Succinct explanation of black hole mass, diameter, shape?

Succinct explanation of black hole mass, diameter, shape?

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I don't have any formal education in physics and I have found it hard to find a succinct and somewhat simple to comprehend explanation of what we think is the actual reality of a black hole. I'm asking after seeing a statement saying that the mass of the central supermassive black hole in the Phoenix Cluster was 20 billion solar masses and the diameter we think to be approximately 118 billion kilometres across.

Is someone able to point me to a resource or give me a simple explanation as to what we think a black hole actually is in shape? Is it a solid sphere with a central point and a radius of approximately 59 billion kilometres? A spinning disc with a face that is 118 billion kilometres across and if so what are the other measurements?

Am I thinking about this all wrong with regards to trying to understand it as a shape at all? If I understand correctly, mass doesn't give any indication of size as it is dependent on density. Is a black hole just basically a somewhat spherical body of mass like any other that just has an absolutely massive density and spin?

I should start off by saying that black holes are enigmas. In describing our universe, we have the General Theory of Relativity (GR) to help us describe gravity and objects which are very massive. We also have quantum mechanics (QM) and quantum field theory to help us describe small objects such as particles. For the most part, these two realms are completely separate and these two important theories don't mix. After all, you don't need QM to describe the physics of orbiting the Sun, and you don't need GR to describe electrons orbiting an atomic nucleus.

A problem arises though, when you begin talking about objects which require both QM and GR, and black holes fall very nicely into this regime. Often we find that when we mix the two theories, we wind up with nonsensical answers. It is highly probable that our understanding of the mechanics of a black hole is incomplete. What we really need is a quantum gravity theory to talk about black holes and as yet we don't have one.

That being said, let me lay out the basic structure of a black hole based on what current theory suggests to be true. Fortunately, black holes are relatively simple in structure, as dictated by the No-Hair Theorem (which basically says you only need a few parameters to completely describe the state of a black hole, as opposed to what you'd need to fully describe the physics of a person or even an atom). The (somewhat simplified) anatomy of a black hole is shown below.

In this diagram there are a few important parts. The first being the singularity. When you put a bunch of mass together, gravity acts to squeeze that mass into a ball. That is what drives the fusion in our Sun and makes our planet round. Normally there is some resistive force that stops the matter from collapsing completely, such as the structural integrity of rocks in the Earth or fusion in the Sun. At some point though, if you pack on enough mass, that resistive force can't hold out and gravity wins. In this case, all the matter collapses down as far as it can go. It becomes a point of matter known as a singularity. This singularity has no size, it is literally (and mathematically) a point. All the mass of the black hole exists here. So when they say a black hole is 20 billion solar masses, they mean that the singularity contains the matter equivalent to 20 billion Suns, all confined to that single point.

The other important concept for a black hole is the event horizon. I should stress that the event horizon is not a physical object in space. It is a mathematical boundary. Without getting into the nitty-gritty and in basic terms, the event horizon is where our current physics "stops working". We cannot describe inside the event horizon with our current physics because we are in that region where both QM and GR are important and they don't play well together. The event horizon is also the boundary where, if crossed, you're trapped forever in the black hole. There's a lot more physics involved with the event horizon, but that's the gist. Usually when someone refers to the size of a black hole, they're talking about the event horizon. Thus if they say the black hole is 118 billion kilometers across, they mean that the event horizon has a diameter of 118 billion kilometers. Note, from the image above, that the radius of the event horizon is easily calculated from only the mass of the singularity (and a few physical constants).

There are further components to a black hole such as the ergosphere or photon sphere, and often black holes have accretion disks of material around them. I'll leave those concepts to another question though.

What is the shape of a black hole?

Black holes are an infinitely small object themselves, being smaller than the size of an atom. Which in turn means they have no shape. However, the area their gravity affects is round because they pull equally in all directions.

Black holes are spherical.


A black hole is defined by its event horizon. This is defined to be the Schwarzschild radius #r_s# .

Where #G# is the gravitational constant, #M# is the mass of the black hole and #c# is the speed of light.

Nothing can escape the event horizon.

This means that the black hole is spherical.

The Schwarzschild solution to Einstein's field equations assumes that the black hole is not spinning. If it is it will be a slightly flattened sphere in shape.

Universal Mechanism for Ejection of Matter by Black Holes Proposed

The process occurs in active-core nuclei. A molecular gas cloud that accumulates in the central region is blown away by radiation from the black hole’s accretion disk, forming a huge expanding hot bubble, whose radius can reach 300 light years.

