Rocket Science with
Dr. John C. Mather
By Cherry Chow
周卓瑩
“I
really can’t guess,” Dr.
John C. Mather answered, when
he was asked what he would see
himself doing if he had not become a
scientist. The Nobel Laureate has been interested
in science since he was a child. “My parents
took me to the natural history museum and I saw
dinosaur bones and the planetarium show and I
was hooked immediately. My parents also read
out loud to me and my sister from biographies of
Darwin and Galileo, when I was about 8 years
old. It was obvious that science was exciting, very
important, and a little dangerous. How could you
not want to do it?” His undying passion seems to
be the key for his success.
Dr. Mather is a Senior Astrophysicist in the
Obser vational Cosmology Laborator y at the
U.S. space agency’s (NASA) Goddard Space
Flight Center. After obtaining his Ph.D. in Physics
at the University of California, Berkeley in 1974,
he became an NRC Postdoctoral Fellow at the
Goddard Institute for Space Studies (New York
City). Over the years, he has served on advisory
and working groups for projects from NASA and
the National Science Foundation among others.
He has also received numerous awards and honors
in recognition of his contributions, particularly in
infrared astronomy and cosmology. In 2006, Dr.
Mather and Prof. George Smoot shared the Nobel
Prize in Physics for their discovery of the blackbody
form and an i sot ropy of cosmi c mi crowave
background radiation (CMB), during their work on
the Cosmic Background Explorer Satellite (COBE).
The COBE satellite was launched on November
18, 1989 to measure the spectrum of the CMB
radiation, and compare the spectrum of the
CMB with a preci se blackbody. Dr. Mather
and his team found that CMB radiation has a
blackbody spectrum within 50 ppm, providing
suppor t for the Big Bang Theor y. According
to the B ig Bang theor y, mu ltiple scat ter i ng
photons in the universe’s infancy, just as optical
light wanders through a dense fog, produces a
blackbody spectrum of photons. The data from
the instruments on the COBE showed a perfect
fit between the frequency spectrum of the CMB
and the theoretical curve for a black body. “The
fact that the measured spectrum has the perfect
blackbody form is very strong evidence for the
Big Bang Theory. None of the alternative theories
include the high temperature equilibrium that
produces the per fect spectrum,” Dr. Mather
explained.
The mission proved to be a challenge from the
get go. “The biggest problem was that nobody
knew how to design the mission, at fi rst. We
asked for extreme sensitivity and precision, and
we needed instruments to work at liquid helium
temperatures, around 1.5 Kelvin.” In addition,
Dr. Mather and the COBE team experienced an
unexpected crisis while working on the project.
When the COBE mission was almost ready to
be assembled, the Space Shuttle Challenger
tragically disintegrated after launch, leading to
the deaths of seven crew members. The original
plan to launch the COBE became a seemingly
impossible task. “So we had to redesign the
equipment for launch on a Delta rocket. Engineers
and technicians worked round the clock for
almost 3 years to do that,” Dr. Mather recalled, “But
it worked.”
As the Senior Project Scientist, Dr. Mather now
dedicates most of his time on the James Webb
Space Telescope (JWST), the planned successor
to the Hubble Space Telescope to be launched
in 2018. Due to its sensitivity to infrared radiation
from stars and from cooler objects below room
temperature, he foresees that the JWST will extend
the scientific discoveries of the Hubble to “greater
distances, farther back in time”. He is also working
on what telescope should be built after the JWST.
“It needs to be even bigger and more powerful,
so that it can detect signs of life on planets
around other stars.”
