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Hubble and Webb Telescopes Uncover Secrets of Trans-Neptunian Objects, Challenging Planet Formation Theories

Hubble and Webb Telescopes Uncover Secrets of Trans-Neptunian Objects, Challenging Planet Formation Theories

Scientists have, for the first time, combined observations from NASA’s Hubble Space Telescope and the James Webb Space Telescope to study some of the smallest and dimmest Trans-Neptunian Objects (TNOs) beyond Neptune. These icy worlds are considered relics from the early solar system, representing planetesimals that never fully developed into planets. The collaborative effort, led by PhD candidates Marielle Eduardo (University of Victoria) and Anastasia Morgan (Northern Arizona University), involved simultaneous observations where Hubble recorded visible light and Webb measured infrared signatures. They examined the colors, compositions, sizes, and orbits of 27 newly discovered TNOs, some as small as 5 kilometers across, which are beyond the reach of ground-based telescopes. The findings, published in The Astronomical Journal, revealed fewer tiny TNOs than expected and indicated that their surfaces have preserved their primordial states far better than previous models predicted. This suggests that collisio...

LAGEOS-1 Satellite Continues Passive Geodynamic Measurements Decades After Launch

LAGEOS-1 Satellite Continues Passive Geodynamic Measurements Decades After Launch

The LAGEOS-1 (LAser GEOdynamic Satellite), launched in 1976, remains an active scientific satellite despite lacking internal instrumentation, electronics, or propulsion. This spherical satellite, weighing nearly 407 kg, is designed for entirely passive operation. Its surface is covered with corner cube retroreflectors, which precisely return incident laser light to its source. Ground stations on Earth emit short laser pulses towards LAGEOS-1 and measure the time it takes for the light to return. This time-of-flight ranging technique, combined with LAGEOS-1's highly stable orbit, provides a reliable reference point for detecting minute changes in Earth's characteristics. The satellite's design minimizes atmospheric drag and other disturbances, ensuring its longevity. LAGEOS-1 also carries two plaques designed by Dr. Carl Sagan, intended as a message to the future. LAGEOS-2, a similar satellite, was launched in 1992, and data from both have been utilized in tests of general relativity.

New Research Suggests Hierarchical Mergers Common for Binary Black Holes

New Research Suggests Hierarchical Mergers Common for Binary Black Holes

Recent research indicates that many binary black hole pairs, which are black holes orbiting each other, are formed through 'hierarchical mergers.' This means that one of the black holes in the pair is a large, fast-spinning black hole that resulted from a previous merger, and it subsequently found another partner in the cosmos. Traditionally, it was thought that most binary black holes originated from stars that lived and died together, collapsing into a pair that eventually merged. However, new studies, including one led by Cailin Plunkett, a Ph.D. candidate at the Massachusetts Institute of Technology, suggest that approximately 14 percent of black hole duos may be hierarchical mergers. These findings are based on analyzing data from the Laser Interferometer Gravitational-Wave Observatory (LIGO) and other observatories, which track merging black holes through the spacetime ripples they release.

Intermediate-Mass Black Holes Can Trigger Lopsided Supernovae by Shredding White Dwarfs

Intermediate-Mass Black Holes Can Trigger Lopsided Supernovae by Shredding White Dwarfs

New simulations reveal that intermediate-mass black holes (IMBHs), which weigh between 100 and 100,000 times the mass of the Sun, can cause a unique type of supernova by tidally disrupting white dwarfs. These IMBHs are difficult to detect directly but are thought to reside in the dense cores of some star clusters. When a white dwarf, a dense stellar remnant, strays too close to an IMBH, it can be torn apart. This disruption can lead to a thermonuclear supernova, an explosion that resembles those from double-white-dwarf mergers but exhibits a strong dependence on the viewing angle for its brightness and spectra. The study, led by CITA Postdoctoral Fellow Pavan Vynatheya, used high-resolution hydrodynamic simulations and radiative-transfer modeling to predict how these events would appear from Earth.

