Why do Earth's hemispheres look equally bright when viewed from space?

When seen from space, Earth's hemispheres -- northern and southern -- appear equally bright. This is particularly unexpected because the Southern Hemisphere is mostly covered with dark oceans, whereas the Northern Hemisphere has a vast land area that is much brighter than these oceans. For years, the brightness symmetry between hemispheres remained a mystery. In a new study, published in the Proceedings of the National Academy of Sciences (PNAS), Weizmann Institute of Science researchers and their collaborators reveal a strong correlation between storm intensity, cloudiness and the solar energy reflection rate in each hemisphere. They offer a solution to the mystery, alongside an assessment of how climate change might alter the reflection rate in the future.

As early as the 1970s, when scientists analyzed data from the first meteorological satellites, they were surprised to find out that the two hemispheres reflect the same amount of solar radiation. Reflectivity of solar radiation is known in scientific lingo as "albedo." To better comprehend what albedo is, think about driving at night: It is easy to spot the intermittent white lines, which reflect light from the car's headlights well, but difficult to discern the dark asphalt. The same is true when observing Earth from space: The ratio of the solar energy hitting the Earth to the energy reflected by each region is determined by various factors. One of them is the ratio of dark oceans to bright land, which differ in reflectivity, just like asphalt and intermittent white lines. The land area of the Northern Hemisphere is about twice as large as that of the Southern, and indeed when measuring near the surface of the Earth, when the skies are clear, there is more than a 10 percent difference in albedo. Still, both hemispheres appear to be equally bright from space.

In this study, the team of researchers, led by Prof. Yohai Kaspi and Or Hadas of Weizmann's Earth and Planetary Sciences Department, focused on another factor influencing albedo, one located in high altitudes and reflecting solar radiation -- clouds. The team analyzed data derived from the world's most advanced databases, including cloud data collected via NASA satellites (CERES), as well as data from ERA5, which is a global weather database containing information collected using a variety of sources in the air and on the ground, dating back to 1950. ERA5 data was utilized to complete cloud data and to cross-correlate 50 years of this data with information on the intensity of cyclones and anticyclones.

Next, the scientists classified storms of the last 50 years into three categories, according to intensity. They discovered a direct link between storm intensity and the number of clouds forming around the storm. While Northern Hemisphere and land areas in general are characterized by weaker storms, above oceans in the Southern Hemisphere, moderate and strong storms prevail. Data analysis showed that the link between storm intensity and cloudiness accounts for the difference in cloudiness between the hemispheres. "Cloud albedo arising from strong storms above the Southern Hemisphere was found to be a high-precision offsetting agent to the large land area in the Northern Hemisphere, and thus symmetry is preserved," says Hadas, adding: "This suggests that storms are the linking factor between the brightness of Earth's surface and that of clouds, solving the symmetry mystery."

Could climate change make one of the hemispheres darker?

Earth has been undergoing rapid change in recent years, owing to climate change. To examine whether and how this could affect hemispheric albedo symmetry, the scientists used CMIP6, a set of models run by climate modeling centers around the world to simulate climate change. One of these models' major shortcomings is their limited ability to predict the degree of cloudiness. Nevertheless, the relation found in this study between storm intensity and cloudiness enables scientists to assess future cloud amounts, based on storm predictions.

Models predict global warming will result in a decreased frequency of all storms above the Northern Hemisphere and of weak and moderate storms above the Southern Hemisphere. However, the strongest storms of the Southern Hemisphere will intensify. The cause of these predicted differences is "Arctic amplification," a phenomenon in which the North Pole warms twice as fast as Earth's mean warming rate. One might speculate that this difference should break hemispheric albedo symmetry. However, the research shows that a further increase in storm intensity might not change the degree of cloudiness in the Southern Hemisphere because cloud amounts reach saturation in very strong storms. Thus, symmetry might be preserved.

"It is not yet possible to determine with certainty whether the symmetry will break in the face of global warming," says Kaspi. "However, the new research solves a basic scientific question and deepens our understanding of Earth's radiation balance and its effectors. As global warming continues, geoengineered solutions will become vital for human life to carry on alongside it. I hope that a better understanding of basic climate phenomena, such as the hemispheric albedo symmetry, will help in developing these solutions."

