Hubble Tension
The “Hubble Tension” refers to a significant discrepancy in measurements of the universe’s expansion rate, depending on whether the measurements are taken from observations of the early universe or from more local, recent observations. The tension arises because different techniques suggest different expansion rates: observations of the early universe through the cosmic microwave background suggest a slower expansion rate than those measured more locally using the cosmic distance ladder, which involves Cepheid variable stars and supernovae. Efforts by the Hubble and the more recent James Webb Space Telescope to resolve this discrepancy have not eliminated it but confirmed the accuracy of each other’s measurements, suggesting the need for new physical theories or understanding of dark energy to explain the variance.
