The dense peaks in the wavelength distribution graph observed in a Lyman-Alpha forest indeed resemble many small trees. Each of those peaks represents a sudden drop in “light” at a specific and narrow wavelength, effectively mapping the matter that light has encountered on its journey to us.
Have you ever wondered what the universe looked like after the Big Bang when it was still in its infancy, a mere billion years old? With NASA’s new Nancy Grace Roman Space Telescope, we’re about to get a glimpse of the cosmic dawn.
This cosmic time machine is set to explore an era known as the cosmic dawn, a significant transition when the universe went from a foggy opacity to the stunning, star-filled expanse we observe today.
Behind this ambitious project is the esteemed astrophysicist Michelle Thaller from NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
A team of astrophysicists led by Caltech has managed for the first time to simulate the journey of primordial gas dating from the early universe to the stage at which it becomes swept up in a disk of material fueling a single supermassive black hole. The new computer simulation upends ideas about such disks that astronomers have held since the 1970s and paves the way for new discoveries about how black holes and galaxies grow and evolve.
“Our new simulation marks the culmination of several years of work from two large collaborations started here at Caltech,” says Phil Hopkins, the Ira S. Bowen Professor of Theoretical Astrophysics.
The first collaboration, nicknamed has focused on the larger scales in the universe, studying questions such as how galaxies form and what happens when galaxies collide. The other, dubbed STARFORGE, was designed to examine much smaller scales, including how stars form in individual clouds of gas.
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].
Posted in cosmology
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.
