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The Knoxville News-Sentinel

Counting the years until Our Favorite Planet goes kaput | Sam Venable

Counting the years until Our Favorite Planet goes kaput | Sam Venable

Sam Venable writes: The problem is with an asteroid named Bennu that is racing through outer space at bazillions of miles per hour.

NASA Astronaut Shannon Lucid's Record-Setting Mir Mission Highlighted

NASA Astronaut Shannon Lucid's Record-Setting Mir Mission Highlighted

On September 23, 1996, NASA Astronaut Shannon W. Lucid concluded her record-setting 188-day mission aboard the Russian Mir Space Station. Lucid, one of NASA's first six female astronauts, spent six months conducting life science studies and other microgravity experiments alongside two Russian cosmonauts. Prior to her departure on space shuttle Atlantis, she checked on wheat plants growing in the Svet greenhouse. Her mission established new records for both a woman and an American in space duration. Lessons learned from her time on Mir were crucial in preparing NASA for the psychological and cultural challenges associated with long-duration missions on the International Space Station.

Curiosity Rover Captures Detailed Mosaics of Martian Landscape and Sand Fields

Curiosity Rover Captures Detailed Mosaics of Martian Landscape and Sand Fields

The Curiosity rover on Mars has captured several detailed mosaics of the Martian landscape, focusing on buttes named 'Mishe Mokwa' and 'Cordillera,' and looking back at 'La Linea.' Additionally, the rover documented the 'Chocolatal' scuff and a larger mosaic of the 'Sullivan Field' sand field. These imaging efforts were conducted by the ChemCam long-distance imager and camera teams. The 'Sullivan Field' is notable for containing sand ripples, mega ripples, and transverse aeolian ridges, and was named in honor of Robert Sullivan, a recognized expert on Martian sands and a member of the Curiosity science team. The rover is currently traversing a subtly banded area within 'Valle Grande,' characterized by sparse, nodular outcrops and significant sand deposits. Recent activities included investigating brushed nodular bedrock at 'Cerro Armazones' and 'Monte Melimoyu,' and acquiring LIBS data on dark-toned nodules at 'Tuta Huallpas' and float rock 'Acllahuasi.'

Astronomers Detect Radio Signals from Exoplanet Beta Pictoris b, Indicating Strong Magnetic Field

Astronomers Detect Radio Signals from Exoplanet Beta Pictoris b, Indicating Strong Magnetic Field

An international team of astronomers, utilizing South Africa’s MeerKAT radio telescope array, has successfully detected direct radio wave emissions originating from Beta Pictoris b, a massive gas giant exoplanet located approximately 63 light-years from Earth. This marks the first time a radio signal has been confirmed as coming from a single exoplanet, rather than from an entire star system. The discovery allows researchers to calculate the strength of Beta Pictoris b's magnetic field, which is thousands of times stronger than Earth's. The physics behind these signals is similar to the mechanisms that create auroral displays on planets within our Solar System, where energetic, charged particles spiral along magnetic field lines towards a planet's polar regions, exciting atmospheric particles.

European Space Agency and JAXA Activate Ramses Planetary Defense Spacecraft

European Space Agency and JAXA Activate Ramses Planetary Defense Spacecraft

The European Space Agency (ESA) and Japan Aerospace Exploration Agency (JAXA) have successfully powered on their Ramses planetary defense spacecraft for the first time. This event marks a significant milestone in the spacecraft's development, which is on a time-critical schedule to rendezvous with the Apophis asteroid. The Core Module of Ramses, containing its main electronics, is currently being assembled at OHB Italia's Milan facility. Key units, including the On-Board Computer, Mass Memory Unit, Power Conditioning and Distribution Unit, and multiple Remote Terminal Units, have been integrated and linked via the spacecraft harness. This initial power-on allowed for the first integrated functional testing, verifying the performance of these interconnected systems. The Ramses mission is designed to reach space by spring 2028 to intercept the Apophis asteroid as it passes Earth on April 13, 2029, necessitating a rapid development timeline of less than three and a half years from contract signing to lift-off...

Scientists Investigate Neutrino Role in Stellar Collapse and Supernova Formation

Scientists Investigate Neutrino Role in Stellar Collapse and Supernova Formation

Scientists are investigating the role of neutrinos, often called 'ghost particles,' in determining whether massive stars explode as supernovas or collapse into black holes. When a massive star exhausts its fuel, its core implodes, generating immense heat and pressure that crush protons and electrons into neutrons, releasing a flood of neutrinos. These neutrinos can heat the star's outer layers, potentially triggering a supernova explosion and forming a neutron star. However, if this neutrino heating is insufficient, the star may instead collapse directly into a black hole. Researchers, including Mariam Gogilashvili and Irene Tamborra from the University of Copenhagen's Niels Bohr Institute, emphasize that neutrinos carry approximately 99% of the energy released during core collapse, and even minor changes in their behavior can significantly alter a star's ultimate fate. The study involved simulating the collapse of 195 stars, ranging from nine to 120 solar masses, to analyze how neutrino flavor conversion ...