Small Magellanic Cloud Stars Exhibit Dispersed Motions, Suggesting Tidal Disruption by Larger Neighbor

Small Magellanic Cloud Stars Exhibit Dispersed Motions, Suggesting Tidal Disruption by Larger Neighbor

Astronomers have observed that massive stars within the Small Magellanic Cloud (SMC) are moving in opposing directions, a pattern that suggests the galaxy is being stretched and disrupted by tidal forces from its larger neighbor, the Large Magellanic Cloud (LMC). A team from Nagoya University, led by Satoya Nakano and Kengo Tachihara, analyzed data from the European Space Agency’s Gaia mission, mapping the motions of 7,426 massive stars in the SMC. Their findings, published in The Astrophysical Journal Supplement Series, indicate that stars in the eastern regions of the SMC are generally moving southeast towards the LMC, while those in the western regions are moving northwest, away from it. This observed motion does not align with the orderly galactic rotation previously assumed for the SMC, leading researchers to believe that tidal forces, possibly combined with ram pressure, are tearing the smaller galaxy apart.

Astronomers Reconstruct Continuous Video of Black Hole Jet, Revealing Plasma Motion

Astronomers Reconstruct Continuous Video of Black Hole Jet, Revealing Plasma Motion

Astronomers have successfully reconstructed a continuous, high-resolution video of a relativistic outflow from a black hole, providing unprecedented detail into plasma motion within its jet. This achievement was made possible by compiling 116 Very Long Baseline Array (VLBA) observations collected over 27 years. Researchers developed a new imaging framework called 'kine,' which uses neural fields to reconstruct continuous radio videos from sparse interferometric data. This technique allows for the measurement of the continuous physical flow of plasma, moving beyond previous methods that only tracked isolated emission features. The study, published in Nature, applied this method to the blazar 3C 345, reconstructing all observational epochs simultaneously and recovering fine-scale kinematics across both space and time. This advancement offers a more comprehensive understanding of how magnetized flows transport energy, which is crucial for broader astrophysics.

Mercury's Shrinkage Underestimated by Scientists, New Study Reveals

Mercury's Shrinkage Underestimated by Scientists, New Study Reveals

Recent scientific research indicates that the planet Mercury has contracted significantly more than previously understood. A new study, published in the journal Geophysical Research Letters, suggests that Mercury may have shrunk 10% to 30% more than earlier estimates. This increased shrinkage translates to a potential loss of up to 14.5 miles (23 kilometers) in its total diameter since its formation, rather than the previously estimated 2.5 to 10 miles. Scientists attribute this phenomenon to the cooling of Mercury's interior, which causes its outer rocky layers to crumple and crack, forming tectonic features such as scarps and ridges. The study's lead author, Gaku Nishiyama, explained that impact debris in rough areas of Mercury's surface has likely obscured these 'shrinkage wrinkles,' leading to an underestimation of the planet's contraction. By analyzing less disrupted areas and applying those findings to the entire planet, Nishiyama and his team were able to estimate the true extent of the shrinkage.

Astronomers Detect Planetary-Mass Object Orbiting Brown Dwarf, Challenging Classification as Exomoon

Astronomers Detect Planetary-Mass Object Orbiting Brown Dwarf, Challenging Classification as Exomoon

Astronomers have detected a planetary-mass object orbiting the brown dwarf CD-35 2722 B, but are hesitant to classify it definitively as an exomoon. Kevin Hoy, a PhD student at Universidad Diego Portales, stated that while the team is confident in the object's existence, its classification remains uncertain, leading them to use the generic term 'exosatellite.' This object differs from previous exomoon candidates where the existence of the object itself was less certain. The brown dwarf, CD-35 2722 B, is an intermediate object between a planet and a star, about 10% as massive as its host star, and has a highly eccentric orbit. The candidate exosatellite also exhibits an eccentric orbit. The detection was made using radial velocity measurements from CRIRES+, a high-resolution infrared spectrograph on the Very Large Telescope (VLT), by observing the subtle wobbles in the brown dwarf's motion caused by the orbiting companion. The team successfully predicted future observations based on their model, which signi...

