Vol. 7, Issue 2, Part C (2025)

An increasing body of observational data gathered over recent decades has presented substantial evidence that most of the universe consists of two “dark” elements: an enigmatic, collisionless dark matter that binds galaxies and an even more puzzling, nearly uniform dark energy component with negative isotropic pressure that causes cosmic acceleration. Collectively, these elements account for nearly 96% of the current cosmic energy budget. Dark energy accounts for approximately 74%, whereas dark matter makes up nearly 25%, rendering it six times more prevalent than visible matter. The observable matter constitutes a tiny fraction of the universe, as it accounts for roughly 4% of it. Every atom and photon in the universe constitutes under five percent of the entire contents of the cosmos. The remainder consists of dark energy and dark matter, which are unseen yet govern the universe's structure and development. Dark matter constitutes the majority of the mass within galaxies and galaxy clusters, influencing the large-scale organization of galaxies. Dark energy, on the other hand, refers to the enigmatic force causing the rapid expansion of the universe. The nature of these substances and their mechanisms pose significant challenges for contemporary astronomers.