The Hidden Reality_ Parallel Universes and the Deep Laws of the Cosmos - Brian Greene [24]
As Gamow first realized and as Alpher and his collaborator Robert Herman worked out with greater fidelity, all this means that if the big bang theory is correct, then space everywhere should now be filled with remnant photons from the creation event, streaming every which way, whose vibrational frequencies are determined by how much the universe has expanded and cooled during the billions of years since they were released. Detailed mathematical calculations showed that the photons should have cooled close to absolute zero, placing their frequencies in the microwave part of the spectrum. For this reason, they are called the cosmic microwave background radiation.
I recently reread the papers of Gamow, Alpher, and Herman that in the late 1940s announced and explained these conclusions. They are marvels of theoretical physics. The technical analyses involved require hardly more than a grounding in undergraduate physics, and yet the results are profound. The authors concluded that we are all immersed in a bath of photons, a cosmic heirloom bequeathed to us by the universe’s fiery birth.
With that buildup, you may find it surprising that the papers were ignored. This was mostly because they were written during an era dominated by quantum and nuclear physics. Cosmology had yet to make its mark as a quantitative science, so the physics culture was less receptive to what seemed like fringe theoretical studies. To some degree, the papers also languished because of Gamow’s unusually playful style (he once modified the authorship of a paper he was writing with Alpher to include his friend the future Nobel laureate Hans Bethe, just to make the paper’s byline—Alpher, Bethe, Gamow—sound like the first three letters of the Greek alphabet), which resulted in some physicists taking him less seriously than he deserved. Try as they might, Gamow, Alpher, and Herman could not interest anyone in their results, let alone persuade astronomers to devote the significant effort required to attempt to detect the relic radiation they predicted. The papers were quickly forgotten.
In the early 1960s, unaware of the earlier work, the Princeton physicists Robert Dicke and Jim Peebles went down a similar path and also realized that the big bang’s legacy should be the presence of a ubiquitous background radiation filling space.1 Unlike the members of Gamow’s team, however, Dicke was a renowned experimentalist and so didn’t need to persuade anyone to seek the radiation observationally. He could do it himself. Together with his students David Wilkinson and Peter Roll, Dicke devised an experimental scheme to capture some of the big bang’s vestigial photons. But before the Princeton researchers could put their plan to the test, they received one of the most famous telephone calls in the history of science.
While Dicke and Peebles had been calculating, the physicists Arno Penzias and Robert Wilson at Bell Labs, less than thirty miles from Princeton, had been struggling with a radio communications antenna (coincidentally, it was based on a design Dicke had come up with in the 1940s). No matter what adjustments they made, the antenna hissed with a steady, unavoidable background noise. Penzias and Wilson were convinced that something was wrong with their equipment. But then came a serendipitous chain of conversations. It began with a talk Peebles gave in February 1965 at Johns Hopkins University, which was attended by the Carnegie Institution radio astronomer Kenneth Turner, who mentioned the results he heard Peebles present to his MIT colleague Bernard Burke, who happened to be in touch with Penzias at Bell Labs. Hearing of the Princeton research, the Bell Labs team realized that their antenna was hissing for good reason: it was picking up the cosmic microwave