Astronomers Discover Chaotic Merger of Two Giant Stars 60 Years Ago

Astronomers Discover Chaotic Merger of Two Giant Stars 60 Years Ago

Astronomers have discovered a chaotic merger of two giant stars in the system IRAS 07299−1651, located approximately 5,300 light-years from Earth. This event, which occurred about 60 years ago in cosmic time, involved two massive protostars that formed separately and later approached each other. Observations over eight years, utilizing an international network of telescopes including ALMA, VLA, JWST, and VLT, allowed scientists to construct a complete three-dimensional model of the system. The findings revealed highly elongated, or eccentric, orbits for the stars, with their protostellar disks positioned at sharp angles to each other and to the overall orbital plane. This misaligned geometry suggests that the stars did not form together from a single nebula, challenging previous assumptions about binary star formation.

New Study Suggests Mercury is Shrinking Faster Than Previously Estimated

New Study Suggests Mercury is Shrinking Faster Than Previously Estimated

Recent scientific analysis indicates that Mercury, the solar system's smallest and innermost planet, may be shrinking at a rate 30% greater than earlier models predicted. This new research, conducted by scientists from the German Aerospace Center’s Institute of Space Research and led by Gaku Nishiyama, suggests Mercury's diameter could have decreased by as much as 14 miles since its formation 4.5 billion years ago. The planet's hot iron core cools and contracts, causing the mantle and crust to tighten. The study, published in the journal Geophysical Research Letters, posits that Mercury's rough surface, constantly reshaped by impact craters, might have obscured the full extent of this contraction. By comparing maps of faults and other geological signs of contraction with newer maps highlighting surface roughness, researchers found that the roughest areas showed fewer shrinkage wrinkles, which they believe could be buried under impact debris. This updated understanding is based on measurements from NASA’s M...

Mercury's Shrinkage Exceeds Previous Estimates, New Research Reveals

Mercury's Shrinkage Exceeds Previous Estimates, New Research Reveals

New research indicates that the planet Mercury has shrunk significantly more than previously understood. Scientists have long known that Mercury is contracting due to the cooling of its interior, which causes its rocky outer layers to crumple and crack, forming distinctive wrinkles on its surface. However, a study published on September 10 in the journal Geophysical Research Letters suggests that Mercury may have shrunk by up to 30% more than earlier estimates. This means the planet could have lost as much as 14.5 miles of its diameter since its formation, a considerable increase from the previously estimated range of 2.5 to 10 miles. The discrepancy is attributed to debris and depressions from asteroid and comet impacts, which have obscured the full extent of these shrinkage-related wrinkles. Researchers combined existing geological maps with newer maps that account for Mercury's roughened surface to arrive at these revised figures.

Astronomers Propose Gamma-Ray Burst GRB 220101A as Dual Supernovae Event Forming Pulsar and Black Hole

Astronomers Propose Gamma-Ray Burst GRB 220101A as Dual Supernovae Event Forming Pulsar and Black Hole

On New Year’s Day in 2022, the Neil Gehrels Swift Observatory detected a significant burst of gamma rays, designated GRB 220101A, originating from a distant galaxy. After four years of extensive analysis, a team of astronomers, led by Remo Ruffini of the International Center for Relativistic Astrophysics Network in Italy, has put forth a complex theory to explain this event. They propose that GRB 220101A was not a singular occurrence but a series of catastrophic stellar events. The process began with the collapse of the core of a massive, older star, which had previously undergone nuclear reactions to become a carbon and oxygen mixture. This initial collapse is believed to have released an accelerating cloud of electrons and positrons, termed an 'HB supernova.' This cloud then impacted a nearby white dwarf, causing it to collapse and transform into a neutron star. This white dwarf's collapse subsequently triggered a second supernova blast merely 3.5 seconds after the first. The second blast then struck a t...