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5 Interesting Facts About Black Holes

1. You can't see a black hole

Not even light can escape a black hole

Scientists detect their presence based on the effects of gravitational force

2. Two black holes can merge with each other to get larger

Their centers will merge into an even greater black hole

In about 4.5 billion years, black holes in our galaxy will merge with the Andromeda galaxy

3. Time slows down near a black hole

The strong gravitational pull of the black hole moves so fast that it slows down time itself

4. Black holes have 3 layers

Outer layer: gravitational pull isn’t strong

Inner layer: gravitational pull is so strong that not even light can escape from it

Singularity (the center): has the strongest gravitational pull

5. Largest black hole is found in the center of the galaxy

Milky Way: Saggitaruis A

A supermassive black hole at the center

Andromeda: Has a supermassive black hole at its center

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Advantages & Disadvantages of Black Holes Holding Secret Universes

ADVANTAGES
1. Expanded Knowledge of Space

Revolutionize our understanding of the universe's structure and complexity

Develop new technology to travel within a black hole

2. Human Exploration

Open up entirely new realms for exploration and potential colonization

Advancements in travel

3. Advancement of Physics

Provides us with insights into the fundamental laws of physics

Potentially reveals new dimensions

DISADVANTAGES
1. Destroy Earth

Black holes can easily tear apart plants and stars

2. New Objects

Space junk could get sucked into the black hole, entering the universe inside

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Context on Black Holes

Located in space

Gravity is extremely strong, causing matter and light to be trapped

Forms when a massive star "dies" or collapses under its own gravitational pull

Pull is so intense that nothing can escape from it

Different sizes

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What Is a Wormhole?

A tunnel between two distant points in our universe that cuts the travel time from one point to the other

Using a wormhole could theoretically reduce travel time between galaxies from millions of years to hours or minutes

Wormholes Create Bridges

A wormhole could be created within a black hole

A wormhole leads to an entirely separate universe

Could be the explanation for how to travel in a black hole

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Astronomers recently discovered massive black holes in the universe’s tiniest galaxies

And black holes wandering at their galaxies’ edges

As galaxies grow, they collide and merge over time

"Feed" on new stars, gas, and dust particles

Of about 25,000 dwarf galaxies, 151 of them appeared to have big black holes

"Baby universes" can thus form within these massive black holes

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Where the Discovery and Idea of Black Holes Came From

1915: Albert Einstein proposed his groundbreaking theory of General Relativity

The theory states, "any mass which falls within that radius would be unable to escape"

WWII:  Great discoveries were made but unconsidered due to the war and lack of proof

1963: Princeton University physicist John Wheeler officially shared black bodies as ‘black holes.’

1964: First black hole was discovered

2023: Only a dozen black holes have been discovered, the nearest one is 1,600 light-years away

There are about 100 billion galaxies "close" to the region visible to Earth, and each galaxy has about 100 million stellar-mass black holes

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The First Black Hole

Cygnus X-1 was the first black hole discovered in 1964

Located within the Milky Way

In the constellation of Cygnus (the Swan)

Astronomers saw the first signs of the black hole when a sounding rocket detected celestial sources of X-rays

In 1971,  determined that the X-rays were coming from a bright blue star orbiting a strange dark object

Suggested the X-rays were a result of stellar material being pulled away from the bright star and "gobbled" up by the dark object; an all-consuming black hole.

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Can black holes hold secret universes?

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Facts About the Largest Black Hole in the Milky Way

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Facts About the Largest Black Hole in the Milky Way

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Information on Sagittarius A*

Distance from Earth: 26,000 light-years

Size: 4.6 million times the mass of the Sun

Type: Supermassive black hole

Location in the sky: Sagittarius Constellation

Location in the universe: Center of our Milky Way galaxy

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Importance of Learning About Black Holes

Understanding black holes helps astronomers understand all of space

Tests Einstein's theory of general relativity

Describes how mass, space, and time are related to one another

Supermassive black holes play an important role in the life of galaxies

Explains how the Universe works on the largest and the smallest scales

New discoveries can help find if there is life in space

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Link: https://www.sciencenews.org/article/black-holes-weird-secrets-early-universe

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Our galaxy's heart is a gluttonous monster. Like the mythical Kammapa of the Sotho people of southern Africa, the Milky Way's central, supermassive black hole has swallowed nearly everything around it, growing heftier and heftier the more it eats. And it's not alone. Black holes weighing as much as thousands, millions or even billions of suns sit at the center of nearly all known massive galaxies.

