Hoary tales

Analysis of about
90 quasars in the
ongoing quasar
survey at the 500 cm
telescope at Mount
Palomar, California, has
shed some interesting light on the
ages of quasars (see accompanying
story). From the
redshift data, it
seems that most of
the quasars formed and
faded away in a
short time period
(by cosmological
scales). This is
the conclusion of M Schmidt, D
Schneider and J Gunn
who conducted the
study (Science, Vol 269).

They believe that
there may have been an era of
quasars some 2 billion years after the big hang when these objects were formed
and flourished.