Black holes can expel a thousand times more matter than they capture. The mechanism that governs both ejection and capture is the accretion disk, a vast mass of gas and dust spiraling around the black hole at extremely high speeds. The disk is hot and emits light as well as other forms of electromagnetic radiation. Part of the orbiting matter is pulled toward the center and disappears behind the event horizon, the threshold beyond which neither matter nor light can escape. Another, much larger, part is pushed further out by the pressure of the radiation emitted by the disk itself.

Every galaxy is thought to have a supermassive black hole at its center, but not all galaxies have, or still have, accretion disks. Those that do are known as active galaxies, on account of their active galactic nuclei. The traditional model posits two phases in the matter that accumulates in the central region of an active galaxy: a high-speed ionized gas outflow of matter ejected by the nucleus, and slower molecules that may flow into the nucleus.

The process occurs in active galactic nuclei. A molecular gas cloud that accumulates in the central region is blown away by radiation from the black hole’s accretion disk, forming a huge expanding hot bubble, whose radius can reach 300 light years (image of galaxy NGC 4151 (left), with close-up of central region (right). Central circle in right-hand image delimits outflow region, from which ejected gas spreads out at high speed to a considerable distance. Credit: Adam Block/University of Arizona and Judy Schmidt

A new model that integrates the two phases into a single scenario has now been put forward by Daniel May, a postdoctoral researcher in the University of São Paulo’s Institute of Astronomy, Geophysics and Atmospheric Sciences (IAG-USP) in Brazil. “We found that the molecular phase, which appears to have completely different dynamics from the ionized phase, is also part of the outflow. This means there’s far more matter being blown away from the center, and the active galactic nucleus plays a much more important role in the structuring of the galaxy as a whole,” May told Agência FAPESP.

An article on the study by May and collaborators was published in the journal Monthly Notices of the Royal Astronomical Society. The study was supported by FAPESP via a doctoral scholarship and a postdoctoral scholarship awarded to May. João Steiner, Full Professor at IAG-USP and a co-author of the article, supervised May’s PhD and postdoc research.

May identified the pattern on the basis of a study of two active galaxies: NGC 1068, which he investigated in 2017, and NGC 4151, which he investigated in 2020. NGC stands for New General Catalogue of Nebulae and Clusters of Stars, established in the late nineteenth century.

Accretion disk (in purple, out of scale). The process occurs in active-core nuclei. A molecular gas cloud that accumulates in the central region is blown away by radiation from the black hole’s accretion disk, forming a huge expanding hot bubble, whose radius can reach 300 light years. Credit: Daniel May

“Using a highly meticulous image treatment methodology, we identified the same pattern in two very different galaxies. Most astronomers today are interested in studying very large datasets. Our approach was the opposite. We investigated the individual characteristics of these two objects in an almost artisanal manner,” May said.

“Our study suggests that initially a cloud of molecular gas in the central region of the galaxy collapses and activates its nucleus, forming the accretion disk. The photons emitted by the disk, which reaches temperatures on the order of a million degrees, push most of the gas a long way outward, while a smaller part of the gas is absorbed by the disk and eventually plunges into the black hole. As the cloud is sucked into the disk, two distinct phases take shape: one is ionized owing to exposure to the disk, and the other is molecular and overshadowed by its radiation. We discovered that the molecular part is entirely tied to the ionized part, which is known as the outflow. We were able to relate the two phases of the gas, previously considered disconnected, and fit their morphologies into a single scenario.”

The ionized gas derives from fragmentation of this molecular gas, May explained. As it fragments, it is pushed further out in an expanding hot bubble that can be as large as 300 light years in radius. For the sake of comparison, it is worth recalling that this is almost 70 times the distance from Earth to Proxima Centauri, the nearest star to the Solar System.

“When we observe the central regions of these two galaxies, we see this enormous bubble in profile, delineated by its walls of molecules,” May said. “We see the walls fragmenting and the ionized gas being driven out. The accretion disk appears as an extremely bright spot. All the information that reaches us from it corresponds to a pixel, so we don’t have enough resolution to discern its possible parts. The black hole is known about only from its effects.”

In the ancient Universe there was much more available gas, so the effect of a process such as that described by him was more intense, May explained. What he observed in relatively nearby galaxies such as NGC 1068 and NGC 4151 is a mild form of the process that occurred in more distant galaxies, whose active nuclei in the remote past are now detected as quasars.

