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Archive for the ‘physics’ category: Page 78

Aug 12, 2023

ESA’s Gaia satellite spots ‘retired stars’ passing through young star-forming area

Posted by in categories: computing, physics, space

These waves can reach heights comparable to stacking three suns on top of each other.

Astronomers have discovered a strange star system with “monster” tidal waves breaking on one of its stars. Astrophysicists from the Center for Astrophysics | Harvard & Smithsonian (CfA) developed new computer models to better understand the impact of huge surface waves.

The new models reveal “titanic waves” created by the tides of a smaller companion star to be repeatedly crashing on the colossal star in the system. This phenomenon has never been detected on a star, making it a significant discovery.

Continue reading “ESA’s Gaia satellite spots ‘retired stars’ passing through young star-forming area” »

Aug 10, 2023

Metaphysical knowledge and natural sciences: Metaphysics without physics

Posted by in category: physics

Rene Descartes, the father of cartesian philosophy, puts forward the relationship between sciences and especially the relation of metaphysics with other sciences through a metaphor known as the “Tree of Knowledge.” He describes knowledge as a tree and sciences are connected with each other as if they are parts of a tree. Its trunk is physics, its branches are other sciences and the fruit, which is considered to be the goal of a tree, is the science of morals. We are familiar with this metaphor and its varieties in philosophy and Sufism. In particular, it is a common metaphor to accept morals as “the fruit.” Morals, which are the intent of scientific activity, are deemed worthy of being the fruit, or the goal, by many thinkers. As a matter of fact, Ibn Arabi and Qunawi also used the same metaphor. They categorized the science of morals that is often identified with Sufism as the fruit of a tree and the goal of all human endeavors. Descartes completes his metaphor by saying that the tree’s roots are metaphysics. It is the roots that sustain a tree; the trunk, branches and fruits all depend on roots and are nourished by them, which makes the roots the most indispensable part. In this respect, this metaphor can be interpreted as a tribute to metaphysics.

While the tree of knowledge designates the place metaphysics holds among sciences, it seems to correspond with classical metaphysics, at least formally. Because the principal and subsidiary divisions of science (root and branch) are used by classical metaphysics to explain the relation of metaphysics with other sciences, the concepts of “principle and subsidiary” can be replaced by “universal and divisive,” and the meaning will not change: Metaphysics is a universal science and all other sciences serve to it as its particulars. It separates from other sciences, which examine the being from a specific angle, as metaphysics examines being qua being. Its superiority comes from this unique field of research. Because of its superior status, metaphysics is entrusted with another duty: Universal science is the most fundamental field as it certifies the principles of other sciences. The most controversial part of this assertion is whether such a superior science is possible and, if so, what method it has to attain knowledge. We will get to that, but now it is enough to state that: Despite the formal similarities, it is unlikely that Descartes could form a metaphysical understanding through this metaphor in the classical sense.

Aug 10, 2023

Physicists demonstrate how sound can be transmitted through vacuum

Posted by in categories: alien life, nanotechnology, physics

The classic film “Alien” was once promoted with the tagline “In space, no one can hear you scream.” Physicists Zhuoran Geng and Ilari Maasilta from the Nanoscience Center at the University of Jyväskylä, Finland, have demonstrated that, on the contrary, in certain situations, sound can be transmitted strongly across a vacuum region.

In a recent article published in Communications Physics they show that in some cases, a can jump or “tunnel” fully across a vacuum gap between two solids if the materials in question are piezoelectric. In such materials, vibrations (sound waves) produce an electrical response as well, and since an can exist in vacuum, it can transmit the .

The requirement is that the size of the gap is smaller than the wavelength of the sound wave. This effect works not only in audio range of frequencies (Hz–kHz), but also in ultrasound (MHz) and hypersound (GHz) frequencies, as long as the vacuum gap is made smaller as the frequencies increase.

Aug 9, 2023

After 15 years, pulsar timing yields evidence of cosmic background gravitational waves

Posted by in categories: physics, space

The universe is humming with gravitational radiation—a very low-frequency rumble that rhythmically stretches and compresses spacetime and the matter embedded in it.

That is the conclusion of several groups of researchers from around the world who simultaneously published a slew of journal articles in June describing more than 15 years of observations of millisecond pulsars within our corner of the Milky Way galaxy. At least one group—the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) collaboration—has found compelling evidence that the precise rhythms of these pulsars are affected by the stretching and squeezing of spacetime by these long-wavelength .