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James Webb spots super old, massive galaxies that shouldn't exist

In a new study, an international team of astrophysicists has discovered several mysterious objects hiding in images from the James Webb Space Telescope: six potential galaxies that emerged so early in the universe’s history and are so massive they should not be possible under current cosmological theory.

Each of the candidate galaxies may have existed at the dawn of the universe roughly 500 to 700 million years after the Big Bang, or more than 13 billion years ago. They’re also gigantic, containing almost as many stars as the modern-day Milky Way Galaxy.

“It’s bananas,” said Erica Nelson, co-author of the new research and assistant professor of astrophysics at the University of Colorado Boulder. “You just don’t expect the early universe to be able to organize itself that quickly. These galaxies should not have had time to form.”
        
Nelson and her colleagues, including first author Ivo Labbé of the Swinburne University of Technology in Australia, published their results Feb. 22 in the journal Nature.

The latest finds aren’t the earliest galaxies observed by James Webb, which launched in December 2021 and is the most powerful telescope ever sent into space. Last year, another team of scientists spotted four galaxies that likely coalesced from gas around 350 million years after the Big Bang. Those objects, however, were downright shrimpy compared to the new galaxies, containing many times less mass from stars.

The researchers still need more data to confirm that these galaxies are as big as they look, and date as far back in time. Their preliminary observations, however, offer a tantalizing taste of how James Webb could rewrite astronomy textbooks.

“Another possibility is that these things are a different kind of weird object, such as faint quasars, which would be just as interesting,” Nelson said.

Fuzzy dots

There’s a lot of excitement going around: Last year, Nelson and her colleagues, who hail from the United States, Australia, Denmark and Spain, formed an ad hoc team to investigate the data James Webb was sending back to Earth.

Their recent findings stem from the telescope’s Cosmic Evolution Early Release Science (CEERS) Survey. These images look deep into a patch of sky close to the Big Dipper—a relatively boring, at least at first glance, region of space that the Hubble Space Telescope first observed in the 1990s.

Nelson was peering at a postage stamp-sized section of one image when she spotted something strange: a few “fuzzy dots” of light that looked way too bright to be real.

“They were so red and so bright,” Nelson said. “We weren’t expecting to see them.”

She explained that in astronomy, red light usually equals old light. The universe, Nelson said, has been expanding since the dawn of time. As it expands, galaxies and other celestial objects move farther apart, and the light they emit stretches out—think of it like the cosmic equivalent of saltwater taffy. The more the light stretches, the redder it looks to human instruments. (Light from objects coming closer to Earth, in contrast, looks bluer).

The team ran calculations and discovered that their old galaxies were also huge, harboring tens to hundreds of billions of sun-sized stars worth of mass, on par with the Milky Way.

These primordial galaxies, however, probably didn’t have much in common with our own.  

 “The Milky Way forms about one to two new star every year,” Nelson said. “Some of these galaxies would have to be forming hundreds of new stars a year for the entire history of the universe.”

Nelson and her colleagues want to use James Webb to collect a lot more information about these mysterious objects, but they’ve seen enough already to pique their curiosity. For a start, calculations suggest there shouldn’t have been enough normal matter—the kind that makes up planets and human bodies—at that time to form so many stars so quickly.

“If even one of these galaxies is real, it will push against the limits of our understanding of cosmology,” Nelson said.

Seeing back in time

For Nelson, the new findings are a culmination of a journey that began when she was in elementary school. When she was 10, she wrote a report about Hubble, a telescope that launched in 1990 and is still active today. Nelson was hooked.

“It takes time for light to go from a galaxy to us, which means that you're looking back in time when you're looking at these objects,” she said. “I found that concept so mind blowing that I decided at that instant that this was what I wanted to do with my life.”

The fast pace of discovery with James Webb is a lot like those early days of Hubble, Nelson said. At the time, many scientists believed that galaxies didn’t begin forming until billions of years after the Big Bang. But researchers soon discovered that the early universe was much more complex and exciting than they could have imagined.