Reference: ” The nuclear architecture of NGC 4151: on the path toward a universal outflow mechanism in light of NGC 1068″ by D May, J E Steiner, R B Menezes, D R A Williams, J Wang, 4 June 2020, Monthly Notices of the Royal Astronomical Society.
DOI: 10.1093/mnras/staa1545

Scientists reveal first image of a black hole: 'We are delighted'

The Event Horizon Telescope project is the culmination of a century of speculation about black holes, collapsed masses where gravity is so intense that no matter or even light can escape. Until now, scientists eager to understand these enigmas could study them only by indirect means: testing theories with computer simulations or watching how black holes’ intense gravitation affects matter and space around them. Now the objects are visibly, almost tangibly real.

Even more, the first picture of a black hole heralds a new era in physics. Now that they can observe these bizarre objects directly, experts say we can expect an avalanche of new observations — and new cosmic discoveries.

Einstein keeps acing the tests

One of the most striking things about the image of Pōwehi is how closely it resembles black hole simulations created with the help of computer models. Those models are all based on Einstein’s general theory of relativity, making the match an impressive vindication of the famous physicist’s ideas.

“We were surprised by how clear the signature was,” Doeleman told NBC News MACH in an email. “Einstein’s theory of gravity predicts that we should see a ring of light, but to have it come through so clearly rocked us back on our heels.” (A small irony: Einstein himself didn’t believe in black holes, arguing that while his equations indicated that such objects were theoretically possible, they “do not exist in physical reality.”)


Science First-ever photo of a black hole reveals what had been unseeable

The light ring around Pōwehi is distinctly lopsided, another predicted effect. Gas around the black hole is orbiting furiously, and the side that is circling toward Earth appears brighter than the side that is circling away. The pattern indicates that the black hole is rotating clockwise from our perspective, Heino Falcke, a radio astronomer at Radboud University in the Netherlands and a member of the Event Horizon Telescope team, said in an email.

The picture doesn’t reveal what happens at the event horizon, the theoretical “surface” of a black hole. The event horizon is one of the strangest predictions of Einstein’s relativity, the point of no return where time comes to a standstill. So far, the Event Horizon Telescope observations cannot confirm even the existence of an event horizon.

“It looks like an event horizon and it quacks like an event horizon, but you can never exclude something that is almost like an event horizon producing a similar shadow,” Falcke said. “Each competing model has to be tested one by one. The cool thing is — now we can.”

To warped space … and beyond

The astonishing power of the Event Horizon Telescope means that a lot of other outstanding questions in astronomy become suddenly answerable, too.

“It gives us, for the first time, a way to test our predictions for how black holes digest matter and launch powerful jets of material that can disrupt entire galaxies,” Doeleman said. Such jets can grow 100,000,000 times as wide as the black hole itself, and nobody knows exactly how they form.

The regions around black holes are also extreme places where gas is heated to millions of degrees and whipped around at nearly the speed of light. They are natural laboratories for testing the outer limits of the laws of physics. “The next step is to sharpen the image further so we can study the dynamics of the black hole — how does it change, how does it affect its surroundings. This will let us go from making still images of black holes to making movies,” Doeleman said.

Pōwehi is just one of billions of supermassive black holes now thought to exist across the universe, in the centers of most large galaxies. Future upgrades to the Event Horizon Telescope will bring more of these objects into view, including Sagittarius A* (pronounced Sagittarius A star), the huge black hole at the center of our own Milky Way galaxy. Falcke and the rest of the team have already made attempts to see Sagittarius A*, but our local black hole flickers rapidly, making it what he termed “an extra challenge."

The Event Horizon Telescope will be a godsend for many other kinds of astronomical observations beyond black holes.

“The resolving power of the telescope is just astonishing,” Mustafa Amin and Andrea Isella, astronomers at Rice University, said in an email. (Its acuity is equivalent to reading the emails off an iPhone in New York City while lounging in a café in Paris.) They are eager to exploit that power to watch infant planets forming around other stars or to observe delicate structures in distant galaxies.

The possibilities are almost endless. First, though, Falcke and the other black hole sleuths are looking forward to some well-earned sleep. “People were worn out to get this massive amount of work done under this pressure,” he said. “It would be really good to pause for a moment and rethink the way we do things.”



