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Sharks are known as the ocean’s most feared predators, relying on their razor-sharp, constantly regrowing teeth to survive. But scientists say rising ocean acidity could gradually weaken those powerful weapons. That is the conclusion of a study by German researchers who examined how more acidic seawater affects shark teeth. Scientists say human activities such as burning coal, oil and gas are increasing the amount of carbon dioxide absorbed by the oceans, making seawater more acidic. The study found that as acidity increases, shark teeth could become structurally weaker and more prone to cracking and breaking. This could eventually threaten sharks’ position at the top of the marine food chain. “The ocean won’t suddenly be filled with toothless sharks,” said lead researcher Maximilian Baum, a marine biologist at Heinrich Heine University Düsseldorf. “But weaker teeth would be another serious threat for animals already facing pollution, overfishing, climate change and habitat loss.” Baum said the team discovered clear signs of corrosion on shark teeth, warning that the predators’ ecological dominance could be at risk over time. The findings were published in the journal Frontiers in Marine Science as concern grows worldwide over ocean acidification. According to the US National Oceanic and Atmospheric Administration (NOAA), acidification happens when oceans absorb more carbon dioxide from the atmosphere. Scientists estimate the ocean could become nearly 10 times more acidic by the year 2300. For the study, researchers collected more than 600 discarded teeth from an aquarium housing blacktip reef sharks, a species found in the Pacific and Indian oceans. The teeth were placed in water reflecting today’s acidity levels and the projected acidity of the year 2300. Teeth exposed to the more acidic water showed severe damage, including cracks, holes, root corrosion and overall structural degradation. Some dogs can learn new words just by eavesdropping The researchers said the results indicate ocean acidification will have a significant impact on the physical strength of shark teeth. Shark teeth are highly specialised tools designed for slicing through flesh rather than resisting chemical corrosion. Over a lifetime, a shark can grow and lose thousands of teeth, which are essential for hunting and maintaining balance in marine ecosystems. Many shark species are already under threat. According to the International Union for Conservation of Nature, more than a third of all shark species face the risk of extinction. Nick Whitney, a senior scientist at the New England Aquarium who was not involved in the research, said the study was scientifically sound. However, he noted that shark teeth develop inside mouth tissue and may be somewhat protected from changing ocean chemistry for a time. “Sharks have survived for about 400 million years and have adapted to many environmental changes,” Whitney said. Gavin Naylor, director of the Florida Program for Shark Research, said ocean acidification is a concern but stressed that overfishing remains the biggest threat to sharks worldwide. Scientists weigh prospects, hurdles of asteroid mining Scientists also warn that acidification will affect much more than sharks. Shellfish such as oysters and clams may struggle to build shells, while fish scales could become weaker and more brittle. Baum said ocean acidification should not be ignored as a growing danger for sharks. Some species are already close to extinction, and worsening ocean chemistry could push them even closer. “The evolutionary success of sharks depends on their perfectly developed teeth,” he said.

An ailing astronaut returned to Earth early on Thursday along with three crewmates, cutting short their mission aboard the International Space Station by more than a month in NASA’s first-ever medical evacuation from orbit. A SpaceX capsule splashed down in the Pacific Ocean near San Diego shortly after midnight, less than 11 hours after the astronauts departed the space station. They were taken directly to a nearby hospital for overnight medical checks. “Obviously, we took this action because it was a serious medical condition,” NASA Administrator Jared Isaacman said after the splashdown. “The astronaut is fine right now, in good spirits and undergoing the proper medical evaluations.” The mission, which began in August, ended unexpectedly and left the orbiting laboratory temporarily staffed by only one American and two Russian astronauts. NASA and SpaceX said efforts are underway to move up the launch of a replacement crew of four, currently scheduled for mid-February. Read more: James Webb finds black hole killed Pablo’s Galaxy Returning to Earth were NASA astronauts Zena Cardman and Mike Fincke, Japan’s Kimiya Yui, and Russia’s Oleg Platonov. Officials declined to identify which crew member became ill or to disclose details of the condition, citing medical privacy. NASA said the astronaut’s condition was stable in orbit but that an early return was deemed necessary to allow full medical care and diagnostic testing on Earth. The re-entry and splashdown followed standard procedures, and the recovery ship carried its usual team of medical specialists. The astronauts exited the capsule within an hour of landing, were placed on reclining stretchers for routine checks and then transported to the hospital. Isaacman observed the recovery from Mission Control in Houston along with the astronauts’ families. NASA decided several days earlier to send the entire crew directly to a San Diego-area hospital and even conducted practice helicopter flights from the recovery ship. The health issue first emerged on Jan 7, forcing NASA to cancel a scheduled spacewalk the following day and ultimately leading to the decision to end the mission early. Officials stressed that the situation was not considered an emergency and that this marked the first time NASA has shortened a space mission for medical reasons. NASA said the space station can continue operating with a reduced crew for now, but no spacewalks can be conducted until the next team arrives. Read more: Scientists weigh prospects, hurdles of asteroid mining Isaacman said it is too early to know whether the launch of the replacement crew will take priority over NASA’s upcoming crewed moon mission, which is preparing for key tests at Kennedy Space Center. “For now, we’re moving ahead with both missions in parallel,” he said.