“This is key evidence for gravitational waves at very low frequencies,” says Vanderbilt University’s Stephen Taylor, who co-led the search and is the current chair of the collaboration. “After years of work, NANOGrav is opening an entirely new window on the gravitational-wave universe.”

Aug 8, 2023

Smoking-gun evidence for modified gravity at low acceleration from Gaia observations of wide binary stars

Posted by in categories: physics, space

A new study reports conclusive evidence for the breakdown of standard gravity in the low acceleration limit from a verifiable analysis of the orbital motions of long-period, widely separated, binary stars, usually referred to as wide binaries in astronomy and astrophysics.

The study carried out by Kyu-Hyun Chae, professor of physics and astronomy at Sejong University in Seoul, used up to 26,500 wide binaries within 650 (LY) observed by European Space Agency’s Gaia space telescope. The study was published in the 1 August 2023 issue of the Astrophysical Journal.

For a key improvement over other studies Chae’s study focused on calculating gravitational accelerations experienced by as a function of their separation or, equivalently the orbital period, by a Monte Carlo deprojection of observed sky-projected motions to the three-dimensional space.

Aug 8, 2023

The Impact of chatGPT talks (2023) — Prof. Max Tegmark (MIT)

Posted by in categories: education, physics, robotics/AI

The Impact of chatGPT and other large language models on physics research and education (2023)
Event organizers: Kevin Burdge, Joshua Borrow, Mark Vogelsberger.
Session 1: The computer science underlying large language models.

“Keeping AI under control through mechanistic interpretability“
Speaker: Prof. Max Tegmark (MIT)

Aug 7, 2023

New strategy decodes dynamic structure of proteins within cells

Posted by in categories: chemistry, physics

Protein dynamics play a crucial role in diverse functions. The intracellular environment significantly influences protein dynamics, particularly for intrinsically disordered proteins (IDPs).

A research group led Prof. Zhang Lihua from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS), in collaboration with Assoc. Prof. Gong Zhou from the Precision Measurement Science and Technology Innovation Research Institute of CAS, has proposed a strategy using in-vivo chemical cross-linking and (in-vivo XL-MS) to decode the dynamic structure of proteins within .

In-vivo XL-MS is potential for analyzing the dynamic structure of proteins within cells due to its high throughput, high sensitivity, and low requirements for protein purity.

Aug 7, 2023

Scientists Detect Highest-Energy Light Ever Seen From The Sun

Posted by in categories: energy, physics

The most energetic light ever seen emanating from the Sun has just been detected, creating a new puzzle for solar physicists to solve.

A 6-year observing campaign by more than 30 institutions across North America, Europe, and Asia has resulted in the first ever detection of solar gamma radiation in the teraelectronvolt (TeV) range.

Continue reading “Scientists Detect Highest-Energy Light Ever Seen From The Sun” »

Aug 6, 2023

Planet Vulcan: The Lost 19th Century World Einstein “Erased” From Our Solar System

Posted by in categories: physics, space

In 1,846, astronomer and mathematician Urbain Le Verrier sat down and attempted to locate a planet that had never been seen before by humans. Uranus (grow up) had been moving in unexpected ways, as predicted by the Newtonian theory of gravity.

Though the discrepancies were small, there was a difference between the observed orbit of Uranus and the way Newtonian physics predicted its orbit to be. In July, Le Verrier proposed that the difference could be explained by another planet beyond Uranus, and made predictions as to the orbit of this previously unknown body.

Continue reading “Planet Vulcan: The Lost 19th Century World Einstein ‘Erased’ From Our Solar System” »

Aug 5, 2023

Unraveling the Mysteries of Topology: Scientists Debunk Existing Assumptions

Posted by in categories: materials, physics

Topology has become a critical factor in the field of modern condensed matter physics and beyond. It explains the way solid materials may possess two distinct and seemingly conflicting characteristics. An example of this is topological insulators, materials whose bulk acts as an insulator, and can still conduct electricity at their surfaces and edges.

Over the past several decades, the idea of topology has revolutionized the understanding of electronic structure and the overall properties of materials. Additionally, it has opened doors to technological advancements by facilitating the integration of topological materials into electronic applications.

At the same time, topology is quite tricky to measure, often requiring combinations of multiple experimental techniques such as photoemission and transport measurements. A method known as high harmonic spectroscopy has recently emerged as a key technique to observe the topology of a material. In this approach a material is irradiated by intense laser light.

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