Tiny newfound 'Unicorn' is closest known black hole to Earth

'The Unicorn' lies a mere 1,500 light-years from us and is just three times more massive than the sun.

Astronomers have apparently found the closest known black hole to Earth, a weirdly tiny object dubbed "The Unicorn" that lurks just 1,500 light-years from us.

The nickname has a double meaning. Not only does the black hole candidate reside in the constellation Monoceros ("the unicorn"), its incredibly low mass — about three times that of the sun — makes it nearly one of a kind.

"Because the system is so unique and so weird, you know, it definitely warranted the nickname of 'The Unicorn,'" discovery team leader Tharindu Jayasinghe, an astronomy Ph.D. student at The Ohio State University, said in a new video the school made to explain the find.

"The Unicorn" has a companion — a bloated red giant star that's nearing the end of its life. (Our sun will swell up as a red giant in about five billion years.) That companion has been observed by a variety of instruments over the years, including the All Sky Automated Survey and NASA's Transiting Exoplanet Survey Satellite.

Jayasinghe and his colleagues analyzed that big dataset and noticed something interesting: The red giant's light shifts in intensity periodically, suggesting that another object is tugging on the star and changing its shape.

The team determined that the object doing the tugging is likely a black hole — one harboring a mere three solar masses, based on details of the star's velocity and the light distortion. (For perspective: The supermassive black hole at the heart of our Milky Way galaxy packs about 4.3 million solar masses.)

"Just as the moon's gravity distorts the Earth's oceans, causing the seas to bulge toward and away from the moon, producing high tides, so does the black hole distort the star into a football-like shape with one axis longer than the other," study co-author Todd Thompson, chair of Ohio State's astronomy department, said in a statement. "The simplest explanation is that it's a black hole — and in this case, the simplest explanation is the most likely one."

That explanation, likely though it may be, is not set in stone "The Unicorn" remains a black hole candidate at the moment.

Very few such super-lightweight black holes are known, because they're incredibly hard to find. Black holes famously gobble up everything, including light, so astronomers have traditionally detected them by noticing the impact they have on their surroundings (though we did recently get our first direct image of a black hole, thanks to the Event Horizon Telescope). And the smaller the black hole, the smaller the impact.

But efforts to find extremely low-mass black holes have increased significantly in recent years, Thompson said, so we could soon learn much more about these mysterious objects.

"I think the field is pushing toward this, to really map out how many low-mass, how many intermediate-mass and how many high-mass black holes there are, because every time you find one it gives you a clue about which stars collapse, which explode and which are in between," he said in the statement.

Jayasinghe and his team report the detection of "The Unicorn" in a paper that's been accepted for publication in the journal Monthly Notices of the Royal Astronomical Society. You can read it for free at the online preprint site

Mike Wall is the author of "Out There" (Grand Central Publishing, 2018 illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.

Astronomers Discover Closest Known Black Hole Candidate

An artist’s impression of the V723 Mon binary system. Image credit: Lauren Fanfer / Ohio State University.

V723 Mon is a bright, evolved red giant located 1,500 light-years away in the constellation of Monoceros.

Also known as HD 45762, SAO 133321, and TIC 43077836, the star has the same mass as the Sun, but is 25 times larger.

V723 Mon had been well-documented by several telescope systems, including KELT, ASAS, and NASA’s Transiting Exoplanet Survey Satellite (TESS).

But when Ohio State University astronomer Tharindu Jayasinghe and colleagues analyzed the archival data, they noticed something they couldn’t see appeared to be orbiting the red giant, causing the light from that star to change in intensity and appearance at various points around the orbit.

Something, they realized, was tugging at the red giant and changing its shape. That pulling effect, called a tidal distortion, offers astronomers a signal that something is affecting the star.

One option was a black hole, but it would have to be small — less than five times the mass of the Sun, falling into a size window that astronomers call the ‘mass gap.’

“When we looked at the data, this black hole — dubbed the Unicorn — just popped out,” Jayasinghe said.

“The simplest explanation is that it’s a black hole — and in this case, the simplest explanation is the most likely one,” added Dr. Todd Thompson, also from the Ohio State University.

The velocity of V723 Mon, the period of the orbit and the way in which the tidal force distorted the red giant told them the black hole’s mass, leading the team to conclude that the Unicorn black hole was about three solar masses.

“In recent years, more large-scale experiments to try and locate smaller black holes have launched, and I expect to see more mass gap black holes discovered in the future,” Dr. Thompson said.

