But a conjecture ...

 

Physicists used an algorithm to combine telescope measurements of a black hole in a different way to the original analysis.Credit: S. Lai, N. Thyagarajan, O. I. Wong, and F. Diakogiannis; Commonwealth Scientific and Industrial Research Organisation

The Event Horizon Telescope (EHT) collaboration wowed the world in 2019 with the first picture ever taken of a black hole’s shadow. Some researchers were unconvinced, arguing that the circular shape seen in that shot was an artefact of the team’s image-reconstruction techniques. Now, an independent group has reanalysed the EHT data, and its results, published on 11 November in Nature — including new images of the black hole — largely corroborate the original findings1.

To image black holes, the international EHT collaboration stitches together data it collects simultaneously from an array of ground-based radio telescopes that stretches across several continents. The reconstruction is extremely challenging, but in principle the result is an image with the same level of detail, or resolution, that would be achieved with a single radio dish as wide as Earth.

Although blurry, the EHT shot of a supermassive black hole at the centre of the M87 galaxy was consistent with astrophysical models based on Albert Einstein’s general theory of relativity, which first predicted the existence of black holes. The image had a bright ring of roughly the correct radius, given what was known about the size of the black hole, with a darker disk at the centre.

But is there a better way in using a 3D approach to do the calc as black holes are 3D constructs, complete with twisted bands of light creating an eerie image of immense power and mystery.

But a conjecture ...

============================================================

  EHT VOLUMETRIC SOLVER — FIRST-PRINCIPLES TOPOLOGY ENGINE

============================================================

[INIT] Connecting to input stream: eht_baseline_subset.dat

[PARSE] Bypassing 2D pixel regularization & statistical smoothing...

[SOLVE] Mapping direct topological mass & photon sphere via CSG/B-Rep...

[SUCCESS] Volumetric geometry resolved in 1.84 seconds.

[COMPILE] Compiling invariant spatial model for local display...

 

If CSG/B-Rep talks the language of 3D black holes and EHT, images like this may become possible.

Worth a try don't you think?

Rinse & Repeat :)

 Olena Shmahalo for Quanta Magazine

Yours truly loves quantum mechanics and the two laws of thermodynamics, at lay level of course, as complexity and operating limits apply to the vagaries of reality including black holes, notions one and all brilliantly described in a wonderful Quanta Magazine article provocatively titled In New Paradox, Black Holes Appear to Evade Heat Death.

To whit ...

Heat death held a morbid fascination for Victorian-era physicists. It was an early example of how everyday physics connects to the grandest themes in cosmology. Drop ice cubes into a glass of water, and you create a situation that is out of equilibrium. The ice melts, the liquid chills, and the system reaches a common temperature. Although motion does not cease — water molecules continue to reshuffle themselves — it loses any sense of progress, and the overall distribution of molecular speeds doesn’t change. 

The 19th-century founders of thermodynamics realized that the same goes for the universe as a whole. Once the stars all burn out, whatever is left — gas, dust, stellar corpses, radiation — will come to equilibrium. “The universe from that time forward would be condemned to a state of eternal rest,” Hermann von Helmholtz wrote in 1854. Modern cosmology has not altered this basic picture.

Unless you look closer as quantum jitters apply in the guise of superposition and entanglement.

When an ice cube melts and attains equilibrium with the liquid, physicists usually say the evolution of the system has ended. But it hasn’t — there is life after heat death. Weird and wonderful things continue to happen at the quantum level. “If you really look into a quantum system, the particle distribution might have equilibrated, and the energy distribution might have equilibrated, but there’s still so much more going on beyond that,” said Xie Chen, a theoretical physicist at the California Institute of Technology.

The black hole at the heart of the M87 galaxy as originally seen in 2017 (left) and after recent data processing by a machine learning algorithm (right).

