TALESFROM THEFIELD
A book I read in high school by Isaac
Asimov opened my eyes to the big
bang’s afterglow. It said that research-
ers had discovered this light that could
have come from the explosion. My jaw
dropped. In graduate school, I joined a
team mapping the stuff with a satellite.
Later on, I led a similar mission.
Normal photographs capture lightthat bounces off the subject a fraction
of a second before reaching the lens.
Our picture was based on photons that
streamed from the cosmos when its ear-
liest clouds cleared, around 375,000
years after the big bang.
Physicists call these particles “cosmic
microwave background” (CMB). They
took billions of years to reach us. Today
they exist everywhere, but the universe’s
expansion stretched them into micro-
waves that the human eye can’t detect.
Pictures of the cosmos’s first light
helped us establish our origin story. By
2003, my team had calculated that
the universe was 13.8 billion years old
and appeared almost perfectly flat.
Now even more information is being
gathered. The CMB has been incredibly
valuable, and we’re not done yet.a picture worth a
billion light-years
as told to Charlie WoodCHUCK BENNETT,PROFESSOR
OF PHYSICS AND ASTRONOMY
AT JOHNS HOPKINS UNIVERSITY