“Even though we learned our lesson already from Hubble, we still didn’t expect James Webb to see such mature galaxies existing so far back in time,” Nelson said. “I’m so excited.”

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Successful cure of HIV infection after stem cell transplantation, study suggests

Haematopoietic stem cell transplantation for the treatment of severe blood cancers is the only medical intervention that has cured two people living with HIV in the past. An international group of physicians and researchers from Germany, the Netherlands, France, Spain, and the United States has now identified another case in which HIV infection has been shown to be cured in the same way. In a study published this week in Nature Medicine, in which DZIF scientists from Hamburg and Cologne played a leading role, the successful healing process of this third patient was for the first time characterised in great detail virologically and immunologically over a time span of ten years.

An infection with the human immunodeficiency virus (HIV) was previously considered incurable. The reason for this is that the virus "sleeps" in the genome of infected cells for long periods of time, making it invisible and inaccessible to both the immune system and antiviral drugs. The "Düsseldorf patient," a 53-year-old man, is now the third person in the world to be completely cured of the HI virus by a stem cell transplant.

The patient, treated at the University Hospital Düsseldorf for his HIV infection, had received a stem cell transplant due to a blood cancer. As in the cases of the first two patients named "Berlin" and "London," the Düsseldorf patient received stem cells from a healthy donor whose genome contains a mutation in the gene for the HIV-1 co-receptor CCR5. This mutation makes it impossible for most HI viruses to enter human CD4+ T-lymphocytes, their major target cells.

Following transplantation, the patient was carefully monitored virologically and immunologically for almost ten years. Using a variety of sensitive techniques, the researchers analysed the patient's blood and tissue samples to closely monitor immune responses to HIV and the continued presence or even replication of the virus. Already shortly after transplantation and over the entire course of the study years, neither replicating virus nor antibodies or reactive immune cells against HIV were detected. More than four years ago, the antiviral therapy against HIV was discontinued. Ten years after transplantation and four years after the end of anti-HIV therapy, the Düsseldorf patient could be declared cured by the international research consortium.

"This case of curing a chronic HIV infection by stem cell transplantation shows that HIV can in principle be cured," says Prof. Julian Schulze zur Wiesch, DZIF scientist at the University Medical Center Hamburg-Eppendorf and one of the study leads. "In particular, the results of this study are also enormously important for further research into a cure for HIV for the vast majority of people living with HIV for whom stem cell transplantation is not an option."

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Evolution of dinosaur body size through different developmental mechanisms

The meat-eating dinosaurs known as theropods that roamed the ancient Earth ranged in size from the bus-sized T. rex to the smaller, dog-sized Velociraptor. Scientists puzzling over how such wildly different dinosaur sizes evolved recently found -- to their surprise- that smaller and larger theropod dinosaurs like these didn't necessarily get that way merely by growing slower or faster.

In a new paper published in Science, "Developmental strategies underlying gigantism and miniaturization in non-avialan theropod dinosaurs," researchers including Ohio University professor Patrick O'Connor and Ph.D. student Riley Sombathy discovered through examining the bones of dinosaurs that there was no relationship between growth rate and body size.

"Most animals are thought to evolve to be larger by growing faster than their ancestors, but this study shows that it's just as likely that bigger and smaller animals grew for longer or shorter periods of time during growth spurts," said Michael D. D'Emic, a paleontologist at Adelphi University and lead author of the study.

The bones of many animals, including dinosaurs, slowed or paused growth every year, leaving marks like tree rings that indicate the animal's age and can be used to estimate the rate of growth. "Rings like these are called cortical growth marks," said D'Emic. "Widely spaced rings indicate faster growth and narrowly spaced rings tell us that an animal was growing more slowly."

D'Emic, O'Connor, Sombathy and a team of international researchers measured about 500 such growth rings in about 80 different theropod bones, the two-legged, mostly meat-eating species of dinosaurs closely related to birds.

