Listening to the Cosmos

Fifty years ago, two Bell Labs physicists pointed a giant antenna at the sky. The hissing sounds they heard turned out to be the ultimate clue to the Big Bang theory.

He Got An Earful: Former Bell Labs astronomer Robert Wilson is dwarfed by the horn-reflector antenna in Holmdel, where in 1964 he and colleague Arno Penzias made the discoveries about the cosmos that would earn them the Nobel Prize for physics.
Photo by Christopher Lake

They thought it might be pigeon droppings. In May 1964, Robert Wilson and Arno Penzias—two young astronomers working at Bell Labs in Holmdel—were taking radio-wave measurements of the sky using Bell’s 20-foot horn-reflector antenna when they encountered something unexpected. They had designed a measuring system that would, in theory, eliminate superfluous background noise, yet when they pointed the antenna at the Milky Way, it picked up a constant, inexplicable hiss.

After ruling out a variety of suspects, including radio noise from New York City and the remnants of a recent nuclear test detonation, they concluded there had to be a problem with the antenna itself. Noticing that a pair of nesting pigeons had taken up residence in the horn-shaped antenna, Wilson and Penzias began to wonder if the droppings could be the culprit. But after trapping and releasing the birds and cleaning the antenna, the stubborn hiss persisted.

Flummoxed by the source of the interference, the two astronomers decided to ignore the problem and move ahead with their measurements. For the next year, they continued to search for evidence of a gaseous halo around the Milky Way. Neither suspected that they had inadvertently made a discovery that would shake up the scientific community, alter our vision of the cosmos and garner them a Nobel Prize.

They never did find any halo. But one day in 1965, Penzias was discussing the hiss with a colleague who suggested he get in touch with Robert Dicke, a physicist at Princeton. At the time, physicists tended to back one of two competing theories of the origin of the universe. The Steady State theory—proposed in 1948 by scientists Hermann Bondi, Thomas Gold and Fred Hoyle—held that the universe was essentially unchanging and would look the same from every vantage point within it. Wilson himself started out a Steady State believer. Opposing that was something called the Big Bang theory, an idea first posited by Belgian cosmologist George Lemaitre, who theorized that the universe had begun with a massive explosion that created immense amounts of radiation, which gradually cooled but continued to expand from the force of the explosion.

Penzias telephoned Dicke at Princeton, and reached him in his lab as he and his team were eating lunch together. During the call, Dicke’s assistants heard him speak the words “atmospheric radiation,” “sky brightness” and “antenna temperature”—all highly relevant to the work they were doing. David Wilkinson, one of the assistants and later an eminent physicist, would tell Wilson that when Dicke put down the phone, he turned to his team. “Boys,” Dicke told them, “we’ve been scooped.”

Dicke had been searching for evidence of the Big Bang theory, which he expected to find in the form of microwave radiation.

As subsequent tests confirmed, the hiss that had pestered Wilson and Penzias was, in fact, radiation left over from the Big Bang. Known as the Cosmic Microwave Background (CMB), it was the very evidence Dicke had been searching for.

Wilson responded to Dicke’s explanation with relief. “So they had what seemed to us this slightly crazy theory that the Big Bang was the source of the radiation, and we were extremely happy to have some source for it,” he says. He and Penzias wrote a paper about their discovery and sent it off to the peer-reviewed scientific publication Astrophysical Journal Letters, not certain how the scientific world might respond—if at all.

Tall, slim and soft spoken, Wilson tends to avoid hyperbole. He’s as eager to show off the newly installed solar panels on his house in Holmdel—he and his wife, Betty, he says, both drive hybrids and “are sort of trying to be environmentalists”—as he is to describe the events that led to his receiving the Nobel Prize in physics in 1978. But when he gets to talking about it, the details are all still there, as vivid as ever.

Exactly a year after they first heard the hiss, Wilson says, his father, visiting from Houston, got up early and headed into Holmdel village to pick up the day’s New York Times. “There, on the front page,” says Wilson, “was a picture of our antenna and an article about this new result in cosmology.” The story, headlined “Signals Imply a ‘Big Bang’ Universe,” detailed what the article’s author, the noted science reporter Walter Sullivan, suggested might be “one of the most remarkable coincidences in scientific history.” For the first time, it occurred to Wilson that “maybe people are really taking this cosmology seriously, and I’d better learn something about it.”