New Mathematical Analysis Re-evaluates Primordial Black Holes as Dark Matter Candidates

New Mathematical Analysis Re-evaluates Primordial Black Holes as Dark Matter Candidates

Physicist Stefano Profumo of the University of California, Santa Cruz, has conducted a new mathematical analysis challenging long-held assumptions about dark matter theories. Published in Physical Review D, the study applied a consistent mathematical test, the Barbieri-Giudice measure, to 16 different dark matter theories, including primordial black hole formation scenarios and various particle candidates like Weakly Interacting Massive Particles (WIMPs). The findings indicate that some primordial black hole models are as mathematically stable and 'natural' as the most trusted particle theories, while certain WIMP models are less stable than previously believed. This research directly contradicts the common argument that primordial black holes are 'too fine-tuned' to be viable dark matter candidates. The study assessed how sensitive each theory's prediction for the observed amount of dark matter is to small changes in its input parameters, with less sensitivity indicating greater naturalness.

James Webb Telescope's 'Little Red Dots' May Be Early Supermassive Black Holes

James Webb Telescope's 'Little Red Dots' May Be Early Supermassive Black Holes

Observations from NASA's James Webb Space Telescope have revealed mysterious 'little red dots' in a region of the universe dating back hundreds of millions of years after the Big Bang. Max Planck Institute astrophysicist Sunmyon Chon and his colleagues propose in a new paper published in 'Nature' that these red dots could represent the earliest stages of supermassive black holes. Their simulations suggest that rapidly forming black holes could emit light while accreting material, appearing as these 'seeds' detected by the James Webb. These newly formed 'overmassive' black holes are theorized to rapidly develop dense, optically thick disks, producing broad hydrogen-alpha emission comparable to what is seen in the red dots. Chon's team posits that these black holes could evolve into 'overmassive' quasars, which are extremely bright celestial objects powered by gas being absorbed by a supermassive black hole, and could be the progenitors of today's supermassive black holes within less than a billion years.

New Study Suggests Neutrino Flavor Changes Influence Star's Fate, Impacting Supernova and Black Hole Formation

New Study Suggests Neutrino Flavor Changes Influence Star's Fate, Impacting Supernova and Black Hole Formation

A new study indicates that the ability of neutrinos to change 'flavors' (electron, muon, and tau) might significantly influence whether massive stars explode as supernovas or collapse into black holes. When a massive star's core collapses, it releases a tremendous amount of neutrinos. These neutrinos can interact with the star's outer layers, potentially heating them enough to trigger a supernova explosion, leaving behind a neutron star. However, if this heating is insufficient, the star collapses to form a black hole. The study, which simulated the collapse of 195 stars ranging from nine to 120 solar masses, found that neutrino flavor conversion could make it less likely for massive stars to explode as supernovas and more likely to form black holes. This finding could help explain why fewer supernovas are observed than theoretically predicted and why some red supergiant stars appear to vanish without an explosion.

Fastest Milky Way Star S301 Offers Direct Measurement of Sagittarius A*'s Spin

Fastest Milky Way Star S301 Offers Direct Measurement of Sagittarius A*'s Spin

Astronomers have identified S301 as the fastest known star in the Milky Way, orbiting Sagittarius A*, the supermassive black hole at the galaxy's center. S301 reaches speeds of approximately 25,000 kilometers per second, or over 8% of the speed of light, and passes closer to Sagittarius A* than any previously observed star, at a mere 12 times the Earth-to-Sun distance. This extreme proximity makes S301 the first star that could potentially be used to directly measure the spin of Sagittarius A*. According to Einstein's general theory of relativity, a rotating black hole drags and twists the surrounding spacetime, subtly altering the orbits of nearby objects. The closer an object is to a rapidly rotating black hole, the stronger this effect becomes. The discovery was made using the European Southern Observatory's Very Large Telescope Interferometer (ESO’s VLTI) and its GRAVITY instrument.

John Bell's Quantum Theory Work Transforms Philosophical Debate into Experimental Science

John Bell's Quantum Theory Work Transforms Philosophical Debate into Experimental Science

John Bell's groundbreaking work in 1964 transformed a philosophical debate about quantum mechanics into an experimentally testable question. Einstein, Podolsky, and Rosen had previously questioned whether quantum mechanics provided a complete description of reality, proposing the idea of 'hidden variables' where particles might already 'know' their responses before measurement. Bell developed a mathematical limit, known as Bell's inequality, which quantifies how strongly results can be correlated if these local hidden variables exist. This inequality established a clear distinction: Bell-local models predict a maximum correlation value of 2, while quantum mechanics predicts a higher value, up to 2√2 (approximately 2.828). This numerical gap allowed physicists to design experiments to determine which model better describes reality.

Astronomers Discover Universal Rule Governing Black Hole Jet Formation Across All Sizes

Astronomers Discover Universal Rule Governing Black Hole Jet Formation Across All Sizes

An international team of astronomers, co-led by Andrew Mummery of the Institute for Advanced Study and Adelle Goodwin of Curtin University, has identified a universal rule that dictates the production of powerful jets from black holes. This rule applies to black holes of all sizes, from stellar-mass black holes (approximately ten times the mass of our sun) to supermassive black holes (millions of times heavier). The research, published in Nature Astronomy, focused on tidal disruption events (TDEs), where a star passes too close to a supermassive black hole and is torn apart by intense gravitational forces. These events provide a unique opportunity to observe black hole behavior after a sudden influx of stellar material. The study combined years of observations from telescopes across multiple wavelengths, including optical, ultraviolet, X-ray, and radio waves, from various locations globally and in space. The team analyzed ten high-quality TDEs to determine the black hole's feeding rate and the timing of it...