into siderophores is new, this study demonstrates their clear impact on the movement of nutrients in the ocean’s twilight zone.
“For a full picture of how nutrients shape marine biogeochemical cycles, future studies will need to take these findings into account,” said Daniel Repeta, senior scientist at Woods Hole Oceanographic Institution and co-author of the article. “In other words, experiments near the surface must expand to include the twilight zone.”
Click here for images and a PDF of the journal article
###
About the University of South Florida
The University of South Florida, a high-impact research university dedicated to student success and committed to community engagement, generates an annual economic impact of more than $6 billion. With campuses in Tampa, St. Petersburg and Sarasota-Manatee, USF serves approximately 50,000 students who represent nearly 150 different countries. U.S. News & World Report has ranked USF as one of the nation’s top 50 public universities for five consecutive years, and this year USF earned its highest ranking ever among all universities public or private. In 2023, USF became the first public university in Florida in nearly 40 years to be invited to join the Association of American Universities, a prestigious group of the leading universities in the United States and Canada. Through hundreds of millions of dollars in research activity each year and as one of the top universities in the world for securing new patents, USF is a leader in solving global problems and improving lives. USF is a member of the American Athletic Conference. Learn more at www.usf.edu.
Left to right: CTD technician Kyle McQuiggan, Research Technician Keith Shadle and multi-talented Data Analyst Joseph Gum work together to repair the trace metal CTD rosette’s connection to the ship.
Co-chief Scientist Phoebe Lam of the University of California, Santa Cruz and others removed the pump’s damaged section of cable from the wi
Journal
Nature
Method of Research
Observational study
Subject of Research
Not applicable
Article Title
Microbial iron limitation in the ocean’s twilight zone
Article Publication Date
25-Sep-2024'
Nanostructures in the deep ocean floor hint at life’s origin
RIKEN
image:
a) Photograph of HV precipitates collected from the Shinkai Seep Field. b) Cross-polarized optical microscope images of precipitates in cross section. c,d) Scanning electron images showing layers within the precipitates. f) Magnification showing sublayers in the boxed area of d.
Researchers led by Ryuhei Nakamura at the RIKEN Center for Sustainable Resource Science (CSRS) in Japan and The Earth-Life Science Institute (ELSI) of Tokyo Institute of Technology have discovered inorganic nanostructures surrounding deep-ocean hydrothermal vents that are strikingly similar to molecules that make life as we know it possible. These nanostructures are self-organized and act as selective ion channels, which create energy that can be harnessed in the form of electricity. Published Sep. 25 in Nature Communications, the findings impact not only our understanding of how life began, but can also be applied to industrial blue-energy harvesting.
When seawater seeps way down into the Earth through cracks in the ocean floor, it gets heated by magma, rises back up to the surface, and is released back into the ocean through fissures called hydrothermal vents. The rising hot water contains dissolved minerals gained from its time deep in the Earth, and when it meets the cool ocean water, chemical reactions force the mineral ions out of the water where they form solid structures around the vent called precipitates.
Hydrothermal vents are thought to be the birthplace of life on Earth because they provide the necessary conditions: they are stable, rich in minerals, and contain sources of energy. Much of life on Earth relies on osmotic energy, which is created by ion gradients—the difference in salt and proton concentration—between the inside and outside of living cells. The RIKEN CSRS researchers were studying serpentinite-hosted hydrothermal vents because this kind of vent has mineral precipitates with a very complex layered structure formed from metal oxides, hydroxides, and carbonates. “Unexpectedly, we discovered that osmotic energy conversion, a vital function in modern plant, animal, and microbial life , can occur abiotically in a geological environment,” says Nakamura.
The researchers were studying samples collected from the Shinkai Seep Field, located in the Pacific Ocean’s Mariana Trench at a depth of 5743 m. The key sample was an 84-cm piece composed mostly of brucite. Optical microscopes and scans with micrometer-sized X-ray beams revealed that brucite crystals were arranged in continuous columns that acted as nano-channels for the vent fluid. The researchers noticed that the surface of the precipitate was electrically charged, and that the size and direction of the charge—positive or negative—varied across the surface. Knowing that structured nanopores with variable charge are the hallmarks of osmotic energy conversion, they next tested whether osmotic energy conversion was indeed occurring naturally in the inorganic deep-sea rock.
