Unraveling the Mystery of Dark Energy in an Expanding Universe

Dark energy, a mysterious force driving the accelerating expansion of the universe, makes up about 68.3 to 70% of the cosmos. Its existence was confirmed in the late 1990s, but its origins can be traced back to early 20th-century astronomical observations. Scientists have proposed various theories to explain dark energy, including vacuum energy, quintessence, cosmic defects, and modifications to general relativity. NASA is involved in missions and projects, such as Euclid, the Nancy Grace Roman Space Telescope, and the Vera C. Rubin Observatory, to map the universe and investigate dark energy, ushering in a new era of cosmological discovery.