Black holes are most often discussed in terms of their mass, but how much volume do these hefty, invisible objects actually have?

An artist illustration of a supermassive black hole.image source : https://time.com

Lying in the center of the Milky Way is a catastrophic black hole that is several million times larger than the Sun. Like all black holes, this supermassive monster called Sagittarius A * falls near anything, including light. However, the material consumed is that these monsters actually grow to celestial dimensions, which reach the weight of nature. Although astronomers often talk about black holes as massive objects, they should generally remember that they represent the mass of an object, not its physical size.

So, the obvious question is how much space do different types of black holes take up?

Black hole weight classes

When a massive star (about 8 solar masses) reaches the end of its life, a standard black hole called the star-mass black hole forms. After destroying the rest of its nuclear fuel, the star's uncontrolled gravity collapses rapidly before returning to space in an epic explosion called a supernova. Depending on the mass of the star, the remainder becomes a neutron star or black hole. These stellar-mass black holes are several dozen times larger than a couple of times the mass of the Sun. However, the origin of supermassive black holes such as Sagittarius A *, whose mass is millions to billions of times that of the Sun, is unknown. Astronomers know that their enormous size and mass are thought to be related to the galaxies they call home, the largest supermassive black holes found in the center of galaxies.

This evidence - recent evidence for a classless class of intermediate-mass black holes known as intermediate-mass black holes (hundreds to one million solar masses) suggests that they may have grown after supermassive black holes: innumerable stellar-mass and intermediate-mass black holes merge into ions. And although it is clear that different types of black holes can vary significantly in mass, it is not clear how much they differ in size.

What if Earth and the Sun were black holes?

To find out the size of a black hole, start by looking at the first two objects we know best: the earth and the sun. The mass of the earth is 6x1024 kg. Although in fact it is heavier than any human can understand, when it comes to black holes, the earth will be punished.

To create a black hole, you need enough mass to prevent the gravity of the object from any external forces from falling all over. Thus there are no unknown black holes in the form of light like Earth - they do not have mass to collapse completely. (However, some scientists speculate that there may be fake ancient black holes in the first few moments after the big bang. These theoretical black holes are thousands of times larger than the mass of the Sun from paper.)

The spacetime fabric in the center of the black hole is believed to have an infinite gravitational well, called a gravitational pull. This eccentricity is infinitely dense, and everything that reaches it will be there for good. The outer edge of the black hole, called the event horizon, is the boundary where nothing can happen, including the gravitational pull of the black hole. This event depends on the mass of the black hole where the horizon begins and was first calculated in 1916 by the German astronomer Karl Schwarzschild.

Using the Squareschild radius calculation, the black hole has a radius of less than an inch from the Earth, which is as large as a ping pong ball. On the other hand, the radius of the sun is just under two miles.

Using the Event Horizon Telescope, scientists obtained an image of the black hole at the center of galaxy M87, outlined by emission from hot gas swirling around it under the influence of strong gravity near its event horizon. Image Source : https://www.nasa.gov

What are the smallest known black holes?

Black holes are very difficult for scientists. This is because, unlike the stars, the event of a black hole is never visible to light falling within the horizon. However, sometimes a black hole has an accretion disk - the flow of material around the black hole glows violently as it grinds together. It is possible for optical scientists to find these otherwise invisible objects emanating from such an accretion disk. Astronomers also observe how black holes affect other objects, including stars. For example, scientists discovered Sagittarius A * after detecting odd behavior, placing seven stars in orbit.

With these methods, scientists have found a number of black hole candidates, the smallest black hole in the binary system, called the macro J1655–40. A companion star found in the system dumps gas into the black hole, which produces energy for the microaxer.

Quasars develop into very bright active galaxy nuclei, the centers of which are galaxies with a supermassive black hole surrounded by a bright and powerful accretion disk. The black hole at Gross J1655–40 is estimated to be 5.4 times the mass of the Sun, giving a radius of 10 miles. By studying such microcorsors, astronomers hope to better understand the relationship between the giants hidden in the galaxy core and the black holes that pervade the galaxy.

In 2008, scientists believed they still had a small black hole, but it was later corrected by the same team. Any small black hole could be caused by the fusion of two neutron stars without the star collapsing. The laser interferometer was the first to detect gravitational waves since the neutron star merged in 2017, two years after the gravitational-wave observatory detected gravitational waves. The gravitational waves emitted during the merger give scientists a new way to detect black holes 100 million light years from Earth.

At the other end of the spectrum, the size of the star-mass black hole depends on how large the actual star is. The largest star so far is R136a1 and weighs 315 times the mass of the Sun. If it were at current mass, the black hole produced by its inevitable collapse would be about 578 miles. Although larger than the smallest known black holes, this massive star is also a massive black hole compared to its supersonic cousin.

RO J1655-40 (in blue) is the second so-called 'microquasar' discovered in our galaxy. Image Source : https://www.spacetelescope.org

How big are intermediate-mass black holes?

The difference between stellar-mass black holes and supermassive black holes Inter-mass black holes: the long-sought "missing link" in black hole evolution. To date only a few intermediate-mass black hole candidates have been discovered, including those who discovered the Hubble Space Telescope earlier this year. These objects are more difficult to find because they become less active without “fuel”.

The recently discovered black hole Hubble is 50,000 times the mass of the Sun. Found in a distant, dense star cluster on the outskirts of a large galaxy, astronomers hope to find evidence for these "missing links". At thousands of solar masses, the intermediate-mass black hole candidate has about one-fifth the radius of the Sun or twice the radius of Jupiter.

And very large, intermediate-mass black holes have only 100 to 100,000 solar masses. Meanwhile, supermassive black holes reach billions of times the mass of the Sun.

Sizing up supermassive black holes

Sagittarius A *, the central black hole of our galaxy, 26,000 light-years away from the Sun, is 17 times the radius of the Sun, meaning it sits well in Mercury's orbit. Although it weighs about 4 million solar masses, the Milky Way's black hole is smaller than other supermassive black holes in the center of other galaxies.

The largest supermassive black hole has been discovered inside the Abel 85 galaxy cluster. At the center of the cluster is Galaxy Holm 15A, with an estimated mass of 2 trillion solar masses. This galactic center is almost as large as a large Magellanic cloud with a radius of 7,000 light years.

700 million light-years from Earth, the cluster was twice the size of the previous black hole when the USM Wendelstein Observatory of Ludwig-Maximilians-University and the European Southern Observatory launched very large telescope data. They found that the black hole between Holm 15A was at 40 billion solar masses, or two thirds of the mass of all the stars in the Milky Way. In that mass, it is the size of the entire solar system, a surprising size for any one object.

But the observable universe is 46.5 billion light years in any direction, which means that astronomers have only scratched the surface of black hole observations. A year ago the event Horizon Telescope with eight telescopes from around the world released the first image of the black hole. In addition, the LIGO-Virgo Gravity-Wave Association is expected to find 40 binary star mergers each year, with new updates revealing nearby black holes and neutron stars. With new telescopes like NASA's James Web Space Telescope and ESO's Extremely Large Telescope, we're going to receive first-light in the next decade, no way to tell how big the monster scientists are coming. You will be plunged into darkness in time. Years.