Astronomers using the James Webb Space Telescope and the Atacama Large Millimeter Array have uncovered how a distant galaxy known as “Pablo’s Galaxy” was slowly starved to death by its own supermassive black hole. The findings, published in the journal Nature Astronomy, show that the galaxy, officially named GS-10578, lost the cold gas needed to form new stars after repeated outbursts from the black hole at its centre. Pablo’s Galaxy, located about 11 billion light-years away, was once a massive and active star-forming system roughly three billion years after the Big Bang. Scientists estimate it had a mass equivalent to about 200 billion suns. Researchers found that powerful winds driven by the black hole pushed gas out of the galaxy at speeds of up to 2.2 million miles per hour, gradually draining its fuel supply in what they described as a “death by a thousand cuts.” Observations from ALMA detected no carbon monoxide in the galaxy, a key indicator of cold, star-forming gas, confirming that it has been almost completely depleted. The galaxy is currently losing about 60 solar masses of gas every year and could exhaust its remaining fuel within 16 million to 220 million years, scientists said. Despite its decline, Pablo’s Galaxy remains a calm, rotating disc, suggesting it did not suffer a major collision with another galaxy. Instead, repeated episodes of black hole activity likely prevented fresh gas from returning and restarting star formation. Scientists say the discovery helps explain why the James Webb telescope has spotted many “old-looking” galaxies in the early universe and suggests that slow starvation by supermassive black holes may be a common process.   With inputs from NDTV

While most dogs excel at commands like “sit” or “stay,” only a select group can remember the names of toys. New research shows these gifted dogs can expand their vocabulary by eavesdropping on conversations. In a study, ten dogs, including a Border collie named Basket and a Labrador named Augie, watched their owners introduce a new toy while speaking to someone else. Seven of the ten successfully retrieved the correct toy later, even when the object was hidden from view. “This is the first time that we see a specific group of dogs that can learn labels from overhearing interactions,” said Shany Dror, study author. Only a few other animals, like parrots and apes, have demonstrated this ability. While similar to how young children pick up words, the brain mechanisms in adult dogs are likely different. Experts say the findings reveal dogs’ advanced cognitive abilities and raise questions about how they learn from subtle cues.

Europa, one of Jupiter’s moons long considered a promising site for extraterrestrial life, may not have the conditions necessary to support life, according to a new study. Despite its vast subsurface ocean, scientists say the moon’s rocky seafloor is too rigid to allow tectonic or volcanic activity that could generate essential nutrients and chemical energy. Europa is unique in the solar system because it possesses liquid water, organic compounds on its icy surface, and energy from Jupiter’s strong gravitational pull. Its salty ocean is believed to contain nearly twice the volume of all Earth’s oceans combined. However, researchers found that cracks or fractures on the seafloor are likely minimal, limiting the chemical interactions needed for sustaining life. Planetary scientist Paul Byrne of Washington University in St Louis noted that tectonic activity on Earth exposes new rocks to water, triggering chemical reactions that produce elements like methane, which microorganisms use. Without similar processes on Europa, life would find the environment extremely harsh. Europa, measuring about 3,100 kilometers in diameter—roughly a quarter of Earth’s size—is covered by an icy crust estimated to be 15 to 25 kilometers thick, under which lies a 60 to 150 kilometer deep ocean. The moon ranks fourth among Jupiter’s 95 officially recognised satellites. Geologist Christian Klimczak of the University of Georgia said hydrothermal activity such as underwater volcanoes, deep trenches, or black smokers is unlikely on Europa, though he remained hopeful that future missions might challenge these findings. NASA’s Europa Clipper spacecraft, launched in 2024, aims to explore the moon and investigate whether it can support life. The mission will conduct multiple close flybys beginning in 2031 to study the mysteries hidden beneath Europa’s icy surface.   With inputs from NDTV

