206 Quasars and Pulsars
and that the quasars must be over a billion light years away—the most distant objects ever
detected!
But now the dim light of the quasars was too bright for a single star at that distance
—often 1,000 times as bright as whole galaxies. Sandage and Schmidt proposed that each
quasar must really be a distant galaxy. However, the measured radio signals varied too
much (on the order of days and hours) to be a galaxy of separate stars. That indicated a compact mass, not a galaxy.
Quasars remained a perplexing mystery until, in 1967, it was proposed that they were
really the material surrounding massive black holes. Quasars instantly became the most interesting and important objects in distant space.
That same year (in July 1967) Cambridge University Astronomy professor Antony
Hewish completed a 4.5-acre radio antenna field to detect radio frequency transmissions
from the farthest corners of space. This gargantuan maze of wire would be the most sensitive radio frequency receiver on Earth.
The radio telescope printed 100 feet of output chart paper each day. Graduate assistant
Jocelyn Bell had the job of analyzing this chart paper. She compared the chart’s squiggly
lines to the position of known space objects and then compared the known electromagnetic
emissions of these bodies to the chart’s squiggles and spikes in order to account for each
mark on the chart.
Two months after the telescope started up, Bell noticed an unusual, tight-packed pattern of lines that she called a “bit of scruff”—a squiggling pattern she couldn’t explain. She
marked it with a question mark and moved on.
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