Black Holes, Dark Matter, and the Cosmic Unknown: What We Still Don’t Know

Despite centuries of discovery, the universe still holds secrets that defy explanation. Black holes—once thought to be bottomless pits—are now known to emit faint Hawking radiation and may eventually evaporate. The first photograph of a black hole, taken in 2019, revealed a glowing ring around a dark center, confirming decades of theory and opening new questions about the nature of space and time.

Dark matter is even more mysterious. We know it exists because of its gravitational effects on galaxies, but we have never detected it directly. It makes up about 27% of the universe, yet it remains invisible and elusive. Dark energy is stranger still, driving the universe’s accelerating expansion and comprising nearly 70% of all cosmic energy. What are these substances? Are they particles, fields, or something entirely new?

Kaku’s book explores these mysteries with awe and optimism. He describes how new telescopes and experiments may soon reveal the nature of dark matter and energy, and how black holes could be laboratories for quantum gravity. These puzzles are not just obstacles—they are opportunities. Each unanswered question is a doorway to new physics, perhaps even a hint toward the elusive God Equation.

As we peer deeper into the cosmos, we are reminded that science is a journey, not a destination. The greatest mysteries are not behind us, but ahead—and they await the next generation of explorers.