Contrary to what the name suggests, black holes are not voids but celestial entities.

These ancient objects often have lifespans that span billions of years. Their existence was first predicted by Albert Einstein’s general theory of relativity.

German astronomer Karl Schwarzschild, while solving Einstein's gravitational field equations, discovered that compressing a certain amount of matter into a single point would create a region called the "event horizon." Within this boundary, not even light can escape.

Astrophysics PhD holder and science communicator Sun Zhengfan noted that many astronomers were initially skeptical about black holes, doubting their existence despite theoretical predictions. It wasn’t until advances in observational technology that black holes were confirmed.

The term "black hole" was popularized during a conference in New York, where American physicist John Archibald Wheeler used it while explaining Einstein’s theory and the associated discoveries.

When assessing a black hole, three main indicators are used: mass, angular momentum, and charge. However, the internal properties of black holes remain a mystery due to current technological limitations.

Falling Into a Black Hole: Is Survival Possible?

Black holes are among the universe's most enigmatic phenomena, inspiring imaginative depictions in books and films. For instance, in the movie Interstellar, astronauts survive after falling into a black hole and even uncover valuable information.

The outcome of falling into a black hole depends on its characteristics. Smaller black holes have steep gravitational gradients, akin to sheer cliffs, which would stretch a person into "spaghetti-like" strands before they even reach the event horizon.

Larger black holes, with gentler gravitational fields, might allow someone to slide into them more safely, akin to descending a incline. However, even if a person survives the entry, communicating any findings back to the outside world would be impossible.

Physicists rely on mathematical models to hypothesize what lies within black holes, but direct observation or verification remains out of reach. Approaching black holes is as infeasible as getting too close to the Sun with current technological means.

Fascinating Facts About the Universe

The universe’s matter is composed of familiar building blocks like neutrons, atoms, and electrons. According to Sun Zhengfan, astrophysics applies laboratory-discovered physical laws to celestial phenomena, enabling researchers to understand cosmic material under specific conditions.

However, the universe is full of extreme scenarios. For example, while some regions approach absolute zero in temperature, the Sun’s surface, at approximately 6,000 degrees Celsius, seems relatively cool compared to its atmosphere, which reaches over a million degrees. This paradox remains unexplained.

Wormholes, as often depicted in science fiction, are another intriguing concept. They theoretically connect distant regions of spacetime, but Sun Zhengfan emphasizes that they currently exist only as speculative ideas in science fiction.

Similarly, "white holes," described as celestial bodies that emit energy and matter without absorbing anything, are a mathematical construct rather than a physically proven entity. Both concepts challenge foundational principles of physics.

The Universe's Unsolved Mysteries

The cosmos holds numerous mysteries, such as dark matter and dark energy. Popular science books like Astrophysics for Busy People delve into the universe’s origins and phenomena like invisible light.

Sun Zhengfan highlighted the importance of science communication, explaining that public understanding of astronomy can clarify many misconceptions. For instance, Jupiter, with sufficient energy accumulation and internal nuclear fusion, could emit light, but only the Sun in our solar system achieves this.

Scientific exploration often reveals truths that defy imagination. The role of experts in science communication is to ensure that people aren’t misled by the literal meanings of scientific terms.

“There are still countless secrets in the universe waiting for humanity to uncover,” Sun Zhengfan concluded.