"We found that there was no relationship between growth rate and size," said D'Emic. "Some gigantic dinosaurs grew very slowly, slower than alligators do today. And some smaller dinosaurs grew very fast, as fast as mammals that are alive today." This made sense to co-author Thomas Pascucci, whose graduate thesis contributed to the project: "Extinct animals like dinosaurs inspire awe because of how different they seem from our modern world, but they were animals that grew under similar constraints and environmental factors as those that exist today."

According to O'Connor, this study opens the door to future investigations of how animals regulate their growth. "Alteration of different growth control mechanisms, at molecular or genetic levels, likely accounts for the range of developmental strategies our team observed in theropod dinosaurs. Future studies of living organisms provide an opportunity to elucidate mechanisms related to the evolution of body size in vertebrates more generally."

Sombathy hopes to take up some of those investigations, adding "One of the things that interests me most about the results is the apparent decoupling between growth rate and body size. My Ph.D. dissertation will investigate the impacts of growth rate and body size on bone shape and function."

"This has really important implications because changes in rate versus timing can correlate to many other things, like how many or how large your offspring are, how long you live, or how susceptible to predators you are," D'Emic added. "Hopefully this research spurs investigations into other groups, both alive and extinct, to see what developmental mechanisms are most important in other types of animals."

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Discovery of massive early galaxies defies prior understanding of the universe

Six massive galaxies discovered in the early universe are upending what scientists previously understood about the origins of galaxies in the universe.

"These objects are way more massive? than anyone expected," said Joel Leja, assistant professor of astronomy and astrophysics at Penn State, who modeled light from these galaxies. "We expected only to find tiny, young, baby galaxies at this point in time, but we've discovered galaxies as mature as our own in what was previously understood to be the dawn of the universe."

Using the first dataset released from NASA's James Webb Space Telescope, the international team of scientists discovered objects as mature as the Milky Way when the universe was only 3% of its current age, about 500-700 million years after the Big Bang. The telescope is equipped with infrared-sensing instruments capable of detecting light that was emitted by the most ancient stars and galaxies. Essentially, the telescope allows scientists to see back in time roughly 13.5 billion years, near the beginning of the universe as we know it, Leja explained.

"This is our first glimpse back this far, so it's important that we keep an open mind about what we are seeing," Leja said. "While the data indicates they are likely galaxies, I think there is a real possibility that a few of these objects turn out to be obscured supermassive black holes. Regardless, the amount of mass we discovered means that the known mass in stars at this period of our universe is up to 100 times greater than we had previously thought. Even if we cut the sample in half, this is still an astounding change."

In a paper published today (Feb. 22) in Nature, the researchers show evidence that the six galaxies are far more massive than anyone expected and call into question what scientists previously understood about galaxy formation at the very beginning of the universe.

"The revelation that massive galaxy formation began extremely early in the history of the universe upends what many of us had thought was settled science," said Leja. "We've been informally calling these objects 'universe breakers' -- and they have been living up to their name so far."

Leja explained that the galaxies the team discovered are so massive that they are in tension with 99% percent of models for cosmology. Accounting for such a high amount of mass would require either altering the models for cosmology or revising the scientific understanding of galaxy formation in the early universe -- that galaxies started as small clouds of stars and dust that gradually grew larger over time. Either scenario requires a fundamental shift in our understanding of how the universe came to be, he added.

"We looked into the very early universe for the first time and had no idea what we were going to find," Leja said. "It turns out we found something so unexpected it actually creates problems for science. It calls the whole picture of early galaxy formation into question."

On July 12, NASA released the first full-color images and spectroscopic data from the James Webb Space Telescope. The largest infrared telescope in space, Webb was designed to see the genesis of the cosmos, its high resolution allowing it to view objects too old, distant or faint for the Hubble Space Telescope.

"When we got the data, everyone just started diving in and these massive things popped out really fast," Leja said. "We started doing the modeling and tried to figure out what they were, because they were so big and bright. My first thought was we had made a mistake and we would just find it and move on with our lives. But we have yet to find that mistake, despite a lot of trying."

Leja explained that one way to confirm the team's finding and alleviate any remaining concerns would be to take a spectrum image of the massive galaxies. That would provide the team data on the true distances, and also the gasses and other elements that made up the galaxies. The team could then use the data to model a clearer of picture of what the galaxies looked like, and how massive they truly were.

