Dark matter supposedly makes up 85% of the matter in the universe, but so far, efforts to catch hypothesized dark matter particles have all ended in failure. Weakly interacting massive particles (WIMPs) are no-shows at grand experiments housed in Italy, Canada, and the United States. Even tinier axions have not been detected either. Neutralinos, born out of supersymmetry, may look nice on paper but so far have no bearing on reality.
Posted in cosmology, particle physics
The standard model of modern cosmology is unthinkable without dark matter, although direct detections are still missing. A broad perspective of how dark matter was postulated and became accepted is presented, from prehistory, over observations of galaxy clusters, galaxy rotation curves, the search for baryonic dark matter, possible alternative explanations via modified gravity, up to the hunt for dark matter particles. The interplay is described between observational discoveries and theoretical arguments which led finally to the adoption of this paradigm.
Black Hole Entropy and Soft Hair was completed in the days before the physicist’s death in March.
• Black holes and soft hair: why Stephen Hawking’s final work is important.
Posted in cosmology
The international collaborative n_TOF, in which a group of University of Seville researchers participated, has made use of the unique capacities of three of the world’s nuclear facilities to carry out a new experiment aimed at finding an explanation of the cosmological lithium problem. This problem is among the still unresolved questions of the current standard description of the Big Bang. The new experimental results, their theoretical interpretations and their implications have been published in Physical Review Letters.
When listening to world science festival’s latest episode on youtube, Pondering the Imponderables: The Biggest Questions of Cosmology, I found myself to be most in line with George F.R. Ellis’ line of thinking overall.
Big Bang cosmology, chemical and biological evolutionary theory, and associated sciences have been extraordinarily successful in revealing and enabling us to understand the development of the.
Cosmology is today a precision science with masses of high quality data every increasing our understanding of the physical universe, but paradoxically theoretical cosmology is simultaneously.
Professor George Ellis FRS Introduced by Prof. Alister McGrath Followed by a panel discussion with Prof. Ard Louis and Prof. Denis Noble Mathematical Institute, Oxford.
Since the 1970s, astronomers and physicists have been gathering evidence for the presence in the universe of dark matter: a mysterious substance that manifests itself through its gravitational pull. However, despite much effort, none of the new particles proposed to explain dark matter have been discovered. In a review that was published in Nature this week, physicists Gianfranco Bertone (UvA) and Tim Tait (UvA and UC Irvine) argue that the time has come to broaden and diversify the experimental effort, and to incorporate astronomical surveys and gravitational wave observations in the quest for the nature of dark matter.
Over the past three decades, the search for dark matter has focused mostly on a class of particle candidates known as weakly interacting massive particles (or WIMPs). WIMPs appeared for a long time as a perfect dark matter candidate as they would be produced in the right amount in the early universe to explain dark matter, while at the same time they might alleviate some of the most fundamental problems in the physics of elementary particles, such as the large discrepancy between the energy scale of weak interactions and that of gravitational interactions.
Matter ejected from a spinning disc of doom surrounding a black hole a mere 15,000 light years away has produced some of the most energetic rays of light ever witnessed from an object of its kind.
The insanely powerful photons of gamma radiation were produced by a never-before-seen phenomenon surrounding a miniature quasar. The discovery could help us better understand what goes on deep in the chaotic heart of the Milky Way.
SS 433 is a smaller version of the kinds of maelstrom of death you’d find lurking at the core of most galaxies. It’s also in our neighbourhood, more or less, making it relatively easy to study.
