Black Holes Archives

June 5, 2020February 17, 2023 by Evan Gough

Supermassive Black Holes Grew by Consuming Gas and Entire Stars

This artist’s impression of a supermassive black hole and accretion disk, along with a relativistic jet emanating from its poles. Credit & ©: ESO/L. Calçada

Where do they come from, those beguiling singularities that flummox astrophysicists—and the rest of us. Sure, we understand the processes behind stellar mass black holes, and how they form from the gravitational collapse of a star.

But what about the staggering behemoths at the center of galaxies, those supermassive black holes (SMBH) that can grow to be billions of times more massive than our Sun?

How do they get so big?

June 3, 2020June 3, 2020 by Evan Gough

About 3.5 Million Years Ago, a Stream of Gas Outside the Milky Way Would Have Lit Up the Night Sky

An illustration of our hominid ancestors, likely Australopithecus, walking at night, under the lit up stream of gas about 3.5 million years ago. Image Credit: NASA, ESA, G. Cecil (UNC, Chapel Hill), and J. DePasquale (STScI)

It’s a truism to point out that modern humans have only been around for the blink of an eye, relative to the age of the Universe. But the Universe was an active place long before we were around to observe all of that activity. And about 3.5 million years ago, it’s possible—if only remotely—that our ancient ancestors noticed something change in the night sky.

Would it have stirred something inside them? Impossible to know.

June 2, 2020June 2, 2020 by Evan Gough

New Simulations Show How Black Holes Grow, Through Mergers and Accretion

Artist's impression of two merging black holes. Credit: Bohn, Throwe, Hébert, Henriksson, Bunandar, Taylor, Scheel/SXS

One of the most pressing questions in astronomy concerns black holes. We know that massive stars that explode as supernovae can leave stellar mass black holes as remnants. And astrophysicists understand that process. But what about the supermassive black holes (SMBHs) like Sagittarius A-star (Sgr A*,) at the heart of the Milky Way?

SMBHs can have a billion solar masses. How do they get so big?

June 1, 2020June 1, 2020 by Evan Gough

Black Hole Seen Blasting Out Jets at Close to the Speed of Light

MAXI J1820+070 is a binary pair that has one black hole and one star. The black hole is emitting relativistic jets, and Chandra made a movie of it. Image Credit: Chandra X-Ray Observatory

The Chandra X-Ray Observatory has spotted a distant black hole shooting out jets of material, at close to the speed of light. No worries, this beast is about 10,000 light years away from us. It’s more of a spectacle than a danger.

But it’s a spectacle laden with scientific insights.

May 2, 2020May 3, 2020 by Matt Williams

Supermassive Black Hole Orbits an Even More Massive Black Hole, Crashing Through its Accretion Disk Every 12 Years

This image shows two massive black holes in the OJ 287 galaxy. The smaller black hole orbits the larger one, which is also surrounded by a disk of gas. When the smaller black hole crashes through the disk, it produces a flare brighter than 1 trillion stars. Credit: NASA/JPL-Caltech

NASA’s Spitzer Space Telescope may be retired, but the things it witnessed during its sixteen and a half year mission will be the subject of study for many years to come. For instance, Spitzer is the only telescope to witness something truly astounding occurring at the center of the distant galaxy OJ 287: a supermassive black hole (SMBH) orbited by another black hole that regularly passes through its accretion disk.

Whenever this happens, it causes a flash that is brighter than all the stars in the Milky Way combined. Using Spitzer‘s observations, an international team of astronomers was able to finally create a model that accurately predicts the timing of these flashes and the orbit of the smaller black hole. In addition to demonstrating General Relativity in action, their findings also provide validation to Stephen Hawking‘s “no-hair theorem.”

April 25, 2020April 25, 2020 by Matt Williams

A Star is Orbiting the Milky Way’s Black Hole and Moving Exactly How Einstein Predicted it Should

Observations made with ESO’s Very Large Telescope (VLT) have revealed for the first time that a star orbiting the supermassive black hole at the centre of the Milky Way moves just as predicted by Einstein’s theory of general relativity. Its orbit is shaped like a rosette and not like an ellipse as predicted by Newton's theory of gravity. This effect, known as Schwarzschild precession, had never before been measured for a star around a supermassive black hole. This artist’s impression illustrates the precession of the star’s orbit, with the effect exaggerated for easier visualisation.

At the center of our galaxy, roughly 26,000 light-years from Earth, is the Supermassive Black Hole (SMBH) known as Sagittarius A*. The powerful gravity of this object and the dense cluster of stars around it provide astronomers with a unique environment for testing physics under the most extreme conditions. In particular, it offers them a chance to test Einstein’s Theory of General Relativity (GR).

