Tag Archives: larger

Mars Might Have Once Hosted Larger Moons

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Gale Crater on Mars

ZUMA Press, Inc./Alamy

There may have been ancient tides on Mars, suggesting the presence of larger moons capable of influencing the planet’s waters. Currently, Mars has two small moons that aren’t sufficient for this theory.

Suniti Karunatilake and researchers from Louisiana State University discovered signs of tidal activity in Gale Crater’s sedimentary layers.

By examining these layers, they inferred the nature of the tidal cycles and the potential moon responsible for them. If such a moon existed, it would have been significantly larger than Phobos, Mars’ biggest moon, yet still smaller than Earth’s moon. The two current Martian moons might be remnants of a larger satellite.

Mr. Karunatilake is set to present the findings at the upcoming American Geophysical Union meeting in New Orleans, Louisiana.

The sedimentary rocks that supported their conclusions were captured by NASA’s Curiosity rover, displaying alternating layers of varying thicknesses and colors. These strata are termed rhythmite, indicating that they were formed by winds or ocean currents of fluctuating strength. In tidal scenarios, sand is transported back and forth, covered by fine mud when the tide recedes.

The rhythm of strong winds leaves thin, dark lines indicative of “mud drapes,” which “resemble Earth’s tidal patterns closely,” notes team member Priyabrata Das, also from Louisiana State University.

To bolster their hypothesis, Ranjan Sarkar from Germany’s Max Planck Institute for Solar System Research utilized a standard mathematical technique called the Fourier transform to evaluate the layered structures in Martian rocks. This analysis revealed additional periodicity in layer thicknesses, implying that both the sun and a past moon may have influenced the tides.

This analysis may validate the idea initially put forth by Rajat Mazumdar from the German Institute of Technology in Oman. In 2023, Mazumdar suggested that layered formations observed by NASA’s Perseverance rover in Jezero Crater could indicate tidal activity. Unfortunately, the resolution of these images was insufficient for Fourier analysis. Enthused by the Gail rhythmite findings, Mazumdar emphasizes that rhythmite on Earth is strong evidence of tidal conditions.

However, skepticism remains. The lakes in Jezero and Gale craters, sized at 45 kilometers and 154 kilometers respectively, are considered too small to exhibit significant tidal flooding. Nicholas Mangold, a member of NASA’s Perseverance Mars team at the Institute for Planetary and Earth Sciences in Nantes, France, argues that larger moons wouldn’t have left tidal traces in these locations.

Christopher Fed, a professor at the University of Tennessee working with NASA on the Curiosity mission, also finds the notion of a larger moon problematic, suggesting that tidal-like patterns could emerge from varying river inflows instead.

Nevertheless, Sarkar believes a tidal connection is feasible. “The ocean might have linked to Gale, and even subsurface porosity could create tides. Mars’ surface is extensively cracked and crated, meaning porosity isn’t an issue,” he argues.

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Source: www.newscientist.com

New Research Reveals Larger Dinosaurs Don’t Have Stronger Bites Than Expected

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It’s not that the enormous, carnivorous dinosaurs weren’t the terrifying, bone-crushing predators we envision.

A new study published in the journal Current Biology reveals that a variety of bipedal carnivorous dinosaurs, including Tyrannosaurus Rex, Spinosaurus, and Allosaurus, have evolved to possess the necessary skull strength for powerful bites.

Utilizing 3D scanning and computer modeling, the researchers examined the skull biomechanics of 18 species of theropods.

The findings indicated that while T. Rex and other giants had skulls designed to deliver immense bite forces capable of breaking bones, they actually possessed relatively weak jaws and employed diverse hunting strategies.

“The skull of a T. Rex was specifically optimized for high bite force, which led to significant skull stress,” stated the lead author, Dr. Andrew Lowe from the University of Bristol, UK. “In contrast, stress patterns in other giants like Giganotosaurus suggested they had relatively mild bites. This implies a variety of evolutionary pathways for these carnivorous giants.”

Giganotosaurus is larger than T. rex, reaching 13m (43 feet) long and weighing almost 14 tons – Credit: Getty

Instead of adhering to a singular evolutionary path to apex status, large carnivorous dinosaurs evolved various skull shapes and feeding strategies. Some, like T. Rex, would bite down akin to a crocodile, while others, such as Allosaurus and Spinosaurus, employed thrashing or ripping techniques reminiscent of modern Komodo dragons and big cats.

