Astronomers have made a significant breakthrough in their understanding of dark energy, the mysterious force driving the expansion of the Universe. For years, scientists have known that the Universe is not only expanding but also accelerating in its expansion. This phenomenon has been attributed to dark energy, an invisible and elusive substance that permeates the cosmos.
In a recent study, astronomers from the Dark Energy Survey (DES) collaboration released a precise measurement of the amount of dark energy over the past 9 billion years. Using a powerful telescope in Chile, the team scanned a portion of the sky, searching for supernovas, which are stellar explosions that emit a bright flash visible across vast distances.
By analyzing the brightness and spectrum of these supernovas, astronomers could determine their distance from Earth as well as their velocity. These measurements allowed them to reconstruct the expansion history of the Universe and make an important discovery about dark energy.
Previous measurements indicated that the density of dark energy remains constant as the Universe expands. However, these early measurements carried some uncertainty, impacting our understanding of the Universe’s evolution. The DES team’s new measurement provided a more precise value for a parameter known as “w,” which represents the density of dark energy.
According to the currently accepted theory, if the density of dark energy is constant, w should equal -1. The DES measurement yielded a value of -0.80, with an uncertainty ranging from -0.66 to -0.96. This small discrepancy between prediction and measurement implies that the density of dark energy could indeed be constant.
The DES findings were further strengthened when combined with earlier measurements from the Planck group, resulting in a more precise value of w = -0.955, with an uncertainty range of -0.923 to -0.992. While this measurement aligns closely with prediction, scientists remain cautious due to the residual discrepancy and plan to refine their results through further analyses.
Understanding the constant density of dark energy is crucial for predicting the future evolution of the Universe. Whether the acceleration of the expansion will continue, slow down, or even speed up depends on this important parameter. Future measurements, including those planned at the Vera C. Rubin Observatory, will contribute to refining our understanding of dark energy and its role in shaping the cosmos.
The source of the article is from the blog elektrischnederland.nl