“I think the field is pushing toward this, to really map out how many low-mass, how many intermediate-mass and how many high-mass black holes there are, because every time you find one it gives you a clue about which stars collapse, which explode and which are in between.”

T. Jayasinghe et al. 2021. A Unicorn in Monoceros: the 3M dark companion to the bright, nearby red giant V723 Mon is a non-interacting, mass-gap black hole candidate. MNRAS, in press arXiv: 2101.02212

If we can't see them, how do we know they are there?

Since stellar black holes are small (only a few to a few tens of kilometers in diameter), and light that would allow us to see them cannot escape, a black hole floating alone in space would be hard, if not impossible, to see in the visual spectrum.

However, if a black hole passes through a cloud of interstellar matter, or is close to another "normal" star, the black hole can accrete matter into itself. As the matter falls or is pulled towards the black hole, it gains kinetic energy, heats up and is squeezed by tidal forces. The heating ionizes the atoms, and when the atoms reach a few million Kelvin, they emit X-rays. The X-rays are sent off into space before the matter crosses the Schwarzschild radius and crashes into the singularity. Thus we can see this X-ray emission.

The optical companion of
the black hole candidate Cygnus X-1

Binary X-ray sources are also places to find strong black hole candidates. A companion star is a perfect source of infalling material for a black hole. A binary system also allows the calculation of the black hole candidate's mass. Once the mass is found, it can be determined if the candidate is a neutron star or a black hole, since neutron stars always have masses of about 1.5 times the mass of the Sun. Another sign of the presence of a black hole is its random variation of emitted X-rays. The infalling matter that emits X-rays does not fall into the black hole at a steady rate, but rather more sporadically, which causes an observable variation in X-ray intensity. Additionally, if the X-ray source is in a binary system, and we see it from certain angles, the X-rays will be periodically cut off as the source is eclipsed by the companion star. When looking for black hole candidates, all these things are taken into account. Many X-ray satellites have scanned the skies for X-ray sources that might be black hole candidates.

Cygnus X-1 (Cyg X-1) is the longest known of the black hole candidates. It is a highly variable and irregular source, with X-ray emission that flickers in hundredths of a second. An object cannot flicker faster than the time required for light to travel across the object. In a hundredth of a second, light travels 3,000 kilometers. This is one fourth of Earth's diameter. So the region emitting the X-rays around Cyg X-1 is rather small. Its companion star, HDE 226868 is a B0 supergiant with a surface temperature of about 31,000 K. Spectroscopic observations show that the spectral lines of HDE 226868 oscillate with a period of 5.6 days. From the mass-luminosity relation, the mass of this supergiant is calculated as 30 times the mass of the Sun. Cyg X-1 must have a mass of about 7 solar masses, or it would not exert enough gravitational pull to cause the wobble in the spectral lines of HDE 226868. Other estimate put the mass of Cyg X-1 to as much as 16 solar masses. Since 7 solar masses is too large to be a white dwarf or neutron star, it must be a black hole.

An illustration of Cygnus X-1, showing the companion star HDE 226868,
the black hole, material streaming from the companion to the black hole,
and the emission of X-rays near the black hole.

There are now about 20 X-ray binaries (as of early 2009) with known black holes (from measurements of the black hole mass). The first of these, an X-ray transient called A0620-00, was discovered in 1975, and the mass of the compact object was determined in the mid-1980's to be greater than 3.5 solar masses. This very clearly excludes a neutron star, which has a mass near 1.5 solar masses, even allowing for all known theoretical uncertainties. The best case for a black hole is probably V404 Cygni, whose compact star is at least 10 solar masses. There are an additional 20 X-ray binaries which are likely to contain black holes - their behavior is the same as the confirmed black holes, but mass measurements have not been possible.

Black hole: Tiny black hole called 'The Unicorn' found 'near' Earth

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Black hole: Scientists discover one of smallest on record

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Astronomers have discovered a tiny black hole relatively near to Earth. It has been dubbed 'The Unicorn' and has a mass around three times that of the Sun. The smallest black holes to have previously been discovered are at least six times the mass of the Sun, so the newly found one could fall into a new category.

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For a black hole to form, it had been assumed that a star would need to be at least six times that of the Sun when it collapses in on itself, creating a tear in the fabric of spacetime.

The Unicorn opens up a world of possibilities on what other black holes may be out there.