“The Tyrannosaurus took a different approach,” remarked Steve Brusatte, a professor and paleontologist at the University of Edinburgh who was not part of the study, as reported by BBC Science Focus. “They developed immense bite strength, allowing them to crush the bones of their prey. This created a perilous lifestyle, subjecting the skull’s bones and muscles to significant stress.”

The results also challenge the belief that larger dinosaurs necessarily had stronger bites. Some smaller species may actually exert more stress on their skulls due to increased muscle mass, indicating that size alone isn’t the key factor in bite power.

The variability in bite strength and skull architecture hints at a more specialized ecological landscape in dinosaur ecosystems, offering multiple strategies for dominance in the prehistoric food chain.

“There wasn’t a singular ‘best’ skull design for being a predatory giant. Various designs proved effective,” noted Lowe. “This biomechanical diversity implies that dinosaur ecosystems supported a more extensive range of giant carnivorous ecological niches than we typically consider, with less competition and greater specialization.”

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About our experts

Steve Brusatte is a professor and paleontologist at the University of Edinburgh, and author of the book Mammal Ascending and Governing (20 pounds, Picador), focusing on 325 million years of mammalian evolution and fossils.

Source: www.sciencefocus.com

A Solar-Powered Drone Larger than a Jumbo Jet Can Stay Airborne for Months

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Skydweller drone

Skydweller

A solar-powered surveillance drone boasting a wingspan larger than that of the Boeing 747 is capable of flying continuously for weeks or even months, as claimed by its operators. A test flight is currently underway off the US Gulf Coast this month.

Run by the US-Spanish venture Skydweller Aero, the Skydweller drone features a 72-meter wingspan, surpassing the width of most commercial jets. Weighing approximately 2,500 kilograms—similar to a Ford F-150 truck—this drone aims to achieve the first solar-powered flight globally, which was targeted for 2016, with a mission to carry out “pure targeted flights” over 13 kilometers during daylight, while aspiring towards building a “comparable solar-powered carbon fiber drone.”

The Skydweller drone executed the world’s inaugural autonomous solar-powered flight in April 2024, with several subsequent test flights conducted throughout the year. Military funding evaluations are focusing on the viability of marine drone patrols. Military funding is assessing the feasibility of marine drone patrols.

Most recently, the solar-powered drone accomplished its longest flight after departing from Stennis International Airport in Mississippi on July 20. According to the Flightradar24 Flight Tracking Service, it remained aloft over the Gulf Coast for more than three days, landing on July 23. The service also indicated that, on July 14, the drone had flown for over 18 hours.

The wingspan of the Skydweller drone is nearly double that of major surveillance drones, such as the Northrop Grumman RQ-4 Global Hawk used by the US Air Force. Its payload capacity of 400 kilograms significantly surpasses the lifting capabilities of most solar drones. Recently, the French aerospace company Thales contributed to the development of the Skydweller drone by equipping it with air surveillance radar. Equipment was provided for enhancing its capabilities.

However, experts suggest that the decades-long pursuit of commercializing solar drones has largely been marked by unmet promises and monumental failures. Arthur Holland Michele, a research partner at the Oslo Peace Institute, points out that both Google and Facebook attempted to create solar-powered drones for internet services but eventually discontinuing their initiatives. Aerospace manufacturer Airbus, too, has heavily invested in smaller Zephyr solar-electric drones, yet “we haven’t observed significant returns thus far,” states Michele.

“The military has funded solar drone demonstration flights for over ten years, and no one has yet acquired the technology,” Michele explains. “While solar drones are impressive and theoretically meaningful, their practical sustainability as a business case remains unclear.”

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Source: www.newscientist.com

Bite Marks Indicate the Terrobird Was Likely Preyed Upon by an Even Larger Creature 13 Million Years Ago

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Sporting a shaft-like beak capable of inflicting devastating blows, the infamous terrorist birds have emerged as formidable adversaries for many species.