The team used an electrode to record the current-voltage of the samples. When the samples were exposed to high concentrations of potassium chloride, the conductance was proportional to the salt concentration at the surface of the nanopores. But at lower concentrations, the conductance was constant, not proportional, and was determined by the local electrical charge of the precipitate’s surface. This charge-governed ion transport is very similar to voltage-gated ion channels observed in living cells like neurons.
By testing the samples with chemical gradients that exist in the deep ocean from where they were extracted, the researchers were able to show that the nanopores act as selective ion channels. At locations with carbonate adhered to the surface, the nanopores allowed positive sodium ions to flow through. However, at nanopores with calcium adhered to the surface, the pores only allowed negative chloride ions to pass through.
“The spontaneous formation of ion channels discovered in deep-sea hydrothermal vents has direct implications for the origin of life on Earth and beyond,” says Nakamura. “In particular, our study shows how osmotic energy conversion, a vital function in modern life, can occur abiotically in a geological environment.”
Industrial power plants use salinity gradients between seawater and river water to generate energy, a process called blue-energy harvesting. According to Nakamura, understanding how nanopore structure is spontaneously generated in the hydrothermal vents could help engineers devise better synthetic methods for generating electrical energy from osmotic conversion.
Ionic transport by hydrothermal vent precipitates
Schematic showing osmotic power generation upon exposure to potassium chloride (KCl). Overlap of electric double layers within nanopores establishes a screening barrier that is permeable only to ions with specific charges.
The hype surrounding machine learning, a form of artificial intelligence, can make it seem like it is only a matter of time before such techniques are used to solve all scientific problems. While impressive claims are often made, those claims do not always hold up under scrutiny. Machine learning may be useful for solving some problems but falls short for others.
In a new paper in Nature Machine Intelligence, researchers at the U.S. Department of Energy’s Princeton Plasma Physics Laboratory (PPPL) and Princeton University performed a systematic review of research comparing machine learning to traditional methods for solving fluid-related partial differential equations (PDEs). Such equations are important in many scientific fields, including the plasma research that supports the development of fusion power for the electricity grid.
The researchers found that comparisons between machine learning methods for solving fluid-related PDEs and traditional methods are often biased in favor of machine learning methods. They also found that negative results were consistently underreported. They suggest rules for performing fair comparisons but argue that cultural changes are also needed to fix what appear to be systemic problems.
“Our research suggests that, though machine learning has great potential, the present literature paints an overly optimistic picture of how machine learning works to solve these particular types of equations,” said Ammar Hakim, PPPL’s deputy head of computational science and the principal investigator on the research.
Comparing results to weak baselines
PDEs are ubiquitous in physics and are particularly useful for explaining natural phenomena, such as heat, fluid flow and waves. For example, these kinds of equations can be used to figure out the temperatures along the length of a spoon placed in hot soup. Knowing the initial temperature of the soup and the spoon, as well as the type of metal in the spoon, a PDE could be used to determine the temperature at any point along the utensil at a given time after it was placed in the soup. Such equations are used in plasma physics, as many of the equations that govern plasmas are mathematically similar to those of fluids.
Scientists and engineers have developed various mathematical approaches to solving PDEs. One approach is known as numerical methods because it solves problems numerically, rather than analytically or symbolically, to find approximate solutions to problems that are difficult or impossible to solve exactly. Recently, researchers have explored whether machine learning can be used to solve these PDEs. The goal is to solve problems faster than they could with other methods.
The systematic review found that in most journal articles, machine learning hasn’t been as successful as advertised. “Our research indicates that there might be some cases where machine learning can be slightly faster for solving fluid-related PDEs, but in most cases, numerical methods are faster,” said Nick McGreivy. McGreivy is the lead author of the paper and recently completed his doctorate at the Princeton Program in Plasma Physics.
Numerical methods have a fundamental trade-off between accuracy and runtime. “If you spend more time to solve the problem, you’ll get a more accurate answer,” McGreivy said. “Many papers didn’t take that into account in their comparisons.”
Furthermore, there can be a dramatic difference in speed between numerical methods. In order to be useful, machine learning methods need to outperform the best numerical methods, McGreivy said. Yet his research found that comparisons were often being made to numerical methods that were much slower than the fastest methods.
Two rules for making fair comparisons
Consequently, the paper proposes two rules to try to overcome these problems. The first rule is to only compare machine learning methods against numerical methods of either equal accuracy or equal runtime. The second is to compare machine learning methods to an efficient numerical method.
