Cosmic affair
Studies of distant supernovae reveal
that the expansion of the universe is accelerating. This
graph shows the cosmological constant (ΩΛ) plotted
against the amount of observable matter in the
universe as a fraction of critical density (ΩM). The data
are given to confidence levels of 68.3% (red), 95.4%
(green) and 99.7% (blue), with the solid lines referring
to data used by the High-Z Supernova Search team
(A G Riess et al. 1998 Astron. J. 116 1009) and the
dashed lines to those used by the Supernova
Cosmology Project (S Perlmutter et al. 1999
Astrophys. J. 517 565).