We will talk about the “Black Hole,” a mysterious concept that the scientific community has always focused on and continues to explore—featured in multiple films, written about in books, sometimes doubted for its existence, and as terrifying as it is fascinating. What is a black hole? How does it form? What are the conditions required for its formation? What is inside a black hole? Is it possible to escape a black hole? What happens if we enter one? What is the closest and most recently discovered black hole to our planet? And finally, is it possible to turn the Earth into a black hole? Let's explore these questions together. First, let’s get to know what a black hole is.
WHAT IS A BLACK HOLE?
In astrophysics, a black hole is a massive celestial object and gravitational field so powerful that nothing—not even radiation—can escape its pull. In fact, black holes are the remnants of dead stars. When a massive star exhausts its fuel, it collapses on itself, and as a result, a black hole is formed.
HOW DOES IT FORM?
Where do these so-called black holes come from, and how are they formed? Let's explore this now.
We can say that the formation of a black hole represents both death and rebirth. As mentioned earlier, black holes are formed from dead stars—when a massive star runs out of fuel, it collapses and creates a black hole. So, stellar black holes are formed by the death of massive stars. Now, let’s briefly talk about a star’s birth and move toward its transformation into a black hole.
Stars, known as nebulae in space, form when clouds of gas and dust with high temperatures compress intensely. These stars possess gas masses far larger than Earth. Although not living beings, they are born, grow, and eventually die, much like living creatures. As they enter the dying process, their colors change, and they explode, scattering their fragments into space. Massive stars are giants, about 30 to 40 times the mass of our Sun. These types of stars are rare but can sometimes form near smaller stars. Massive stars consume their hydrogen fuel much faster. After a few million years, they can no longer sustain nuclear fusion in their cores and explode. Once fusion stops, gravity causes the core to collapse, forming a neutron star. The outer layers of the star crash into the neutron star, triggering a supernova explosion. If the star’s core is heavy enough, the neutron star continues to collapse into a point of infinite density, ultimately creating a black hole. Black holes also grow by accumulating matter or merging with other black holes. When such a merger occurs, gravitational waves—detected by scientists—are generated.
HOW DID IT GET ITS NAME?
We’ve always wondered where the name "black hole" came from. Let's address this question.
The term "black hole" was coined in 1967 by American theoretical physicist John Wheeler. Before that, the term "Collapsed Star" was used. However, the French objected to this term because its French equivalent, "trou noir," was an obscene expression referring to female genitalia. Eventually, they gave in, and the term "black hole" was adopted worldwide.
WHAT'S INSIDE A BLACK HOLE?
To answer briefly: We don't know. However, there are several theories. One of the most popular suggests that black holes are part of what we call wormholes. A wormhole is essentially a tunnel through space and time. These tunnels are imagined as connecting different parts of the universe. It is thought that at one end of these tunnels are black holes, and at the other end are "white holes"—objects that expel everything. However, the existence of wormholes has not been fully proven, even theoretically. Currently, we remain uncertain about their existence.
IS IT POSSIBLE TO ESCAPE A BLACK HOLE?
Now imagine water swirling and flowing downward into a hole. At the edge of that hole—what we call the event horizon—there’s a branch. Once at this edge, there is no return for that branch. Black holes are so powerful that even light cannot escape once it reaches the event horizon. Therefore, even the light swallowed by a black hole cannot be seen. This is why they are called "black." Thus, nothing can escape beyond the event horizon—not even light. To explain this further: falling past the event horizon is like going over Niagara Falls in a canoe. If you paddle hard enough early on, you might escape. But if you get too close to the edge, there's no way back.
WHAT HAPPENS IF WE ENTER A BLACK HOLE?
If you enter a black hole feet first, gravity will pull your feet harder than your head since they are closer to the hole. As a result, you will be stretched lengthwise and compressed sideways—just like spaghetti. You will be elongated and torn apart. Of course, this effect can vary depending on the black hole’s mass.
WHAT IS THE CLOSEST AND MOST RECENTLY DISCOVERED BLACK HOLE TO EARTH?
Now, let’s say hello to the supermassive black hole at the center of our galaxy: SAGITTARIUS A*, with a mass of 4 million Suns.
Located at the center of the Milky Way, Sagittarius A* is 4.4 million solar masses and approximately 26,600 light-years away from Earth. Due to large amounts of dust between us and the black hole, it’s difficult to observe directly. In general, black holes are hard to see because, as we've said, not even light escapes from them. However, fast-moving gas jets heat up due to atomic friction and emit X-rays, which can be observed with VLA telescopes.
IS IT POSSIBLE TO TURN THE EARTH INTO A BLACK HOLE?
For the universe to become a black hole, it must comply with the Schwarzschild equation. The definition of this equation is as follows: if we compress a mass into a sphere such that the escape velocity at its surface equals the speed of light, we define the radius of this sphere as the “Schwarzschild Radius.” To turn matter into a black hole, we need to follow this equation. If all conditions are met, no force can prevent it from becoming a black hole. The equation is expressed as: rs = 2GM/c²
So, to turn an object into a black hole, it must meet this equation. Now, let's calculate this for Earth. If we do the math, Earth's Schwarzschild radius would be about 1 cm. In principle, anything compressed within its Schwarzschild radius becomes a black hole. However, imagining compressing Earth to this size is nearly impossible. On the other hand, when supermassive stars die, supernova explosions are so powerful that they compress the already dense cores even further, exceeding the Schwarzschild limit and forming black holes. For Earth to become a black hole, we would need to add much more mass. Eventually, it would reach its Schwarzschild radius and collapse into a black hole. As mentioned, if Earth were compressed to that radius, our planet could indeed become a black hole.
Orhan Açıkgöz
Yücel Cultural Foundation
Voluntary Author
YKV Content:1616