Black Holes Archives

January 15, 2025January 15, 2025 by Matt Williams

Recent Observations Challenge our Understanding of Giant Black Holes

Artist's impression of a white dwarf embedded in the disk of a giant black hole. Credit: NASA/Sonoma State University, Aurore Simonnet

Black holes are among the most mysterious and powerful objects in the Universe. These behemoths form when sufficiently massive stars reach the end of their life cycle and experience gravitational collapse, shedding their outer layers in a supernova. Their existence was illustrated by the work of German astronomer Karl Schwarzschild and Indian-American physicist Subrahmanyan Chandrasekhar as a consequence of Einstein’s Theory of General Relativity. By the 1970s, astronomers confirmed that supermassive black holes (SMBHs) reside at the center of massive galaxies and play a vital role in their evolution.

However, only in recent years were the first images of black holes acquired by the Event Horizon Telescope (EHT). These and other observations have revealed things about black holes that have challenged preconceived notions. In a recent study led by a team from MIT, astronomers observed oscillations that suggested an SMBH in a neighboring galaxy was consuming a white dwarf. But instead of pulling it apart, as astronomical models predict, their observations suggest the white dwarf was slowing down as it descended into the black hole – something astronomers have never seen before!

January 15, 2025January 15, 2025 by Evan Gough

About a Third of Supermassive Black Holes are Hiding

A supermassive black hole surrounded by a torus of gas and dust is depicted in four different wavelengths of light in this artist’s concept. Visible light (top right) and low-energy X-rays (bottom left) are blocked by the torus; infrared (top left) is scattered and reemitted; and some high energy X-rays (bottom right) can penetrate the torus. Image Credit: NASA/JPL-Caltech

Supermassive black holes can have trillions of times more mass than the Sun, only exist in specific locations, and could number in the trillions. How can objects like that be hiding? They’re shielded from our view by thick columns of gas and dust.

However, astronomers are developing a way to find them: by looking for donuts that glow in the infrared.

January 15, 2025January 15, 2025 by Andy Tomaswick

Astronomers See Flares Coming from the Milky Way’s Supermassive Black Hole

This artist’s conception of the mid-IR flare in Sgr A* captures the variability, or changing intensity, of the flare as the black hole’s magnetic field lines bunch together. This bunching results in magnetic reconnection, which produces particles and energy that spiral along the magnetic field lines until they cool and release their energy, spiking the intensity of the flare. Credit: CfA/Melissa Weiss

There’s plenty of action at the center of the galaxy, where a supermassive black hole (SMBH) known as Sagittarius A* (Sgr A*) literally holds the galaxy together. Part of that action is the creation of gigantic flares from Sgr A*, which can give off energy equivalent to 10 times the Sun’s annual energy output. However, scientists have been missing a key feature of these flares for decades – what they look like in the mid-infrared range. But now, a team led by researchers at Harvard’s Center for Astrophysics and the Max Planck Institute for Radio Astronomy has published a paper that details what a flare looks like in those frequencies for the first time.

January 14, 2025January 14, 2025 by Evan Gough

Webb Provides an Explanation for “Little Red Dots”

A team of astronomers sifted through James Webb Space Telescope data from multiple surveys to compile one of the largest samples of “little red dots” (LRDs) to date. From their sample, they found that these mysterious red objects that appear small on the sky emerge in large numbers around 600 million years after the big bang and undergo a rapid decline in quantity around 1.5 billion years after the big bang. Image Credit: NASA, ESA, CSA, STScI, Dale Kocevski (Colby College)

When a new space telescope is launched, it’s designed to address specific issues in astronomy and provide critical answers to important questions. The JWST was built with four overarching science goals in mind. However, when anticipating new telescopes, astronomers are quick to point out that they’re also excited by the unexpected discoveries that new telescopes make.

There has been no shortage of unexpected discoveries regarding the JWST, especially regarding the very early Universe.

January 14, 2025January 14, 2025 by Brian Koberlein

Here's How We Could Measure the Mass of SgrA* to Within One Solar Mass

Image of the supermassive black hole Sag A* seen in polarized light. Credit: EHT Collaboration

There is a gravitational monster at the heart of our galaxy. Known as Sagittarius A*, it is a supermassive black hole with a mass of more than four million Suns. Long-term observations of the stars closely orbiting Sag A* place it at about 4.3 solar masses, give or take 100,000 or so. Observations of light near its horizon by the Event Horizon Telescope pin the mass down to 4.297 solar masses, give or take about 10,000. Those results are astoundingly precise given how difficult the mass is to measure, but suppose we could determine the mass of our galaxy’s black hole to within a single solar mass. That might be possible with gravitational wave astronomy.

