Stephen Hawking’s black hole prediction finally comes true – why it’s a breakthrough for science

Stephen Hawking, one of the most famous physicists in history, made a bold prediction in 1971 that the surface of a black hole, called its event horizon, can never shrink. For decades, this remained a theory without direct proof.

Now, scientists using the Laser Interferometer Gravitational-Wave Observatory, or LIGO, have captured an event that confirms Hawking’s idea. On January 14, 2025, two black holes collided and merged into a single, larger black hole, producing ripples in space-time known as gravitational waves. By analyzing these waves, researchers saw that the new black hole was bigger than the two that combined. This discovery not only validates a decades-old theory but also opens new doors for understanding black holes and the extreme physics of the universe.

Stephen Hawking’s theory comes to life

In 1971, Hawking proposed what is now known as the second law of black hole mechanics: the surface area of a black hole’s event horizon can never decrease, similar to how entropy in the universe always increases. This idea was revolutionary because it connected gravity, quantum mechanics, and thermodynamics in a way no one had seen before. Until now, there was no way to directly observe black holes merging to test this theory.

The LIGO detection provides concrete evidence that Hawking’s idea is correct, decades after it was first suggested. Scientists can now study black holes not just as points of infinite density, but as dynamic objects that behave like thermodynamic systems with measurable entropy.

How LIGO “heard” the black holes

LIGO is a highly sensitive gravitational wave detector with twin observatories in Hanford, Washington, and Livingston, Louisiana.

It measures tiny ripples in space-time caused by massive cosmic events, like black hole collisions. On January 14, 2025, LIGO recorded gravitational waves from two black holes merging, a process that lasts only seconds but produces enormous energy. By analyzing the pitch, duration, and “ringing” pattern of these waves, scientists could determine the size, shape, and spin of the resulting black hole.

This event, called GW250114, confirmed that the new black hole’s surface area was larger than the sum of the two originals, validating Hawking’s decades-old prediction.

What this means for science

Confirming Hawking’s theory is more than just ticking a box in physics. It provides strong evidence that black holes can be treated as thermodynamic objects with entropy, temperature, and radiation. This supports decades of research on quantum effects near event horizons, including Hawking radiation, which suggests black holes slowly emit energy and could eventually evaporate. Understanding black hole mechanics also gives scientists a window into the most extreme conditions in the universe, including the physics that governed the Big Bang and the formation of galaxies.

Each merger observed adds to our knowledge of how black holes grow, interact, and influence surrounding space.

Future of black hole observations

The LIGO-Virgo-KAGRA collaboration continues to refine its detectors, spotting black hole mergers more frequently and with greater precision. In the next decade, LIGO-India will improve localization of gravitational wave sources, while proposed projects like the Cosmic Explorer in the U.S. and the Einstein Telescope in Europe will have even larger interferometers, increasing sensitivity.

These upgrades will allow scientists to “hear” smaller and more distant mergers, track the formation of black holes throughout the universe, and possibly detect the earliest black hole collisions shortly after the Big Bang.

Each observation brings us closer to understanding the life cycle of these cosmic giants.

The significance for everyday understanding

While black holes seem distant and abstract, confirming Hawking’s prediction shows the power of theoretical physics to describe real phenomena. It proves that human understanding can predict the behavior of objects billions of light-years away, connecting abstract math with observable reality. These discoveries inspire further research in fundamental physics, astronomy, and cosmology, and they encourage new generations of scientists to explore the universe’s most mysterious phenomena.