Of 82 journal articles studied, 76 claimed the machine learning method outperformed when compared to a numerical method. The researchers found that 79% of those articles touting a machine learning method as superior actually had a weak baseline, breaking at least one of those rules. Four of the journal articles claimed to underperform when compared to a numerical method, and two articles claimed to have similar or varied performance.
“Very few articles reported worse performance with machine learning, not because machine learning almost always does better, but because researchers almost never publish articles where machine learning does worse,” McGreivy said.
The researchers created the image above to convey the cumulative effects of weak baselines and reporting biases on samples. The circles or hexagons represent articles. Green indicates a positive result, for example, that the machine learning method was faster than the numerical method, while red represents a negative result. Column (a) shows what the system would likely look like if strong baselines were used and reporting bias was not an issue. Column (b) depicts the likely results without reporting bias. Column (c) shows the actual results seen in the published literature. (Image credit: Nick McGreivy)
McGreivy thinks low-bar comparisons are often driven by perverse incentives in academic publishing. “In order to get a paper accepted, it helps to have some impressive results. This incentivizes you to make your machine learning model work as well as possible, which is good. However, you can also get impressive results if the baseline method you’re comparing to doesn’t work very well. As a result, you aren’t incentivized to improve your baseline, which is bad,” he said. The net result is that researchers end up working hard on their models but not on finding the best possible numerical method as a baseline for comparison.
The researchers also found evidence of reporting biases, including publication bias and outcome reporting bias. Publication bias occurs when a researcher chooses not to publish their results after realizing that their machine learning model doesn’t perform better than a numerical method, while outcome reporting bias can involve discarding negative results from the analyses or using nonstandard measures of success that make machine learning models appear more successful. Collectively, reporting biases tend to suppress negative results and create an overall impression that machine learning is better at solving fluid-related PDEs than it is.
“There’s a lot of hype in the field. Hopefully, our work lays guidelines for principled approaches to use machine learning to improve the state of art,” Hakim said.
To overcome these systemic, cultural issues, Hakim argues that agencies funding research and large conferences should adopt policies to prevent the use of weak baselines or require a more detailed description of the baseline used and the reasons it was selected. “They need to encourage their researchers to be skeptical of their own results,” Hakim said. “If I find results that seem too good to be true, they probably are.”
This work was completed with funding from DOE grants DE-AC02-09CH11466 and DE-AC02-09CH11466.
A long-term study by the Universities of Zurich and Utrecht has confirmed a dynamic correlation between self-esteem and sexual satisfaction. The results provide valuable insights about longstanding questions about whether better sex makes you feel better, feeling better makes you have better sex, or both.
Various theories suggest that people with higher self-esteem tend to have more satisfying sexual relationships and that the two factors influence each other. However, little research has been done to date on how this interaction develops over time.
A new study based on a nationally representative sample of more than 11,000 German adults provides some interesting insights. The study was conducted by researchers from the Universities of Zurich (UZH) and Utrecht who analyzed 12-year data of people’s self-esteem and sexual experiences.
Long-term study shows a reciprocal effect
“People with higher self-esteem tend not only to be sexually active more often, but also to be more satisfied with their sexual experiences,” explain lead authors Elisa Weber and Wiebke Bleidorn from the Department of Psychology at UZH. There were also significant correlations over time: changes in sexual satisfaction led to changes in a person’s self-esteem, and vice versa. These intra-individual associations show that self-esteem and sexual satisfaction can influence each other.
Findings on the dynamic interaction between self-esteem and sexual well-being are supported by theories that view self-esteem as a kind of social barometer that indicates the extent to which we feel accepted and valued in our relationships with other people.
Positive experiences in social and intimate relationships can increase self-esteem, while negative experiences are interpreted as a kind of warning signal for social rejection and are reflected in lower self-esteem in the long term. At the same time, people with high self-esteem may be better able to communicate their desires and preferences to intimate partners, resulting in greater sexual well-being in the long term.
Age and gender matter
However, the study also showed that the correlations are not equally pronounced for all people. Age and gender matter: older people and women tended to show a stronger connection between self-esteem and sexual well-being than younger people and men. Interestingly, relationship status did not appear to be relevant, as the link between self-esteem and sexual well-being was as strong for single people as it was for people in relationships.