For decades, scientists thought that was the only place they'd find such behemoths, because only massive galaxies had enough material to feed the monsters' excessive appetites. But beginning about two decades ago, computer simulations of the earliest black holes started turning up oddities - big black holes that weren't smack-dab where they were expected. These misfits must be nothing more than flukes, many scientists reasoned at the time, dismissing the results without a second thought.

But others weren't so certain the oddballs should be cast off. If observations show that these unusual black holes exist in the nearby universe, these astrophysicists speculated, they could be untapped clues to the universe's infancy and adolescence.

"We can, weirdly, [learn about] the super-beginning of the universe by looking at things really close to us," says theoretical astrophysicist Jillian Bellovary of Queensborough Community College in New York City.

The notion remained just an idea for years. But now, the existence of these misfits isn't so easy to ignore. Astronomers have turned up signs of a number of unexpectedly massive black holes in the universe's tiniest galaxies, and surprisingly, some of those black holes don't appear to sit at their galaxies' centers. Even more intriguing, astronomers have spotted evidence of black holes wandering at their galaxies' edges, and in rare cases, being kicked from their homes into intergalactic space.

Perhaps these black holes aren't merely cosmic nonconformists but instead big players in the story of our universe. If so, they are a tool for probing one of the greatest mysteries in all of astrophysics - how the cosmic Kammapas we see today came to be.

"Without understanding what black holes are doing, you cannot understand galaxy evolution," says Xiaohui Fan, a cosmologist at the University of Arizona in Tucson, making it impossible to explain the landscape of the universe.

Little galaxies can have big black holes

Our current cosmological understanding of how black holes got so big goes something like this: As galaxies grow, collide and merge over cosmic time, they take on gobs of new stars, gas and dust. The black holes at the galaxies' centers grow in lockstep, ballooning as they merge with one another and feed on the newly acquired material. A rough estimate puts a supermassive black hole's heft at somewhere around a thousandth of the mass of its home galaxy.

In this scenario, the universe's littlest galaxies, called dwarf galaxies, probably didn't go through many mergers in the past. Tipping the scales at only about a trillionth the mass of the Milky Way, they should have relatively runty black holes, or none at all.

But in the late 2000s, astrophysicist Marta Volonteri of Institut d'Astrophysique de Paris at Sorbonne University helped run computer simulations that tracked the evolution of massive black holes from birth to today. In those efforts, almost as soon as they popped into existence, even the smallest galaxies could have surprisingly large black holes. As time passed, some of those galaxies never grew or merged with others, leaving them unmarred after billions of years of cosmic evolution.

A wild idea occurred to Volonteri and her colleagues: These galaxies and their black holes were relics of the universe's birth. If massive black holes in dwarf galaxies did exist, and if astronomers could find them, those black holes would be an unprecedented window into how the first black holes formed.

The first hints that they do exist came from a serendipitous find by astronomer Amy Reines. More than a decade ago, she was in graduate school at the University of Virginia in Charlottesville poring through telescope data on a dwarf galaxy 30 million light-years from Earth. It was bursting with stars, and Reines was trying to learn more about how these balls of hot gas are born.

Initially Reines looked at data from the galaxy, called Henize 2-10, in radio and near-infrared wavelengths of light. She spotted a cosmic baby rattle, a roughly 300-light-year-long bridge of gas connecting two dusty balls swaddling newly coalescing stars. A deeper dive into the data revealed extreme radio emissions right in the middle of the rattle, along with bright X-rays coming from the same spot, inklings of a huge black hole with a mass of a million suns.

