In a landmark series of calculations, physicists have proved that black holes can shed information, which seems impossible by definition. The work appears to resolve a paradox that Stephen Hawking first described five decades ago.
Category: physics – Page 214
Researchers at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) have gained a better understanding of a promising method for improving the confinement of superhot fusion plasma using magnetic fields. Improved plasma confinement could enable a fusion reactor called a spherical tokamak to be built smaller and less expensively, moving the world closer to reproducing on Earth the fusion energy that powers the sun and stars.
The improved confinement is made possible by the so-called enhanced pedestal (EP) H-mode, a variety of the high performance, or H-mode, plasma state that has been observed for decades in tokamaks around the world. When a fusion plasma enters H-mode, it requires less heating to get to the superhot temperatures necessary for fusion reactions.
The new understanding reveals some of the underlying mechanics of EP H-mode, a condition that researchers discovered more than a decade ago. Scientists led by physicists at PPPL have now found that the EP H-mode improves upon H-mode in spherical tokamaks by lowering the density of the plasma edge.
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Cosmic Loners
The problem with the GEODE hypothesis is that the strange objects need to resemble but not act like black holes. The only way that GEODEs could expand the universe without destroying everything around them is if they were isolated in empty pockets of the cosmos. But black holes often sit smack dab in the middle of galaxies.
“This becomes a problem if you want to explain the accelerating expansion of the universe,” lead author Kevin Croker said in a press release. “If they moved like black holes, staying close to visible matter, galaxies like our own Milky Way would have been disrupted.”
The catalogue also provides information on how the black holes spin, which holds the key to understanding how the objects came to orbit each other before they merged. It shows that, in some binary systems, the two black holes have misaligned axes of rotation, which would imply that they formed separately. But many other binaries appear to have roughly aligned axes of rotation, which is what astrophysicists expect when the two black holes began their lives as a binary star system. Two schools of thought in astrophysics have each favoured one of the two scenarios, but it now appears that both were correct, Fishbach says.
Astrophysicists now have enough black-hole mergers to map their frequency over the cosmos’s history.
Only a few years ago, scientists the world over celebrated as the first-ever gravitational waves were detected—confirming a long-held scientific theory and opening up an entirely new field of research.
Now, the international research team responsible for detecting gravitational waves has announced a further 39 gravitational wave events, bringing the total number of confirmed detections to 50.
The Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo Collaborations, which include researchers from the University of Portsmouth, have today published a series of papers that record events including the mergers of binary black holes, binary neutron stars and, possibly, neutron star-black holes.
This could lead to artificial gravity like we see on star trek.
Many physicists said that gravitons exist but some believe that it is impossible to observe it in the natural world. Recent studies suggest that gravitons create ‘noise’ making them easier to spot.
NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA) has confirmed, for the first time, water on the sunlit surface of the Moon. This discovery indicates that water may be distributed across the lunar surface, and not limited to cold, shadowed places.
SOFIA has detected water molecules (H2O) in Clavius Crater, one of the largest craters visible from Earth, located in the Moon’s southern hemisphere. Previous observations of the Moon’s surface detected some form of hydrogen, but were unable to distinguish between water and its close chemical relative, hydroxyl (OH). Data from this location reveal water in concentrations of 100 to 412 parts per million – roughly equivalent to a 12-ounce bottle of water – trapped in a cubic meter of soil spread across the lunar surface. The results are published in the latest issue of Nature Astronomy.
“We had indications that H2O – the familiar water we know – might be present on the sunlit side of the Moon,” said Paul Hertz, director of the Astrophysics Division in the Science Mission Directorate at NASA Headquarters in Washington. “Now we know it is there. This discovery challenges our understanding of the lunar surface and raises intriguing questions about resources relevant for deep space exploration.”
An international team of astronomers has gained new insights into the physical conditions prevailing in the gas tail of so-called jellyfish galaxies. They are particularly interested in the parameters that lead to the formation of new stars in the tail outside the galaxy disk. They analyzed, for example, the strength and orientation of the magnetic fields in the galaxy JO206.
Ancla Müller and Professor Ralf-Jürgen Dettmar from Ruhr-Universität Bochum describe their findings together with Professor Christoph Pfrommer and Dr. Martin Sparre from the Leibniz Institute for Astrophysics in Potsdam as well as colleagues from the INAF—Italian national institute of Astrophysics in Padua, Selargius and Bologna in the journal Nature Astronomy from 26 October 2020.
Earlier this month, Roger Penrose, Reinhard Genzel, and Andrea Ghez split the 2020 physics Nobel Prize for decades of work on black holes. Click here to learn more about their monumental achievement and about the history of our understanding of these exotic objects in space.
From prow to stern, this little boat measures 30 micrometers, about a third of the thickness of a hair. It has been 3D-printed by Leiden physicists Rachel Doherty, Daniela Kraft and colleagues.
The image was made using an electron microscope and can be found in their article about 3D printing synthetic microswimmers in the scientific journal Soft Matter.