"A spectrum will immediately tell us whether or not these things are real," Leja said. "It will show us how big they are, how far away they are. What's funny is we have all these things we hope to learn from James Webb and this was nowhere near the top of the list. We've found something we never thought to ask the universe -- and it happened way faster than I thought, but here we are."

Read more at Science Daily

Novel air filter captures wide variety of pollutants

An air filter made out of corn protein instead of petroleum products can concurrently capture small particulates as well as toxic chemicals like formaldehyde that current air filters can't.

The research could lead to better air purifiers, particularly in regions of the world that suffer from very poor air quality. Washington State University engineers report on the design and tests of materials for this bio-based filter in the journal Separation and Purification Technology.

"Particulate matter is not that challenging to filter but to simultaneously capture various kinds of chemical gas molecules, that's more significant," said Katie Zhong, professor in WSU's School of Mechanical and Materials Engineering and a corresponding author on the paper. "These protein-based air filtering materials should be very promising to capture multiple species of air pollutants."

Poor air quality is a factor in diseases such as asthma, heart disease and lung cancer. Commercial air purifiers remove tiny particles in soot, smoke or car exhaust, which could be inhaled directly into the lungs, but air pollution also often contains other hazardous gaseous molecules, such as carbon monoxide, formaldehyde and other volatile organic compounds.

With micron-sized pores, typical high efficiency particulate air filters, also known as HEPA filters, can capture the small particles but aren't able to capture gaseous molecules. They are most often made of petroleum products and glass, which leads to secondary pollution when old filters are thrown away, Zhong said.

The WSU researchers developed a more environmentally friendly air filter made from corn protein fibers that was able to simultaneously capture 99.5% of small particulate matter, similar to commercial HEPA filters, and 87% of formaldehyde, which is higher than specially designed air filters for those types of toxics.

The researchers chose corn to study because of its abundance as an agricultural product in the U.S. The corn protein is also hydrophobic, which means that the protein repels water and could work well in a moist environment such as in a mask.

The amino acids in the corn protein are known as functional groups. When exposed at the protein's surface, these functional groups act like multiple hands, grabbing the toxic chemical molecules. The researchers demonstrated this by exposing a functional group at the protein surface, where it grabbed formaldehyde. They theorize that further rearrangement of the proteins could develop a tentacle-like set of functional groups that could grab a variety of chemicals from the air.

"From the mechanism, it's very reasonable to expect that this protein-based air filter could capture more species of toxic chemical molecules," Zhong said.

The three-dimensional structure that they developed also offers more promise for a simple manufacturing method than thin films of proteins that the research team developed previously. They used a small amount of a chemical, polyvinyl alcohol, to glue the nanofibers together into a lightweight foam-like material.

"This work provides a new route to fabricating environmentally friendly and multi-functional air filters made from abundant natural biomass," Zhong said. "I believe this technology is very important for people's health and our environment, and it should be commercialized."

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Skipping breakfast may compromise the immune system

Fasting may be detrimental to fighting off infection, and could lead to an increased risk of heart disease, according to a new study by the Icahn School of Medicine at Mount Sinai. The research, which focused on mouse models, is among the first to show that skipping meals triggers a response in the brain that negatively affects immune cells. The results that focus on breakfast were published in the February 23 issue of Immunity, and could lead to a better understanding of how chronic fasting may affect the body long term.

"There is a growing awareness that fasting is healthy, and there is indeed abundant evidence for the benefits of fasting. Our study provides a word of caution as it suggests that there may also be a cost to fasting that carries a health risk," says lead author Filip Swirski, PhD, Director of the Cardiovascular Research Institute at Icahn Mount Sinai. "This is a mechanistic study delving into some of the fundamental biology relevant to fasting. The study shows that there is a conversation between the nervous and immune systems."

Researchers aimed to better understand how fasting -- from a relatively short fast of only a few hours to a more severe fast of 24 hours -- affects the immune system. They analyzed two groups of mice. One group ate breakfast right after waking up (breakfast is their largest meal of the day), and the other group had no breakfast. Researchers collected blood samples in both groups when mice woke up (baseline), then four hours later, and eight hours later.