For example, in the past thirty years, astronomers have been observing a star in the vicinity of Sagittarius A* (S2) to see if its orbit conforms to what is predicted by General Relativity. Recent observations made with the ESO’s Very Large Telescope (VLT) have completed an observation campaign that confirmed that the star’s orbit is rosette-shaped, once again proving that Einstein theory was right on the money!

April 16, 2020April 16, 2020 by Matt Williams

Light Behaves Really Strangely Around a Black Hole

Combining observations done with ESO's Very Large Telescope and NASA's Chandra X-ray telescope, astronomers have uncovered the most powerful pair of jets ever seen from a stellar black hole. The black hole blows a huge bubble of hot gas, 1,000 light-years across or twice as large and tens of times more powerful than the other such microquasars. The stellar black hole belongs to a binary system as pictured in this artist's impression. Credit: ESO/L. Calçada — Artist's impression of a Star feeding a black hole. Credit: ESO/L. Calçada

Black holes are famous for being inescapable. Within the event horizon of these celestial objects, matter and even light enter and then disappear forever. However, beyond the event horizon, black holes are known to form accretion disks from which light can escape. In fact, this is how astronomers are able to confirm the presence of black holes and determine their properties (i.e. mass, spin rate, etc.)

However, according to a recent NASA-funded study led by researchers from the California Institute of Technology (Caltech), there is evidence that not all light emanating from a black hole’s disk simply escapes. According to their observations, some of the light escaping from the disk is pulled back in by the black hole’s gravity and reflected off the disk again. These observations confirm something astronomers have theorized for about forty years.

March 30, 2020March 30, 2020 by Matt Williams

How were Supermassive Black Holes Already Forming and Releasing Powerful Jets Shortly After the Big Bang?

A supermassive black hole has been found in an unusual spot: an isolated region of space where only small, dim galaxies reside. Image credit: NASA/JPL-Caltech — A team of astronomers from South Africa have noticed a series of supermassive black holes in distant galaxies that are all spinning in the same direction. Credit: NASA/JPL-Caltech

In the past few decades, astronomers have been able to look farther into the Universe (and also back in time), almost to the very beginnings of the Universe. In so doing, they’ve learned a great deal about some of the earliest galaxies in the Universe and their subsequent evolution. However, there are still some things that are still off-limits, like when galaxies with supermassive black holes (SMBHs) and massive jets first appeared.

According to recent studies from the International School for Advanced Studies (SISSA) and a team of astronomers from Japan and Taiwan provide new insight on how supermassive black holes began forming just 800 million years after the Big Bang, and relativistic jets less than 2 billion years after. These results are part of a growing case that shows how massive objects in our Universe formed sooner than we thought.

March 24, 2020March 24, 2020 by Matt Williams

How Researchers Produce Sharp Images of a Black Hole

In April of 2019, the Event Horizon Telescope collaboration history made history when it released the first image of a black hole ever taken. This accomplishment was decades in the making and triggered an international media circus. The picture was the result of a technique known as interferometry, where observatories across the world combined light from their telescopes to create a composite image.

This image showed what astrophysicists have predicted for a long time, that extreme gravitational bending causes photons to fall in around the event horizon, contributing to the bright rings that surround them. Last week, on March 18th, a team of researchers from the Harvard-Smithsonian Center for Astrophysics (CfA) announced new research that shows how black hole images could reveal an intricate substructure within them.

March 3, 2020March 3, 2020 by Nancy Atkinson

Even Though it Was Observing an Asteroid, OSIRIS-REx Accidentally Spotted a Black Hole

This image shows the X-ray outburst from the black hole MAXI J0637-043, detected by the REXIS instrument on NASA's OSIRIS-REx spacecraft. The image was constructed using data collected by the X-ray spectrometer while REXIS was making observations of the space around asteroid Bennu on Nov. 11, 2019. The outburst is visible in the center of the image, and the image is overlaid with the limb of Bennu (lower right) to illustrate REXIS’s field of view. Credits: NASA/Goddard/University of Arizona/MIT/Harvard

While the OSIRIS-REx spacecraft was orbiting asteroid Bennu, one of the instruments on board happened to catch a glimpse of a black hole ‘out of the corner of its eye,’ so to speak.

While intently focusing on the asteroid, the Regolith X-Ray Imaging Spectrometer (REXIS) happened to catch the X-rays from a newly flaring stellar mass black hole. While the flare occurred 30 thousand light years away, the flash in distant space was visible just off the limb of asteroid Bennu, in the edge of the instrument’s field of view.