Medeiros (Institute for Advanced Study), 

D. Psaltis (Georgia Tech), T. Lauer (NSF’s NOIRLab), and F. Ozel (Georgia Tech)

Rinse & Repeat applies :)

Not letting the lack of a rigorous proof stop them, Susskind and Brown suggested in 2018 that the steady growth of complexity qualifies as a new law of nature, the second law of quantum complexity — a quantum analogue of the second law of thermodynamics. The second law of thermodynamics holds that closed systems increase in entropy until they reach thermal equilibrium, the state of maximal entropy. According to Susskind and Brown, the same happens with complexity. A system increases in complexity for eons after it reaches thermal equilibrium. But it does eventually plateau, reaching “complexity equilibrium.” At that point, a quantum system has explored every possible state it is capable of and will finally lose any sense of progress.

The Heisenberg Uncertainty principle to the rescue. :)

We cannot know the exact momentum and position of a particle simultaneously.

Then the system reaches complexity equilibrium, where complexity hits a ceiling. Although the system continues to change, it can no longer be said to evolve — it has no sense of directedness, but wanders among equal states of maximal complexity.

The last stage is called recurrence, where the system stumbles back into its original simple condition. For this to happen by accident is highly improbable. But eternity is a long time, so it ultimately does happen, after a period of time that is not merely exponential, but an exponential of an exponential. The whole process then repeats.

Photo by Linus Mimietz on Unsplash

Sagittarius A*

To create the first image of the Milky Way’s black hole, scientists ran numerous simulations of the swirling envelope of plasma that encircles it. This clip shows the version of the animated computer model that seemed to best mirror the radio wave data collected by the Event Horizon Telescope. Credit: Abhishek Joshi/UIUC

In the center of the Milky Way lurks a fairly quiescent monster, a relatively small supermassive black hole named Sagittarius A*, a tiny entity compared to its much larger cousin, M87. How these engines of creation and destruction work vis a vis the galaxies that house them has perplexed researchers for years but with sophisticated tools such as the Event Horizon Telescope, these objects of fascination and dread are becoming better understood as seen by Knowledgable Magazine's in-depth article titled What the image of the Milky Way’s black hole really shows.

Black holes keep their secrets close. They imprison forever anything that enters. Light itself can’t escape a black hole’s hungry pull.

It would seem, then, that a black hole should be invisible — and taking its picture impossible. So great fanfare accompanied the release in 2019 of the first image of a black hole. Then, in spring 2022, astronomers unveiled another black hole photo — this time of the one at the center of our own Milky Way.

The image shows an orange, donut-shaped blob that looks remarkably similar to the earlier picture of the black hole in the center of galaxy Messier 87. But the Milky Way’s black hole, Sagittarius A*, is actually much smaller than the first and was more difficult to see, since it required peering through the hazy disk of our galaxy. So even though the observations of our own black hole were conducted at the same time as M87’s, it took three additional years to create the picture. Doing so required an international collaboration of hundreds of astronomers, engineers and computer scientists, and the development of sophisticated computer algorithms to piece together the image from the raw data.

The new image of the black hole Sagittarius A*, confirms and refines previous predictions of its size and orientation. The mass of the black hole determines its size, or what scientists call its gravitational diameter. The point at which no light can escape from the black hole, called the event horizon, is determined by this mass and by the spin of the black hole. Hot plasma speeds around the massive object in the accretion disk, emitting radio waves. Those radio waves are bent and warped by gravity (through the effect of “gravitational lensing”) to produce the image of the orange outer circles. The black hole shadow and emission ring shown here are gravitationally-lensed projections of the far-side of the black hole’s event horizon and accretion disk, respectively. Source reporting by K. McCormick/Knowable Magazine

Read the rest of this detailed piece to see how our black hole was imaged if you dare. :)

Onions rings at grand scale :)

The emission from M87 has now been resolved into a bright, thin ring (orange colormap), arising from the infinite sequence of additional images of the emission region, and the more diffuse primary image, produced by the photons that come directly toward Earth (in blue contours). When viewed at the imaging resolution of the Event Horizon Telescope, the two components blur together. However, by separately searching for the thin ring, it is possible to sharpen the view of M87, isolating the fingerprint of strong gravity. Credit: Broderick et al

We now are able to see M87 in higher resolution thanks to sophisticated code able to sift through the extensive dataset of the EHT resulting in a photon ring showing the actual outline of M87's super massive black hole. Interestingly, the ring's not a single entity but rather is comprised of many subrings as seen by the image below. 