When examining the blood work, researchers noticed a distinct difference in the fasting group. Specifically, the researchers saw a difference in the number of monocytes, which are white blood cells that are made in the bone marrow and travel through the body, where they play many critical roles, from fighting infections, to heart disease, to cancer.

At baseline, all mice had the same amount of monocytes. But after four hours, monocytes in mice from the fasting group were dramatically affected. Researchers found 90 percent of these cells disappeared from the bloodstream, and the number further declined at eight hours. Meanwhile monocytes in the non-fasting group were unaffected.

In fasting mice, researchers discovered the monocytes traveled back to the bone marrow to hibernate. Concurrently, production of new cells in the bone marrow diminished. The monocytes in the bone marrow -- which typically have a short lifespan -- significantly changed. They survived longer as a consequence of staying in the bone marrow, and aged differently than the monocytes that stayed in the blood.

The researchers continued to fast mice for up to 24 hours, and then reintroduced food. The cells hiding in the bone marrow surged back into the bloodstream within a few hours. This surge led to heightened level of inflammation. Instead of protecting against infection, these altered monocytes were more inflammatory, making the body less resistant to fighting infection.

This study is among the first to make the connection between the brain and these immune cells during fasting. Researchers found that specific regions in the brain controlled the monocyte response during fasting. This study demonstrated that fasting elicits a stress response in the brain -- that's what makes people "hangry" (feeling hungry and angry) -- and this instantly triggers a large-scale migration of these white blood cells from the blood to the bone marrow, and then back to the bloodstream shortly after food is reintroduced.

Dr. Swirski emphasized that while there is also evidence of the metabolic benefits of fasting, this new study is a useful advance in the full understanding of the body's mechanisms.

"The study shows that, on the one hand, fasting reduces the number of circulating monocytes, which one might think is a good thing, as these cells are important components of inflammation. On the other hand, reintroduction of food creates a surge of monocytes flooding back to the blood, which can be problematic. Fasting, therefore regulates this pool in ways that are not always beneficial to the body's capacity to respond to a challenge such as an infection," explains Dr. Swirski. "Because these cells are so important to other diseases like heart disease or cancer, understanding how their function is controlled is critical."

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Trained brains rapidly suppress visual distractions

Have you ever found yourself searching for your keys or phone only to end up getting distracted by a brightly colored object that grabs your attention? This type of attentional capture by objects that stand out from their surroundings is known as 'pop-out'. Pop-out is often functional, for instance when we want people to pay attention to bright red road signs. It can however also distract us from our goals, for instance when a brightly colored binder prevents us from finding our keys on a cluttered desk. Would it not be nice if pop-out for distracting items could somehow be blocked or suppressed to avoid distractions and help us find whatever we are looking for faster?

New research from the Vision and Cognition group at the Netherlands Institute for Neuroscience, published in PNAS, demonstrates that this is indeed possible. After training, the visual brain can suppress neuronal responses to pop-out distractors that are usually enhanced compared to responses to other, non-distracting, items. The researchers trained monkeys to play a video game in which they searched for a unique shape among multiple items, while a uniquely colored item tried to distract them. As soon as the monkeys found the unique shape, they made an eye movement to it to indicate their choice. After some training, monkeys became very good at this game and almost never made eye movements to the distractor.

Neurons in area V4 of the visual cortex, a brain area that processes visual information relatively early after is is captured by the eyes, showed consistently enhanced responses to the shape target stimuli. Responses to the distracting color stimuli on the other hand were only very briefly enhanced but became rapidly suppressed. It appears that the brain first briefly detects the presence of the distracting stimulus, and then quickly suppresses it to avoid that it will interfere with the search for the shape target. The color pop-out signal that might cause distraction is thus essentially inverted into a kind of negative pop-out, or "pop-in," to avoids distraction.

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'Forbidden' planet orbiting small star challenges gas giant formation theories

A team of astronomers led by Carnegie's Shubham Kanodia has discovered an unusual planetary system in which a large gas giant planet orbits a small red dwarf star called TOI-5205. Their findings which are published in The Astronomical Journal, challenge long-held ideas about planet formation.