"I hadn't seen this before," says Reines, now at Montana State University in Bozeman. Dwarf galaxies, she too had assumed, shouldn't have big black holes. She remained skeptical of her interpretation until a few months later when she attended a talk in Seattle at the 2011 American Astronomical Society meeting.

It was there that Bellovary, then a postdoctoral researcher at the University of Michigan in Ann Arbor and collaborating with Volonteri, presented new simulations of galaxy formation. Bellovary described the formation of galaxies with a range of masses and histories, and discussed how the results could make predictions about how massive black holes are scattered throughout the universe.

Like Volonteri's earlier work, Bellovary's simulations suggested that big galaxies were not the only ones to harbor big black holes; scrawny galaxies could have them too.

In a session at the same meeting, Reines highlighted her discovery of dwarf galaxy Henize 2-10 and its uncharacteristically massive black hole. Like two black holes circling each other and then colliding, unexpected computer simulations met unexpected real-world observations.

The combined work suggested that not only do massive galaxies have big black holes, but maybe a majority of galaxies do too, Fan says. And that raised a lot of new questions about how black holes and galaxies grow up together.

After hearing Bellovary's talk and publishing her own findings, Reines shifted her research focus from the birth of stars to finding big black holes. The behemoths pulled her in. She launched an effort to search for them in dwarf galaxies. Like other astronomers, she decided to scan the skies for the rings of cosmic crumbs that burn brightly around feeding black holes at the centers of galaxies - active galactic nuclei. That's where black holes should be, she assumed. "I mean, it's in the name, active galactic nuclei," she explains.

Reines combed through data from the Sloan Digital Sky Survey looking for the visible-light signatures of central black holes. Of the roughly 25,000 dwarf galaxies in her analysis, 151 of them appeared to harbor a big black hole, she and colleagues reported in 2013.

Volonteri says she was elated by the results. They validated her wild idea that dwarf galaxies could have really big black holes, and possibly that those black holes could tell us something about the very first black holes.

A key clue may be in the masses of dwarf galaxies' black holes. The two leading ideas for how the first black holes formed create black holes of different masses. One idea supposes that these black holes formed from the implosion of the first stars and would tend to be relatively lightweight. The other idea suggests that the first black holes formed from the direct collapse of giant gas clouds and would be heavier. If the gas cloud idea is correct, it could explain another cosmic puzzle: how black holes in the early universe got so big so fast. "We observe them, and they are already huge," Bellovary says. If the history of the universe was displayed on a clock, these monsters would have mere seconds to form, she explains.

If big black holes in dwarf galaxies are indeed ancient relics from the early universe, their masses should be akin to the masses of the first black holes. If so, they could help explain how the seeds of some of the heftiest black holes we see today formed.

According to a recent estimate, the black hole in Henize 2-10 tips the scales at a few million suns ( SN: 9/11/21, p. 12). That's a data point in favor of the direct cloud collapse idea, but it's just one measurement with a lot of assumptions. For now, measuring black holes' masses is no easy task.

Misfit predictions

In computer simulations, big black holes don't show up only at galaxy centers. Simulations predict that this galaxy has many in its halo (black circles). The five heftiest black holes (orange) include four that are off-kilter. Simulated gas and X-ray views show how these black holes might appear to astronomers in telescope images.

A. RICARTE A. RICARTE ET AL/ET AL/ASTROPHYSICAL JOURNAL LETTERS 2021 ASTROPHYSICAL JOURNAL LETTERS 2021

Wandering black holes may offer cosmic clues

Fortunately, there's another way to get a clue to the masses of early black holes. It relies heavily on another type of oddball - big black holes that don't sit exactly at the center of dwarf galaxies.

When Bellovary shared her simulations back in 2011, the idea of big black holes in scrawny galaxies wasn't the only surprise. Her work also predicted that some Kammapas would be off-kilter from their galactic centers, wandering around the dwarfs' edges after failing to fall to their cores.