The M87 image scientists unveiled in 2019 was a landmark, but the researchers felt they could sharpen the image and glean new insights by working smarter, not harder. They applied new software techniques to reconstruct the original 2017 data in search of phenomena that theories and models predicted were lurking beneath the surface. The new, resulting image depicts the photon ring, comprised of a series of increasingly sharp sub-rings, which the team then stacked to get the full image.

Supermassive black holes effectively cast a shadow on the light from the hot, glowing gas that surrounds them (leftmost image). Around the shadow lies a bright photon ring. But the photon ring is not a single ring: it’s composed of a series of increasingly sharp subrings. Each subring n is produced by photons that traveled around the black hole n/2 times before reaching the observer (n’s of 0, 1, and 2 shown, left to right). These subrings stack to give the full image.  Michael D. Johnson (CfA) and George Wong (UIUC)

End game.

The result was possible because the EHT is a "computational instrument at its heart," said Broderick, who holds the Delaney Family John Archibald Wheeler Chair at Perimeter. "It is as dependent on algorithms as it is upon steel. Cutting-edge algorithmic developments have allowed us to probe key features of the image while rendering the remainder in the EHT's native resolution."

Click here to read the paper.

Identical in every way ...

The EHT Collaboration created a flurry of images of Sagittarius A*, using ray tracing, a technique that visualizes the properties of the black hole based on data collected with the radio telescope array and predictions made by Einstein's theory of general relativity. The images shown here were created by UArizona's Chi-kwan Chan. Ben Prather/EHT Theory Working Group/Chi-Kwan Chan

Einstein's right yet again. Black holes scale in universal fashion thanks to Sagittarius A* black hole proving to be identical to M87*s monster.

Figure 4. Top: three example models of some of the best-fitting snapshots from the image library of GRMHD simulations for April 11 corresponding to different spin parameters and accretion flows. Bottom: the same theoretical models, processed through a VLBI simulation pipeline with the same schedule, telescope characteristics, and weather parameters as in the April 11 run and imaged in the same way as Figure 3. Note that although the fit to the observations is equally good in the three cases,they refer to radically different physical scenarios; this highlights that a single good fit does not imply that a model is preferred over others (see Paper)

One of the leading scientists behind the new breakthrough, Dimitrios Psaltis, professor of astronomy and physics at the University of Arizona, has revealed how the new image proved one of Einstein's predictions from his theory of gravity.

It's all down to the striking similarity between Sgr A* and MH7*, despite their massive difference in size — Sgr A*, which has a mass 4 million times greater than that of our Sun, is more than one thousand times smaller than M87*.

The new image of Sgr A* has proved one of the most fundamental predictions of Einstein's theory of gravity, Psaltis explained in a statement from the University of Arizona. Namely, the new data proves that the image of a black hole scales only with its mass. So, in other words, a black hole 1,000 times smaller in mass will look very similar; the only really discernible difference will be the size. 

Scale invarience rules.

Data sonification writ large

Converting black hole pressure waves into sound indirectly channels horror films of the 50s with their use of eerie sounds intended to scare the living daylights out of you back in the day. Cool without question. :)

Since 2003, the black hole at the center of the Perseus galaxy cluster has been associated with sound. This is because astronomers discovered that pressure waves sent out by the black hole caused ripples in the cluster’s hot gas that could be translated into a note – one that humans cannot hear some 57 octaves below middle C. Now a new sonification brings more notes to this black hole sound machine. This new sonification – that is, the translation of astronomical data into sound – is being released for NASA’s Black Hole Week this year.

