Several new instruments, including the Vera Rubin Observatory, NASA’s Nancy Grace Roman Space Telescope, and the European Space Agency’s Euclid mission, are set to come online in the near future. According to Frieman, the field of cosmology has seen significant advancements in the last 25 years, with even bigger leaps on the horizon.
Researchers may find that dark energy remains constant, as it has for a generation, or they may discover that it is weakening, which could have profound implications. If dark energy is indeed weakening, it cannot be a cosmological constant but rather a scalar field that fills space with energy that appears constant at first but slowly diminishes over time.
This revelation would challenge the notion that we are living in a vacuum and could potentially lead to a shift in our understanding of the cosmos. The fate of the universe would depend on how quickly the cosmological constant declines and whether it reaches zero, causing cosmic acceleration to stop or potentially leading to a contraction of space.
String theorists also speculate about the nature of dark energy, suggesting that it must either decrease gently over time or suddenly drop to zero or a negative value. Observational evidence for a gradual decline in dark energy would be a significant discovery, according to Vafa.
While the DESI analysis has provided some preliminary insights, cosmologists will need to observe millions more galaxies before considering a paradigm shift seriously. Riess believes that the next few years hold immense potential for deepening our understanding of the universe.
The original story was sourced from Quanta Magazine, an editorially independent publication of the Simons Foundation that aims to enhance public understanding of science by covering developments in mathematics and the physical and life sciences.
