According to current scientific understanding, dark matter does make up a significant portion of the total mass in our universe. Observational evidence suggests that approximately 26.8% of the total mass-energy content of the universe is composed of dark matter. This estimate comes from measurements of the cosmic microwave background radiation, galaxy clustering, gravitational lensing, and other cosmological observations.
The presence of dark matter is inferred through its gravitational effects on visible matter and light. Although dark matter does not interact directly with electromagnetic radiation, it exerts a gravitational pull on visible matter and can influence the motion of galaxies and galaxy clusters.
The exact nature of dark matter remains a mystery, as it does not emit, absorb, or reflect light, making it extremely challenging to detect directly. Various theoretical models propose that dark matter could consist of yet-undiscovered particles, such as weakly interacting massive particles (WIMPs) or axions, but no conclusive evidence has been found thus far.
It's important to note that the remaining fraction of the universe's mass-energy content is primarily composed of dark energy, which is an even more mysterious component responsible for the observed accelerated expansion of the universe. Dark energy is estimated to make up approximately 68.3% of the universe, leaving ordinary matter—such as atoms, protons, and neutrons—with a relatively small contribution of around 4.9%.
Understanding the precise nature of dark matter and dark energy remains a significant focus of scientific research and exploration. Numerous experiments and observations are being conducted to shed light on these elusive components and their role in shaping the structure and evolution of the universe.