January 13, 2025January 13, 2025 by Mark Thompson

LIGO Has Detected Unusual Black Holes Merging, But they Probably Don’t Explain Dark Matter

The traditional theory of black hole formation seems to struggle to explain how black holes can merge into larger more massive black holes yet they have been seen with LIGO. It’s possible that they may have formed at the beginning of time and if so, then they may be a worthy candidate to explain dark matter but only if there are enough of them. A team of researchers recently searched for microlensing events from black holes in the Large Magellanic Cloud but didn’t find enough to account for more than a fraction of dark matter.

January 6, 2025January 6, 2025 by Evan Gough

An Early Supermassive Black Hole Took a Little Break Between Feasts

This artist’s impression shows a black hole about 800 million years after the Big Bang, during one of its short periods of rapid growth. Image Credit: Jiarong Gu

In the last couple of decades, it’s become increasingly clear that massive galaxies like our own Milky Way host supermassive black holes (SMBHs) in their centres. How they became so massive and how they affect their surroundings are active questions in astronomy. Astronomers working with the James Webb Space Telescope have discovered an SMBH in the early Universe that is accreting mass at a very low rate, even though the black hole is extremely massive compared to its host galaxy.

What’s going on with this SMBH, and what does it tell astronomers about the growth of these gargantuan black holes?

December 23, 2024December 23, 2024 by Brian Koberlein

How Did Black Holes Grow So Quickly? The Jets

Artist’s impression of a bright, very early active galactic nucleus. Credit: NSF/AUI/NSF NRAO/B. Saxton

Within nearly every galaxy is a supermassive black hole. The beast at the heart of our galaxy contains the mass of millions of suns, while some of the largest supermassive black holes can be more than a billion solar masses. For years, it was thought that these black holes grew in mass over time, only reaching their current size after a billion years or more. But observations from the Webb telescope show that even the youngest galaxies contain massive black holes. So how could supermassive black holes grow so large so quickly? The key to the answer could be the powerful jets black holes can produce.

December 22, 2024December 17, 2024 by Paul M. Sutter

Quantum Correlations Could Solve the Black Hole Information Paradox

Artist view of a black hole ringing down into a stable state. Credit: Yasmine Steele at University of Illinois – Urbana Champaign

The black hole information paradox has puzzled physicists for decades. New research shows how quantum connections in spacetime itself may resolve the paradox, and in the process leave behind a subtle signature in gravitational waves.

December 22, 2024December 22, 2024 by Matt Williams

M87 Releases a Rare and Powerful Outburts of Gamma-ray Radiation

A Hubble Space Telescope image of the giant galaxy M87 shows a 3,000-light-year-long jet of plasma blasting from the galaxy's 6.5-billion-solar-mass central black hole. The blowtorch-like jet seems to cause stars to erupt along its trajectory. These novae are not caught inside the jet, but are apparently in a dangerous neighbourhood nearby. During a recent 9-month survey, astronomers using Hubble found twice as many of these novae going off near the jet as elsewhere in the galaxy. The galaxy is the home of several trillion stars and thousands of star-like globular star clusters. [Image description: A Hubble photo of galaxy M87, which resembles a translucent, fuzzy white cotton ball. The brightness decreases gradually out in all directions from a bright white point of light at the centre. A wavy blue-white jet of material extends from the point-like core outward to the upper right, about halfway across the galaxy. Stars speckle the background.]

In April 2019, the Event Horizon Telescope (EHT) collaboration made history when it released the first-ever image of a black hole. The image captured the glow of the accretion disk surrounding the supermassive black hole (SMBH) at the center of the M87 galaxy, located 54 million light-years away. Because of its appearance, the disk that encircles this SMBH beyond its event horizon (composed of gas, dust, and photons) was likened to a “ring of fire.” Since then, the EHT has been actively imaging several other SMBH, including Sagittarius A* at the center of the Milky Way!

In addition, the EHT has revealed additional details about M87, like the first-ever image of a photon ring and a picture that combines the SMBH and its relativistic jet emanating from its center. Most recently, the EHT released the results of its latest observation campaign. These observations revealed a spectacular flare emerging from M87’s powerful relativistic jet. This flare released a tremendous amount of energy in multiple wavelengths, including the first high-energy gamma-ray outburst observed in over a decade.