 |
| Anisotropy
in the cosmic microwave background
radiation. |
Since 1964, when cosmic microwave
background radiation was first discovered,
scientists have searched the skies
for evidence of temperature variations
that might reflect the origins of
the universe. In 1977, a team led
by astrophysicist George Smoot of
Lawrence Berkeley National Laboratory
reported the first measurements of
temperature variations in the microwave
sky, but this irregularity was attributed
to the motion of the Earth's galaxy
in space. Smoot and colleagues already
had begun developing a highly sensitive
radiometer for detecting ancient microwaves,
and it finally was launched aboard
a satellite in 1989. Since then, Lawrence
Berkeley scientists have used radiometers
and powerful computers and algorithms
to observe hot and cold ripples in
the microwave radiation afterglow
of the Big Bang. Today, this anisotropy
is thought to be the primordial seed
from which, over billions of years,
the galaxies and large structures
of the present-day universe grew.
Scientific Impact:
The temperature and size of the spots
detected are in agreement with theories
suggesting that up to 90 percent of
the universe consists of mysterious
"dark matter," the existence of which
is inferred only because its gravity
influences the motion of ordinary
matter. Understanding of microwave
background radiation, when combined
with the eventual discovery of dark
matter, will unify physics on the
largest and smallest scales, fusing
together the fields of cosmology and
particle physics.
Social Impact: The
patterns observed in microwave sky
are like footprints left by the Earth's
ancestors 15 billion years ago, only
these footprints are gravitational
effects. Thus, this work expands human
understanding of how the universe
evolved and contributes to science
education.
Reference: "Structure
in the COBE DMR First Year Maps,"
G.F. Smoot et al., Astrophys.
J. 396:L1-L5 (1992).
URL: http://www.nersc.gov/research/annrep98/smoot.html
Technical Contact:
Dr. George Smoot, gfsmoot@lbl.gov
Press Contact: Jeff
Sherwood, DOE Office of Public Affairs,
202-586-5806
SC-Funding Office:
Office of High Energy and Nuclear
Physics |
