Dark matter is an elusive form of matter that almost never emits, absorbs or reflects light, while only weakly interacting with regular matter. These properties make it very difficult to detect using conventional experimental techniques and instruments.
Over the past decades, physicists have inferred the existence of dark matter indirectly, by probing its influence on the gravity of stars, galaxies and other cosmological objects. As it has never been directly observed before, the exact composition and nature of dark matter remain unknown.
A hypothetical dark matter particle is the axion, an ultralight particle that is predicted to be highly abundant in the universe. Most existing work describes axions as a classical field, a wave-like entity that resembles an electromagnetic field.
Researchers at The University of Alabama in Huntsville (UAH), a part of The University of Alabama System, have identified a promising new method for measuring the mass of galaxies orbiting the Milky Way by using pulsars, some of the universe’s most precise natural clocks, to detect tiny gravitational effects across our galaxy.
The work, published on the arXiv preprint server, offers a novel approach for studying the hidden dark matter contained within nearby satellite galaxies. The findings could have broad implications for astrophysics and cosmology.
The study was authored by UAH astrophysicists Dr. Thomas Donlon, postdoctoral research assistant II, and Dr. Sukanya Chakrabarti, a professor and Pei-Ling Chan Endowed Chair in the College of Science, in collaboration with Dr. Jason A. S. Hunt, an astrophysicist at the University of Surrey, U.K. The research examines how the gravitational pull of neighboring dwarf galaxies subtly disturbs the Milky Way.
Black holes are regions in space where gravity is so strong that nothing, even light, can escape. Einstein’s theory of general relativity breaks down inside black holes, either by the presence of a so-called “curvature singularity” or “Cauchy horizon.”
A curvature singularity is a point where density and spacetime curvature become infinite, the laws of physics break down, and matter is crushed into an infinitely small space. A Cauchy horizon, on the other hand, is a boundary beyond which the future cannot be reliably predicted by known physics theories.
Francesco Di Filippo, a researcher at the Institute for Theoretical Physics in Frankfurt, recently carried out a theoretical study that challenges the assumption that black holes must inevitability possess either a singularity or a Cauchy horizon. His paper, published in Physical Review Letters, shows that the combination of electromagnetic repulsion from electric charge and quantum effects described by Stephen Hawking’s radiation theory could prevent the formation of singularities and Cauchy horizons in some black holes.
A team from Vienna and Frankfurt has found a formula describing a strange phenomenon: Space and time can form a kind of “crystal” that may turn into a black hole. The results are described in Physical Review Letters.
Alongside the famous gigantic black holes, physics also allows for microscopic versions. They emerge from so-called critical states, when spacetime organizes itself into a regular, crystal-like structure during a process known as critical collapse. A team from Goethe University Frankfurt and TU Wien has now succeeded, for the first time, in describing this phenomenon with an exact mathematical formula using an unusual mathematical trick.
Black holes usually form in spectacular events, such as the death of a massive star. But in theory, arbitrarily small black holes are also possible: tiny microscopic objects that can emerge from special critical states after the slightest addition of energy. Such states may have existed shortly after the Big Bang, when the universe was still a chaotic mixture of particles, potentially giving rise to so-called primordial black holes.
How come our universe is full of disorder, when all elementary particles appear to follow strictly ordered laws of physics? And are there organizing principles behind disorder and apparent chaos?
One avenue of studying these fundamental questions is through an assembly of spins: the quantum property that makes electrons behave like tiny bar magnets, with a preferred orientation of either up or down. Neighboring spins align either in parallel (up-up) or antiparallel (up-down-up-down), as in ferromagnets and antiferromagnets, respectively. This simple ruleset makes spin systems very attractive for studying the emergence of order.
However, while the theory of spin is well-established, creating the material conditions for observing spin disorder has proven notoriously elusive. While physicists have been able to create exotic materials that exhibit spin disorder, tracing the evolution from order to disorder within materials has been challenged by the lack of a clean starting point.
LSU researchers helped uncover what may be the first clear detection of gamma rays from a superluminous supernova, using data from NASA’s Fermi Gamma-ray Space Telescope—a breakthrough that offers new insight into the powerful magnetars believed to drive some of the universe’s brightest stellar explosions.
