How does weak gravitational lensing help scientists study dark energy?

Weak gravitational lensing is a powerful tool in cosmology used to investigate the influence of dark energy on the evolution of the universe.

Because dark energy acts as a repulsive force that counteracts gravity, it retards the formation of large-scale structures, such as galaxies and clusters of galaxies. Scientists use weak lensing to measure this effect by observing subtle, statistical distortions in the shapes of distant galaxies caused by the bending of space by intervening matter.12

By analyzing these distortions, astronomers can track how the growth of cosmic structure has been suppressed over the last few billion years—the period during which dark energy became the dominant component of the universe. This data helps researchers understand the history of the universe's expansion and provides critical insights into the nature of dark energy, including its equation of state and its role in gravitational physics.2