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Astronomers have assembled the largest-ever compilation of high-precision galaxy distances, called Cosmicflows-4. Galaxies, such as the Milky Way, are the building blocks of the universe, each comprised of up to several hundred billion stars. Galaxies beyond our immediate neighborhood are rushing away, faster if they are more distant, which is a consequence of the expansion of the universe that began at the moment of the Big Bang. Measurements of the distances of galaxies, coupled with information about their velocities away from us, determine the scale of the universe and the time that has elapsed since its birth.

“Since galaxies were identified as separate from the Milky Way a hundred years ago, astronomers have been trying to measure their distances,” said Brent Tully, astronomer at the University of Hawaii at Manoa. “Now by combining our more accurate and abundant tools, we are able to measure distances of galaxies, and the related expansion rate of the universe and the time since the universe was born with a precision of a few per cent.”

From the newly published measurements, the researchers derived the expansion rate of the universe, called the Hubble Constant, or H0. The team’s study gives a value of H0=75 kilometers per second per megaparsec or Mpc (1 megaparsec = 3.26 million light years), with very small statistical uncertainty of about 1.5 percent.

There are a number of ways to measure galaxy distances. Generally, individual researchers focus on an individual method. The Cosmicflows program spearheaded by Tully and Kourkchiincludes their own original material from two methods, and additionally incorporates information from many previous studies. Because Cosmicflows-4 includes distances derived from a variety of independent, distinct distance estimators, intercomparisons should mitigate against a large systematic error.

Astronomers have assembled a framework that shows the universe’s age to be a little more than 13 billion years old, however, a dilemma of great significance has arisen in the details.

Physics of the evolution of the universe based on the standard model of cosmology predicts H0=67.5 km/s/Mpc, with an uncertainty of 1 km/s/Mpc. The difference between the measured and predicted values for the Hubble Constant is 7.5 km/s/Mpc – much more than can be expected given the statistical uncertainties. Either there is a fundamental problem with our understanding of the physics of the cosmos, or there is a hidden systematic error in the measurements of galaxy distances.

Cosmicflows-4 is also being used to study how galaxies move individually, in addition to flowing with the overall expansion of the universe. Deviations from this smooth expansion arise due to the gravitational influences of clumps of matter, on scales ranging from our Earth and Sun up to congregations of galaxies on scales of a half billion light years. The mysterious dark matter is the dominant component on larger scales. With knowledge of the motions of galaxies in response to the mass around them, we can recreate the orbits that galaxies have followed since they were formed, giving us a better understanding of how the universe’s vast, dark-matter-dominated structures have formed over the eons of time.


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Amber Found in Antarctica for the First Time

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Amber Found in Antarctica for the First Time

The discovery of amber in Antarctica has been reported for the first time, as detailed in a recent study published in Antarctic Science. Dr. Johann Klages from the University of Bremen, alongside a team of researchers, uncovered this specimen in sediment cores from the Pine Island trough in West Antarctica. This ancient amber, originating from approximately 83 to 92 million years ago during the mid-Cretaceous period, offers valuable insights into prehistoric environmental conditions near the South Pole.

Unveiling the First Antarctic Amber

The study was published in Antarctic Science journal and reveals that the amber, known as Pine Island amber, was retrieved using the MARUM-MeBo70 drill rig during a 2017 expedition on the RV Polarstern vessel. This mid-Cretaceous resin is considered a significant breakthrough as it suggests that a swampy temperate rainforest, dominated by coniferous trees, thrived in the region during a much warmer period in Earth’s history. According to Dr. Henny Gerschel from the Saxon State Office for the Environment, Agriculture and Geology, the amber likely contains tiny fragments of tree bark, preserved through micro-inclusions. Its solid, translucent quality indicates that it was buried close to the surface, protecting it from thermal degradation.

Insights into Prehistoric Forest Ecosystems

The presence of pathological resin flow within the amber offers clues into the defence mechanisms used by ancient trees against environmental stressors like parasites or wildfires. “This discovery hints at a much richer forest ecosystem near the South Pole during the mid-Cretaceous,” Dr. Klages explained, noting the resin’s defensive chemical and physical properties that protected it from insect attacks and infections.

Reconstructing Ancient Antarctic Environments

The amber’s discovery marks a key step in reconstructing ancient polar climates, supporting the idea that temperate forests once spanned across all continents. Researchers aim to explore further by analysing whether signs of past life are preserved in the amber. This study, beyond unearthing Antarctic amber, opens new opportunities to deepen understanding of Earth’s climatic past and the adaptability of prehistoric ecosystems.

