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Categories: Physics: Acoustics and Ultrasound, Space: Cosmology

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The earliest galaxies are thought to have formed as the gravitational pull of dark matter, which has been impossible to study directly, slowly drew in enough hydrogen and helium to ignite stars. But astrophysicists now show that after the Big Bang, hydrogen and helium gas bounced at supersonic speeds off dense, slowly moving clumps of cold dark matter. When the gas fell back in millennia later, stars formed all at once, creating small, exceptionally bright galaxies. If models of cold dark matter are correct, the James Webb Space Telescope should be able to find patches of bright galaxies in the early universe, potentially offering the first effective test for theories about dark matter. If it doesn't, scientists have to go back to the drawing board with dark matter.

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Researchers are developing a new type of sensor that reacts to certain sound waves, causing it to vibrate. The sensor is a metamaterial that acquires its special properties through the structuring of the material. Passive sound-sensitive sensors could be used to monitor buildings, earthquakes or certain medical devices and save millions of batteries.

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A new study describes the best method to improve images obtained by the James Webb Science Telescope (JWST) using a mathematical approach called deconvolution.

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Instead of tubular commercial aircraft, other designs could be used in the future: Jets with a blended wing body would fly more efficiently and make less noise -- but how would the noise emissions from these new types of aircraft affect people?

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Owls produce negligible noise while flying. While many studies have linked the micro-fringes in owl wings to their silent flight, the exact mechanisms have been unclear. Now, a team of researchers has uncovered the effects of these micro-fringes on the sound and aerodynamic performance of owl wings through computational fluid dynamic simulations. Their findings can inspire biomimetic designs for the development of low-noise fluid machinery.

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Scientists have revealed that low-frequency ultrasound influences blood parameters. The findings suggest that ultrasound's effect on haemoglobin can improve oxygen's transfer from the lungs to bodily tissues. The research was undertaken on 300 blood samples collected from 42 pulmonary patients.

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A team of scientists has succeeded in cooling traveling sound waves in wave-guides considerably further than has previously been possible using laser light. This achievement represents a significant move towards the ultimate goal of reaching the quantum ground state of sound in wave-guides. Unwanted noise generated by the acoustic waves at room temperature can be eliminated. This experimental approach both provides a deeper understanding of the transition from classical to quantum phenomena of sound and is relevant to quantum communication systems and future quantum technologies.

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An international team of astronomers have found a new and unknown object in the Milky Way that is heavier than the heaviest neutron stars known and yet simultaneously lighter than the lightest black holes known.

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Researchers have discovered the oldest black hole ever observed, dating from the dawn of the universe, and found that it is 'eating' its host galaxy to death.

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Researchers have achieved a successful contrast agent-free imaging of complex structure of kidney vessels.

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High-resolution images captured by the James Webb Space Telescope are offering powerful insights into the complex dust patterns of nearby star-forming galaxies.

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Astronomers have created the most sensitive radio image ever of a globular cluster, an ancient ball of tightly-packed stars.

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Astronomers analyzing 13 years of data from NASA's Fermi Gamma-ray Space Telescope have found an unexpected and as yet unexplained feature outside of our galaxy.

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The world is filled with a myriad of sounds and vibrations -- the gentle tones of a piano drifting down the hall, the relaxing purr of a cat laying on your chest, the annoying hum of the office lights. Imagine being able to selectively tune out noises of a certain frequency. Researchers have now synthesized polymer networks with two distinct architectures and crosslink points capable of dynamically exchanging polymer strands to understand how the network connectivity and bond exchange mechanisms govern the overall damping behavior of the network. The incorporation of dynamic bonds into the polymer network demonstrates excellent damping of sound and vibrations at well-defined frequencies.

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In summer 2022, astronomers detected the most powerful and most distant fast radio burst (FRB) ever observed. Now, astronomers have pinpointed the extraordinary object's birthplace -- and it's rather curious, indeed. Using images from NASA's Hubble Space Telescope, the researchers traced the FRB back to not one galaxy but a group of at least seven galaxies.

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In the culmination of a decade's worth of effort, scientists analyzed an unprecedented sample of more than 1,500 supernovae classified using machine learning. They placed the strongest constraints on the expansion of the universe ever obtained with the DES supernova survey. While consistent with the current standard cosmological model, the results do not rule out a more complex theory that the density of dark energy in the universe could have varied over time.

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We don't know how magnetic fields in the cosmos formed. Now a new theoretical research tells how the invisible part of our universe could help us find out, suggesting a primordial genesis, even within a second of the Big Bang.

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Researchers have analyzed more than one million galaxies to explore primordial fluctuations that seeded the formation of the structure of the entire universe.

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 A new snapshot of an ancient, far-off galaxy could help scientists understand how it formed and the origins of our own Milky Way.   At more than 12 billion years old, BRI 1335-0417 is the oldest and furthest known spiral galaxy in our universe. The researchers were able to not only capture the motion of the gas around BRI 1335-0417, but also reveal a seismic wave forming -- a first in this type of early galaxy.  

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In November 2023, NASA's James Webb Space Telescope observed a massive cluster of galaxies named MACS J0138.0-2155. Through an effect called gravitational lensing, first predicted by Albert Einstein, a distant galaxy named MRG-M0138 appears warped by the powerful gravity of the intervening galaxy cluster. In addition to warping and magnifying the distant galaxy, the gravitational lensing effect caused by MACS J0138 produces five different images of MRG-M0138.