Astronomers have found a possible way to map the spread and
structure of the universe, guided by the light of quasars. The technique,
combined with the expected discovery of millions more far-away quasars over the
next decade, could yield an unprecedented look back to a time shortly after the
Big Bang, when the universe was a fraction the size it is today.
Researchers found the key while analyzing the visible light
from a small group of quasars. Patterns of light variation over time were
consistent from one quasar to another when corrected for the quasar's redshift.
This redshift occurs because an expanding universe carries the quasars away
from us, thus making the light from them appear redder (hence the term), and
also making the time variations appear to occur more slowly.