"I always like to think about the outliers, or the weird little rejects, or the nonconformists," Bellovary says. She chose to rerun her simulations, zooming in on the littlest galaxies. When she did, she found that half of the massive black holes in dwarf galaxies should be off-center, she reported in early 2019 in Monthly Notices of the Royal Astronomical Society.

As if on cue, Reines came in a few months later with observations that bolstered Bellovary's simulations. Using the Very Large Array of radio telescopes in New Mexico, Reines and colleagues had peered at emissions coming from 111 dwarf galaxies, 13 of which most likely had big black holes. Of those 13 big black holes, a few appeared to sit off-center from their galaxies' cores ( SN: 6/22/19, p. 12).

Finding wanderers was a jackpot. "Once a black hole starts wandering, it does not grow in mass anymore," Volonteri says. The lowest-mass wanderers should roughly match the initial mass of the very first black holes, making them a good proxy for the seeds that would later grow into supermassive black holes.

Unfortunately, the mass of wanderers is even harder to figure out than the mass of Kammapas sitting at their galaxies' cores. Researchers are instead turning to these wanderers' overall numbers for clues. If the earliest black holes - the seeds of today's supermassive black holes - formed from the direct collapse of huge gas clouds flowing into galaxies, then wanderers shouldn't be very common in dwarf galaxies. That's because converting a gas cloud's mass into a massive black hole is difficult and thus expected to be a rare phenomenon, Volonteri explains. An easier way to form early black holes - through the implosion of the first stars - would result in many more wanderers.

Another possible scenario that scientists are now considering is whether mergers of early stars or black holes in dense galaxy cores could have made the seeds of supermassive black holes. That process would also result in a lot of wanderers. But these black holes would be somewhat more massive than black holes formed from stellar implosions.

Because signs of wanderers keep popping up, researchers are leaning away from the direct collapse idea. But to truly get a better sense of how big black holes formed, researchers need to census wandering black holes not only in the nearby universe but also further back in time, says Angelo Ricarte of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. We need to know if what's happening now is similar to what happened then, because the environment in the early universe was very different.

"I always like to think about the outliers, or the weird little rejects, or the nonconformists."
Jillian Bellovary

Are rogue black holes real?

Massive galaxies appear to have wanderers too, some that are flying across their host galaxies at 10 times the speed of wanderers in dwarf galaxies.

But scientists aren't entirely sure if these black holes gone rogue are real. When one turned up in 2003 in Volonteri's simulations, scientists blew it off. The rogues showed up again in Bellovary's simulations. The reaction? Skepticism. And that skepticism remained even when astronomers announced bright, flashy X-ray signals coming from candidate rogues.

Several years ago, a Hubble Space Telescope image and data from other observatories offered evidence of a black hole with a billion suns' worth of mass getting booted to the edge of its galaxy ( SN: 4/29/17, p. 16). And earlier this year, images from Hubble and the Keck Observatory revealed the possibility of a trifecta of supermassive black holes interacting, with one given so much oomph that it's been ejected to intergalactic space ( SN: 4/8/23, p. 11). But a separate team proposes that what some scientists are calling a rogue black hole might instead be a galaxy viewed edge on.

Volonteri continues to track each candidate rogue, along with other oddball black holes astronomers have put forward. They all somehow have to fit into our full understanding of the history of supermassive black holes, she says. And once again, how often they show up in observations could provide clues to the fuller picture.

If observations show that slow-moving wanderers are abundant, then collisions and mergers of really big black holes are presumably rare. Slow-moving wanderers haven't interacted with other black holes and so haven't picked up extra zing relative to the stars around them. The story the universe would be telling us is that the supermassive black holes we see today didn't grow through repeated mergers after all. But, Volonteri says, if there are a lot of supermassive black holes being shot from the centers of their galaxies to the distant edges, black hole interactions, including mergers, must be common.

With a few dozen candidate oddballs in dwarf galaxies and only a few far-flung rogue candidates identified, the picture is not yet clear. What we do know, Fan explains, is that understanding cosmic evolution requires a good sense of the birth and evolution of the "dark sector" of galaxies - including black holes.