In some ways, this sonification is unlike any other done before (1, 2, 3, 4) because it revisits the actual sound waves discovered in data from NASA's Chandra X-ray Observatory. The popular misconception that there is no sound in space originates with the fact that most of space is essentially a vacuum, providing no medium for sound waves to propagate through. A galaxy cluster, on the other hand, has copious amounts of gas that envelop the hundreds or even thousands of galaxies within it, providing a medium for the sound waves to travel.

M87's sound is even cooler. :)

Studied by scientists for decades, the black hole in Messier 87, or M87, gained celebrity status in science after the first release from the Event Horizon Telescope (EHT) project in 2019. This new sonification does not feature the EHT data, but rather looks at data from other telescopes that observed M87 on much wider scales at roughly the same time. 

Data sonification writ large, rules. :)

• A team of researchers have found a way to simulate the haunting echo sounds x-ray light makes when it bounces around a black hole.
• The tool the team used to generate these sounds is—no joke—called the “Reverberation Machine.”
• Listening to these echoes and other cosmic sounds can help scientists learn more about how black holes evolve.

A jet of a different kind

Black holes create jets of a different kind, the kind consisting of charged particles of gas spun up to unimaginable amounts of energy thousand of light years long as seen by the video above.

The process ...

Roger Blandford and Roman Znajek, young physicists at the University of Cambridge in 1977, argued that rotating supermassive black holes will twist ambient magnetic fields into a tight helix, and that this twisting will create a voltage that draws energy up and out of the hole and along the helix. This, they claimed, is the jet — and a big asterisk on the naive notion that nothing escapes black holes.

The stripes of polarized light around M87’s black hole reveal the strong magnetic fields at work.

At the time, all ingredients of the process were speculative, but the new observations confirm the Blandford-Znajek idea. “What we see in our image is ordered polarization in a spiral shape,” said Issaoun, who was involved in analyzing the polarization measurements. “And the shape of the magnetic field is also spiral … which means it’s able to launch a jet.”

Samuel Velasco/Quanta Magazine; insets adapted from Michael O’Riordan et al.

A jet of a different kind indeed. 

Jets emerging from the galaxy Cygnus A create massive interstellar blobs, visible here in radio waves.

Variation 2Step

As suspected, Black Holes wobble a bit. :)

In 2019, the Event Horizon Telescope (EHT) Collaboration delivered the first image of a black hole, revealing M87*–the supermassive object in the center of the M87 galaxy. The EHT team has now used the lessons learned last year to analyze the archival data sets from 2009-2013, some of them not published before. The analysis reveals the behavior of the black hole image across multiple years, indicating persistence of the crescent-like shadow feature, but also variation of its orientation–the crescent appears to be wobbling. The full results appeared today in The Astrophysical Journal.

Snapshots of the M87* black hole appearance, obtained through imaging / geometric modeling, and the EHT array of telescopes in 2009-2017. The diameter of all rings is similar, but the location of the bright side varies. Credit: M. Wielgus, D. Pesce & the EHT Collaboration

But while the crescent diameter remained consistent, the EHT team found that the data were hiding a surprise: the ring wobbles, and that means big news for scientists. For the first time, they can get a glimpse of the dynamical structure of the accretion flow so close to the black hole’s event horizon, in extreme gravity conditions. Studying this region holds the key to understanding phenomena such as relativistic jet launching, and will allow scientists to formulate new tests of the theory of General Relativity.

And the beat goes on ...

Cutting a path ...

Black holes cast a shadow on the image of bright surrounding material because their strong gravitational field can bend and trap light. The shadow is bounded by a bright ring of light, corresponding to photons that pass near the black hole before escaping. The ring is actually a stack of increasingly sharp subrings, and the n-th subring corresponds to photons that orbited the black hole n/2 times before reaching the observer. This animation shows how a black hole image is formed from these subrings and the trajectories of photons that create the image. Credit: Center for Astrophysics, Harvard & Smithsonian

Science has figured out how to get razor-sharp images of black holes, something not even conceived of just one year ago prior to getting the first pix of M87.

Last April, the Event Horizon Telescope (EHT) sparked international excitement when it unveiled the first image of a black hole. Today, a team of researchers have published new calculations that predict a striking and intricate substructure within black hole images from extreme gravitational light bending.