Asteroid mining, long popular in science fiction, is increasingly being examined by scientists as a potential source of valuable space-based resources, though major technical, economic and legal challenges remain. A recent study assessed the feasibility, opportunities and obstacles associated with mining asteroids, noting that many of these space rocks contain significant quantities of metals such as platinum, gold and iron, as well as water that could be used as rocket fuel. Some asteroids are believed to hold minerals worth trillions of dollars. The research focused on C-type, or carbon-rich, asteroids, which make up about 75 percent of known asteroids. The study, led by scientists from the Institute of Space Sciences (ICE-CSIC) and published in the Monthly Notices of the Royal Astronomical Society, suggests such bodies could become an important future source of raw materials. Professor Jacinto Alonso-Azcarate of the University of Castilla-La Mancha analysed asteroid samples selected by the research team. The study’s lead author, astrophysicist Josep M. Trigo-Rodriguez of ICE-CSIC, said these meteorites provide crucial insights into the chemical makeup and evolutionary history of small, undifferentiated asteroids. Researchers said years of experimental work helped them better understand how space conditions affect asteroid properties and mineral composition, calling the findings the result of sustained collaborative effort. Despite the potential, scientists cautioned that asteroid mining faces steep barriers. The cost of reaching asteroids and extracting resources remains extremely high, and the required technologies are still underdeveloped. Processing materials in low-gravity environments and managing waste could also pose serious environmental and operational risks. Trigo-Rodriguez noted that extracting water from water-rich carbonaceous asteroids may be more realistic in the near term, as it could support space exploration by serving as fuel or a basic resource for missions to other worlds. In addition to technical and financial hurdles, regulatory uncertainty remains a major concern. The 1967 Outer Space Treaty bars nations from claiming ownership of celestial bodies, raising complex legal questions about commercial exploitation in space.   With inputs from NDTV

Electrolyte drinks have become popular among casual exercisers, marketed as essential for performance and recovery. But experts say most people don’t need them for regular workouts, reports BBC. Electrolytesminerals like sodium, potassium, and magnesium, regulate fluid balance, nerves, and muscles. Professor Graeme Close, a sports nutrition researcher at Liverpool John Moores University, said the body usually maintains electrolyte levels naturally. “Most people get enough through a balanced diet,” he noted. Electrolyte drinks are mainly useful for long, intense exercise in hot conditions, particularly for those who sweat heavily. They can also increase thirst, helping maintain hydration during prolonged activity. For moderate workouts like gym sessions or a 5K run, water is sufficient. Close suggested homemade alternatives: mix two-thirds water, one-third fruit juice, and a pinch of salt to make a simple carbohydrate and electrolyte solution. He added that breakfast foods like omelettes provide more electrolytes than commercial sachets. While sports drinks can help top up carbohydrates during long exercise, there is little evidence that extra electrolytes improve performance. For everyday exercise, water and a balanced diet are all that’s needed.            

