Multiple approaches
Using cosmological measurements we can trace the increasing distance between galaxies as a
function of time — i.e. chart the evolution of the expansion of the universe back in time from the
present (at time 0 and distance set equal to 1) or forward in time from the Big Bang (distance
equals 0). Combining different observational techniques such as supernovae, weak lensing
and baryon oscillations allows astronomers to map out a wide range of the universe's history
and check the results of one method versus another to obtain a clearer understanding of the
nature of the accelerating universe.