NASA has confirmed that two massive asteroids, 2024 XY5 and 2024 XB6, will safely pass by Earth today, December 16th, posing no imminent threat. These close encounters underscore the importance of monitoring asteroids to understand their origins and potential impact on our planet. Asteroid 2024 XY5 The larger of the two, 2024 XY5, measures 71 feet across and will make its closest approach at 12:26 AM IST. Traveling at 10,805 miles per hour, it will pass Earth at a distance of approximately 2,180,000 miles—16 times farther than the Moon. Scientists have confirmed it poses no danger. Asteroid 2024 XB6 Slightly smaller, asteroid 2024 XB6 is 56 feet in diameter and traveling at a remarkable speed of 14,780 miles per hour. It will pass Earth at a safe distance of about 4,150,000 miles. Asteroids like these are remnants of the early solar system, formed 4.6 billion years ago. By studying them, scientists can uncover vital clues about the formation of Earth and the history of the universe. Events such as the asteroid impact that caused the extinction of the dinosaurs highlight the importance of tracking these celestial objects.

Astronomers have found an Earth-sized planet orbiting a white dwarf 4,000 light-years away in the constellation Sagittarius, offering a glimpse into Earth’s distant future. This rocky planet, comparable in mass to Earth, orbits its star at twice the distance between Earth and the sun. The white dwarf—a dense remnant of a once-sun-like star—illustrates a possible outcome for our solar system, raising questions about how Earth might evolve. As the sun ages, it will expand into a red giant, potentially engulfing planets like Mercury and Venus. However, scientists suggest Earth may avoid this fate if the sun’s mass loss pushes planets into wider orbits, which might allow Earth to escape the red giant’s reach. This scenario was explored by University of California, Berkeley astronomers using the Keck Telescope, hinting that Earth might survive the sun’s transformation, although its habitability would still be severely affected. “Whether Earth will be swallowed when the sun becomes a red giant is still uncertain,” said UC Berkeley astronomer Jessica Lu. “The crucial question is whether Earth can avoid being consumed.” Eventually, the sun’s habitable zone will shift closer to Jupiter and Saturn. Moons such as Europa, Callisto, and Ganymede could emerge as potential habitats, especially as Earth’s oceans are expected to vaporize within a billion years due to the greenhouse effect. Lead researcher Keming Zhang remarked, “Humanity may need to consider these outer solar system refuges for survival.”

Deep inside Earth is a solid metal ball that rotates independently of our spinning planet, like a top whirling around inside a bigger top, shrouded in mystery. This inner core has intrigued researchers since its discovery by Danish seismologist Inge Lehmann in 1936, and how it moves — its rotation speed and direction — has been at the center of a decades-long debate. A growing body of evidence suggests the core's spin has changed dramatically in recent years, but scientists have remained divided over what exactly is happening — and what it means. Part of the trouble is that Earth's deep interior is impossible to observe or sample directly. Seismologists have gleaned information about the inner core's motion by examining how waves from large earthquakes that ping this area behave. Variations between waves of similar strengths that passed through the core at different times enabled scientists to measure changes in the inner core's position and calculate its spin. 'Differential rotation of the inner core was proposed as a phenomenon in the 1970s and '80s, but it wasn't until the '90s that seismological evidence was published,' said Dr. Lauren Waszek, a senior lecturer of physical sciences at James Cook University in Australia. But researchers argued over how to interpret these findings, 'primarily due to the challenge of making detailed observations of the inner core, due to its remoteness and limited available data,' Waszek said. As a result, 'studies which followed over the next years and decades disagree on the rate of rotation, and also its direction with respect to the mantle,' she added. Some analyses even proposed that the core didn't rotate at all. One promising model proposed in 2023 described an inner core that in the past had spun faster than Earth itself, but was now spinning slower. For a while, the scientists reported, the core's rotation matched Earth's spin. Then it slowed even more, until the core was moving backward relative to the fluid layers around it. At the time, some experts cautioned that more data was needed to bolster this conclusion, and now another team of scientists has delivered compelling new evidence for this hypothesis about the inner core’s rotation rate. Research published June 12 in the journal Nature not only confirms the core slowdown, it supports the 2023 proposal that this core deceleration is part of a decades-long pattern of slowing down and speeding up. The new findings also confirm that the changes in rotational speed follow a 70-year cycle, said study coauthor Dr. John Vidale, Dean's Professor of Earth Sciences at the University of Southern California’s Dornsife College of Letters, Arts and Sciences. 'We've been arguing about this for 20 years, and I think this nails it,' Vidale said. 