But do not be fooled by its small size - it still has a gravitational pull which can consume anything around it.

The black hole was discovered by researchers at the Ohio State University, which said it was "hiding in plain sight".

Black hole: Tiny black hole called 'The Unicorn' found 'near' Earth (Image: OHIO STATE UNIVERSITY)

Astronomers have discovered a tiny black hole relatively near to Earth (Image: GETTY)

It is located 1,500 light-years from Earth in the constellation Monoceros.

The Unicorn has a companion star which is a red giant, "meaning that the two are connected by gravity."

Experts cannot see the black hole but were able to determine it is there by the way the light from the star changes when it passes behind it.

Researchers from Ohio State University realised something was tugging and changing the shape of the red giant - something known as tidal distortion.

It is located 1,500 light-years from Earth in the constellation Monoceros (Image: GETTY)

Related articles

Todd Thompson, co-author of the study, chair of Ohio State&rsquos astronomy department and university distinguished scholar, said: &ldquoJust as the moon&rsquos gravity distorts the Earth&rsquos oceans, causing the seas to bulge toward and away from the moon, producing high tides, so does the black hole distort the star into a football-like shape with one axis longer than the other.

&ldquoThe simplest explanation is that it&rsquos a black hole &ndash and in this case, the simplest explanation is the most likely one.&rdquo

Efforts to find extremely low mass black holes have increased in recent years as astronomers hope to unravel the mysteries of the strange entities.

Mr Thompson continued: "I think the field is pushing toward this, to really map out how many low-mass, how many intermediate-mass and how many high-mass black holes there are, because every time you find one it gives you a clue about which stars collapse, which explode and which are in between."

What is a black hole? (Image: EXPRESS)


Kris Stanek, study co-author, astronomy professor at Ohio State and university distinguished scholar, said: &ldquoWhen you look in a different way, which is what we&rsquore doing, you find different things.

"[Lead author Tharindu Jayasinghe, a doctoral student in astronomy at The Ohio State University] looked at this thing that so many other people had looked at and instead of dismissing the possibility that it could be a black hole, he said, &lsquoWell, what if it could be a black hole?&rsquo&rdquo

Mr Jayasinghe stated: &ldquoWhen we looked at the data, this black hole &ndash the Unicorn &ndash just popped out."

The predicted radius of the photon ring is $ r_p = sqrt <27>frac>, $ for a non-spinning black hole. The result is only slightly different for a fast spinning black hole. By dividing $r_p$ by the distance to the source $D$ , we have a relationship between the angular radius and the black hole mass.

If the angular radius is measured to be 21 $mu$ arcsec, then this suggests a mass of 6.9 billion solar masses.

The difference between this and the final result of 6.5 billion solar masses is down to a more sophisticated modelling of the image using a radiative transfer model and a spinning black hole.

If you are talking about the diameter of the event horizon, we can use the Schwarzschild radius to get a quick estimate. The Schwarzschild radius is given by

in SI units and using the given data (we only really need the mass of the black hole which is $M = 6.6 imes 10^9 imes 2 imes 10^ <30>approx 13.2 imes 10^ <39> ext$ where the mass of the sun is approximately $2 imes 10^<30>$ kg) it is straightforward to calculate the Schwarzschild radius in SI units

A light-day is approximately $25.9 imes 10^ <12> ext$ and hence you get that the diameter is approximately

$ 19.6 imes 2 div 25.9 approx 1.51 ext < light-days >$

or in SI units if you like $ 3.92 imes 10^ <13> ext < m >$

I have taken just a few significant figures since the most crucial data (mass of the blackhole) is accurate to at most 2 significant figures.


Well, what can I say? Black holes are weird.

As it so happens, there was a lot more that could be said about them, of course. What about wormholes? What about how they form? what about Hawking radiation? Can black holes totally evaporate?

You can find answers to these and other questions elsewhere on the web (and even on this very blog) I couldn’t cover everything in just ten sections! But I’ll note (shocker) that chapter 5 of my book Death from the Skies! talks in detail about how they form, and what they can do if you get too close to them. Later chapters also talk about the black hole in the core of the Milky Way, and what will happen to black holes a long time from now… literally, 1060, 1070, even a googol years from now.

But even then, that’s not the scariest thing about black holes. I almost didn’t put this in the post, it’s so over the top mind-numbingly horrifying. But I’m a scientist, and we’re skeptics here, so we can take it. So I present to you, the worst thing about black holes of all: