Can a black hole ever shrink or disappear?

In one line

The rule

Black holes can lose mass and energy over time by emitting Hawking radiation, and if they lose enough, they can eventually vanish.

There is no simple school formula for this, but the main idea is: Energy lost by Hawking radiation → black hole mass decreases → black hole can disappear

Let's understand it simply

Imagine you have a big block of ice in the sun. Slowly, it melts and gets smaller. Now, think of a black hole as a super-heavy, invisible ball in space. For a long time, people thought nothing could escape from it. But, just like ice melts, black holes can also lose a tiny bit of themselves over a very, very long time.

This happens because of a strange rule in physics: even empty space is not truly empty. Tiny particles pop in and out of existence everywhere. Near a black hole, sometimes one of these particles falls in, and the other escapes. The escaping one takes away a bit of the black hole's energy. This is called Hawking radiation.

How it works

1. Quantum particles appear: In empty space, pairs of tiny particles and antiparticles (opposites) keep popping up and disappearing.
2. Near the black hole: If this happens just at the edge (event horizon) of a black hole, one particle can fall in, and the other can escape.
3. Escaping particle: The one that escapes carries away a tiny bit of energy.
4. Black hole loses mass: Because energy and mass are linked (E = mc²), the black hole loses a tiny amount of mass.
5. Shrinking over time: This process is super slow for big black holes, but over billions or trillions of years, they can shrink and finally vanish.

The story behind it

For a long time, scientists believed that nothing could ever escape a black hole. But in 1974, a British scientist named Stephen Hawking used the rules of quantum physics and Einstein’s theory of gravity together. He found that black holes are not completely black—they can give off a faint glow (Hawking radiation). This was a huge surprise and changed how we think about black holes.

Hawking made this discovery while lying in a hospital bed, unable to move much due to illness, but his mind was sharp and curious. His work showed that black holes could eventually disappear.

Where you see it in real life

• Black holes in space: The black holes we know are losing mass by Hawking radiation, but so slowly that it is impossible to notice with today’s tools.
• Evaporation of tiny black holes: If tiny black holes were made in the early universe, they could have already disappeared by now.
• Science fiction: Many movies and books talk about black holes shrinking or exploding at the end of their life.
• Physics research: Scientists use the idea of Hawking radiation to study the deepest laws of the universe.
• Particle accelerators: Some experiments try to create tiny black holes to see if they evaporate, but none have been found yet.
• Future universe: In the far future, after stars die, black holes will be the last things to vanish, leaving behind only faint energy.

Why it matters

• Solves a big puzzle: Shows that black holes are not forever—they can end, just like stars.
• Links two big theories: Connects quantum physics (tiny things) and gravity (big things), which is a major goal in science.
• Affects the fate of the universe: Tells us what will happen to all matter in the far future.
• Inspires new science: Hawking’s idea led to many new questions about space, time, and information.

Worked example

Let’s see how long a black hole takes to disappear. Suppose a black hole has the mass of our Sun (about 2 × 10³⁰ kg). The time to evaporate (disappear) is roughly:

Given: Mass of black hole (M) = 2 × 10³⁰ kg
Step 1: Use the formula for evaporation time (not in school books):
        t ≈ 10⁶⁷ × (M / mass of Sun)³ years
Step 2: Plug in M = mass of Sun
        t ≈ 10⁶⁷ × (1)³ = 10⁶⁷ years
Step 3: Answer: It will take about 10⁶⁷ years (a 1 with 67 zeros!) to disappear

This is much, much longer than the age of the universe (about 10¹⁰ years).

Common mistakes

• Thinking black holes last forever: They can disappear, but it takes a very long time.
• Believing nothing escapes a black hole: Hawking radiation does escape, but it is extremely weak.
• Confusing shrinking with eating: Black holes can grow if they eat matter, but if left alone, they shrink by Hawking radiation.
• Assuming we can see it happen: The shrinking is too slow to notice for big black holes.

Remember it

Black holes can melt away like ice—very, very slowly—by giving off Hawking radiation.