Wiebke Bleidorn puts the study’s findings in context: “Answering these questions is of immense importance. Our results suggest that self-esteem plays an important role in our sexual experience, particularly with regard to sexual well-being. At the same time, changes in sexual well-being can also lead to changes in self-esteem. The results of this study help to understand the complex interplay between self-esteem and sexual experience and provide important impetus for future research in this area,” according to the author.
Webb discovers 'weird' galaxy with gas outshining its stars
Royal Astronomical Society
image:
The newly-discovered GS-NDG-9422 galaxy appears as a faint blur in this James Webb Space Telescope NIRCam (Near-Infrared Camera) image. It could help astronomers better understand galaxy evolution in the early Universe.
Credit: NASA, ESA, CSA, STScI, Alex Cameron (Oxford)
The discovery of a "weird" and unprecedented galaxy in the early Universe could "help us understand how the cosmic story began", astronomers say.
GS-NDG-9422 (9422) was found approximately one billion years after the Big Bang and stood out because it has an odd, never-before-seen light signature — indicating that its gas is outshining its stars.
The "totally new phenomena" is significant, researchers say, because it could be the missing-link phase of galactic evolution between the Universe's first stars and familiar, well-established galaxies.
This extreme class of galaxy was spotted by the $10billion (£7.6billion) James Webb Space Telescope (JWST), a joint endeavour of the US, European and Canadian space agencies, which has been designed to peer back in time to the beginning of the Universe.
"My first thought in looking at the galaxy's spectrum was, 'that's weird,' which is exactly what the Webb telescope was designed to reveal: totally new phenomena in the early Universe that will help us understand how the cosmic story began," said lead researcher Dr Alex Cameron, of the University of Oxford.
Cameron reached out to colleague Dr Harley Katz, a theorist, to discuss the strange data. Working together, their team found that computer models of cosmic gas clouds heated by very hot, massive stars, to an extent that the gas shone brighter than the stars, was nearly a perfect match to Webb's observations.
"It looks like these stars must be much hotter and more massive than what we see in the local Universe, which makes sense because the early Universe was a very different environment," said Katz, of Oxford and the University of Chicago.
In the local Universe, typical hot, massive stars have a temperature ranging between 70,000 to 90,000 degrees Fahrenheit (40,000 to 50,000 degrees Celsius). According to the team, galaxy 9422 has stars hotter than 140,000 degrees Fahrenheit (80,000 degrees Celsius).
The researchers suspect that the galaxy is in the midst of a brief phase of intense star formation inside a cloud of dense gas that is producing a large number of massive, hot stars. The gas cloud is being hit with so many photons of light from the stars that it is shining extremely brightly.
In addition to its novelty, nebular gas outshining stars is intriguing because it is something predicted in the environments of the Universe's first generation of stars, which astronomers classify as Population III stars.
"We know that this galaxy does not have Population III stars, because the Webb data shows too much chemical complexity. However, its stars are different than what we are familiar with – the exotic stars in this galaxy could be a guide for understanding how galaxies transitioned from primordial stars to the types of galaxies we already know," said Katz.
At this point, galaxy 9422 is one example of this phase of galaxy development, so there are still many questions to be answered. Are these conditions common in galaxies at this time period, or a rare occurrence? What more can they tell us about even earlier phases of galaxy evolution?
Cameron, Katz, and their research colleagues are now identifying more galaxies to add to this population to better understand what was happening in the Universe within the first billion years after the Big Bang.
"It's a very exciting time, to be able to use the Webb telescope to explore this time in the Universe that was once inaccessible," Cameron said.
"We are just at the beginning of new discoveries and understanding."
Caption: The newly-discovered GS-NDG-9422 galaxy appears as a faint blur in this James Webb Space Telescope NIRCam (Near-Infrared Camera) image. It could help astronomers better understand galaxy evolution in the early Universe.
Credit: NASA, ESA, CSA, STScI, Alex Cameron (Oxford)
This image of galaxy GS-NDG-9422, captured by the James Webb Space Telescope's NIRCam (Near-Infrared Camera) instrument, is presented with compass arrows, scale bar, and colour key for reference.
Caption: This comparison of the Webb data with a computer model prediction highlights the same sloping feature that first caught the eye of lead researcher Alex Cameron. The bottom graphic compares what astronomers would expect to see in a "typical" galaxy, with its light coming predominantly from stars (white line), with a theoretical model of light coming from hot nebular gas, outshining stars (yellow line).
