Scientists have uncovered the strongest evidence yet for the existence of elusive intermediate-mass black holes (IMBHs), long thought to be the missing link between stellar-mass and supermassive black holes. By tracking a hypervelocity star, J0731+3717, that appears to have been ejected from the
What can astronomers learn from observing black holes that suddenly wake up? This is what a recent study published in Nature Astronomy hopes to address as an international team of researchers investigated what a black hole looks like when it goes active and starts accumulating matter in its environment. This study has the potential to help researchers better understand the peculiar nature of black holes, which remains one of the most intriguing and mysterious objects in the universe.
For the study, the researchers observed a black hole residing at the center of SDSS1335+0728, which is located approximately 300 million light-years from Earth in the constellation Virgo. This study builds on observations first made in 2019 of activity of this particular black hole, which was nicknamed “Ansky”, and has since been designated as an active galactic nucleus. But new observations made in 2024 revealed Ansky was emitting X-ray bursts regularly, and the astronomers pounced at the chance to observe a black hole waking up, so to speak.
“This rare event provides an opportunity for astronomers to observe a black hole’s behavior in real time, using X-ray space telescopes XMM-Newton and NASA’s NICER, Chandra and Swift,” said Dr. Lorena Hernández-García, who is a researcher at Valparaiso University in Chile and lead author of the study. “This phenomenon is known as a quasiperiodic eruption, or QPEs are short-lived flaring events. And this is the first time we have observed such an event in a black hole that seems to be waking up.”
Researchers from the University of Waterloo have proposed a new method to measure the Hubble constant that could help resolve one of modern cosmology’s pressing puzzles: the Hubble tension.
The study published in Physical Review Letters aims to resolve the Hubble tension, a discrepancy between the value of the Hubble constant (H0) from the local (distance ladder) method and the cosmic microwave background (CMB) method.
Phys.org spoke to the first author of the study, Dr. Alex Krolewski, a postdoctoral researcher at the University of Waterloo.
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VIDEO NOTES
Brian Greene is a professor of physics and mathematics at Columbia University, director of its centre for theoretical physics, and the chairman of the World Science Festival. He is best known for his work on string theory, especially in his book “The Elegant Universe”, which turns 25 this year.
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Black holes are fundamental to the structure of galaxies and critical in our understanding of gravity, space, and time. A stellar mass black hole is a type of black hole that forms from the gravitational collapse of a massive star at the end of its life cycle. These black holes typically have masses ranging from about 3 to 20 times the mass of our sun.
Sometimes black holes generate beams of ionized gas (plasma) that shoot outward at nearly light speed. Although discovered more than a century ago, how and why jets occur has remained a mystery, described as one of the “wonders of physics.”
Prof. Kazutaka Yamaoka from Nagoya University in Japan, along with his colleagues from the University of Toyama and other international institutes, have discovered key conditions needed for a stellar black hole to create plasma jets. Their findings, published in Publications of the Astronomical Society of Japan, show that when superheated gas material experiences a rapid shrinkage toward the black hole, jet formation occurs.
The universe doesn’t come with an instruction manual—but if it did, University of Missouri Assistant Professor Charles Steinhardt suspects a few pages are missing. Either the universe has been playing by different rules all along, or humanity has been reading the script wrong.
Traditionally, astronomers have grouped galaxies into two different categories: blue, which are young and actively forming stars, and red, which are older and have ceased star formation. Now, Steinhardt is challenging the traditional understanding of galaxies by proposing a third category: red star-forming. They don’t fit neatly into the usual blue or red—instead, they’re somewhere in between.
“Red star-forming galaxies primarily produce low-mass stars, making them appear red despite ongoing star birth,” he said. “This theory was developed to address inconsistencies with the traditional observed ratios of black hole mass to stellar mass and the differing initial mass functions in blue and red galaxies—two problems not explainable by aging or merging alone. However, what we learned is that most of the stars we see today might have formed under different conditions than we previously believed.”
Top quarks and antiquarks have been detected in heavy-ion collisions at the Large Hadron Collider, showing that all six quark flavors were present in the Universe’s first moments.
Quarks, the fundamental building blocks of matter, are usually confined within hadrons, such as protons and neutrons, by the strong force. But in the first moments after the big bang, quarks and gluons moved freely in an extremely hot, dense state of matter called a quark–gluon plasma (QGP) [1]. This “primordial soup” was the Universe’s first form of matter, existing for roughly 10 microseconds after the big bang, until the Universe cooled sufficiently for quarks and gluons to combine [2]. Scientists recreate and study these early-Universe conditions by smashing together ultrarelativistic heavy nuclei at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory in New York, the Large Hadron Collider (LHC) at CERN in Switzerland, and similar facilities.
A new theory links gravity to quantum entropy and introduces the G-field, possibly explaining dark matter and cosmic expansion. In a recent study published in Physical Review D, Professor Ginestra Bianconi, a Professor of Applied Mathematics at Queen Mary University of London, presents a groundbr
Dr. Richard Lieu, a physics professor at The University of Alabama in Huntsville (UAH), a part of The University of Alabama System, has published a paper in the journal Classical and Quantum Gravity that proposes a universe built on steps of multiple singularities rather than the Big Bang alone to account for the expansion of the cosmos.
The new model forgoes the need for either dark matter or dark energy as explanations for the universe’s acceleration and how structures like galaxies are generated.
The researcher’s work builds on an earlier model hypothesizing that gravity can exist without mass.
