Source: Ashtekar A, Paraizo DE, Shu J (2026). “Thermodynamics of Black Holes, Far from Equilibrium.” Physical Review Letters. DOI 10.1103/3c1r-v8f1. Published June 24, 2026. Selected as Editor’s Suggestion. Penn State University. ScienceDaily, July 13, 2026. Quotes: Abhay Ashtekar, Penn State. Video.
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The mysterious substance that binds galaxies together could naturally be “in tune” with a hidden fifth dimension, according to a new University of Sheffield theory aiming to shed light on one of science’s biggest enigmas: dark matter.
Dark matter has been explored by scientists and science fiction writers for decades, inspiring everything from planet-destroying vortexes in “Star Trek” to the “dust” that sustains the multiverse in Philip Pullman’s “His Dark Materials” fantasy trilogy.
Yet it remains one of the greatest open problems in physics. While scientists are certain it exists because of its immense gravitational effect—acting as an invisible “cosmic glue” holding galaxies together—it has never been observed, and its true nature remains a mystery.
The massive globular star cluster Omega Centauri has puzzled astronomers for decades. It should be filled with black holes left behind by exploding stars, yet evidence for them is scarce. Now, astronomers using archival data from NASA’s Hubble Space Telescope and supporting observations from NASA’s James Webb Space Telescope have finally located the first stellar-mass black hole in this cluster. Discovering the first of this missing black hole population will help refine current theories on black hole formation within environments such as Omega Centauri. The team’s findings were published in The Astrophysical Journal Letters.
Omega Centauri consists of 10 million gravitationally bound stars. Though the astronomical community previously found evidence using Hubble that an intermediate-mass black hole lurks at its center, models suggest this star cluster should also contain about 10,000 smaller, stellar-mass black holes. This notable population of black holes evaded detection in previous observational studies, which used the radial velocity method or looked for radio and X-ray emission from material falling onto black holes.
Our universe is known to be remarkably homogeneous and isotropic. This essentially means that matter is distributed evenly throughout the universe and that it looks almost the same in all directions.
Physics theories, however, predict that in its early days, the universe may have been far less orderly, with different regions expanding at varying rates. Yet how the universe could have evolved from this potentially uneven beginning into the smoothness we observe today remains unclear.
Researchers at Baylor University, Jiangxi Normal University, State University of Rio de Janeiro and Universidade Federal Fluminense recently delineated a mechanism that could explain how the universe shifted from early unevenness (i.e., anisotropy) to its current homogeneity. Their theoretical paper, published in Physical Review Letters, models the evolution of the early universe using a framework known as the modified loop quantum cosmology (mLQC-I) model.
A strange “chirping” signal from a distant supernova has revealed the birth of a magnetar, confirming that these incredibly magnetic neutron stars can power the universe's brightest stellar explosions. The discovery also marks the first time Einstein's general relativity has been used to explain the mechanics of a supernova.
More than half a century ago, Sir Roger Penrose envisioned a scenario in which energy could be extracted from a black hole spinning at extreme speeds. He proposed that a particle entering its ergosphere—a region of space dragged around by a rotating black hole—could split into two. One part could fall into the black hole while the other escaped carrying more energy than the original particle. Building on this theory, physicist Yakov Zel’dovich later predicted that a wave interacting with a sufficiently fast, rotating object could extract energy from it and become amplified.
Inspired by this theoretical construct, researchers at the Advanced Science Research Center at the CUNY Graduate Center (CUNY ASRC) have published a paper in Nature demonstrating a new approach to wave amplification through interaction with rotating bodies. Rather than mechanically rotating matter, however, the team engineered a radio-frequency device with properties modulated in space and time to mimic spinning. The device creates a synthetic form of ultrafast rotation that enables access to rotational speeds far beyond what can be achieved mechanically, allowing researchers to overcome limitations that have long hindered experimental studies of ultrafast rotational dynamics.
“Our approach facilitates a new method of wave–matter interaction in which waves with selected rotational properties extract energy from synthetic time-engineered rotation, producing a form of broadband selective amplification,” said principal investigator Andrea Alù, distinguished professor and Einstein Professor of Physics at the CUNY Graduate Center and founding director of the CUNY ASRC’s Photonics Initiative.
Decades-old experiments have now been enlisted to set new bounds on the properties of a hypothetical particle that bears a tiny fraction of the electron’s charge.
One candidate for the mysterious dark matter believed to pervade the Universe is a hypothetical form of matter called millicharged particles (mCPs), which carry a tiny fraction of the charge on an electron. A research team has now proposed that such particles, if they exist, might be detected by letting them accumulate in simple laboratory-scale devices already used for creating and measuring electric charge [1, 2]. The team has shown that previous measurements made with such devices can be used to set new limits on the properties of mCPs.
The standard model of particle physics accommodates the 17 particles that make up regular, visible matter, but researchers are seeking to extend it to include gravity or dark matter or both. Dark matter seems to be demanded by astronomical observations and—aside from its gravitational interactions—should interact minimally, if at all, with light and with other matter.
For nearly a century, astronomers have known that the universe is expanding. In the late 1990s, two independent teams, the Supernova Cosmology Project, led by Saul Perlmutter, and the High-Z Supernova Search Team, led by Brian Schmidt and Adam Riess, discovered something strange: The expansion is speeding up. The finding earned them the 2011 Nobel Prize in Physics. The leading explanation for this acceleration is “dark energy,” a mysterious force usually modeled as a constant called Lambda, pushing space apart. Combined with cold dark matter, this gives us the LCDM model, the standard picture of the cosmos for the past 25 years.
LCDM is remarkably successful. It fits observations of the cosmic microwave background (CMB), i.e., the leftover glow from the Big Bang, as well as maps of galaxy clustering and the brightness of exploding stars called Type Ia supernovae. But it has one nagging problem: the Hubble tension.
Cosmologists have proposed dark energy that switches sign over cosmic history. A rigorous new analysis published in Physical Review D checks whether it actually closes the gap.