# Unveiling the Mysterious Dark Side of Our Universe: An Expert Guide to Understanding Dark Matter and Dark Energy Our magnificent universe hides many secrets beyond what our eyes can see and technology can detect. The normal matter that makes up galaxies, stars, and planets comprises only about 5% of the cosmos. The rest is dark matter and dark energy – invisible substances that govern the universe’s behavior on the grandest scales. Read on for an extensive primer on these dark cosmic puzzles that have scientists racking their brains. Illuminating the Nature of Dark Matter Dark matter is aptly named – it neither absorbs, emits, nor reflects light. Its existence is only inferred from gravitational effects on visible matter. So what is this transparent matter that permeates galaxies and the universe? Galactic Rotation Reveals Dark Matter Our first clues to dark matter came from the rotation of galaxies. Based on the visible mass, galaxies should spin more slowly. Howev...