| Andrew
Lange, Ph.D. and
Saul Perlmutter, Ph.D.
2003 California Scientists of the
Year
>
BACK TO PAST WINNERS
Dr.
Andrew Lange is Marvin L. Goldberger Professor of Physics
at the California Institute of Technology in Pasadena,
and Dr. Saul Perlmutter is Senior Scientist and Group
Leader at the Lawrence Berkeley National Laboratory in
Berkeley. Using two very different techniques, Lange and
Perlmutter’s experimental efforts have confirmed
a remarkable theory of how the universe expanded and evolved
after “the big bang.”
According
to the most widely held theory of cosmic evolution, the
universe went though an inflationary phase where its size
rapidly increased and where the universe’s geometrical
structure took on a very specific form: parallel lines
never meet, the sum of the angles inside an astronomically
sized triangle add to 180 degrees. Scientists refer to
this particular form of geometry as being mathematically
“flat.” According to General Relativity, a
mathematically flat universe places constraints on the
amount of mass and energy in the universe. Unfortunately,
astronomers could not account for the requisite mass and
energy. Therefore, either the standard cosmological or
“big bang” theory was incorrect and the universe’s
geometrical structure was not that of Euclid, or the astronomers
were missing something important.
 |
| Andrew
Lange, Ph.D. |
Dr.
Lange studies fluctuations in the Cosmic Microwave Background
(CMB) radiation, a relic of the primeval “fireball”
that filled the early universe. These signals, which are
visible today at microwave frequencies, provide a clear
“snapshot” of the embryonic universe, at an
epoch long before the first stars or galaxies had formed.
In general, this radiation reaches the earth uniformly
from all directions in the sky. However, at the level
of 0.003% there is an intricate pattern of fluctuations
in the CMB. Using novel detectors developed at the Jet
Propulsion Laboratory and flown on a balloon-borne telescope
high above Antarctica, Dr. Lange’s group was able
to make the first resolved images of these very faint
patterns. The images demonstrate that the radiation fluctuates
on an angular scale of one degree, which is exactly what
scientists expected from a mathematically flat universe.
 |
| Saul
Perlmutter, Ph.D. |
Since
the 1930s, scientists have known that galaxies are all
moving away from one another, and there has been a concerted
effort to study the rate of this expansion. Prior to Perlmutter’s
efforts, almost all astronomers expected that the expansion
of the universe was slowing, due to the gravitational
attraction of galaxies and other matter. However, Perlmutter’s
group found that the universe is actually expanding at
an accelerating rate, as if a “negative pressure”
was pushing everything apart. This negative pressure may
be what scientists call the cosmological constant, first
hypothesized by Albert Einstein in an attempt to prescribe
a stable universe but later rejected by him. Perlmutter’s
estimates of the cosmological constant’s magnitude
are consistent with Lange’s observations of a flat
universe.
Lange’s
work demonstrates that the universe is mathematically
flat, and that the standard cosmological theory is correct,
while Perlmutter’s work indicates that the source
of astronomical energy giving rise to a flat universe
comes from a type of negative gravitational pressure or
dark energy permeating the universe. The nature of this
dark energy remains a mystery.
Dr.
Lange's site:
Caltech
Observational Cosmology Group
Dr.
Perlmutter's site:
Supernova
Cosmology Project |
