The Origins of the Black Hole Information Paradox

Artist's impression of an ultramassive black hole (UBH). Credit: ESA/Hubble/DSS/Nick Risinger/N. Bartmann

While physics tells us that information can neither be created nor destroyed (if information could be created or destroyed, then the entire raison d’etre of physics, that is to predict future events or identify the causes of existing situations, would be impossible), it does not demand that the information be accessible. For decades physicists assumed that the information that fell into a black hole is still there, still existing, just locked away from view.

Continue reading “The Origins of the Black Hole Information Paradox”

The Maddening Simplicity of Black Holes

This artist’s impression depicts a rapidly spinning supermassive black hole surrounded by an accretion disc. This thin disc of rotating material consists of the leftovers of a Sun-like star which was ripped apart by the tidal forces of the black hole. Shocks in the colliding debris as well as heat generated in accretion led to a burst of light, resembling a supernova explosion. Credit: ESO, ESA/Hubble, M. Kornmesser

Black holes.

The name is said to come from the Black Hole of Calcutta, an infamous prison that you cannot escape from. It is a fitting name, for black holes are the ultimate cosmological prison.

Continue reading “The Maddening Simplicity of Black Holes”

Growing Black Hole Seen Only 470 Million Years After the Big Bang

A composite Chandra and JWST image of a quasar whose light shone through an intervening galaxy cluster. The black hole at the heart of the quasar formed some 470 million years after the Big Bang. Credit: X-ray: NASA/CXC/SAO/Ákos Bogdán; Infrared: NASA/ESA/CSA/STScI; Image Processing: NASA/CXC/SAO/L. Frattare & K. Arcand
A composite Chandra and JWST image of a quasar whose light shone through an intervening galaxy cluster. The black hole at the heart of the quasar formed some 470 million years after the Big Bang. Credit: X-ray: NASA/CXC/SAO/Ákos Bogdán; Infrared: NASA/ESA/CSA/STScI; Image Processing: NASA/CXC/SAO/L. Frattare & K. Arcand

One of the big questions in cosmology asks when black holes first showed up in the early Universe. Recently astronomers discovered the most distant (and therefore earliest) supermassive black hole ever seen. It appears as it did when the Universe was only 470 million years old.

Continue reading “Growing Black Hole Seen Only 470 Million Years After the Big Bang”

If We Could Find Them, Primordial Black Holes Would Explain a Lot About the Universe

Artist view of small black holes in the accretion disk of a supermassive black hole. Credit: Caltech/R. Hurt (IPAC)

There are three known types of black holes in the Universe: supermassive black holes that lurk in the centers of galaxies, stellar-mass black holes that are the remnants of massive stars, and intermediate-mass black holes that can be found in dense clusters of stars. But there is a fourth, hypothetical type of black hole known as primordial black holes (PBHs). If they exist, they could solve a few cosmological mysteries.

Continue reading “If We Could Find Them, Primordial Black Holes Would Explain a Lot About the Universe”

Sometimes Compact Galaxies Hide Their Black Holes

Illustration of an active quasar. What role does its dark matter halo play in activating the quasar? Credit: ESO/M. Kornmesser
Illustration of an active quasar. New research shows that SMBHs eat rapidly enough to trigger them. Credit: ESO/M. Kornmesser

Quasars, short for quasi-stellar objects, are one of the most powerful and luminous classes of objects in our Universe. A subclass of active galactic nuclei (AGNs), quasars are extremely bright galactic cores that temporarily outshine all the stars in their disks. This is due to the supermassive black holes in the galactic cores that consume material from their accretion disks, a donut-shaped ring of gas and dust that orbit them. This matter is accelerated to close to the speed of light and slowly consumed, releasing energy across the entire electromagnetic spectrum.

Based on past observations, it is well known to astronomers that quasars are obscured by the accretion disk that surrounds them. As powerful radiation is released from the SMBH, it causes the dust and gas to glow brightly in visible light, X-rays, gamma-rays, and other wavelengths. However, according to a new study led by researchers from the Centre for Extragalactic Astronomy (CEA) at Durham University, quasars can also be obscured by the gas and dust of their entire host galaxies. Their findings could help astronomers better understand the link between SMBHs and galactic evolution.

Continue reading “Sometimes Compact Galaxies Hide Their Black Holes”

Roman Could Finally Tell Us if Primordial Black Holes Exist

An image based on a supercomputer simulation of the cosmological environment where primordial gas undergoes the direct collapse to a black hole. Credit: Aaron Smith/TACC/UT-Austin.

When the Universe erupted into existence with the Big Bang, all of its matter was compressed into a tiny area. Cosmologists theorize that in some regions, subatomic matter may have been so tightly packed that matter collapsed into primordial black holes. If these primordial black holes exist, they’re small, and they could be hiding among the population of free-floating planets.

Continue reading “Roman Could Finally Tell Us if Primordial Black Holes Exist”

Next Generation Gravitational Wave Observatories Could Detect 100-600 Solar Mass Black Hole Mergers

Simulation of merging supermassive black holes. Credit: NASA's Goddard Space Flight Center/Scott Noble

Humans are born wonderers. We’re always wondering about the next valley over, the next horizon, what we’ll understand next about this vast Universe that we’re all wrapped up in.

In 2015, we finally detected our first long-awaited and long-theorized gravitational wave from the distant merger of two stellar mass black holes. But now we want to know more, and only better detectors can feed our appetite.

Continue reading “Next Generation Gravitational Wave Observatories Could Detect 100-600 Solar Mass Black Hole Mergers”

The Milky Way's Black Hole is Spinning as Fast as it Can

Simulation of glowing gas around a spinningblack hole. Credit: Chris White, Princeton University

Pick any object in the Universe, and it is probably spinning. Asteroids tumble end over end, planets and moons rotate on their axes, and even black holes spin. And for everything that spins, there is a maximum rate at which it can rotate. The black hole in our galaxy is spinning at nearly that maximum rate.

Continue reading “The Milky Way's Black Hole is Spinning as Fast as it Can”

New Stars Forming Uncomfortably Close to the Milky Way’s Supermassive Black Hole

Artist view of an active supermassive black hole. Credit: ESO/L. Calçada

Astronomers examining a star cluster near Sgr A*, the Milky Way’s supermassive black hole, found that the cluster has some unusually young members for its location. That’s difficult to explain since the region so close to the powerful black hole is infused with powerful radiation and dominated by the black hole’s extremely powerful gravitational force. According to our understanding of stellar formation, young stars shouldn’t be there.

Continue reading “New Stars Forming Uncomfortably Close to the Milky Way’s Supermassive Black Hole”

Here's What it Would Take to See a Black Hole's Photon Ring

The EHT image of M87* compared to its photon ring. Credit: Left: EHT Collaboration, Right: A.E. Broderick et al, 2022

Supermassive black holes are elusive creatures. Massive gravitational beasts that can power immensely bright quasars, or can lurk quietly among the bright stars of a galactic core. We mostly study them indirectly through their bright accretion disks or powerful jets of plasma they create, but we have been able to observe them more directly, such as our images of M87* and Sag A*. But what still eludes us is capturing a direct image of the enigmatic photon ring. A new work in Acta Astronautica proposes how this might be done.

Continue reading “Here's What it Would Take to See a Black Hole's Photon Ring”