What is Dark Matter?

When I gaze at the night sky, I can’t help but wonder about the unseen parts of our universe. We see stars, galaxies, and glowing clouds of gas. But astronomers have discovered that all this visible matter is only a tiny fraction of what actually exists in the universe. In fact, about $27\%$ of the universe is made of something which is invisible to us known as dark matter.

Dark matter does not emit or absorb light, so we cannot detect it directly with telescopes. Instead, its presence is revealed by the way it interacts with gravity. For example, when scientists observe how galaxies spin, they find that stars at the edges move much faster than they should if only visible matter were present. It is as if an invisible hand is holding these galaxies together. That invisible hand is dark matter.

Despite decades of research, we still do not know exactly what dark matter is made of. Some theories suggest it could be a new kind of particle that does not interact with light, while others propose more exotic explanations. Physicists around the world, including researchers here at Kyushu University, are developing new models to search for these mysterious particles.

Understanding dark matter is not just a scientific puzzle. It is essential for understanding the structure and fate of our universe. As I continue my own studies at Kyushu University, I feel connected to this ongoing quest to unravel one of the universe’s deepest secrets. Our research here is part of a larger effort to bring light to the darkness that surrounds us.