More observational evidence of oddballs would help, and more astronomers have joined the search. In 2021, a team including Reines and Mallory Molina of the University of Utah in Salt Lake City reported a new way to spot signs of massive black holes in dwarfs, specifically if the behemoths are feeding on gas and dust. The technique searches dwarfs for a red glow given off by an unusual type of iron. And a team from Dartmouth reported last year that very-high-energy X-rays may also reveal obscure behemoths.

Future observatories may aid in the hunt too. The Vera C. Rubin Observatory, located in Chile and slated to turn on next year, can sweep the skies looking for wanderers. And the next-generation Very Large Array, a proposed radio observatory, will be sensitive enough to spot signs of black holes in dwarf galaxies.

With the goal of detecting collisions of very massive black holes, the Laser Interferometer Space Antenna, or LISA, and the proposed Einstein Telescope may one day offer clues to how common cataclysmic black hole interactions are and have been.

Time and new technology will tell. For now, oddball black holes spark our imagination, prompting us to ask big questions and uncover new evidence in the pursuit of a deeper understanding of cosmic history. With each purported discovery, you can't help but wonder: What else is hidden out there? Perhaps there are other oddities not yet discovered that could tie us to the earliest universe, Bellovary says, and reveal our cosmic origins. But only if we're willing to chase the misfits and their stories.

Questions or comments on this article? E-mail us at feedback@sciencenews.org | Reprints FAQ

Citations

M. Volonteri, G. Lodato and P. Natarajan. The evolution of massive black hole seeds. MNRAS, Vol. 383, Jan. 21, 2008, p. 1079. doi: 10.1111/j.1365-2966.2007.12589.x.

J. Bellovary et al. The formation and evolution of massive black holes in cosmological simulations. American Astronomical Society, AAS Meeting #217, Bulletin of the American Astronomical Society, Vol. 43, January 2011.

A. Reines et al. An actively accreting massive black hole in the dwarf starburst galaxy Henize 2-10. Nature, Vol. 470, February 2011, p. 66. doi: 10.1038/nature09724.

A. Reines, Jenny E. Greene and Marla Geha. Dwarf galaxies with optical signatures of active massive black holes. ApJ, Vol. 775, September 13, 2013, p. 116. doi: 10.1088/0004-637X/775/2/116.

J. Bellovary et al. Multimessenger signatures of massive black holes in dwarf galaxies. MNRAS, Vol. 482, January 2019, p.2913. doi: 10.1093/mnras/sty2842.

A. Ricarte and N. Priyamvada. The observational signatures of supermassive black hole seeds. MNRAS, Vol. 481, December 2018, p.3278. doi: 10.1093/mnras/sty2448.

M. Volonteri, F. Haardt and P. Madau. The Assembly and Merging History of Supermassive Black Holes in Hierarchical Models of Galaxy Formation. ApJ. Vol. 582, January 2003, p. 559. doi: 10.1086/344675.

M. Mollina et al. A sample of massive black holes in dwarf galaxies detected via [Fe x] coronal line emission: Active galactic nuclei and/or tidal disruption events. ApJ. Vol. 922, December 2021, p. 155. doi: 0.3847/1538-4357/ac1ffa.

R. Hickox, et al. Uncovering a hidden mini-monster: A heavily obscured AGN in a dwarf star-forming galaxy. Bulletin of the AAS, Vol. 54. Published April 2, 2022.

Ashley Yeager is the associate news editor at Science News. She has worked at The Scientist, the Simons Foundation, Duke University and the W.M. Keck Observatory, and was the web producer for Science News from 2013 to 2015. She has a bachelor's degree in journalism from the University of Tennessee, Knoxville, and a master's degree in science writing from MIT.

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Weird black holes may hold secrets of the early universe

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Our galaxy's heart is a gluttonous monster. Like the mythical Kammapa of the Sotho people of southern Africa, the Milky Way's central, supermassive black hole has swallowed nearly everything around it, growing heftier and heftier the more it eats. And it's not alone.