'I think we've ended the debate on whether the inner core moves, and what's been its pattern for the last couple of decades.' But not all are convinced that the matter is settled, and how a slowdown of the inner core might affect our planet is still an open question — though some experts say Earth's magnetic field could come into play. Buried about 3,220 miles (5,180 kilometers) deep inside Earth, the solid metal inner core is surrounded by a liquid metal outer core. The inner core is made mostly of iron and nickel, and it is estimated to be as hot as the surface of the sun — about 9,800 degrees Fahrenheit (5,400 degrees Celsius). Earth's magnetic field yanks at this solid ball of hot metal, making it spin. At the same time, the gravity and flow of the fluid outer core and mantle drag at the core. Over many decades, the push and pull of these forces cause variations in the core's rotational speed, Vidale said. The sloshing of metal-rich fluid in the outer core generates electrical currents that power Earth's magnetic field, which protects our planet from deadly solar radiation. Though the inner core's direct influence on the magnetic field is unknown, scientists had previously reported in 2023 that a slower-spinning core could potentially affect it and also fractionally shorten the length of a day. When scientists attempt to 'see' all the way through the planet, they are generally tracking two types of seismic waves: pressure waves, or P waves, and shear waves, or S waves. P waves move through all types of matter; S waves only move through solids or extremely viscous liquids, according to the US Geological Survey. Seismologists noted in the 1880s that S waves generated by earthquakes didn't pass all the way through Earth, and so they concluded that Earth's core was molten. But some P waves, after passing through Earth's core, emerged in unexpected places — a 'shadow zone,' as Lehmann called it — creating anomalies that were impossible to explain. Lehmann was the first to suggest that wayward P waves might be interacting with a solid inner core within the liquid outer core, based on data from a massive earthquake in New Zealand in 1929. By tracking seismic waves from earthquakes that have passed through the Earth's inner core along similar paths since 1964, the authors of the 2023 study found that the spin followed a 70-year cycle. By the 1970s, the inner core was spinning a little faster than the planet. It slowed around 2008, and from 2008 to 2023 began moving slightly in reverse, relative to the mantle. NASA's Solar Dynamics Observatory (SDO) scientists used their computer models to generate a view of the Sun's magnetic field on August 10, 2018. The bright active region right at the central area of the Sun clearly shows a concentration of field lines, as well as the small active region at the Sun's right edge. For the new study, Vidale and his coauthors observed seismic waves produced by earthquakes in the same locations at different times. They found 121 examples of such earthquakes occurring between 1991 and 2023 in the South Sandwich Islands, an archipelago of volcanic islands in the Atlantic Ocean to the east of South America's southernmost tip. The researchers also looked at core-penetrating shock waves from Soviet nuclear tests conducted between 1971 and 1974. When the core turns, Vidale said, that affects the arrival time of the wave. Comparing the timing of seismic signals as they touched the core revealed changes in core rotation over time, confirming the 70-year rotation cycle. According to the researchers' calculations, the core is just about ready to start speeding up again. Compared with other seismographic studies of the core that measure individual earthquakes as they pass through the core — regardless of when they occur — using only paired earthquakes reduces the amount of usable data, 'making the method more challenging,' Waszek said. However, doing so also enabled scientists to measure changes in the core rotation with greater precision, according to Vidale. If his team’s model is correct, core rotation will start speeding up again in about five to 10 years. The seismographs also revealed that, during its 70-year cycle, the core's spin slows and accelerates at different rates, 'which is going to need an explanation,' Vidale said. One possibility is that the metal inner core isn't as solid as expected. If it deforms as it rotates, that could affect the symmetry of its rotational speed, he said. The team's calculations also suggest that the core has different rotation rates for forward and backward motion, which adds 'an interesting contribution to the discourse,' Waszek said. But the depth and inaccessibility of the inner core mean that uncertainties remain, she added. As for whether or not the debate about core rotation has truly ended, 'we need more data and improved interdisciplinary tools to investigate this further,' Waszek said. Changes in core spin — though they can be tracked and measured — are all but imperceptible to people on Earth’s surface, Vidale said. When the core spins more slowly, the mantle speeds up. This shift makes Earth rotate faster, and the length of a day shortens. But such rotational shifts translate to mere thousandths of a second in day length, he said. 'In terms of that effect in a person's lifetime?' he said. 'I can't imagine it means much.' Scientists study the inner core to learn how Earth's deep interior formed and how activity connects across all the planet's subsurface layers. The mysterious region where the liquid outer core envelops the solid inner core is especially interesting, Vidale added. As a place where liquid and solid meet, this boundary is 'filled with potential for activity,' as are the core-mantle boundary and the boundary between mantle and crust. 'We might have volcanoes on the inner core boundary, for example, where solid and fluid are meeting and moving,' he said. Because the spinning of the inner core affects movement in the outer core, inner core rotation is thought to help power Earth's magnetic field, though more research is required to unravel its precise role. And there is still much to be learned about the inner core's overall structure, Waszek said. 'Novel and upcoming methodologies will be central to answering the ongoing questions about Earth's inner core, including that of rotation.' Mindy Weisberger is a science writer and media producer whose work has appeared in Live Science, Scientific American and How It Works magazine. Source: CNN

