Astronomers have uncovered the secrets behind an epic collision of two massive galaxy clusters, showing that dark matter and regular matter can actually separate during these huge events.
Located billions of light-years away, these clusters are home to thousands of galaxies and provide deep insights into the complexities of our universe.
When they collided, the dark matter — an invisible substance affected by gravity but not light — moved ahead of the normal matter, which includes gas and stars.
NASA’s Fermi Telescope has revealed new details about the brightest of all time gamma-ray burst which may help explain these extreme and mysterious cosmic events.
Gamma-ray bursts (GRBs) usually last less than a second. They originate from the dense remains of a dead giant star’s core, called a neutron star. But what causes neutron stars to release huge amounts of energy in the form of gamma radiation is still a mystery.
In October 2022, astronomers detected the largest gamma-ray burst ever seen – GRB 221009A. It came from a supernova about 2.4 billion light years away. The event had an intensity at least 10 times greater than any other GRB detected. It was dubbed the BOAT, for brightest of all time.
The formation of a black hole from light alone is permitted by general relativity, but a new study says quantum physics rules it out.
Black holes are known to form from large concentrations of mass, such as burned-out stars. But according to general relativity, they can also form from ultra-intense light. Theorists have speculated about this idea for decades. However, calculations by a team of researchers now suggest that light-induced black holes are not possible after all because quantum-mechanical effects cause too much leakage of energy for the collapse to proceed [1].
The extreme density of mass produced by a collapsed star can curve spacetime so severely that no light entering the region can escape. The formation of a black hole from light is possible according to general relativity because mass and energy are equivalent, so the energy in an electromagnetic field can also curve spacetime [2]. Putative electromagnetic black holes have become popularly known as kugelblitze, German for “ball lightning,” following the terminology used by Princeton University physicist John Wheeler in early studies of electromagnetically generated gravitational fields in the 1950s [3].
Did abstract mathematics, such as Pythagoras’s theorem, exist before the big bang?
Simon McLeish Lechlade, Gloucestershire, UK
The notion of the existence of mathematical ideas is a complex one.
One way to look at it is that mathematics is about the use of logical thought to derive information, often information about other mathematical ideas. The use of objective logic should mean that mathematical ideas are eternal: they have always been, and always will be.
Astronomers have discovered a black hole with a mass about 33 times greater than that of our sun, the biggest one known in the Milky Way aside from the supermassive black hole lurking at the center of our galaxy.
The newly identified black hole is located about 2,000 light-years from Earth — relatively close in cosmic terms — in the constellation Aquila, and has a companion star orbiting it, researchers said on Tuesday. A light year is the distance light travels in a year, 5.9 trillion miles.
Black holes are extraordinarily dense objects with gravity so strong that not even light can escape, making it difficult to spot them. This one was identified through observations made in the European Space Agency’s Gaia mission, which is creating a huge stellar census, because it caused a wobbling motion in its companion star. Data from the European Southern Observatory’s Chile-based Very Large Telescope and other ground-based observatories were used to verify the black hole’s mass.
The study found that black holes in old, inactive galaxies have grown significantly in mass over the last 9 billion years, suggesting they interact with the expanding universe.
If black hole mass development happened only through accretion or merging, the masses of these black holes would be anticipated to remain relatively constant. However, if black holes gain mass by interacting with the expanding cosmos, these passively developing elliptical galaxies might disclose this process.
The researchers discovered that the further back in time they examined, the smaller the black holes were in mass compared to their masses today. These changes were significant: black holes were 7 to 20 times bigger now than they were 9 billion years ago, leading the researchers to hypothesize cosmic coupling.
Such decoupling of dark and normal matter has been seen before, most famously in the Bullet Cluster. In that collision, the hot gas can be seen clearly lagging behind the dark matter after the two galaxy clusters shot through each other. The situation that took place in MACS J0018.5+1626 (referred to subsequently as MACS J0018.5) is similar, but the orientation of the merger is rotated, roughly 90 degrees relative to that of the Bullet Cluster.
In other words, one of the massive clusters in MACS J0018.5 is flying nearly straight toward Earth while the other one is rushing away. That orientation gave researchers a unique vantagepoint from which to, for the first time, map out the velocity of both the dark matter and normal matter and elucidate how they decouple from each other during a galaxy cluster collision.
“With the Bullet Cluster, it’s like we are sitting in a grandstand watching a car race and are able to capture beautiful snapshots of the cars moving from left to right on the straightaway,” says Sayers. “In our case, it’s more like we are on the straightaway with a radar gun, standing in front of a car as it comes at us and are able to obtain its speed.”
Researchers have created a quantum tornado in superfluid helium to simulate black hole conditions, advancing our understanding of black hole physics and the behavior of quantum fields in curved spacetimes, culminating in a unique art and science exhibition.
Scientists have, for the first time, created a giant quantum vortex in superfluid helium to mimic a black hole. This breakthrough has enabled them to observe in greater detail how analog black holes behave and interact with their surroundings.
Research led by the University of Nottingham, in collaboration with King’s College London and Newcastle University, has created a novel experimental platform: a quantum tornado. They have created a giant swirling vortex within superfluid helium that is chilled to the lowest possible temperatures. Through the observation of minute wave dynamics on the superfluid’s surface, the research team has shown that these quantum tornados mimic gravitational conditions near rotating black holes. The research has been published today in Nature.
New research may have found a link between supermassive black holes and dark matter particles which might solve an issue which has irked astrophysicists for decades: the “final parsec problem.”
Last year, an international team of researchers discovered a background “hum” of gravitational waves. They hypothesised that this background signal is emanating from millions of merging pairs of supermassive black hole.
Supermassive black holes are hundreds of thousands to billions of times larger than our Sun.
