Dark energy phenomena refer to the mysterious force that is driving the accelerated expansion of the universe. Discovered in the late 1990s through observations of distant supernovae, dark energy is thought to make up about 68% of the universe. Its exact nature remains unknown, but it is believed to have a repulsive effect, counteracting the gravitational pull of matter. Scientists study dark energy through various methods, including analyzing the cosmic microwave background radiation and the distribution of galaxies. Theories such as the cosmological constant, proposed by Albert Einstein, and dynamic models like quintessence aim to explain this enigmatic phenomenon and its implications for the fate of the universe.