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An Asteroid Burned Up Over California Just Hours After Being Spotted

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An Asteroid Burned Up Over California Just Hours After Being Spotted

An asteroid measuring roughly one metre in diameter impacted Earth’s atmosphere on October 22, 2024, only hours after its initial detection. Discovered by the Asteroid Terrestrial-impact Last Alert System (ATLAS) in Hawaii, the object — named 2024 UQ — approached the planet undetected by global impact monitoring systems before disintegrating over the Pacific Ocean off California’s coast. The European Space Agency’s (ESA) Near-Earth Object Coordination Centre later confirmed the event in its November newsletter, reporting that tracking data for the asteroid did not reach monitoring systems until after the impact had already taken place.

Limited Tracking Data Due to Detection Timing

According to ESA’s November newsletter, 2024 UQ had been picked up by ATLAS’ sky-monitoring telescopes. However, the asteroid was only identified as a moving object minutes before it entered Earth’s atmosphere due to its location between two adjacent sky fields in the survey system. This detection delay meant that essential tracking data was delayed and unavailable for impact monitoring centres, which track potential near-Earth object (NEO) threats. Confirmation of the asteroid’s impact was made possible by data from the National Oceanic and Atmospheric Administration’s (NOAA) GOES weather satellites and NASA’s Catalina Sky Survey, which recorded flashes that confirmed the entry of 2024 UQ.

Third Imminent Impact Event in 2024

This incident marked the third imminent impactor event in 2024. In January, a similar object designated as 2024 BX1 burned up over Berlin, while another asteroid, 2024 RW1, exploded above the Philippines in September, with footage of the fireball captured by local observers. These instances underscore the rarity yet growing frequency of small asteroids entering Earth’s atmosphere undetected.

Global Efforts to Monitor Near-Earth Objects

Planetary defence remains a priority as space agencies worldwide develop systems to track potentially hazardous objects. In addition to projects like ATLAS and the Catalina Sky Survey, NASA’s upcoming NEO Surveyor mission aims to use infrared technology to enhance detection capabilities. ESA’s NEO Coordination Centre continues its work on tracking near-Earth objects, while deflection experiments, including NASA’s DART mission in 2022, are also underway to test potential asteroid redirection strategies.

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NASA’s Swift Discovers Twin Black Holes Disturbing Galactic Gas Cloud

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NASA's Swift Discovers Twin Black Holes Disturbing Galactic Gas Cloud

NASA’s Neil Gehrels Swift Observatory has detected a unique signal from two enormous black holes, locked in a cosmic dance that disturbs a dense gas cloud at the centre of a distant galaxy. The phenomenon, known as AT 2021hdr, has sparked considerable interest among astronomers, with researchers observing an unusual cycle of gas disruptions as the black holes orbit one another.

This gas-churning event was first documented in March 2021 by the Zwicky Transient Facility (ZTF) at the Palomar Observatory, California. Led by Dr Lorena Hernández-García, astrophysicist at the Millennium Institute of Astrophysics and the University of Valparaíso in Chile, a study into AT 2021hdr reveals a recurring flare, a pattern that scientists suggest results from the black holes’ gravitational influence on a massive gas cloud. The findings, which appear in the journal Astronomy and Astrophysics, describe how these giant objects tug and heat the gas, triggering light oscillations across different wavelengths.

Uncovering the Source of AT 2021hdr

Located in galaxy 2MASX J21240027+3409114, about 1 billion light-years away in the Cygnus constellation, these black holes together possess a mass 40 million times that of the Sun. Their close proximity—just 16 billion miles apart—produces observable light variations every 130 days. This frequency, scientists predict, could eventually culminate in the black holes’ merger in approximately 70,000 years.

Initially considered a supernova, the recurring nature of these outbursts led astronomers to reevaluate their assumptions. Dr Alejandra Muñoz-Arancibia, a researcher with ALeRCE and the University of Chile, noted that frequent observations over 2022 helped to develop a more precise understanding of this phenomenon. Since November 2022, Swift’s ultraviolet and X-ray observations have aligned with ZTF’s findings in visible light, reinforcing the theory of an orbiting gas cloud undergoing a cyclical disturbance by the black holes’ gravitational forces.

Future Studies and Implications

This discovery offers a unique perspective on supermassive black hole interactions. Continued studies of AT 2021hdr and its host galaxy—currently merging with another—are expected to provide new insights into galactic evolution and black hole behaviour.

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