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Archive for the ‘physics’ category: Page 94

Dec 7, 2022

Study explores the possibility that dark photons might be a heat source for intergalactic gas

Posted by in categories: cosmology, physics

Gas clouds across the universe are known to absorb the light produced by distant massive celestial objects, known as quasars. This light manifests as the so-called Lyman alpha forest, a dense structure composed of absorption lines that can be observed using spectroscopy tools.

Over the past decades, astrophysicists have been assessing the value of these as a tool to better understand the universe and the relationships between cosmological objects. The Lyman alpha forest could also potentially aid the ongoing search for dark matter, offering an additional tool to test theoretical predictions and models.

Researchers at University of Nottingham, Tel-Aviv University, New York University, and the Institute for Fundamental Physics of the Universe in Trieste have recently compared low-redshift Lyman alpha forest observations to hydrodynamical simulations of the intergalactic medium and dark matter made up of dark photons, a renowned dark matter candidate.

Dec 7, 2022

How Nobel Peace Laureates Inspire Youth To Believe In Themselves

Posted by in categories: education, ethics, evolution, physics

Recently, I learned about the World Nobel Peace Summit — fascinating. Young people can go there, mingle with Nobel Peace Laureates, network and share ideas.


Amma introduces the concept of two types of education: one that allows you to earn a living and another to attain a happy, fulfilled life. Modern education should focus on not just academic skills but a culture of human rights and peaceful coexistence of peoples, the ethics of non-violence. Too often, education is propelled by vanity and the desire for individual success. Over and over, it is just competition, pressure, and a vast amount of information pumped into one’s head without instilling the habit of exploring the future consequences of one’s actions. Imagine a good physics student who becomes a scientist just to invent a bomb that could destroy the whole world. We want a child to fulfill their potential — but stay aware of the outcomes of their choices at individual and societal levels. Ethics allows one to maintain this balance. As a society, we may want to establish ethical think tanks that simulate the future and guide us as we develop new technologies and community practices.

JB: Should the ways of peaceful coexistence be taught starting from pre-school age and reinforced over the years?

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Dec 7, 2022

Multiple Realizability (Stanford Encyclopedia of Philosophy)

Posted by in categories: bioengineering, biological, chemistry, neuroscience, physics

In the philosophy of mind, the multiple realizability thesis contends that a single mental kind (property, state, event) can be realized by many distinct physical kinds. A common example is pain. Many philosophers have asserted that a wide variety of physical properties, states, or events, sharing no features in common at that level of description, can all realize the same pain. This thesis served as a premise in the most influential argument against early theories that identified mental states with brain states (psychoneural, or mind-brain identity theories). It also served in early arguments for functionalism. Nonreductive physicalists later adopted this premise and these arguments (usually without alteration) to challenge all varieties of psychophysical reductionism. The argument was even used to challenge the functionalism it initially was offered to support. Reductionists (and other critics) quickly offered a number of responses, initially attacking either the anti-reductionist or anti-identity conclusion from the multiple realizability premise, or advocating accounts of the reduction relation that accommodated multiple realizability. More recently it has become fashionable to attack the multiple realizability premise itself. Most recently the first book-length treatment of multiple realizability and its philosophical import has appeared.

This entry proceeds mostly chronologically, to indicate the historical development of the topic. Its principle focus is on philosophy of mind and cognitive science, but it also indicates the more recent shift in emphasis to concerns in the metaphysics of science more generally. It is worth mentioning at the outset that multiple realizability has been claimed in physics (e.g., Batterman 2000), biochemistry (Tahko forthcoming) and synthetic biology (Koskinen 2019a, b). After more than fifty years of detailed philosophical discussion there still seems to be no end in sight for novel ideas about this persistent concern.

Dec 6, 2022

Five new exotic nuclei revealed in first experiment at FRIB

Posted by in category: physics

The first scientific results from the new Facility for Rare Isotope Beams (FRIB) at Michigan State University have been unveiled by physicists in the US. Heather Crawford at Lawrence Berkeley National Laboratory and colleagues have synthesized new neutron-rich isotopes of three different elements. Each nuclei is near the neutron drip line and the team has measured the isotopes’ lifetimes for the first time. The research provides a taste of how physicists will use FRIB to study exotic nuclei.

