Primordial black holes could be stabilized by a dark, electromagnetic-like interaction, delaying their violent end until the present day.
Category: cosmology – Page 56
Landmark Black Hole Test Marks Decade of Gravitational-Wave Discoveries
The clearest black hole merger signal ever measured has allowed researchers to test the Kerr nature of black holes and validate Stephen Hawking’s black hole area theorem.
Gravitational-wave astronomy is moving at breakneck speed. Just over a decade ago, the direct detection of gravitational waves was considered an elusive goal—perpetually said to be “five-to-ten years away.” Then came the 2015 breakthrough: the first observed merger of two black holes, known as GW150914 [1]. Detections have since become routine, with a catalog of black hole mergers now numbering in the hundreds. There is even evidence for a gravitational-wave background at nanohertz frequencies, plausibly sourced by a population of supermassive black hole binaries throughout the Universe. Now the LIGO detectors have captured the clearest merger signal ever recorded, GW250114 [2]. From such a signal, the LIGO-Virgo-KAGRA (LVK) Collaboration was able to draw two spectacular conclusions. First, it confirmed that the nature of the merging objects is consistent with that of Kerr (spinning) black holes.
Probing the Higgs Mechanism with Particle Collisions and AI
A deep neural network has proven essential in confirming a key prediction of one of the standard model’s cornerstones.
The Higgs mechanism explains why the electromagnetic and weak interactions have such drastically different strengths—that is, how their symmetry became broken a picosecond after the big bang. The Higgs does not interact with photons, rendering them massless, whereas they do interact with the carriers of the weak interaction (the W+, W–, and Z bosons), giving them masses of order 100 GeV. Their nonzero masses allow them to acquire a longitudinal polarization—that is, a spin orientation perpendicular to their direction of motion. Because of special relativity, photons and other massless bosons that travel at the speed of light can’t have longitudinal polarization, but the W and Z bosons and other massive particles can. If electroweak symmetry had been broken not by the Higgs mechanism but by a different interaction, there would be no Higgs boson to find.
QROCODILE experiment advances search for dark matter using superconducting nanowire single-photon detectors
Over the past decades, many research teams worldwide have been trying to detect dark matter, an elusive type of matter that does not emit, reflect or absorb light, using a variety of highly sensitive detectors. Ultimately, these detectors should be able to pick up the very small signals that would indicate the presence of dark matter or its weak interactions with regular matter.
90% Chance: Physicists Predict a Black Hole Could Explode This Decade
UMass Amherst physicists believe such an explosion could occur within the next decade, potentially “revolutionizing physics and rewriting the history of the universe.” Physicists have long thought that black holes end their lives in rare explosions that occur, at most, once every 100,000 years. N
Ringing black hole confirms Einstein and Hawking’s predictions
A decade ago, scientists first detected ripples in the fabric of space-time, called gravitational waves, from the collision of two black holes. Now, thanks to improved technology and a bit of luck, a newly detected black hole merger is providing the clearest evidence yet of how black holes work—and, in the process, offering long-sought confirmation of fundamental predictions by Albert Einstein and Stephen Hawking.
The new measurements were made by the Laser Interferometer Gravitational-Wave Observatory (LIGO), with analyses led by astrophysicists Maximiliano Isi and Will Farr of the Flatiron Institute’s Center for Computational Astrophysics in New York City. The results reveal insights into the properties of black holes and the fundamental nature of space-time, hinting at how quantum physics and Einstein’s general relativity fit together.
“This is the clearest view yet of the nature of black holes,” says Isi, who is also an assistant professor at Columbia University. “We’ve found some of the strongest evidence yet that astrophysical black holes are the black holes predicted from Albert Einstein’s theory of general relativity.”
An exploding black hole could reveal the foundations of the universe
Physicists have long believed that black holes explode at the end of their lives, and that such explosions happen—at most—only once every 100,000 years. But new research published in Physical Review Letters by physicists at the University of Massachusetts Amherst has found a more than 90% probability that one of these black-hole explosions might be seen within the decade, and that, if we are prepared, our current fleet of space and earthbound telescopes could witness the event.
Such an explosion would be strong evidence of a theorized but never observed kind of black hole, called a “primordial black hole,” that could have formed less than a second after the Big Bang occurred, 13.8 billion years ago.
Furthermore, the explosion would give us a definitive catalog of all the subatomic particles in existence, including the ones we have observed, such as electrons, quarks and Higgs bosons, the ones that we have only hypothesized, like dark matter particles, as well as everything else that is, so far, entirely unknown to science. This catalog would finally answer one of humankind’s oldest questions: from where did everything in existence come?
Hawking and Kerr black hole theories confirmed by gravitational wave
Scientists have confirmed two long-standing theories relating to black holes—thanks to the detection of the most clearly recorded gravitational wave signal to date.
Ten years after detecting the first gravitational wave, the LIGO-Virgo-KAGRA Collaboration has (10 Sep) announced the detection of GW250114—a ripple in spacetime which offers unprecedented insights into the nature of black holes and the fundamental laws of physics.
The study confirms Professor Stephen Hawking’s 1971 prediction that when black holes collide, the total event horizon area of the resulting black hole is bigger than the sum of individual black holes—it cannot shrink.
Discovery of young eclipsing binary system offers insight into early stellar evolution
An international team of astronomers reports the discovery of a new pre-main-sequence eclipsing binary system. The newfound binary, designated MML 48, consists of two young low-mass stars. The finding will be published in the upcoming issue of the Astronomy & Astrophysics journal.
Stellar systems showing regular light variations due to one of the stars passing directly in front of its companion are known as eclipsing binaries (EBs). In these systems, the orbit plane of the two stars lies so nearly in the line of sight of the observer that the components undergo mutual eclipses. EBs can provide direct accurate measurement of the mass, radius and effective temperature of stars; therefore, they are essential for testing and calibrating theoretical stellar-evolution models.
Astronomers are especially interested in finding new young EBs. This is due to the fact that such binaries constrain pre-main-sequence (PMS) stellar evolution models in the regime when the temperatures, luminosities, and radii of stars are changing rapidly as they settle onto the main sequence (MS).