An international team studying data from NASA’s Fermi Gamma-ray Space Telescope concludes the mission detected a rare, unusually luminous supernova. The researchers say it likely received its power-up from a supermagnetized neutron star born in the stellar collapse that triggered the explosion.
The Fermi mission is part of NASA’s fleet of observatories monitoring the changing cosmos to help humanity better understand how the universe works.
Lisa Feldman Barrett, Michael Levin and Adam Frank discuss whether science should abandon its materialist framework.
Could a different metaphysics help science to progress further?
With a free trial, you can watch the full debate NOW at https://iai.tv/video/science-beyond-t… centuries, we’ve assumed that science has banished the transcendent and established that reality is entirely physical. But critics argue there are signs that a rigorous materialism might be holding science back. Increasingly, “emergence” is used to account for everything from consciousness to spacetime – a convenient placeholder for what materialist science may be unable to explain. Physicists like Heisenberg and Hawking concluded that science gives us models of reality, rather than final descriptions of its true nature, while there are scientists working in everything from biology to computer science who suggest that dualism is a productive metaphysical framework for their research. Materialism may have enabled science to reach beyond the dogmas of religion, but there are now those who are restlessly probing the limits of materialism itself. Does science need to assume a materialist account of the world or might this have fundamental limitations? Could a different metaphysics help science make progress on key questions, from the origin of life to the mysteries of quantum gravity? Or would abandoning materialism risk returning us to the myths of superstition and religion? #science #materialism #metaphysics Lisa Feldman Barrett is among the most cited scientists in the world for her research on the psychology and neuroscience of emotions. Adam Frank is an astrophysicist who explores the origins of stars, civilizations and consciousness, and is a leading figure in astrobiology and the search for alien life. Michael Levin is a synthetic biologist whose pioneering work in regenerative biology involves building biological robots to probe the nature of life, intelligence and evolution. Güneş Taylor hosts. The Institute of Art and Ideas features videos and articles from cutting edge thinkers discussing the ideas that are shaping the world, from metaphysics to string theory, technology to democracy, aesthetics to genetics. Subscribe today! https://iai.tv/subscribe?utm_source=Y… 0:00 Intro 1:34 Science cannot reveal objective reality 5:28 — History shows that materialism is one of many philosophies of science 8:59 There are some mathematical facts which are discovered, not chosen 12:14 Does materialism prevent mythical and superstitious views of reality? 14:56 There is no 3rd person view of the universe 18:05 Is science truly reproducible? For debates and talks: https://iai.tv For articles: https://iai.tv/articles For courses: https://iai.tv/iai-academy/courses.
For centuries, we’ve assumed that science has banished the transcendent and established that reality is entirely physical. But critics argue there are signs that a rigorous materialism might be holding science back. Increasingly, “emergence” is used to account for everything from consciousness to spacetime – a convenient placeholder for what materialist science may be unable to explain. Physicists like Heisenberg and Hawking concluded that science gives us models of reality, rather than final descriptions of its true nature, while there are scientists working in everything from biology to computer science who suggest that dualism is a productive metaphysical framework for their research. Materialism may have enabled science to reach beyond the dogmas of religion, but there are now those who are restlessly probing the limits of materialism itself.
Does science need to assume a materialist account of the world or might this have fundamental limitations? Could a different metaphysics help science make progress on key questions, from the origin of life to the mysteries of quantum gravity? Or would abandoning materialism risk returning us to the myths of superstition and religion?
Cosmologists have long struggled to determine whether the universe’s accelerating expansion is being driven by a simple cosmological constant, or whether dark energy’s influence is evolving over time. In a new analysis published in Physical Review D, Samsuzzaman Afroz and Suvodip Mukherjee at the Tata Institute of Fundamental Research, Mumbai, have identified a subtle impact on the inference of the nature of dark energy, due to a tiny mismatch between a fundamental cosmological distance relation and two key datasets used to measure the properties of dark energy.
The result casts fresh doubt on the robustness of the recent claims that dark energy could be evolving over time—perhaps bringing us a step closer to solving one of cosmology’s most enduring challenges.
Scientists have developed a new technique that could turn black hole collisions into cosmic detectors for dark matter, revealing faint traces hidden inside gravitational waves.