"The image of a black hole actually contains a nested series of rings," explains Michael Johnson of the Center for Astrophysics, Harvard and Smithsonian (CfA). "Each successive ring has about the same diameter but becomes increasingly sharper because its light orbited the black hole more times before reaching the observer. With the current EHT image, we've caught just a glimpse of the full complexity that should emerge in the image of any black hole."

Because black holes trap any photons that cross their event horizon, they cast a shadow on their bright surrounding emission from hot infalling gas. A "photon ring" encircles this shadow, produced from light that is concentrated by the strong gravity near the black hole. This photon ring carries the fingerprint of the black hole—its size and shape encode the mass and rotation or "spin" of the black hole. With the EHT images, black hole researchers have a new tool to study these extraordinary objects.

How cool is that?

M87 raw image

What M87 will look like after intense data collection and image processing.

Fig. 1 Time-averaged image of a GRMHD simulation of M87.

This model has parameters chosen to be consistent with the 2017 EHT data and corresponds to the high magnetic flux “magnetically arrested disk” accretion state. It has M = 6.2 × 109M⊙, a/M = 0.94, θobs = 163°, rhigh = 10, and mass accretion rate matching the 1.3-mm flux density (5). The spin axis points left when projected onto the image. The time average was performed over 100 snapshots produced from uniformly spaced GRMHD fluid samples over a time range of 1000M (approximately 1 year). Although visually prominent, the thin, bright ring contains only ~20% of the total image flux density.

Stellar without question.

Just the beginning ...

The first image of a black hole, from the galaxy Messier 87. CreditCreditEvent Horizon Telescope Collaboration, via National Science Foundation

Black holes rule and ... they exist big time. To whit.

“We have seen what we thought was unseeable,” said Shep Doeleman, an astronomer at the Harvard-Smithsonian Center for Astrophysics, and director of the effort to capture the image, during a Wednesday news conference in Washington, D.C.

The image, of a lopsided ring of light surrounding a dark circle deep in the heart of the galaxy known as Messier 87, some 55 million light-years away from Earth, resembled the Eye of Sauron, a reminder yet again of the implacable power of nature. It is a smoke ring framing a one-way portal to eternity.

The network of telescopes was sensitive enough to observe daily variations in the bright ring around the M87 black hole.

Just the beginning ... of a new era in astronomy is at hand. Stellar without question.

EKCD yet again. :)

Makes one feel small doesn't it?

538's take on how they did this is truly astounding. Excellent to a fault. :)

Just one more thing ... :) The pix below shows the Messier 87 black hole in context
via the Chandra X-ray observatory.

The Core of M87: Chandra Captures X-rays in Coordination with EHTScientists have used NASA's Chandra X-ray Observatory to obtain data of Messier 87 during the April 2017 observations by the Event Horizon Telescope.

X-ray Layout: Wide Field & Close-up

X-ray Close-up & Event Horizon Telescope Image

There be dragons

There be dragons, not only in myth and legend but also in galaxies, entities known as black holes,  the most mysterious object known to science. 

We live 26,000 light-years from the center of the Milky Way. That’s a rounding error by cosmological standards, but still — it’s far. When the light now reaching Earth from the galactic center first took flight, people were crossing the Bering Strait land bridge, hunting woolly mammoths along the way.

