Lifeboat Foundation

A RUDN physicist demonstrated how to describe the shape of any symmetrical wormhole—a black hole that theoretically can be a kind of a portal between any two points in space and time—based on its wave spectrum. The research would help understand the physics of wormholes and better identify their physical characteristics. The article was published in the Physics Letters B journal.

Modern concepts of the universe provide for the existence of wormholes—unusual curvatures in space and time. Physicists imagine a wormhole as a black hole through which one can see a distant point of the universe in four dimensions. Astrophysicists are still unable to determine the shape and sizes of black holes precisely, let alone theoretical wormholes. A RUDN physicist has now demonstrated that the shape of a wormhole can be calculated based on observable physical characteristics.

In practice, physicists can observe only indirect properties of wormholes, such as red shift—a downward shift in the frequency of gravitational waves in the course of moving away from an object. Roman Konoplya, a research assistant from the RUDN Institute of Gravitation and Cosmology, the author of the work, used quantum mechanical and geometrical assumptions and showed that the shape and mass of a wormhole can be calculated based on the red shift value and the range of gravitational waves in high frequencies.

Our universe is permeated with a vast, unseen force that seems to oppose gravity. Physicists call this force dark energy, and it is thought to be constantly pushing our universe outward.

But in June, a group of physicists published a paper in the preprint journal arXiv implying that dark energy changes over time. This means that the universe will not expand forever but might eventually collapse into the size it was before the Big Bang.

Almost immediately, however, physicists found problems with the theory: Several independent groups subsequently published papers that suggested revisions to the conjecture. Now, a paper published on Oct. 2 in the journal Physical Review D suggests that, as it stands, the original conjecture can’t be true because it can’t explain the existence of the Higgs boson — which we know exists, thanks to the Large Hadron Collider, the massive particle collider on the border between France and Switzerland. [Beyond Higgs: 5 Elusive Particles That May Lurk in the Universe].

The impact of gravitational-microlensing observations from 1993.

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.

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.

George Chapline believes that the Event Horizon Telescope will offer evidence that black holes are really dark energy stars. NASAWhat…

The strictest limits yet on the size of extra dimensions come from the fact that black holes haven’t destroyed the universe.

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.

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.