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Comment by Dr. Krishna Kumari Challa on February 25, 2021 at 8:40am

New study suggests supermassive black holes could form from dark matter

A new theoretical study has proposed a novel mechanism for the creation of supermassive black holes from dark matter. The international team find that rather than the conventional formation scenarios involving 'normal' matter, supermassive black holes could instead form directly from dark matter in high density regions in the centers of galaxies. The result has key implications for cosmology in the early Universe, and is published in Monthly Notices of the Royal Astronomical Society.

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Exactly how supermassive black holes initially formed is one of the biggest problems in the study of galaxy evolution today. Supermassive black holes have been observed as early as 800 million years after the Big Bang, and how they could grow so quickly remains unexplained.

Standard formation models involve normal baryonic matter—the atoms and elements that that make up stars, planets, and all visible objects—collapsing under gravity to form black holes, which then grow over time. However the new work investigates the potential existence of stable galactic cores made of dark matter, and surrounded by a diluted dark matter halo, finding that the centers of these structures could become so concentrated that they could also collapse into supermassive black holes once a critical threshold is reached.

According to the model this could have happened much more quickly than other proposed formation mechanisms, and would have allowed supermassive black holes in the early Universe to form before the galaxies they inhabit, contrary to current understanding.

Carlos R. Argüelles, the researcher at Universidad Nacional de La Plata and ICRANet who led the investigation comments: "This new formation scenario may offer a natural explanation for how supermassive black holes formed in the early Universe, without requiring prior star formation or needing to invoke seed black holes with unrealistic accretion rates."

Another intriguing consequence of the new model is that the critical mass for collapse into a black hole might not be reached for smaller dark matter halos, for example those surrounding some dwarf galaxies. The authors suggest that this then might leave smaller dwarf galaxies with a central dark matter nucleus rather than the expected black hole. Such a dark matter core could still mimic the gravitational signatures of a conventional central black hole, whilst the dark matter outer halo could also explain the observed galaxy rotation curves.

Carlos R Argüelles et al, On the formation and stability of fermionic dark matter haloes in a cosmological framework, Monthly Notices of the Royal Astronomical Society (2020). DOI: 10.1093/mnras/staa3986

https://phys.org/news/2021-02-supermassive-black-holes-dark.html?ut...

Comment by Dr. Krishna Kumari Challa on February 25, 2021 at 8:34am

Asteroid dust found in crater closes case of dinosaur extinction

Researchers think they have closed the case of what killed the dinosaurs, definitively linking their extinction with an asteroid that slammed into Earth 66 million years ago by finding a key piece of evidence: asteroid dust inside the impact crater.

Death by asteroid rather than by a series of volcanic eruptions or some other global calamity has been the leading hypothesis since the 1980s, when scientists found asteroid dust in the geologic layer that marks the extinction of the dinosaurs. This discovery painted an apocalyptic picture of dust from the vaporized asteroid and rocks from impact circling the planet, blocking out the sun and bringing about mass death through a dark, sustained global winter—all before drifting back to Earth to form the layer enriched in asteroid material that's visible today.

Researchers collected nearly 3,000 feet of rock core from the crater buried under the seafloor. Research from this mission has helped fill in gaps about the impact, the aftermath and the recovery of life.

The telltale sign of asteroid dust is the element iridium—which is rare in the Earth's crust, but present at elevated levels in certain types of asteroids. An iridium spike in the geologic layer found all over the world is how the asteroid hypothesis was born. In the new study, researchers found a similar spike in a section of rock pulled from the crater. In the crater, the sediment layer deposited in the days to years after the strike is so thick that scientists were able to precisely date the dust to a mere two decades after impact.

"Globally distributed iridium layer preserved within the Chicxulub impact structure" Science Advances (2021). advances.sciencemag.org/lookup … .1126/sciadv.abe3647

https://phys.org/news/2021-02-asteroid-crater-case-dinosaur-extinct...

Comment by Dr. Krishna Kumari Challa on February 24, 2021 at 1:13pm

How to improve your life using science

https://www.sciencefocus.com/science/improve-your-life-with-science...

