Black holes are powerful objects in space with gravity so strong that nothing can escape them. In the 1970s, Stephen Hawking showed that black holes can slowly lose energy by giving off tiny particles. This process is called Hawking radiation. Over time, the black hole gets smaller and hotter, and in the end, it disappears completely. But new research by Menezes and his team shows something different. Using a theory called Loop Quantum Gravity (LQG), they studied black holes with quantum corrections. In their model, the black hole does not vanish completely. Instead, it stops shrinking when it reaches a very small size. This leftover is called a black hole remnant. They also studied something called grey-body factors, which affect how much energy escapes from a black hole. Their findings show that the black hole cools down and stops losing mass once it reaches a minimum mass. This new model removes the idea of a “singularity” at the center of the black hole and gives us a better understanding of what might really happen. It may even solve the mystery of where lost information goes. This is a big step in understanding black holes and quantum gravity.
Black holes are very strange and powerful objects in space. Their gravity is so strong that nothing, not even light, can escape from them. For a long time, scientists believed that once something falls into a black hole, it is lost forever.
But in the 1970s, a famous scientist named Stephen Hawking showed that black holes are not completely black. He said they can slowly give off energy and shrink over time. This process is called Hawking radiation. According to this idea, black holes slowly lose mass and can eventually disappear completely.
Now, a new study by Menezes and his team shows something surprising. They found that when we include quantum physics in the study of black holes, the story changes. Their research suggests that some black holes do not disappear completely. Instead, they stop shrinking at a certain size and leave behind a small leftover, called a black hole remnant.
1. What Is Hawking Radiation?
Stephen Hawking explained that black holes can give off tiny particles of energy. This happens because of quantum effects near the edge of the black hole, called the event horizon.
Here are some easy facts about Hawking radiation:
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Black holes act a little like hot objects. Just like a hot stove gives off heat, black holes give off tiny bits of energy.
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This energy is called Hawking radiation.
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The smaller the black hole, the hotter it is, and the faster it loses energy.
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As the black hole loses energy, it also loses mass, so it gets smaller.
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In the end, the black hole is supposed to shrink to nothing and disappear.
But if a black hole disappears completely, it creates a big mystery. Where does all the information go? This is called the information loss problem, and it’s a big puzzle in science.
2. Two Different Theories: Gravity vs. Quantum Physics
To understand black holes better, we need to combine two big ideas in physics:
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General Relativity (GR): This is Einstein’s theory. It explains how gravity works in space.
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Quantum Field Theory (QFT): This explains how tiny particles like electrons and photons behave.
But there is a problem. These two theories don’t work well together. Gravity works on large things like planets and stars, while quantum physics works on tiny particles. To fully understand black holes, scientists need a new theory that mixes both.
One idea that tries to do this is called Loop Quantum Gravity (LQG).
3. What Is Loop Quantum Gravity (LQG)?
Loop Quantum Gravity is a theory that tries to mix quantum physics and gravity. It says that space is not smooth and continuous. Instead, it is made of tiny loops or chunks, like building blocks. These loops are extremely small—much smaller than atoms.
LQG helps scientists describe what happens inside a black hole, where normal physics breaks down.
In classical theory (like Einstein’s), the center of a black hole is a point where gravity becomes infinite. This point is called a singularity. But in LQG, this singularity doesn’t exist. Instead, there is a smooth transition from a black hole to something called a white hole.
4. What Did Menezes and His Team Do?
Menezes and his team used ideas from Loop Quantum Gravity to study a new kind of black hole, called a non-singular black hole. This means it has no singularity at the center.
Here’s what they found:
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Inside this black hole, there is a special surface called a transition surface.
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This surface connects two regions: a black hole region and a white hole region.
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Both sides have the same mass.
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There is a minimum mass the black hole can reach. Below this mass, the black hole stops shrinking.
This means that instead of disappearing completely, the black hole stops evaporating when it reaches this smallest mass. This leftover black hole is called a remnant.
5. What Happens During Black Hole Evaporation in This Model?
In normal Hawking radiation:
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A black hole keeps getting hotter as it shrinks.
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It loses mass faster and faster.
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It eventually disappears completely.
But in the model studied by Menezes and his team:
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The black hole starts shrinking as usual.
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But when it reaches a certain size (called minimum mass), the temperature becomes zero.
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The black hole stops evaporating.
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It leaves behind a tiny, stable remnant.
This changes the old idea that all black holes disappear.
6. What Are Grey-Body Factors?
When black holes give off radiation, not all of it escapes into space. Some of it gets pulled back in by the black hole’s gravity. The amount that escapes depends on something called grey-body factors.
These factors measure the chance that particles will:
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Escape the black hole’s pull.
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Travel far into space.