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Costing $730m, FRIB opened earlier this year with the aim of expanding our knowledge of nuclear physics by creating thousands of new isotopes for scientists to study. FRIB comprises a superconducting linear accelerator that can create high-intensity beams of just about every stable isotope. These nuclei are fired at targets, creating unstable isotopes that are collected to form beams – allowing the isotopes to be studied.

Dec 6, 2022

Improving precision of pressure determination in nanosecond X-ray diffraction experiments

Posted by in categories: physics, space

X-ray diffraction measurements under laser-driven dynamic compression allow researchers to investigate the atomic structure of matter at hundreds of thousands of atmospheres of pressure and temperatures of thousands of degrees, with broad implications for condensed matter physics, planetary science and astronomy.

Pressure determination in these experiments often relies on velocimetry measurements coupled with modeling that requires accurate knowledge of the optical and thermomechanical properties of a window material, resulting in significant systematic uncertainty.

In new research published in Physical Review B, Lawrence Livermore National Laboratory (LLNL) scientists report on a series of X-ray diffraction experiments on five metals dynamically compressed to 600 GPa (6,000,000 atmospheres of pressure). In addition to collecting atomic structure information for multiple compressed samples, the team demonstrated a different approach for pressure determination applicable to X-ray diffraction experiments under quasi-isentropic ramp compression.

Dec 6, 2022

Latest Webb Results Could Literally Break All Cosmology

Posted by in categories: cosmology, physics

The James Webb Space Telescope has finally made its first dark matter observations, and the results could lead us to new physics. They have questioned our understanding of dark matter and the large-scale structure-formation of the Universe. Dark matter is one of the most mysterious entities in the cosmos. Our best cosmological models show that 27% of the observable Universe is made of dark matter. We can’t see it, but its existence can be inferred because of its effect on surrounding baryonic matter. The true nature of dark matter is still one of the biggest mysteries in cosmology. The most successful cosmological model to date, the lambda cold dark matter or the LCDM model, makes a critical prediction regarding dark matter. It says that cold dark matter played an important role to form the large-scale structures we observe today.

So far, we did not have the technology to test this prediction. But the James Webb Space Telescope opened the windows to the first billion years and the last unexplored era in the history of the Universe. The super-early galaxies discovered by Webb in its Early Release Science program provided an opportunity to test the predictions made by the LCDM model. And when astronomers did that, the results were completely unexpected. So what do these primordial galaxies discovered by Webb tell us? What did Webb find in its first dark matter observations? Finally, and most importantly, how can these results change the course of cosmology?

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Dec 5, 2022

How Features of Our Consciousness Seem to Define Our Laws of Physics and Maths (Stephen Wolfram)

Posted by in categories: computing, mathematics, neuroscience, physics

Our Wolfram Physics Project has provided a surprisingly successful picture of the underlying (deeply computational) structure of our physical universe. I’ll talk here about how our perception of that underlying structure is determined by what seem to be key features of our consciousness—and how this leads to detailed laws of physics as we experience them. Our Physics Project has led to the concept of the ruliad—the entangled limit of all possible computations—which seems to represent a common underlying structure from which both physics and mathematics emerge. I’ll talk about the comparison between physical and mathematical observers, and how their common features in consciousness lead to implications for general laws of “bulk mathematics”.

Dec 4, 2022

The Theory That Could Rewrite the Laws of Physics

Posted by in category: physics

Chiara Marletto is trying to build a master theory — a set of ideas so fundamental that all other theories would spring from it. Her first step: Invoke the impossible. Read more about Marletto and David Deutsch’s constructor theory at Quanta Magazine: https://www.quantamagazine.org/how-to-rewrite-the-laws-of-ph…-20210429/

Dec 3, 2022

Microwave thruster makes for clean-burning jet

Posted by in categories: energy, physics, space

Year 2020 face_with_colon_three Propellant free thruster.


I usually approach papers on the subject of alternative thrusters with a certain degree of cynicism. But we’ve finally been given a study on microwave thrusters that doesn’t rely on impossible physics. Instead, it used a plain old plasma thruster.

Plasma thrusters have generally been thought of as a means of propulsion in space, but now one has been designed to operate under atmospheric conditions. According to the researchers involved, it’s an air plasma thruster that has the potential to produce the same thrust as a commercial jet engine.

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Dec 3, 2022

Kip Thorne — Is Time Travel Possible?

Posted by in categories: physics, time travel

What does time travel reveal about the nature of space and time? What about the laws of physics under extreme conditions?

For more on information and video interviews with Kip Thorne, please visit http://bit.ly/1DpWJQU

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