Four Degrees K: A Real Example of Science

[Ready for Fall 2026]

Modified: 2026-07-27 12:47 PM CDST

• 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. For that discovery they shared the Nobel Prize in physics in 1978.
  • 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 3°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 3°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.
• 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 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.