Four Degrees K: A Real Example of Science
The discovery of universal microwave background radiation in 1964, by
Arno Penzias and Robert Wilson of Bell Labs, was the first empirical
evidence for the big bang theory of cosmology. Penzias and Wilson
were given a radiotelescope and they were going to use it to measure
signals at a longer wavelength than anyone had before. First, they
had calibrate it by measuring a wavelength at which they expected to
find no stellar signals; then they could show that the antenna itself
was not introducing any signals by itself. But that was not what
happened. Intead, the antenna kept registering a value of 3û K, a
completely unexpected result. They spent the next year attempting to
eliminate the source of the radiation. Being close to New York City,
they pointed it in that direction, they eliminated the Van Allen
belts, temperature, moon phases, direction, and other possible
sources, but the noise persisted. Through a fellow physicist, Penzias
learned that a group at Princeton, led by Robert Dicke' believed that
if a big bang had taken place, there should be some evidence still,
and further, they thought it would be a low temperature signal. They
had begun to collect data to test their theory when Penzias contacted
Dicke. The Princeton group soon came to Bell Labs and met with
Penzias and Wilson. When Dicke first suggested that the 3û K noise
was the remnant of the big bang explosion, Penzias and Wilson were
not convinced, but they mentioned Dicke's possible explanation in
their 1965 article describing their data. Later it became clear that
Penzias and Wilson had detected the echoes of the big bang. For that
discovery they were awarded the Nobel Prize in physics in 1978. In
1989, the Cosmic Background Explorer satellite, or COBE was launched.
That satellite was part of a project, directed by George Smoot, to
measure microwave uniformity in the entire sky. In April of 1992,
Smoot announced the results. They showed that slight microwave
discontinuities existed, as newer versions of the big bang theories
had predicted. The map that the data produced covered the front pages
of many magazines.
Look at how this example shows how science works. A surprising
discovery may be made by scientists who do not realize the
implications of their findings. Later, theorists may make sense of
that data after the discovery, and, they may have even predicted the
discovery before it was made. Communication between scientists may
resolve the implications of the discovery. Then, the discovery and
its explanation led to further experimentation and to a renewed
interest in the theoretical implications of those new discoveries.
The above example, illustrates, on a small scale, the dialectical
nature of science as well as the relationship between experimental
and theoretical scientists.
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