Menezes and his team studied these grey-body factors using a mathematical equation (like a wave equation) for different kinds of particles:
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Spin 0 (like basic particles)
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Spin 1/2 (like electrons)
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Spin 1 (like photons or light particles)
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Spin 2 (like gravity waves)
They used this to find out how fast the black hole loses mass in their model.
7. Heat Capacity and Phase Transition
Heat capacity is a measure of how much heat an object can hold. In normal black holes, heat capacity is negative, which means:
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As the black hole loses mass, it gets hotter, not colder.
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This makes it evaporate faster.
But in the quantum model, things are different:
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When the black hole reaches a certain size (when its mass is M = 3r₀/4), it changes phase.
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This is like how water turns into steam—it’s a phase transition.
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After this point, the black hole cools down instead of heating up.
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When it reaches the minimum mass (M = r₀/2), the temperature is zero, and the black hole stops shrinking.
8. What About Entropy?
Entropy is a measure of disorder or information. For black holes, entropy is related to the area of the horizon.
In classical physics:
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The entropy of a black hole is one-quarter of the area of its event horizon.
In quantum physics:
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The entropy can have corrections.
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As the black hole gets smaller, these corrections become very important.
In the LQG model, when the black hole becomes very small:
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The entropy does not go up forever.
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In fact, it becomes zero when the black hole reaches the minimum size.
This fits with the idea that the smallest black hole (a remnant) doesn’t have much internal disorder. It is like a single building block of space.
9. Why This Is Important
This new model gives us a fresh way to think about black holes:
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No singularity: The scary center point with infinite gravity is replaced by a smooth transition.
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No complete evaporation: The black hole stops shrinking and leaves a remnant.
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Solves old problems: This might help solve the information loss problem, because something is left behind.
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New predictions: It changes how we think about black hole thermodynamics and could guide future experiments or observations.
10. What’s Next?
Menezes and his team have done important work, but there is still more to study:
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How does the entropy behave during the whole evaporation process?
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Can we find real evidence of black hole remnants in space?
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What happens if black holes merge—do remnants merge too?
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Can these ideas help us build a full theory of quantum gravity?
These questions are exciting and will guide future research.
Conclusion: A New Chapter in Black Hole Physics
Thanks to new ideas from Loop Quantum Gravity, scientists are discovering that black holes may not disappear after all. Instead, they might leave behind tiny, stable objects called remnants. This challenges old ideas and opens new doors for science.
The work of Menezes and his team shows that when we look closely at the universe using quantum physics, we find surprising and beautiful answers. Black holes may still be mysterious, but we are getting closer to understanding their true nature.
Reference F. G. Menezes, H. A. Borges, I. P. R. Baranov, S. Carneiro, "Thermodynamics of effective loop quantum black holes", Arxiv, 2025. https://arxiv.org/abs/2504.06964
Technical terms
1. Black Hole
A black hole is an area in space where gravity is so strong that nothing—not even light—can escape from it. It forms when a very massive star collapses.
2. Event Horizon
This is the boundary around a black hole. Once something crosses this line, it can’t come back out. It’s like the “point of no return.”
3. Hawking Radiation
This is the process where black holes slowly release tiny particles (radiation) and lose mass over time. It was discovered by Stephen Hawking.
4. Surface Gravity
It’s the strength of gravity at the event horizon of a black hole. It helps determine how hot the black hole is.
5. Grey-Body Factors
When particles try to escape from a black hole, some get blocked by a “barrier.” Grey-body factors describe the chance that a particle will actually escape. It’s like a filter that changes the final amount of radiation.
6. Loop Quantum Gravity (LQG)
This is a theory that tries to combine quantum physics with gravity. It says space itself is made up of tiny loops—like a very fine fabric.
7. Quantum Corrections
These are small changes to classical physics made by adding quantum effects. They help us better understand extreme conditions, like inside black holes.
8. Heat Capacity
This tells us how much the temperature of an object changes when it gains or loses energy. For black holes, it tells us how they behave as they emit radiation.
9. Komar Energy
A way to measure the energy (or mass) of an object in a gravitational system, especially in a black hole.
10. Transition Surface
In Loop Quantum Gravity models, the black hole doesn’t have a deadly center (singularity). Instead, there’s a “transition surface” that connects a black hole to a white hole (a kind of opposite of a black hole).
11. Planck Scale
The smallest possible size in physics, where quantum gravity becomes important. It’s used to study things like black hole cores.
12. Bekenstein-Hawking Entropy
This is a measure of how much information is hidden inside a black hole. It’s related to the size of the event horizon.
13. Adiabatic Process
This means a process that happens slowly without losing or gaining heat. In black hole terms, it means the evaporation happens gently, not suddenly.
14. Spin Network
In Loop Quantum Gravity, space is described by networks made of lines and nodes. These lines carry “spin,” a property of particles. The network tells us how space is shaped.
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