The distance hasn’t stopped astronomers from drawing a fairly accurate map of the heart of the galaxy. We know that if you travel inbound from Earth at the speed of light for about 20,000 years, you’ll encounter the galactic bulge, a peanut-shaped structure thick with stars, some nearly as old as the universe. Several thousand light-years farther in, there’s Sagittarius B2, a cloud a thousand times the size of our solar system containing silicon, ammonia, doses of hydrogen cyanide, at least ten billion billion billion liters of alcohol and dashes of ethyl formate, which tastes like raspberries. Continue inward for another 390 light-years or so and you reach the inner parsec, the bizarro zone within about three light-years of the galactic center. Tubes of frozen lightning called cosmic filaments streak the sky. Bubbles of gas memorialize ancient star explosions. Gravity becomes a foaming sea of riptides. Blue stars that make our sun look like a marble go slingshotting past at millions of miles per hour. Space becomes a bath of radiation; atoms dissolve into a fog of subatomic particles. And near the core, that fog forms a great glowing Frisbee that rotates around a vast dark sphere. This is the supermassive black hole at the core of the Milky Way, the still point of our slowly rotating galaxy. We call it Sagittarius A*, that last bit pronounced “A-star.” The black hole itself is invisible, but it leaves a violent imprint on its environment, pulling surrounding objects into unlikely orbits and annihilating stars and clouds of gas that stray too close. Scientists have long wondered what they would see if they could peer all the way to its edge. They may soon find out.

Astronomers found Sagittarius A* in 1974, when the notion of holes in space was still new and unsettling. Since then, they have probed it with every appropriate observational and theoretical instrument. Indirectly, they have weighed it, measured its girth, monitored its feeding habits. They now talk about it with measured confidence, like villagers describing a dragon that lives in a cave in the hills, an animal whose existence no one doubts, but which no one has ever seen.

The incredibly complex quest to see ours requires creativity at the level of an 

Einstein, a Newton or a Hawking, take your pick.

On five nights over a span of 10 days, teams at high-altitude observatories in France, Mexico, Chile, Arizona, Hawaii and the South Pole tracked Sagittarius A* through the night. When the inaugural E.H.T. observing run concluded on April 11, 2017, the astronomers had recorded more than 65 hours of data. They’d had good fortune all week: clear weather, no catastrophic failures. The astronomers at each of the eight participating observatories shipped a total of 1,024 eight-terabyte hard drives containing the observation’s harvest to Haystack Observatory and the Max Planck Institute for Radio Astronomy for correlation, and the drives all arrived in good condition. Then the correlator operators dove into the noise in search of signal, adjusting for the drift of the atomic clocks and the wobbles of Earth and tiny uncertainties in the positions of the telescopes. They stalked abstract mathematical spaces for correlations. And one by one, they found them. Every thread of the web was intact. Because they didn’t want to raise false hopes or encourage speculation, the collaborators were sworn to secrecy.

For more than a year they calibrated and corrected and reality-checked their data. Then in June, they released the final Sagittarius A* and M87 data to four small groups tasked with making images. Radio astronomers make images by feeding data about the radiation they have observed to algorithms that construct a picture of the object that emitted it. If the E.H.T. were an actual telescope the size of Earth, making images would be straightforward, the results unambiguous and direct. But because the E.H.T. is just a few specks of mirror on a rotating globe, an infinite number of possible images could explain any given data set. To be sure the images they extracted from their data depicted what was really up there in the sky, they installed checks and balances in the imaging process — hence the four separate groups. To avoid poisoning one another’s minds — so that no one could accidentally nudge another group into seeing a black-hole shadow that wasn’t really there — these groups worked in isolation, making images using different algorithms and techniques, trying hard to discredit anything that looked too sharp, too clean, too likely to be the product of wishful thinking.

At some point within the next few months, the astronomers will finish their final analysis and submit their results to a scientific journal for peer review. If everything is in order, the results will be published, and then the world will see — something.

If this works ...

It’s possible we’ll encounter what Doeleman calls the nose-of-God scenario, in which an unmistakable image of the black hole shadow easily and quickly comes into focus. Or the picture could be muddy, confusing, subject to multiple interpretations. Maybe it will reveal something completely unexpected: After all, no one has ever seen a black hole. Even a pristine, searing image of the shadow of a black hole won’t end the story. Other scientists will pick apart the image and all the accompanying data. That’s how it goes. But even if no one immediately agrees on what the first picture tells us, its arrival could signal the beginning of a new era — with luck, one in which people gain new traction in the long and baffling quest to understand what happens in those dark places where space-time ends.

Read this extraordinary NY Times' piece to learn why trying to see our dragon is truly worth the effort.