Ten years after the first detection of gravitational waves, scientists have captured the clearest signal yet — and it confirms one of Stephen Hawking’s most famous predictions.
Using the upgraded LIGO detectors, researchers observed two black holes colliding over a billion light-years away, producing space-time ripples so precise they could “hear” the black holes ring like cosmic bells.
A new window on the universe.
You can’t have gold until a nucleus decays. The specifics of that process have been hard to pin down, but UT’s nuclear physicists have published three discoveries in one paper explaining key details. The results can help scientists come up with new models to describe the stellar processes that give us heavy elements, as well as make better predictions about the expanding landscape of exotic nuclei.
The work is published in the journal Physical Review Letters.
It sounds bizarre, but they exist: crystals made of rotating objects. Physicists from Aachen, Düsseldorf, Mainz and Wayne State (Detroit, U.S.) have jointly studied these exotic objects and their properties. They easily break into individual fragments, have odd grain boundaries and evidence defects that can be controlled in a targeted fashion.
In an article published in the Proceedings of the National Academy of Sciences, the researchers outline how several new properties of such transverse interaction systems can be predicted by applying a comprehensive theory.
Transverse forces can occur in synthetic systems, such as in certain magnetic solids. They exist in systems of living organisms too, however. In an experiment observing a host of starfish embryos conducted at American university MIT, it was found that, through their swimming movements, the embryos influence each other in a manner leading them to rotate around one another.
EPFL researchers have discovered that a droplet of liquid can bounce for several minutes—and perhaps indefinitely—over a vibrating solid surface. The seemingly simple observation has big implications for physics and chemistry.
If you’ve ever added liquid to a hot frying pan, maybe you noticed how the droplets bubbled up and skittered across the sizzling surface, rather than immediately flattening and wetting. This happens because the pan’s heat starts boiling the undersides of the droplets, producing vapor that acts as an insulating cushion on which they can—momentarily—dance.
Previously, scientists have produced a room-temperature version of this phenomenon—known as the Leidenfrost effect—by replacing the hot surface with a rapidly vibrating liquid bath. In these experiments, the vibrations produced a thin film of air on which the liquid droplets could bounce and hover perpetually.
Networks are systems comprised of two or more connected devices, biological organisms or other components, which typically share information with each other. Understanding how information moves between these connected components, also known as nodes, could help to advance research focusing on numerous topics, ranging from artificial intelligence (AI) to neuroscience.
To measure the directional flow of information in systems, scientists typically rely on a mathematical construct known as transfer entropy, which essentially quantifies the rate at which information is transmitted from one node to another. Yet most strategies for calculating transfer entropy developed so far rely on approximations, which significantly limits their accuracy and reliability.
Researchers at AMOLF, a fundamental physics institute in the Netherlands, recently developed a computational algorithm that can precisely quantify transfer entropy in a wide range of complex networks. Their algorithm, introduced in a paper published in Physical Review Letters, opens new exciting possibilities for the study of information transfer in both biological and engineered networks.
Dr. Sfaradi, who led the research, is a former graduate student of Prof. Assaf Horesh. “This is one of the fascinating discoveries I’ve been part of,” said Prof. Horesh. “The fact that it was led by my former student, Itai, makes it even more meaningful. It’s another scientific achievement that places Israel at the forefront of international astrophysics.”
A black hole far from home
Tidal disruption events occur when a star ventures too close to a massive black hole and is torn apart by its immense gravity.
Why is the universe expanding at an ever-increasing rate? This is one of the most exciting yet unresolved questions in modern physics. Because it cannot be fully answered using our current physical worldview, researchers assume the existence of a mysterious “dark energy.” However, its origin remains unclear to this day.
An international research team from the Center for Applied Space Technology and Microgravity (ZARM) at the University of Bremen and the Transylvanian University of Brașov in Romania has come to the conclusion that the expansion of the universe can be explained—at least in part—without dark energy.
In physics, the evolution of the universe has so far been described by the general theory of relativity and the so-called Friedmann equations. However, in order to explain the observed expansion of the universe on this basis, an additional “dark energy term” must be manually added to the equations.