Measuring Changes in the Expansion Rate
Modern day astronomers have been working hard to establish
which scenario is correct. This can be done by measuring
changes in the expansion rate of the universe.
• The first such measurement came from astronomers studying
distant carbon detonation supernovae
– these supernovae all have similar peak luminosities
– measuring their apparent brightness allows us to
estimate the distances to these supernovae
– this is compared to their parent galaxy’s redshift to
find deviations from the Hubble Law at high redshift