Caption: This image of galaxy GS-NDG-9422, captured by the James Webb Space Telescope's NIRCam (Near-Infrared Camera) instrument, is presented with compass arrows, scale bar, and colour key for reference.
Credit: NASA, ESA, CSA, STScI, Alex Cameron (Oxford)
The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science.
The RAS organises scientific meetings, publishes international research and review journals, recognises outstanding achievements by the award of medals and prizes, maintains an extensive library, supports education through grants and outreach activities and represents UK astronomy nationally and internationally. Its more than 4,000 members (Fellows), a third based overseas, include scientific researchers in universities, observatories and laboratories as well as historians of astronomy and others.
The RAS accepts papers for its journals based on the principle of peer review, in which fellow experts on the editorial boards accept the paper as worth considering. The Society issues press releases based on a similar principle, but the organisations and scientists concerned have overall responsibility for their content.
Artist's illustration of the exoplanet WASP-107 b based on transit observations from NASA's James Webb Space Telescope as well as other space- and ground-based telescopes, led by Matthew Murphy of the University of Arizona and a team of researchers around the world.
Astronomers from the University of Arizona, along with an international group of researchers, observed the atmosphere of a hot and uniquely inflated exoplanet using NASA's James Webb Space Telescope. The exoplanet, which is the size of Jupiter but only a tenth of its mass, is found to have east-west asymmetry in its atmosphere, meaning that there is a significant difference between the two edges of its atmosphere.
The findings are published in the journal Nature Astronomy.
"This is the first time the east-west asymmetry of any exoplanet has ever been observed as it transits its star, from space," said lead study author Matthew Murphy, a graduate student at the U of A Steward Observatory. A transit is when a planet passes in front of its star – like the moon does during a solar eclipse.
"I think observations made from space have a lot of different advantages versus observations that are made from the ground," Murphy said.
East-west asymmetry of an exoplanet refers to differences in atmospheric characteristics, such as temperature or cloud properties, observed between the eastern and western hemispheres of the planet. Determining whether this asymmetry exists or not is crucial for understanding the climate, atmospheric dynamics and weather patterns of exoplanets – planets that exist beyond our solar system.
The exoplanet WASP-107b is tidally locked to its star. That means that the exoplanet always shows the same face to the star it is orbiting. One hemisphere of the tidally locked exoplanet perpetually faces the star it orbits, while the other hemisphere always faces away, resulting in a permanent day side and a permanent night side of the exoplanet.
Murphy and his team used the transmission spectroscopy technique with the James Webb Space Telescope. This is the primary tool that astronomers use to gain insights into what makes up the atmospheres of other planets, Murphy said. The telescope took a series of snapshots as the planet passed in front of its host star, encoding information about the planet's atmosphere. Taking advantage of new techniques and the unprecedented precision of the James Webb Space Telescope, the researchers were able to separate the signals of the atmosphere's eastern and western sides and get a more focused look at specific processes happening in the exoplanet's atmosphere.
"These snapshots tell us a lot about the gases in the exoplanet's atmosphere, the clouds, structure of the atmosphere, the chemistry and how everything changes when receiving different amounts of sunlight," Murphy said.
The exoplanet WASP-107b is unique in that it has a very low density and relatively low gravity, resulting in an atmosphere that is more inflated than other exoplanets of its mass would be.
"We don't have anything like it in our own solar system. It is unique, even among the exoplanet population," Murphy said.
WASP-107b is roughly 890 degrees Fahrenheit – a temperature that is intermediate between the planets of our solar system and the hottest exoplanets known.
"Traditionally, our observing techniques don't work as well for these intermediate planets, so there's been a lot of exciting open questions that we can finally start to answer," Murphy said. "For example, some of our models told us that a planet like WASP-107b shouldn't have this asymmetry at all – so we're already learning something new."
Researchers have been looking at exoplanets for almost two decades, and many observations from both the ground and space have helped astronomers guess what the atmosphere of exoplanets would look like, said Thomas Beatty, study co-author and an assistant professor of astronomy at the University of Wisconsin-Madison.
"But this is really the first time that we've seen these types of asymmetries directly in the form of transmission spectroscopy from space, which is the primary way in which we understand what exoplanet atmospheres are made of – it's actually amazing," Beatty said.
