How a Wrong Theory Brought Good Results
A central issue in astronomy through the 40's, 50's, and early 60's was the contest between Steady State and Big Bang models of cosmology. The Steady State model, although generally dismissed since 1965 with the discovery of the 3K remnant radiation, is still mentioned in the text -- an uncommon compliment to an idea that was largely rejected nearly 40 years ago. How could this wrong idea have such lasting effect?
Although many others were involved, in the popular mind the two main protagonists were Fred Hoyle , for the Steady State model, and George Gamow , for the Big Bang. For two wildly eccentric individuals, they were remarkably similar in many ways, as you can tell by reading the short biographies linked above.
Fred Hoyle was unhappy about accepting an instant of creation, a philosophical problem we have already admitted is beyond the reach of scientific inquiry at least with our current capabilities. His principal scientific challenge to that theory was that there was no 'fossil' record, no remaining traces that led unambiguously to a moment of creation. In attacking the theory, he had dismissively referred to "this hot Big Bang" and inadvertently gave it the name that has lasted. His solution was to stretch the process out over infinite time -- to have matter form very slowly in empty space, driving the expansion of the Universe to keep the average density constant. Thus, he accounted for the expansion but moved the origin of the Universe back to an indeterminate time far, far in the past.
For many, this spontaneous generation of matter was more distasteful than the instantaneous creation of all of it in a single event, and in addition the expansion seemed to be a natural outgrowth of the Theory of Relativity as had been advocated by Lamaitre and others. In 1948, the same year that the first paper on the Steady State theory was published, George Gamow and his student Ralph Alpher published a paper claiming a major breakthrough for the Big Bang. They proposed that the elements were produced in the first few minutes after the Big Bang, through fusion reactions of the subatomic particles at the extremely high temperature and density that prevailed then. Gamow also predicted that the fossil record of the Big Bang might be found in a remnant radiation field, but this possibility was largely ignored.
The advocates of the Steady State could not ignore the production of the elements, and they took up the challenge of finding an alternative. Success was achieved in a classic paper published in 1957, where they showed how the elements could be produced by a combination of fusion in the cores of massive stars (for the lighter ones), capture of free neutrons also in stellar cores, and reaction chains that proceed rapidly in supernova explosions, basically the modern theory that we have already discussed. In the meantime, it was realized that fusion in the Big Bang would not have extended above helium and lithium, so that this event could not have been responsible for the creation of the elements.The Steady State advocates' alternative of formation in stars and supernovae was the correct explanation.
In the early 60's, Bell Labs built a giant antenna in Holmdel, New Jersey, in 1960 as part of a very early satellite transmission system. (picture from WGBH, PBS online).It quickly became obsolete for its original use. Arno Penzias and Robert Wilson refurbished it with improved radio receivers, but they kept coming up against an annoying noise (like static in radio or snow on a TV) that the receivers only seemed to have when they were on the antenna. Such problems were often found to be due to faults in the antenna itself, and Penzias and Wilson worked to make improvements there -- even to removing quantities of Pigeon poop they delicately described in terms more engineering than biological as "a white dielectric substance" -- see below right. Nothing made the noise go away, so they went to visit an eminent radio astronomer, Robert Dicke at the nearby Princeton University -- Dicke was a world-renowned authority on radio receiver noise.
Winning a Nobel Prize can be dirty work!
(picture from Bell Labs,
By strange coincidence, Dicke and a colleague, Jim Peebles, had become interested in
searching for remnant radiation from the Big Bang and had even built a simple receiver and
started searching for it. Dicke immediately suspected that Penzias and Wilson had
blundered onto this source -- "We've been scooped." he reported. The two groups
joined efforts and quickly confirmed that the remnant radiation had indeed been found --
the 'fossil record' that Hoyle had required to accept the Big Bang theory.
Although most astronomers quickly abandoned the Steady State model, Hoyle defended it
doggedly, pointing out flaws and inconsistencies in the Big Bang theories and elaborating
on the Steady State model to provide its own radiation field that might be mistaken for
the remnant of the Big Bang. He continued to defend the theory until his death, in 1999.
Although the later phases of this work were not well received, the earlier ones pointed
out genuine weaknesses in Big Bang theory which others worked to fix. In this way, Hoyle
continued to contribute to the improvement of the theory he opposed.
The story of the Steady State vs. Big Bang theories is remembered because:
1.) it deals with fundamental aspects of the Universe, but in terms that are easily understood.
2.) the Steady State theory, although no longer accepted, contributed substantially to our understanding through the efforts of its advocates to defend it.
3.) Both Hoyle and Gamow wrote popular expositions on their respective points of view. The debate was thus carried out with considerable eloquence and wit as well as scientific rigor.
4.) It led to two Nobel Prizes -- one for the work on formation of the elements in supernovae and the other for the discovery of the remnant radiation.