Overview

• The James Webb Space Telescope has independently confirmed the Hubble Space Telescope's measurements of the universe's expansion rate, known as the Hubble constant.
• Both telescopes report an expansion rate of approximately 73 km/s per megaparsec, conflicting with the 67-68 km/s predicted by the Standard Model of cosmology.
• This discrepancy, called the 'Hubble tension,' suggests gaps in our understanding of fundamental physics, potentially involving dark energy or unknown cosmic phenomena.
• Researchers used three methods to measure distances to galaxies, achieving precision with less than 2% uncertainty, ruling out measurement errors as the cause of the tension.
• The findings open the door to new theories, including early dark energy, exotic particles, or changes in fundamental constants, as scientists work to solve this decade-long puzzle.