Chinese President Xi Jinping on Wednesday highlighted his country’s advances in technology, including artificial intelligence, semiconductors, military equipment, and space exploration, while reiterating that Beijing intends to annex self-ruled Taiwan. In his New Year’s Eve address broadcast by state media, Xi showcased images of humanoid robots performing kung fu, hydropower projects, and other innovations. “We sought to energize high-quality development through innovation,” he said, thanking the Chinese people for their contributions to economic growth over the past five years. China is preparing to discuss its new five-year economic plan in March and aims to strengthen self-reliance in science and technology amid tighter U.S. restrictions on high-tech exports. On Taiwan, Xi emphasized the shared cultural and historical ties across the strait, declaring, “The reunification of our motherland, a trend of the times, is unstoppable.” The remarks came shortly after China conducted two days of military drills around the island, in response to a planned U.S. arms sale. Taiwan President Lai Ching-te pledged to resist Beijing’s “expansionist ambitions” in his own New Year’s address. Source: AP

After years of perilous fieldwork and advanced data analysis, Mexican scientists have produced the first three-dimensional image of the interior of Popocatépetl, one of the world’s most active volcanoes whose eruptions threaten millions of people. A team from the National Autonomous University of Mexico (UNAM) spent five years scaling the volcano before dawn, hauling heavy equipment and braving harsh weather and eruption risks to collect seismic data. Using artificial intelligence to analyze the information, the researchers were able to map where magma accumulates beneath the crater, a breakthrough expected to improve understanding of the volcano’s behavior and help authorities respond more effectively to eruptions. Project leader Marco Calò of UNAM’s Institute of Geophysics said the new image offers unprecedented detail of the 17,883-foot volcano’s internal structure. The 3D cross-section extends about 11 miles below the crater, revealing several magma reservoirs at different depths rather than a single chamber, with more magma concentrated toward the southeast side. Popocatépetl, known locally as El Popo, poses a major risk because about 25 million people live within 100 kilometers of it. Homes, schools, hospitals and five airports could be affected by a major eruption. Although the volcano has been closely monitored, it lacked a high-resolution internal map until now. To achieve this, the team expanded the network of seismographs around the volcano from 12 to 22, allowing them to capture detailed underground vibrations. Doctoral researcher Karina Bernal used artificial intelligence to classify different types of tremors, helping scientists infer the materials, temperatures and depths inside the volcano before turning those findings into a map. Popocatépetl has been active since 1994, releasing gas, ash and smoke almost daily and periodically forming lava domes that later collapse, triggering eruptions. The most recent eruption occurred in 2023. Calò said working directly on the volcano transformed his research, calling Popocatépetl a “majestic” natural laboratory. He noted that firsthand experience helps scientists better understand the limits of their analyses and provide more reliable information to nearby communities. During their expeditions, the team retrieved data from seismic stations high on the volcano’s slopes, sometimes finding equipment damaged by weather, animals or explosions. Despite setbacks, the project has delivered key insights and raised new questions, including why tremors are more frequent on the southeast flank and what that means for future eruptions. With their findings set to be published, the scientists say seeing the volcano’s interior move in 3D makes the risks and effort worthwhile, and fuels their determination to continue climbing and learning more about El Popo.

Russia has successfully placed three Iranian communications satellites into orbit, marking the second such launch this year, according to Iranian state television. The report said a Russian rocket lifted off from the Vostochny Cosmodrome in eastern Russia on Sunday, carrying the satellites into a roughly 500-kilometer (310-mile) orbit around Earth. The satellites have been named Paya, Kowsar and Zafar-2. Among them, Paya is the largest satellite Iran has ever sent into space, weighing about 150 kilograms (330 pounds). Kowsar weighs 35 kilograms (77 pounds), while details about the weight of Zafar-2 were not disclosed. The satellites are capable of capturing images with up to three-meter resolution, which can be used for monitoring water resources, agriculture and environmental conditions. Their expected operational lifespan is up to five years. The launch underscores the close cooperation between Moscow and Tehran, as Russia has periodically assisted Iran in placing satellites into orbit. Earlier in July, a Russian rocket launched Iran’s Nahid-2 communications satellite. Russia and Iran signed a strategic partnership agreement in January. Moscow has also strongly criticized Israeli and US airstrikes on Iran during a 12-day conflict in June that reportedly killed nearly 1,100 people in Iran, including senior military officials and nuclear scientists. Iranian missile attacks in response killed 28 people in Israel. Iran has long pursued satellite development and periodically launches space vehicles to deploy its satellites. The United States has argued that Iran’s satellite launches violate a UN Security Council resolution and has urged Tehran to avoid activities related to ballistic missiles capable of carrying nuclear warheads. However, UN sanctions tied to Iran’s ballistic missile program expired in 2023. Source: AP