The investigation into reports of UFO sightings also concluded that there have been no efforts by US governments to keep the information of aliens hidden from the public. There is no evidence of aliens or extraterrestrial intelligence, a Pentagon report that examined the sighting of Unidentified Flying Objects (UFOs) over the last century said on Friday. The report concluded that most of the sightings reported were misidentified ordinary objects and phenomena, a conclusion that matches the assessment of past US governments into the claims. The report from the Defense Department's All-domain Anomaly Resolution Office (ARRO) analyzed US government investigations since 1945 of UFO sightings. The study which followed a 2022 Pentagon announcement also said that there were no efforts by the US government or private firms to keep the information about them secret. Flying objects: White House says no sign of alien activity "All investigative efforts, at all levels of classification, concluded that most sightings were ordinary objects and phenomena and the result of misidentification," said the report, which was mandated by Congress. Why was the investigation conducted? Over the past several years, US authorities have received a slew of reports of UFO sightings. In 2021, a government report that examined 144 sightings held that no evidence of any extraterrestrial life was found and it called for better data collection. The issue was once again brought to the fore last year after a retired Air Force intelligence officer testified to Congress that the US government hides a longstanding plan that reverse engineers unidentified flying objects. The authors of the report said they wanted to meticulously investigate the subject which has occupied many American minds over the years. "AARO recognizes that many people sincerely hold versions of these beliefs which are based on their perception of past experiences, the experiences of others whom they trust, or media and online outlets they believe to be sources of credible and verifiable information," the report said.    

Scientists have used artificial intelligence to decode text on papyrus that was rolled and charred 2,000 years ago. So AI now looks back as well as forward. Three young scientists have won the grand prize in the Vesuvius Challenge for deciphering passages on a previously unreadable Herculaneum scroll. More than a thousand scrolls were buried and covered in volcanic debris when Mount Vesuvius erupted about 2,000 years ago. They were in a library at a Roman villa in the ancient city of Herculaneum and discovered in the 1800s by a local farmer. Many people have tried to read the ancient papyrus scrolls since then, but most attempts have destroyed the documents, which were left underground rolled, carbonized and fragile, for centuries. The winners — Youssef Nader, Luke Farritor and Julian Schilliger — overcame this challenge by managing to read four passages without ever unrolling the scrolls.   Winning the Vesuvius Challenge They used machine learning, a form of artificial intelligence, to read the ancient Greek text. Nadery, Farritor and Schillinger independently contributed to the Vesuvius scrolls community and now share the grand prize of $700,000 (€650,000). The object was to decipher four passages of text, each of at least 140 characters, with at least 85% of characters "recoverable" — or readable. Their work has revealed what are believed to be unknown texts by Philodemus, the villa's so-called philosopher-in-residence. In the text, Philodemus writes about living a good life through the pleasures of beauty, music and food. Researchers say this and future discoveries in the texts will give them a "unique window into the classical world."   How scientists used AI to read a Herculaneum scroll The scrolls were digitally "unwrapped" using computed tomography (CT) — or X-ray photos — and machine-learning technology. First, in late 2023, the prize organizers had the scrolls imaged at the Diamond Light Source particle accelerator near Oxford in the UK. That produced high-resolution CT scans of scrolls. The scans were then turned into a 3D volume of voxels. Voxels are 3D pixels, similar to the building blocks used in the video game Minecraft. The second step is known as segmentation. They traced crumpled layers of the rolled papyrus in the 3D scan. That allowed them to unroll, or flatten, the images. And the third step was detecting ink on papyrus. They used machine learning to identify regions of ink in the flattened segments of the papyrus. But this is where it gets very clever. The machine-learning model was not trained to spot ancient Greek letters, optical character recognition (OCR), or any other language models. Instead, it simply detected spots of ink in the CT scan and then combined and reconstructed each individual spot — and where letters appeared, that's where there was writing.   Decades of work coming to fruition One of the prize organizers, Brent Seales of the University of Kentucky, had been working on deciphering the Herculaneum scrolls for decades. Seales was the first to use CT scans but found that it was difficult to detect the ink because it had a density similar to the papyrus on which it was written. But developments gained speed when Seales, Silicon Valley entrepreneur Nat Friedman and engineer Daniel Gross launched the competition in March 2023. A breakthrough came within a few months. A former physicist, Casey Handmer, noticed a cracked texture in the text and called it crackle. Co-winner Farritor, an undergraduate student and SpaceX intern, used Handmer's observation to train a machine-learning model and deciphered the first entire ancient Greek word: ΠΟΡΦΥΡΑϹ, which means purple. By October, Nader, an Egyptian PhD student in Berlin, was able to read a few columns of text. Schillinger, a Swiss robotics student, who had previously won three prizes for segmentation, enabled the 3D-mapping of the papyrus scrolls. And there is more to come in 2024. The next Vesuvius Challenge is to read an entire work or scroll by the end of the year.