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Link: https://www.secretsofuniverse.in/a-brief-history-of-black-holes/

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According to the currently accepted black hole mode, a black hole is a spacetime region (the 4-dimensional conceptual model combining the three dimensions of space and the dimension of time) surrounding a point of infinite density, the singularity, where both space and time break down, where the spacetime defining that precise location would cease to exist. Around that point, in a region bound by the event horizon, no particles nor any form of electromagnetic radiation can escape.

To our day, other than being fascinating objects of study, full of grandeur, whose impact, despite the astronomical distances separating us from black holes, can now be detected in laboratories, black holes provide for extreme test cases for theories such as quantum gravity. Equations and laws may seem flawless under laboratory conditions. However, black holes allow scientists to study what happens to these in the most extreme conditions that we know of in our universe with respect to temperature, mass, density, and time.

It is only not so long ago that scientists were able to observe black holes that had remained purely speculative and theoretical objects for centuries. As such, the following article will provide a brief journey through the development of our knowledge on black holes, outlining the most important discoveries and milestones leading up to the first image of a black hole obtained by the Event Horizon Telescope in 2019.
Also Read: Our Basics Of Astrophysics Series
Early postulations

It all started in the year 1784 when a natural philosopher, John Michell, speculated about an astronomical body whose escape velocity, the velocity needed to escape its gravitational pull, would exceed the speed of light and came up with theoretical stars so dense not even a single light particle would be able to escape it and as such would not be seen, hence the name: "dark stars." Shortly after, the mathematician Pierre-Simon Laplace independently calculated the radius of such objects. A process that yielded a radius as small as 6 kilometers for a body as massive as the Sun.

However, this initial concept of black holes was quickly dropped when the light was discovered to be a wave. For around 115 years, scientists could not comprehend how a wave could be affected by gravitational phenomena.

Einstein's theory of relativity

The modern history of black holes began around the year 1915, when physicist Albert Einstein proposed his groundbreaking theory of General Relativity, offering an improved view on the universe and its phenomena, such as the motion and functioning of our universe's massive objects. However, Einstein was not the one to come up with elegant solutions to his equations when studying black holes. Another physicist, Karl Schwarzschild, determined the radius necessary to which a planet of a certain mass had to be shrunk to collapse under its own gravitational pull.

Subsequently, any mass which falls within that radius would be unable to escape. This discovery contributed to a major step in understanding black holes. Today, the said radius is known as the Schwarzschild radius, giving rise to a boundary around the black hole, better known as the event horizon.

Chandrasekhar limit

In 1930, physicist Subrahmanyan Chandrasekhar challenged a theory proposed by his own professor, Arthur Eddington, and contributed to a major step toward understanding the conditions necessary for black hole formation. While studying white dwarfs, extremely dense stars made up of mostly electron-degenerate matter, Eddington proposed that the reasons these stars did not eventually collapse into black holes were that this electron-degenerate matter or close packing of electrons exerted an increasing pressure, countering the pull of gravity towards the stellar core.

However, Chandrasekhar introduced some nuance to this assertion by limiting how massive white dwarf stars can get while still sustaining such pressure. A limit which is today known as the Chandrasekhar limit. Chandrasekhar's work was a milestone in the history of black holes.

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WWII and Oppenheimer

WWII proved to be one of the turning points in the history of black holes. However, it was not recognized as such until about 20 years later due to the distraction brought about by Nazi Germany's invasion of Poland in 1939. During that time, Robert Oppenheimer published a paper suggesting that even more massive stellar bodies than those suggested by Chandrasekhar were susceptible to succumbing to their own gravitational pull. However, in the midst of the war and due to the lack of concrete proofs or observations, Oppenheimer's theories remained widely unconsidered and were discarded.

Scientists supporting relativity remained skeptical but grew keener on the idea of black holes. In 1963, Princeton University physicist John Wheeler officially popularised such black bodies under 'black holes.'

In the same year, physicist Roy Kerr also independently developed another solution to Einstein's equations of General Relativity, which would explain the existence of spinning black holes. To our day, we know that black holes may carry various properties, amongst which are mass, charge, and angular momentum.