Around 13 million years ago, however, one such bird may have fallen prey to even larger predators. A group of Colombian paleontologists made this discovery while analyzing bite marks found on fossilized remnants of the fearsome avian.

Their findings were published in the peer-reviewed journal “Biology Letters.” The researchers hypothesized that the bird was killed and consumed by medium-sized caimans, a crocodilian species.

Andres Link, the study’s lead investigator, shared with NBC News via email, “This represents a captivating tale of interaction between two iconic animals from the past. Not only did we identify the first instance of terrorist birds in northern South America, but we also found the tooth marks of the large caiman that likely preyed on it.”

Most unusual fossils of terrorist birds have previously been found in the southern regions of the continent, as noted in this report.

Link, an associate professor in biological sciences at the University of Los Andes, remarked that while tooth marks are “not uncommon” in the fossil record, it is “thrilling” to find proof that apex predators could fall victim to others.

The paper in “Biology Letters” highlights that there were no signs of healing on the tooth marks, indicating a fatal attack.

This leads researchers to conclude that terrorist birds may have been more vulnerable to predation than previously believed.

Julian Bayona Becerra / Biology Letters

To determine the identity of the predator, Link and his team performed scans of the fossils and examined the size, shape, and arrangement of the tooth marks. By comparing these features with alligator-like teeth from the region, they deduced that the marks likely belong to a caiman measuring about 15 feet long.

Link noted that it was challenging to ascertain whether the caiman consumed the terrorist bird after killing it or scavenged the carcass. If the bird was alive during the encounter, it likely happened while it was drinking at the riverbank; alternatively, if it was already deceased, the caiman may have found it near the water.

“This narrative remains incomplete, as we lack further evidence to support either hypothesis,” Link stated.

The discovery calls into question the traditional view of “linear relationships between predators and their herbivore prey,” he remarked, adding, “The food web is considerably more intricate.”

The lower section of the bird’s left leg featured in this research was excavated two decades ago by local paleontologist Cesar Perdomo in the renowned La Venta fossil layer of Colombia.

Source: www.nbcnews.com

Many Exoplanets Discovered by NASA’s TESS Satellite Could Be Larger Than Expected

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The radius of a planet is a crucial factor in understanding its composition and characteristics. Accurate radius measurements are generally obtained by analyzing the percentage of starlight blocked as the planet transits its host star. NASA’s Transit Exoplanet Survey Satellite (TESS) has identified hundreds of new exoplanets; however, its low angular resolution can lead to the mixing of light from stars hosting exoplanets with that of background stars. If not entirely corrected, this additional light may dilute the transit signal, leading to an underestimation of the planetary radius. In their analysis of the planet Tess, astronomers from the University of California, Irvine revealed that systematically incorrect planetary radii are frequently reported in scientific literature.

Artistic impression of a gas giant exoplanet and its parent red dwarf star. Image credit: Sci.News.

“We have discovered that many exoplanets are larger than previously thought, which shifts our understanding of exoplanet characteristics on a wide scale,” states Tae Han, a doctoral student at the University of California, Irvine.

“This suggests that we may have actually identified Earth-like planets that are fewer than we initially believed.”

Astronomers cannot directly observe exoplanets; they rely on the planets passing in front of their host stars to measure the subtle decrease in starlight.

“Essentially, we are measuring the shadows cast by planets,” remarks Paul Robertson, a professor at the University of California, Irvine.

In their study, the authors examined the observations of hundreds of exoplanets detected by TESS.

They found that light from neighboring stars could “contaminate” the light emitted by the stars under study.

This results in planets transiting in front of their stars appearing smaller than their actual size, receiving less light compared to larger planets.

Astronomers have conducted numerous studies explaining the characteristics of planets discovered by TESS.

They categorized the planets based on how different research teams measured their radii and used computer models to estimate the extent of bias resulting from light interference from adjacent stars.

Data from the ESA Gaia satellite was utilized to assess the impact of light contamination on TESS observations.

“TESS data is indeed contaminated, and our custom models perform better than any existing methods in the field,” stated Professor Robertson.

“What we discovered in this study is that these planets could be systematically larger than we initially assumed.”

“This raises the question: How common are Earth-sized planets?”

Previously, it was thought there were fewer planets resembling Earth in size.

“Among the single-planet systems identified by TESS, only three were believed to have a composition similar to Earth,” Han noted.

“This new finding indicates that all of them are larger than we previously thought.”

This implies that instead of rocky planets like Earth, they are more likely to be water worlds (planets entirely covered by vast oceans that are often larger than Earth) or larger gas giants like Uranus or Neptune.

This could have significant implications for the search for life on distant worlds, as water worlds may harbor life but lack the specific conditions necessary for life to thrive as it does on Earth.

“These insights have important consequences for our understanding of exoplanets, including prioritizing follow-up observations with the NASA/ESA/CSA James Webb Space Telescope and assessing the prevalence of water worlds in our galaxy,” concluded Professor Robertson.

The study was published in Astrophysical Journal Letters.

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Tae Han et al. 2025. Hundreds of TESS exoplanets may be larger than previously thought. ApJL 988, L4; doi: 10.3847/2041-8213/ade794

Source: www.sci.news

New Research Reveals Asian Elephants Have Larger Brains Than Their African Relatives

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Elephants are fascinating creatures. Despite their allure, our understanding of the elephant brain remains limited, and there are notable neuroanatomical differences between the Asian (Elephas Maximus) and African elephants (Loxodonta africana), which have largely gone unexplored. In a recent study, researchers from Humboldt Universität in Berlin and the Leibniz Institute for Zoo and Wildlife Research collected numerous elephant brains to investigate the macroanatomical features that differentiate the species. Surprisingly, they found that Asian elephants possess a larger brain and greater grey matter volume than African elephants, an intriguing contrast given the smaller body size of Asian elephants.

Asian elephant in Myanmar. Image credit: John Jackson.

“The morphological distinctions among elephant species are well-documented,” stated Dr. Marav Schah from Humboldt Universität Berlin and his colleagues.

“For instance, African savanna elephants are larger and have bigger ears than their Asian counterparts.”

“It is also noted that only female African elephants grow larger tusks compared to the minimal tusks found in Asian females.”

“These disparities indicate significant genetic divergence between savanna elephants in Asia and Africa, believed to have arisen 50,000 to 8 million years ago.”

In this research, the team examined the brain weights and structures of both Asian and African elephants via dissections, existing literature, and MRI scans from wildlife and zoo animals.

The findings revealed that adult Asian elephants are significantly heavier than their African counterparts, whose brains average just over 4,400 grams.

This specific finding could not be definitively validated for male elephants, as data for the brain weights in Asian males is limited.

However, the cerebellum appears proportionately heavier in African elephants (22% of total brain body weight) compared to Asian elephants (19%).

Researchers also demonstrated that elephants undergo extensive postnatal brain growth.

By adulthood, an elephant’s brain is roughly three times heavier than at birth.

This indicates that elephants experience notably more brain growth than all primates; except for humans, where the brain weighs only about one-fifth of its final weight at birth.

A boy African elephant in Kenya. Image credit: George Wittemyer.

“The variance in brain weight is likely the most significant difference among these two elephant species,” Dr. Shah noted.

“This accounts for the behavioral variations observed between elephants in Asia and Africa.”

“For instance, the two species display markedly different interactions with humans.”

“Asian elephants have been partially domesticated for millennia and serve as working animals across various cultures and regions.”

“Conversely, only a handful of cases of partial domestication have been somewhat successful with African elephants.”

“It is considerably harder to integrate an African elephant into human society compared to an Asian elephant.”

The study was published today in the journal pnas nexus.

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Marav Shah et al. 2025. The larger and relatively small cerebellum of Asian elephants compared to the African savanna elephants. pnas nexus 4(5): PGAF141; doi: 10.1093/pnasnexus/pgaf141

Source: www.sci.news

Chip tariffs bolster US AI infrastructure as Nvidia looms larger.

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Nvidia, a chip designer, has announced plans to invest up to $500 million (£37.8 billion) in artificial intelligence infrastructure in the United States over the next four years. This move comes in response to President Trump’s tariffs, with signs of manufacturers shifting their investments to American businesses.

The decision follows Trump’s recent tariffs on semiconductors, which are primarily produced by Nvidia in Taiwan. The company’s CEO, Jensen Huang, visited the president at Mar-a-Lago earlier this month, prompting repeated threats from Trump. Nvidia aims to establish fully operational “supercomputer” facilities in the US and collaborate with manufacturing partners to construct factories.

Production of the Blackwell graphics processing unit has already commenced at the TSCM’C factory in Phoenix, Arizona. Additionally, new plants are being developed at Foxconn in Houston and Wistron in Dallas, with expectations of increased mass production within the next 12-15 months.

Huang emphasized that enhancing American manufacturing capabilities is crucial for meeting the growing demand for AI chips and supercomputers, thereby strengthening the company’s supply chain and resilience.

The White House hailed Nvidia’s commitment as a result of the “Trump effect.” Nvidia’s stock market value has surged over the years, driven by the demand for AI chips, but faced challenges due to tariff uncertainties resulting in a drop in stock prices.

Global markets reacted cautiously, hoping for some relief from Trump’s new taxes. While markets in Japan and South Korea rose, Hong Kong and China experienced declines. In Europe, markets showed gradual recovery, with the UK’s FTSE 100 index rising, along with Germany’s DAX and France’s CAC.

Trump’s plans to impose tariffs on semiconductor and drug imports have raised concerns. The US Department of Commerce has launched an investigation into the impact on national security. Amidst these decisions, companies like Novartis are investing in the US drug sector to mitigate tariff threats.

Source: www.theguardian.com

Severe droughts becoming larger, hotter, drier, and longer

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Climate change could increase the frequency and severity of droughts

Zhang Yu/VCG via Getty Images

Severe, perennial droughts have become hotter, drier, and more extensive since the 1980s. These prolonged droughts, some of which are so extreme that they are classified as ‘megadroughts’, can have particularly devastating effects on agriculture and ecosystems.

Rising temperatures associated with climate change are increasing the risk of drought by making the air warmer, retaining more moisture, and increasing evaporation from the land. Combined with changes in precipitation patterns that lead to reduced rainfall, this could exacerbate droughts and lengthen their duration. This is evidenced by the recent megadrought in parts of North and South America, the worst in 1,000 years.

dark cargar Researchers from the Swiss Federal Institute for Forestry, Snow and Landscape Research identified more than 13,000 droughts lasting at least two years from 1980 to 2018 to uncover long-term trends. They found that the most severe multi-year droughts since the 1980s have become drier and hotter.

Droughts are also affecting wider areas of the planet, with the area affected by the 500 most severe droughts each year expanding by around 50,000 square kilometers each year. “That’s an area larger than Switzerland,” Karger says.

Satellite images showing green areas in drought-affected areas also show some ecosystems turning brown, indicating that dry conditions are having an effect. The most dramatic changes were seen in temperate grasslands, which are more sensitive to changes in water availability, while tropical and boreal forests showed smaller responses.

The researchers have not conducted a formal analysis to define how much anthropogenic climate change is contributing to this trend, but they say the pattern is consistent with the rise in temperatures researchers expect. states. benjamin cook from Columbia University in New York was not involved in the study.

The study highlights that long-term droughts can have consequences as severe as climate disasters such as devastating wildfires or powerful hurricanes, Cook said. “It’s the cumulative effects of drought, both for humans and ecosystems, that really matter.”

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Source: www.newscientist.com

Gas bubble on another star found to be 75 times larger than the Sun

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The movement of bubbling gas on the surface of R Doradus

ALMA (ESO/National Astronomical Observatory of Japan/NRAO)/W. Breming

A giant bubble of hot gas more than 75 times the size of our sun has been observed on the surface of a nearby star, and researchers say this could lead to improved computer simulations of the sun.

Wouter Flemings He and his colleagues from Chalmers University of Technology in Gothenburg, Sweden, were looking at R Doradus, a star 178 light-years away from Earth and 350 times the mass of the Sun, in hopes of better understanding how material is ejected from old stars.

Vlemmings says they booked time at the Atacama Large Millimeter/submillimeter Array (ALMA) observatory in Chile — which only gets one in seven applications — and there they collected a single snapshot observation.

The first two attempts were hampered by weather conditions on Earth, and only the third met the stringent quality standards set out in the researchers' Observatory Time application, but this led to the accumulation of multiple images that Vlemmings says were in fact all usable, allowing the team to plot movement over time.

Not only was this the first time such a bubble had been observed in detail outside the solar system, but the image was shaped like a kind of flip-book, allowing the researchers to measure not only its size but also its speed. “That was a bonus,” Flemings says. “We hadn't planned for it, and certainly didn't expect it to all work out that way. [this way].”

They also discovered that giant gas bubbles, more than 100 million kilometres wide, were rising to the surface and then sinking back into the star's interior at a faster rate than expected.

Nuclear fusion reactions inside the star create convection currents, which cause bubbles of hot gas to rise to the surface, then cool and sink back to the core. This process is thought to eject material that escapes the star's gravity and spreads out into space to form new stars and planets. At least in R Doradus, this process appears to be happening three to four times faster than expected, with bubbles forming and disappearing over the course of about a month.

Areas around R Doradas

ESO/Digital Sky Survey 2

Stellar convection has been modeled in computers before, but those models appear to be a bit flawed because the motion isn't nearly as fast as observed in the real world, Vlemings said.

“These bubbles are moving a little faster than expected, so it seems like we're missing something,” he says. “For a long time in our field, the models have basically been ahead of the observations, but we've never really had the observations to test whether those models are correct.”

Doradus R has not been the subject of much study because it's only visible from the Southern Hemisphere, and historically most of the large radio telescopes have been in the Northern Hemisphere. But that's changed with ALMA, Vlemmings says. Because ALMA produces such comprehensive data, he hopes to find even more remnants. Researchers hope to observe similar stars next year to see if the phenomenon can be found in other places.

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Source: www.newscientist.com

Evidence shows pregnant sharks are preyed on by larger sharks

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Prior to giving birth, the pregnant porbeagle shark was expected to give birth soon, when one of the two tracking tags attached to the shark by marine scientists resurfaced near Bermuda.

Surprisingly, the tag emerged much earlier than anticipated. It had been affixed to the 7-foot-long shark only 158 days prior, after conducting an ultrasound scan off the coast of Cape Cod, Massachusetts, in October 2020. The tag was supposed to remain attached for about a year.

“Something seemed amiss,” stated Brooke Anderson, a shark researcher at Arizona State University during that time.

The second tag, which was designed to transmit a signal when the shark’s fin breached the surface, never sent a signal again.

Data collected from the retrieved “pop-off” tag revealed an unusual pattern: for the initial five months, the depth and temperature information appeared normal for this species, but then deviations started to occur.

“Unexpectedly, temperatures suddenly spiked and remained high even at depths of 600 meters,” recounted Anderson.

The diving patterns of the creatures also became peculiar.

Of the 11 porbeagle sharks that researchers tagged, eight were pregnant, including this one.
John Dodd

“All the data pointed in one direction: she had been consumed,” remarked Anderson.

The researchers ascertained that the irregular readings from the tag were due to it having been inside another animal’s stomach for several days.

Their conclusions were detailed in a study published in the Frontiers in Marine Science journal, shedding light on the fact that porbeagle sharks are being preyed upon by much bigger animals.

Naming a few possible predators, the researchers narrowed down their suspects based on biological characteristics – the data didn’t align with a mammal like a killer whale, leading them to focus on warm-blooded sharks with some heat-generating capacity.

“The predator needed to elevate its body temperature above the ambient water, have the size to inflict damage on the porbeagle, and reside in the area of the predation,” explained Anderson.

The researchers inferred that a great white shark or mako shark likely devoured the pregnant porbeagle, temporarily swallowing the tag.

“Our estimation is that it was a mature female great white shark, possibly exceeding 15 feet in length,” disclosed Anderson.

Previously, the notion that porbeagle sharks might fall prey to larger creatures had not been considered, she added.

Originally, their team aimed to track pregnant porbeagle sharks during their gestation period and pinpoint where they typically give birth.

Across two Atlantic seasons, they located and tagged a total of 11 porbeagle sharks, hauling each one onto the boat, treating them with aerated seawater, and concealing their eyes with wet towels.

“We operated like a NASCAR pit crew,” described Anderson. Eight of these sharks were pregnant.

Their expectations didn’t encompass uncovering a profound deep-sea mystery.

Matt Davis, a marine resources scientist from the Maine Department of Marine Resources not involved in the research, acknowledged that the study’s conclusions were plausible.

This incident underscores the continued need for scientific exploration of mid-depth ocean life and predator-prey interactions, added Davis.

The porbeagle shark is categorized as an endangered species by the International Union for Conservation of Nature. Overfishing activities began in the 1960s, causing a population decline of 75 to 80 percent by 2001, as per Anderson.

While the species is recuperating due to fishing regulations, their longer lifespan and lower reproductive rate mean a protracted recovery process.

“We must continue tagging and monitoring these sharks to understand the frequency of such incidents,” emphasized Anderson regarding the predation. “In an instant, this critically endangered species lost not just its essential breeding females, but all its developing offspring as well. It is crucial to grasp both the frequency and impact of such events.”

Their research could play a pivotal role in restoring a healthy shark population in the Atlantic, where sharks prey on sharks.

Source: www.nbcnews.com

The largest sequenced genome is 30 times larger than the human genome

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South American lungfish probably has a lot of 'junk' DNA

Katherine Segers/Louisiana State University

The largest sequenced genome on record, containing 90 billion DNA letters, belongs to a South American lungfish.

“Obviously, making this happen was a technical challenge,” he said. Axel Meyer “This is the largest animal genome ever found,” said researchers from the University of Konstanz in Germany.

South American lungfish (Lepidosiren paradoxaThere are two copies of the human genome, with a total of 180 gigabases (Gb) of DNA, which would stretch to 55 metres if laid out in a line – 30 times the amount of DNA found in a single human cell (6 Gb).

The South American lungfish has 19 chromosomes, 18 of which are larger than a single copy of the human genome, Meyer said.

His team also sequenced a single copy of the 40 Gb African lungfish genome (Protopterus annectens), the researchers have now sequenced all six species of lungfish found around the world, all of which have unusually large genomes.

“It's really puzzling how these fish can tolerate such large genomes,” Meyer says. The nucleus in each cell must be very large to accommodate so much DNA, meaning each cell is larger than normal, he says. Replicating that much DNA also requires a lot of energy with each cell division.

There's no evidence that this extra DNA does anything useful. Rather, it appears to be the result of a “genetic parasite” replicating itself endlessly. It's probably mostly junk, Meyer says.

His team found that mechanisms that other organisms use to limit the spread of genetic parasites appear to be damaged or missing in all lungfish species, resulting in the South American lungfish genome growing by 3.7 Gb every 10 million years – more than one copy of the human genome.

The reason for sequencing all lungfish species is to get a better understanding of what their common ancestor was like, a close relative of the lungfish that evolved into the first tetrapod land animal.

“Of all fish, lungfish are our closest relatives,” Meyer says. As their name suggests, lungfish breathe air and would drown without it.

They can also live for more than 100 years and regrow fins and tails, Meyer said, and his team hopes to figure out how they do this.

Some plant genomes are even larger than that of the South American lungfish: a small fern found on several Pacific islands is thought to have 321 Gb of DNA per cell, but there are no plans to sequence it.

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Source: www.newscientist.com

Lake Eridania, a lake larger than any on Earth, was once present on Mars

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This new image is High resolution stereo camera (HRSC) on board ESA's Mars Express spacecraft Calaris ChaosIt is the collapsed and dried-up remains of a vast ancient Martian lake called Lake Eridania.

This image taken by ESA's Mars Express shows Karalis Chaos, a region on Mars that is thought to have once held abundant water in the form of an ancient lake known as Lake Eridania. Image credit: ESA / DLR / Free University Berlin.

Lake Eridania once held more water than all other lakes on Mars combined, covering an area of ​​over 1 million km.2.

The lake was larger than any known lake on Earth, containing nearly three times the volume of water as the Caspian Sea.

It probably first existed as one large body of water about 3.7 billion years ago, and then as it began to dry out, it emerged as a series of smaller, isolated lakes.

Eventually Lake Eridania disappeared entirely, along with the rest of the Red Planet's water.

“The bottom left portion of the frame reveals remnants of an ancient lake bed,” Mars Express researchers said.

“The boundary of this layer can be seen curving upward from the center of the frame, surrounding a large central crater.”

“The old lake bed is now filled with many raised banks, which are thought to have formed when ancient Martian winds blew dust across Mars.”

“This dust was then covered with water, transformed, and dried up again and broke apart.”

In addition to water, there are clear signs of volcanic activity in and around this area, known as Karalis Chaos.

“The image shows two long cracks running horizontally, crossing both the lake bed and the smoother ground above,” the scientists said.

“These are known as the Sirenum-Fossae faults, and they formed when the Tharsis region of Mars, home to the solar system's largest volcanoes, rose up, putting enormous pressure on the Martian crust.”

“A lot of the wrinkled ridges you see here are also the result of volcanic pressure.”

“These appear as wavy lines running vertically across the frame.”

“Wrinkle ridges are common in volcanic plains and form when new lava layers compress, buckle and deform while still soft and elastic.”

“Also interesting is this impact crater, created by a space rock colliding with Mars.”

Source: www.sci.news

Physicist working on project to construct a telescope larger than Earth

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We live in the age of black hole photography. In 2019, the first photograph of a black hole was published. Naturally, it was difficult to capture. In fact, it required a telescope almost as large as the Earth. But for researchers like Alex Lupsaski of Vanderbilt University in Tennessee, that wasn't enough. Lupsaski and his colleagues aim to capture a more detailed image, but to achieve that, they will need an even larger telescope.

The 2019 groundbreaking photo was taken by a network of radio observatories dotted around Earth, collectively known as the Event Horizon Telescope (EHT). Eight observatories worked together to produce an image as sharp as a single dish larger than anything we could actually build. Lupsaski is part of a team planning the launch of the Black Hole Explorer (BHEX) telescope, which will extend this network 20,000 kilometers from Earth into space, effectively creating a receiver larger than Earth. This, he says, will give researchers the precision they need to measure a mysterious part of a black hole called the photon ring. In this case, the photon ring is produced by the supermassive black hole M87* in a nearby galaxy that appeared in the first photo.

LupsaskaAs deputy project scientist for the BHEX mission, he's a theorist specializing in the physics of extreme environments like the heart of a black hole. He tells us why this is our best hope of beating Albert Einstein's theory of gravity, and why an ambitious space mission is the key to finally unlocking that theory.

Source: www.newscientist.com

New Study Shows Male Mammals Are Not Larger Than Females

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In his influential work Descent of Man, Charles Darwin confidently asserted that male mammals are generally larger than females. This concept, known as sexual size dimorphism (SSD), initially seemed logical. Darwin believed that females needed to invest a significant amount of energy in their offspring during pregnancy and after giving birth, while males needed to be bigger and stronger to compete with other males, particularly in scenarios involving physical combat.

For over 150 years, Darwin’s views on this matter have remained largely unchallenged. However, a recent study conducted by researchers at the City University of New York and Princeton University may radically alter this perspective. The research indicates that in most mammalian species, there is actually no significant difference in body size between males and females.

The study analyzed a total of 429 mammal species, with nine individuals from each species being examined. While in species where sexual dimorphism is present (such as lions and deer, where males and females exhibit distinct physical traits), males tended to be larger. However, this pattern did not hold true for the majority of species.

For instance, many species of bats and rodents show minimal dimorphism, with males and females displaying similar sizes.

“We were surprised to discover that almost half of all bat species have larger females and that half of all rodent species exhibit sexual size monomorphism, where males and females are the same size,” stated Dr. Kaia Tombak, the lead scientist behind the study, in an interview with BBC Science Focus. “These two groups make up the majority of all mammals.”

Past studies on dimorphism have often excluded these species from their findings.

“The concept of ‘larger males’ remains prevalent in evolutionary biology,” Tombak noted. “However, if this research receives sufficient attention, it could lead to significant changes in this area.”

Bat

Yellow-winged bat (Lavia front) in Kenya. In this species, like most bats, females tend to be larger than males. Photo credit: Severin Hex

The most extreme female-biased dimorphism (where females are larger than males) was observed in peninsular tube-nosed bats (Murina Peninsula). Female world leaf-nosed bats (Phyllostomidae) also tended to be larger than males.

Source: www.sciencefocus.com