What Is a Black Hole? The Celestial Wonder, Explained

If you've ever

gazed up at the night sky and thought about the great mysteries that remain unsolved, your mind has likely wandered to one of the most intriguing phenomena of the universe: black holes.

Imagine a cosmic beast with a gravitational pull so strong that nothing, not even light, can escape its clutches. A titan lurking in the distant corners of the universe, enshrining the ultimate secrets of space and time. A cosmic paradox, both terrifying and fascinating. That's the enigma that is a black hole, and you're about to learn the ins and outs of the celestial wonder.

Astronomers estimate that there are around

100 million black holes in the Milky Way galaxy. But what is a black hole, exactly? According to

NASA, "a black hole is a place in space where gravity pulls so much that even light can not get out."

The term "black hole" was

coined in 1967 by American physicist John Wheeler, and it perfectly describes the nature of these extraordinary objects. The "black" is due to the fact that they absorb all light that hits them, reflecting nothing, just like a perfect black body in thermodynamics. The "hole" is a common term for a place where something disappears or where something is missing. 

However, to truly understand black holes, we have to journey into the realm of astrophysics. (And don't worry, you don't need a PhD to grasp the basics! )

Black holes originate from the remains of gigantic stars. When a massive star has consumed all of its nuclear fuel, it undergoes a supernova explosion. If the leftover core has a mass greater than approximately three solar masses, its gravitational force leads it to collapse into a singular point. This point, referred to as a singularity, constitutes the central core of a black hole.

The gravitational pull of a black hole is so intense that nothing, not even light, can escape from it once it crosses a boundary known as the event horizon. This is what makes black holes "black."

Despite the common misconception, black holes exhibit a wide range of sizes. Some can be as diminutive as a single atom, yet possess a mass comparable to that of a mountain. On the other end of the scale, the most massive black holes, known as "supermassive," can exceed the mass of our sun by millions or even billions of times.

In the infinite cosmos above us, black holes stand out as some of the most enigmatic and captivating entities. These celestial bodies are not merely one-dimensional. They vary in size and origin, presenting us with

three primary categories: stellar black holes, intermediate black holes, and supermassive black holes. Each possesses its own unique characteristics, and their existence poses intriguing questions about the universe as we know it. 

Stellar black holes are the most common type of black hole, birthed from the remnants of massive stars. When such a star has exhausted the nuclear fuel, it undergoes a catastrophic collapse under its own gravity, resulting in a supernova explosion. What remains is a black hole—invisible, mysterious, yet incredibly dense. According to

Christopher S. Baird, PhD, an assistant professor of physics at West Texas A&M University, "stellar-mass black holes have masses ranging from about three times the mass of our sun to about

50 times the mass of our sun."

Then we have intermediate black holes. These black holes are believed to form when stars in a cluster collide in a chain reaction. They're significantly larger than their stellar siblings but still pale in size compared to the supermassive ones. Dr. Baird says intermediate black holes have masses that range between "50 times the mass of our sun to about 50,000 times the mass of our sun."

Finally, we arrive at the behemoths of the black hole family—supermassive black holes. These are the largest type of black hole, in terms of mass and size. Dr. Baird says they have a mass "greater than about 50,000 times the mass of our sun and are typically millions to billions times the mass of our sun." These giants reside at the center of most galaxies, including our very own Milky Way. One such black hole is

Sagittarius A*, and it's more than 25,000 light years away from us.

First of all, let's make a deal—stay far away from black holes, okay? Because once you find out what happens if you fall into one, it'll send a shiver down your spine.

As you approach a black hole, the gravitational pull becomes stronger and stronger. This means that your body would be stretched out like a piece of spaghetti in a process called "spaghettification." (Yes, that's a real thing.) The gravitational force acting on your feet would be much stronger than that acting on your head, causing you to be stretched out vertically.

Once you pass the event horizon of the black hole, there's no turning back. The event horizon is the point of no return, where the gravitational pull is so strong that not even light can escape. Simply put, you would be trapped inside the black hole forever.

As you get closer to the singularity at the center of the black hole, the gravitational pull becomes infinitely strong. This means that time and space become distorted. In fact, time would slow down for you, and you would experience everything in slow motion.

As you approach the singularity, the gravitational pull would become so strong that you would be ripped apart. Aka you really don't want to find yourself near a black hole anytime soon.

Black holes, in all their forms, represent one of the most intriguing aspects of our universe. Despite being invisible to the naked eye, they have a profound impact on the cosmos, influencing the structure and evolution of galaxies. So, the next time you gaze into the night sky, remember: there's more than meets the eye.