Also read:

Black holes can emit radiation

Asserted in complete contradiction with a black hole's fundamental concept, which states that nothing, no energy, may escape a black hole: this is what renowned physicist Stephen Hawking concluded in 1974. The universe accounts for continuous quantum fluctuations: the random and temporary change in energy at a set point. These fluctuations may give rise to pairs of particles with their anti-particle, which immediately annihilates.

However, if such an occurrence were to appear right on the event horizon of a black hole, and one of them would fall into the black hole while the other remained on the outside, annihilation would be unable to happen, and the black hole will have emitted a particle under the form a fundamental particle and black holes, over vast timescales would disappear by evaporating due to what is now known as Hawking radiation.

The culmination of our knowledge on black holes

After numerous theoretical phenomena and properties of black holes were concretized over the years, the scientific community and research on black holes reached a high point in 2015 when LIGO (Laser Interferometer Gravitational-Wave Observatory) detected the merger of two black holes while matching the predictions of the Theory of Relativity. This was the first proof of their existence, finally putting an end to growing suspicion in the scientific community.

The most recent milestone came to a climax in April 2019, when the first image of a black hole was finally released. It was developed through data of a radio-telescope, the Event Horizon Telescope. It depicted the supermassive black hole M87*, the center of the gargantuan elliptical galaxy M87, which contained 6.5 billion solar masses and was situated 53 million light-years away.

But, The Debate Continues...

Since the beginning, astronomers have divided opinions on actual mathematical black holes as predicted by General Relativity. Scientists like Einstein, Eddington, McCrea, Mitra, among others, did not believe in true mathematical black holes. On the other hand, scientists like Hawking, Chandrasekhar, Thorne, among others, had a different opinion. Over time, many flaws were found in the currently accepted black holes model, and many alternative models were proposed. Some of them include gravastars, naked singularities, and MECO.

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Of all these models, MECO is quite promising. MECO stands for Magnetospheric eternally collapsing object and was first proposed by Indian astrophysicist Abhas Mitra and later generalized by Darryl J. Leiter and Stanley L. Robertson. One of the major differences between the true black holes and MECOs is that the latter can produce their own magnetic fields, a fact backed by observation. Also, as stated in the currently accepted model, MECOs do not collapse to a singularity. MECOs are eternally collapsing objects. They will only hit singularity at infinity. The entire concept of MECOs is given in this newly published book.

If you want to know more about the MECOs, you can follow this link. In this blog, Prof Mirta has written about the flaws in the current model and how MECOs overcome those flaws and prove to be a better theoretical model. The blog also contains links to all the peer-reviewed publications for reference. You can also contact Prof. Mitra here and watch his TEDx talk on flaws on the current black hole model below.

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A Brief History Of Black Holes From 1784 To 2021.

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According to the currently accepted black hole mode, a black hole is a spacetime region (the 4-dimensional conceptual model combining the three dimensions of space and the dimension of time) surrounding a point of infinite density, the singularity, where both space and time break down, where the spacetime defining that precise location would cease to exist.

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source: https://starlust.org/interesting-facts-about-black-holes/

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10 Interesting Facts About Black Holes | StarLust

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Black holes are some of the most fascinating objects in the universe. Their properties are both mind-blowing and terrifying. Here are 10 cool facts about black holes.

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Link: https://eventhorizontelescope.org/faq/why-it-important-study-black-holes-what-there-be-learned-eht-observations

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Why is it important to study black holes? What is there to be learned from the EHT observations?

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Link:https://www.nationalgeographic.com/science/article/100409-black-holes-alternate-universe-multiverse-einstein-wormholes?loggedin=true&rnd=1685974224662

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Every Black Hole Contains Another Universe?

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And, like cosmic Russian dolls, our universe may be nested inside a black hole in another universe, a new study suggests.

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Link: https://viewspace.org/interactives/unveiling_invisible_universe/black_holes/sagittarius_a

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Identifying our galaxy’s supermassive black hole by tracking stars’ orbits.