The universe we see is only a small fraction of what actually exists. All the stars, planets, galaxies, and nebulae make up less than five percent of the total mass and energy in the cosmos. The rest remains invisible, undetectable by traditional telescopes, and yet it shapes the structure and evolution of everything. Scientists refer to this unseen majority as dark matter and dark energy — mysterious ingredients that hold the key to understanding the true nature of the universe.
The mystery began when astronomers started noticing something strange in the way galaxies moved. Based on the visible matter alone, galaxies should not hold together. They rotate so fast that stars on the outer edges should fly off into space. But they don't. Something must be providing the extra gravity needed to keep them in place. This unseen substance is what scientists call dark matter. It does not emit light, reflect it, or interact with electromagnetic radiation in any detectable way. Yet its gravitational effects are undeniable.
In the 1930s, Swiss astronomer Fritz Zwicky was one of the first to point out this discrepancy. He observed clusters of galaxies and found that there wasn't enough visible mass to account for the gravitational forces at work. He proposed the existence of "dunkle Materie," or dark matter, to explain the missing mass. His ideas were largely ignored at the time, but decades later, further evidence confirmed his observations. Today, dark matter is widely accepted as a fundamental part of the universe, even though we still don't know what it's made of.