Murphy and his team have been working on the observational data they have gathered and are planning to take a much more detailed look at what's going on with the exoplanet, including additional observations, to understand what drives this asymmetry.
"For almost all exoplanets, we can't even look at them directly, let alone be able to know what's going on one side versus the other," Murphy said. "For the first time, we're able to take a much more localized view of what's going on in an exoplanet's atmosphere."
Evidence for morning-to-evening limb asymmetry on the cool low-density exoplanet WASP-107 b
Article Publication Date
24-Sep-2024
Can cosmic radiation in outer space affect astronauts’ long-term cognition?
Wiley
During missions into outer space, galactic cosmic radiation (GCR) will penetrate current spacecraft shielding and thus pose a significant risk to human health. Previous studies have shown that GCR can cause short-term cognitive deficits in male rodents. Now a study published in the Journal of Neurochemistry reveals that GCR exposure can also cause long-lasting learning deficits in female rodents.
The impact of GCR on cognition was lessened when mice were fed an antioxidant and anti-inflammatory compound called CDDO-EA.
Beyond its immediate implications for space exploration, the findings contribute to a broader understanding of radiation’s long-term impact on cognitive health.
“Our study lays the groundwork for future causal delineation of how the brain responds to complex GCR exposure and how these brain adaptations result in altered behaviors,” said co-corresponding author Sanghee Yun, PhD, of the Children’s Hospital of Philadelphia Research Institute and the University of Pennsylvania Perelman School of Medicine.
Additional Information NOTE: The information contained in this release is protected by copyright. Please include journal attribution in all coverage. For more information or to obtain a PDF of any study, please contact: Sara Henning-Stout, newsroom@wiley.com.
About the Journal Owned by the International Society for Neurochemistry, the Journal of Neurochemistry is dedicated to disseminating research covering all aspects of neurochemistry. This includes genetic, molecular, cellular, biochemical and behavioural aspects of the nervous system, with a focus on pathogenesis, biomarkers and treatment of neurological and psychiatric disorders. We prioritize original research that mechanistically demonstrates an advance as well as critical reviews that highlight progression of knowledge in the field.
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The longitudinal behavioral effects of acute exposure to galactic cosmic radiation in female C57BL/6J mice: implications for deep space missions, female crews, and potential antioxidant countermeasures
Article Publication Date
25-Sep-2024
New map of distant planets unveiled by University of Warwick scientists
University of Warwick
image:
Artistic illustration of the Neptunian desert (left) and the Neptunian savanna (right) separated by the Neptunian ridge
A new ‘map’ of distant planets has been unveiled by scientists from The University of Warwick, which finds a ridge of planets in deep space, separating a desert of planets from a more populated savannah.
Researchers from Warwick and other universities examined Neptunian exoplanets – these planets share similar characteristics to our own Neptune, but orbit outside of our solar system.
Scientists discovered a new area called the ‘Neptunian Ridge’ – in between the ‘Neptunian desert’ and the ‘Neptunian Savannah’.
Planets in the desert are very rare, as intense radiation has eroded their atmospheres to the point of destroying them, turning these planets into bare rocky cores.
The savannah is a region located further away from the intense radiation. In this region, environmental conditions are more favourable and allow planets to maintain their atmospheres for millions of years.
In between these two regions, researchers have discovered a new pile-up called the ridge, where there is a large concentration of planets.
Current evidence suggests that many of the planets in the ridge could have arrived from their birthplace through a mechanism called high-eccentricity tidal migration, which can bring planets closer to their stars at any stage of their life.
In contrast, planets in the savannah could have been brought mainly through another type of migration, called disk-driven migration, which occurs just after planets are formed.
Therefore, these two systems driving the movement of planets are populating the savannah and the desert differently. The few planets in the desert could be rare extreme cases pushing the edges of these broad models.
David Armstrong, Associate Professor of Physics at Warwick, commented: “Our work to observe this new structure in space is highly significant in helping us map the exoplanet landscape.
“As scientists, we’re always striving to understand why planets are in the condition they are in, and how they ended up where they are.
“The discovery of the Neptunian ridge helps answer these questions, unveiling part of the geography of exoplanets out there, and is a hugely exciting discovery.”
The full paper was a collaboration between the Centro de Astrobiologia (CAB) annd the Universities of Geneva, Warwick, Coimbra and Paris. It can be read here.