Comment by Dr. Krishna Kumari Challa on February 24, 2021 at 1:10pm

Physicists Just Reached a New Speed Limit For Moving Quantum Information

This latest research answers a fundamental question – how fast can a quantum process be? It's a useful piece of information to know if you want to build a quantum computer or a quantum network, as it tells you some of the limitations inherent in the system.

https://journals.aps.org/prx/abstract/10.1103/PhysRevX.11.011035

https://www.sciencealert.com/a-new-quantum-speed-limit-discovery-sh...

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Scientists begin building highly accurate digital twin of our planet

A digital twin of our planet is to simulate the Earth system in future. It is intended to support policy-makers in taking appropriate measures to better prepare for extreme events. A new strategy paper by European scientists and ETH Zurich computer scientists shows how this can be achieved.

Comment by Dr. Krishna Kumari Challa on February 24, 2021 at 11:39am

More than 87,000 scientific papers on coronavirus since pandemic

Study finds "astonishing" growth even as partnerships shrink

 Scientists from around the world have published more than 87,000 papers about coronavirus between the start of the COVID-19 pandemic and October 2020, a new analysis shows.

Even given the importance of the pandemic, researchers were surprised by the huge number of studies and other papers that scientists produced on the subject in such a short time.

Nearly all of the scientific community around the world turned its attention to this one issue.

https://www.eurekalert.org/pub_releases/2021-02/osu-mt8022221.php

Comment by Dr. Krishna Kumari Challa on February 24, 2021 at 11:07am

Can we regenerate damaged organs in the lab?

Scientists are trying to do just that!

Comment by Dr. Krishna Kumari Challa on February 24, 2021 at 10:56am

Researchers are turning kitchen waste into biofuels

When we eat, our bodies convert food into energy that fuels our lives. But what happens to the energy stored in the several billion pounds of food thrown away annually?

As part of advancing sustainable energy solutions, scientists are converting food waste into clean, renewable fuel that could power our planes, trains and automobiles. Researchers successfully converted food waste  into an energy-dense biofuel that could help replace today's fossil fuels. Early results suggest food waste might deliver a trifecta of efficiency, economic and environmental benefits.

scientists pursuing this  begin by blending the waste, often with the help of customized equipment known as the Muffin Monster that grinds up everything from bones and gristle to seeds, wrappers and packaging. The resulting mush is warmed so it can be continuously pumped into a reactor and converted into fuel.

The researchers are testing different types of food waste to see if they can achieve consistent outcomes. During experiments, they address numerous chemical and process engineering challenges as they arise. They fine-tune the heat exchange design, resolve pumping issues and develop continuous separation techniques.

https://phys.org/news/2021-02-kitchen-biofuels.html?utm_source=nwle...

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Comment by Dr. Krishna Kumari Challa on February 24, 2021 at 9:41am

Simply speaking while infected can potentially spread COVID-19

COVID-19 can spread from asymptomatic but infected people through small aerosol droplets in their exhaled breath. Most studies of the flow of exhaled air have focused on coughing or sneezing, which can send aerosols flying long distances.

However, speaking while near one another is also risky since the virus can be ejected by merely talking.

In Physics of Fluids, scientists in Japan use smoke and laser light to study the flow of expelled breath near and around two people conversing in various relative postures commonly found in the service industry, such as in hair salons, medical exam rooms, or long-term care facilities.

In this study, electronic cigarettes were used to produce artificial smoke consisting of droplets about one-tenth micron in diameter, similar to the size of a virus particle. The liquid used in these vaping devices, a mixture of glycerin and propylene glycol, produces a cloud of tiny droplets that scatter light from a laser, allowing visualization of airflow patterns.

To study the effect of speech on exhalation, the word "onegaishimasu," a typical Japanese greeting in a business setting. The experiments revealed the exhaled air from an unmasked person who is speaking tends to move downward under the influence of gravity. If a customer or patient is lying below, they could be infected. When a mask is worn while standing or sitting, the vapor cloud tends to attach to that person's body, which is warmer than the surrounding air and flows upward along the body. If the technician is leaning over, however, the aerosol cloud tends to detach from that person's body and fall onto the client below.

