Universe is not receding, rather accelerating due to dark energy - a strange force that is still undetected and shrouded in mystery. In cosmology, dark energy is a proposed form of energy that influences the universe on the largest scales. If the current cosmological model is accurate, dark energy makes up about 68% of the total energy in the observable universe, while dark matter and ordinary matter contribute 26% and 5%, respectively. Other components, such as neutrinos and photons, are nearly negligible. Despite its very low density—approximately 7×10−30 g/cm³ or 6×10−10 J/m³—dark energy dominates the universe's mass-energy content due to its uniform distribution across space.