(p. B11) Arno A. Penzias, whose astronomical probes yielded incontrovertible evidence of a dynamic, evolving universe with a clear point of origin, confirming what became known as the Big Bang theory, died on Monday [January 22, 2024] in San Francisco.
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In 1964, while preparing the antenna to measure the properties of the Milky Way galaxy, Dr. Penzias and Dr. Wilson, another young radio astronomer who was new to Bell Labs, encountered a persistent, unexplained hiss of radio waves that seemed to come from everywhere in the sky, detected no matter which way the antenna was pointed. Perplexed, they considered various sources of the noise. They thought they might be picking up radar, or noise from New York City, or radiation from a nuclear explosion. Or might pigeon droppings be the culprit?
Examining the antenna, Dr. Penzias and Dr. Wilson “subjected its electric circuits to scrutiny comparable to that used in preparing a manned spacecraft,” Walter Sullivan wrote in The New York Times in 1965. Yet the mysterious hiss remained.
The cosmological underpinnings of the noise were finally explained with help from physicists at Princeton University, who had predicted that there might be radiation coming from all directions left over from the Big Bang. The buzzing, it turned out, was just that: a cosmic echo. It confirmed that the universe wasn’t infinitely old and static but rather had begun as a primordial fireball that left the universe bathed in background radiation.
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. . . Dr. Penzias’s path to stumbling onto the answer to one of humanity’s most central questions started . . ., when he joined Bell Laboratories as a member of its radio research group in Holmdel.
There, he saw the potential of AT&T’s new satellite communications antenna, a giant radio telescope known as the Holmdel Horn, as a tool for cosmological observation. In teaming up with Dr. Wilson in 1964 to use the antenna, Dr. Wilson said in a recent interview, one of their goals was to advance the nascent field of radio astronomy by accurately measuring several bright celestial sources.
Soon after they started their measurements, however, they heard the hiss. They spent months ruling out possible causes, including pigeons.
“The pigeons would go and roost at the small end of the horn, and they deposited what Arno called a white dielectric material,” Dr. Wilson said. “And we didn’t know if the pigeon poop might have produced some radiation.” So the men climbed up and cleaned it out. The noise persisted.
It was finally Dr. Penzias’s fondness for chatting on the telephone that led to a fortuitous breakthrough. (“It was a good thing he worked for the phone company, because he liked to use their instrument,” Dr. Wilson said. “He talked to a lot of people.”)
In January 1965, Dr. Penzias dialed Bernard Burke, a fellow radio astronomer, and in the course of their conversation he mentioned the puzzling hiss. Dr. Burke suggested that Dr. Penzias call a physicist at Princeton who had been trying to prove that the Big Bang had left traces of cosmological radiation. He did.
Intrigued, scientists from Princeton visited Dr. Penzias and Dr. Wilson, and together they made the connection to the Big Bang. Theory and observation were then brought together in a pair of papers published in 1965.
For the full obituary, see:
(Note: ellipses, and bracketed date, added.)
(Note: the online version of the obituary has the date Jan. 22, 2024, and has the title “Arno A. Penzias, 90, Dies; Nobel Physicist Confirmed Big Bang Theory.”)