Smaller and cooler than our Sun, M dwarfs are the most common stars in our Milky Way galaxy. Due to their small size, these stars tend to be about half as hot as the Sun and much redder. They have very low luminosities, but extremely long lifespans. Although red dwarfs host more planets, on average, than other, more massive types of stars, their formation histories make them unlikely candidates to host gas giants.

The newly discovered planet -- TOI 5205b -- was first identified as a potential candidate by NASA's Transiting Exoplanet Survey Satellite (TESS). Kanodia's team, which included Carnegie's Anjali Piette, Alan Boss, Johanna Teske, and John Chambers, then confirmed its planetary nature and characterized it using a variety of ground-based instruments and facilities.

"The host star, TOI-5205, is just about four times the size of Jupiter, yet it has somehow managed to form a Jupiter-sized planet, which is quite surprising!" exclaimed Kanodia, who specializes in studying these stars, which comprise nearly three-quarters of our galaxy yet can't be seen with the naked eye.

A small number of gas giants have been discovered orbiting older M dwarf stars. But until now no gas giant has been found in a planetary system around a low-mass M dwarf like TOI-5205. To grasp the size comparison here, a Jupiter-like planet orbiting a Sun-like star could be compared to a pea going around a grapefruit; for TOI-5205b, because the host star is so much smaller, it is more like a pea going around a lemon. In fact, when the Jupiter-mass TOI 5205b crosses in front of its host, it blocks about seven percent of its light -- one of the largest known exoplanet transits.

Planets are born in the rotating disk of gas and dust that surrounds young stars. The most commonly used theory of gas planet formation requires about 10 Earth masses of this rocky material to accumulate and form a massive rocky core, after which it rapidly sweeps up large amounts of gas from the neighboring regions of the disk to form the giant planet we see today.

The time frame in which this happens is crucial.

"TOI-5205b's existence stretches what we know about the disks in which these planets are born," Kanodia explained. "In the beginning, if there isn't enough rocky material in the disk to form the initial core, then one cannot form a gas giant planet. And at the end, if the disk evaporates away before the massive core is formed, then one cannot form a gas giant planet. And yet TOI-5205b formed despite these guardrails. Based on our nominal current understanding of planet formation, TOI-5205b should not exist; it is a "forbidden" planet."

The team demonstrated that the planet's very large transit depth makes it extremely conducive for future observations with the recently launched JWST, which could shed some light on its atmosphere and offer some additional clues about the mystery of its formation.

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Tracking how magnetism affects animal behavior

For over 50 years, scientists have observed that the behaviour of a wide variety of animals can be influenced by the Earth's magnetic field. However, despite decades of research, the exact nature of this 'magnetic sense' remains elusive. Will Schneider and Richard Holland from Bangor University in Wales and their co-worker Oliver Lindecke from the Institute for Biology, Oldenburg, Germany have now written a comprehensive overview of this cross-disciplinary field, with an emphasis on the methodology involved. This work is now published in the journal EPJ Special Topics.

This magnetic sense, or 'magnetoreception', was first noticed in birds, and particularly in migratory songbirds. It has now been observed in many other species including mammals, fish and insects. However, the exact relationship between the magnetic field and the behaviour is difficult to pin down because it can be masked by other environmental factors. Experiments must be very carefully designed if their results are to be statistically sound.

"We aim to provide a balanced overview for researchers who wish to enter this exciting area of sensory biology," explains Schneider. He and his co-authors outlined a range of methods that are used to deduce whether an animal's behaviour is affected by a magnetic field. These include using GPS to mark animals' alignment with the Earth's field during normal activities, such as cows grazing; observing behaviour after tissues thought to be responsible for magnetoreception have been removed, or genes knocked out; and attaching small magnets on or near the animals' bodies to disrupt the mechanism. Further work by animal physiologists, neuroscientists, geneticists and others will also be necessary to truly understand this phenomenon.

And this research is not only of academic interest. "Understanding animal magnetoreception will help us to protect animals released into unknown environments in the wild," adds Lindecke.

From Science Daily