The investigators also experimented with face shields and found it can prevent any aerosols that leak from around the technician's mask from traveling down to the customer.

"The face shield promoted the rise of the exhaled breath," said Ishii. "Hence, it is more effective to wear both a mask and a face shield when providing services to customers."

"Relationship between human exhalation diffusion and posture in face-to-face scenario with utterance" Physics of Fluids (2021). DOI: 10.1063/5.0038380

https://phys.org/news/2021-02-simply-infected-potentially-covid-.ht...

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Comment by Dr. Krishna Kumari Challa on February 23, 2021 at 12:27pm

Using Light To Revolutionize Medical Imaging

Comment by Dr. Krishna Kumari Challa on February 23, 2021 at 11:41am

Ghost particle from shredded star reveals cosmic particle accelerator

From a black hole to the South Pole: Scientists identify first neutrino from a tidal disruption event

Tracing back a ghostly particle to a shredded star, scientists have uncovered a gigantic cosmic particle accelerator. The subatomic particle, called a neutrino, was hurled towards Earth after the doomed star came too close to the supermassive black hole at the centre of its home galaxy and was ripped apart by the black hole's colossal gravity. It is the first particle that can be traced back to such a 'tidal disruption event' (TDE) and provides evidence that these little understood cosmic catastrophes can be powerful natural particle accelerators.

The observations also demonstrate the power of exploring the cosmos via a combination of different 'messengers' such as photons (the particles of light) and neutrinos, also known as multi-messenger astronomy.

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The neutrino began its journey some 700 million years ago, around the time the first animals developed on Earth. That is the travel time the particle needed to get from the far-away, unnamed galaxy (catalogued as 2MASX J20570298+1412165) in the constellation Delphinus (The Dolphin) to Earth. Scientists estimate that the enormous black hole is as massive as 30 million suns. "The force of gravity gets stronger and stronger, the closer you get to something. That means the black hole's gravity pulls the star's near side more strongly than the star's far side, leading to a stretching effect. This difference is called a tidal force, and as the star gets closer, this stretching becomes more extreme. Eventually it rips the star apart, and then we call it a tidal disruption event. It's the same process that leads to ocean tides on Earth, but luckily for us the moon doesn't pull hard enough to shred the Earth.

About half of the star's debris was flung into space, while the other half settled on a swirling disc around the black hole.  Before plunging into oblivion, the matter from the accretion disc gets hotter and hotter and shines brightly. This glow was first detected by the Zwicky Transient Facility (ZTF) on Mount Palomar in California on 9 April 2019.

Half a year later, on 1 October 2019 the IceCube neutrino detector at the South Pole registered an extremely energetic neutrino from the direction of the tidal disruption event. It smashed into the Antarctic ice with a remarkable energy of more than 100 teraelectronvolts. For comparison, that's at least ten times the maximum particle energy that can be achieved in the world's most powerful particle accelerator, the Large Hadron Collider at the European particle physics lab CERN near Geneva.The extremely lightweight neutrinos hardly interact with anything, able to pass unnoticed through not just walls but whole planets or stars, and are hence often referred to as ghost particles. So, even catching just one high-energy neutrino is already a remarkable observation. Analysis showed that this particular neutrino had only a one in 500 chance of being purely coincidental with the TDE. The detection prompted further observations of the event with many instruments across the electromagnetic spectrum, from radio waves to X-rays.

- A tidal disruption event coincident with a high-energy neutrino; Robert Stein, Sjoert van Velzen, Marek Kowalski, et al.; Nature Astronomy, 2021, DOI: 10.1038/s41550-020-01295-8

- A concordance scenario for the observed neutrino from a tidal discruption event; Walter Winter and Cecilia Lunardini; Nature Astronomy, 2021, DOI: 10.1038/s41550-021-01305-3

https://www.eurekalert.org/pub_releases/2021-02/ded-gpf021821.php

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