Back then, cosmology—the study of the origin and development of the universe—was in its infancy. “It had never really explained, or measured, anything,” Wilson says. His and Penzias’s discovery of the CMB changed that. “Since then,” he adds, “cosmology has really grown into a full science, with very precise measurements—it’s just entirely different now.”

Accordingly, our concept of the cosmos is entirely different as well. The existence of the CMB effectively dealt a death blow to the Steady State camp. Today, virtually all scientists accept the Big Bang theory: the idea that the universe had a discrete beginning some 13.8 billion years ago (one of the precise measurements Wilson refers to) in the form of an infinitesimally small bundle of immense energy that exploded and has continued to expand ever since.

The Nobel Prize confirmed the importance of Wilson and Penzias’s discovery. But its influence has spread far and wide, like the CMB itself. Without it, an MIT physicist named Alan Guth would never have proposed his 1980 theory of cosmic inflation—the idea that just after the Big Bang, energy and space itself expanded from virtually nothing to the size of a pebble—an inflation of truly mind-boggling proportions—and has continued to expand, though at a slower rate, ever since.

Then there is the Princeton-born kid named John Kovac, who while attending high school in Florida, read about the CMB and, deciding it was “the coolest thing in all of science,” applied to Princeton University to study it. Earlier this year, Kovac travelled to the South Pole where, working inside a massive microwave telescope known as BICEP2, he searched for—and apparently found—a pattern of polarized light lodged within the CMB. This turned out to be evidence of Guth’s proposed cosmic inflation. (Kovac’s findings still have to be confirmed and replicated before being accepted as definitive.)

Like Penzias and Wilson’s discovery, Kovac’s, if confirmed, will sweep aside many streams of thought currently competing to explain cosmic inflation. It’s also likely to shake up our deepest sense of the universe—a sense that there is just one. Kovac’s findings align with a theory called “chaotic inflation,” which supports the existence of a “multiverse” filled with many smaller “pocket” universes (including our own), each conceivably governed by its own unique laws of physics. Scientists have suggested that the multiverse itself, as well as the number of universes within it, could be infinite, giving rise to the possibility that different versions of the planet Earth, and of ourselves, could exist across the vastness of cosmic space and time.

Coming exactly a half-century after Wilson and Penzias were bothered by that persistent hiss, Kovac’s discovery has evinced the kind of superlatives—“absolutely spectacular,” “a grand slam”—that scientists generally reserve for only the most extraordinary events in scientific history. (Wilson merely says, with characteristic understatement, “It’s very satisfying to have been on the ground floor of all that.”)

With those superlatives buzzing in your ears, it’s striking to scale Holmdel’s Crawford Hill, the second-highest point in Monmouth County, and come upon the horn-reflector antenna—essentially, a big ear on the universe—that helped Wilson and Penzias usher in modern cosmology. The size of a small barn, the telescope’s bulky aluminum body looks like a prop out of a 1950s science-fiction film. Flick a switch behind a small door in its belly and the telescope slowly rotates—unless there’s been rain recently and the balky mechanism hasn’t had a chance to dry out.

Visitors reach the room where Wilson and Penzias took their measurements by a set of rickety metal stairs. (Our guide from Alcatel-Lucent, the French telecommunications company that now owns Bell Labs, offered the standard warning to all ascending guests: “Head injuries can be devastating, so if you plan to fall, try to die immediately.”) The stairs lead to the receiver room, a space the size of a walk-in closet, with scuffed, wood-paneled walls and floors covered in floral-patterned linoleum. The “throat” that opens out into the horn-shaped receiver is lodged in the paneling, but if you switched it out for a wall oven, you could easily believe you were standing in the slightly banged-up kitchen of a mid-century mobile home. It would be hard to imagine a less likely location for the launch of a revolution in cosmology.

The big antenna no longer plumbs the cosmos, but Robert Wilson, at 78, is still very much a working astronomer. He left Bell Labs in 1994 for the Harvard Smithsonian Center for Astrophysics in Cambridge, Massachusetts; he still commutes there about once a month from his home in Holmdel. He continues to study CMB radiation, helps design radio telescopes and researches interstellar molecular clouds—agglomerations of gas, plasma and dust, known as stellar laboratories, that are the star-forming regions of the cosmos. “I thought I was going to the Smithsonian for a few years and then retire,” he says, “but it’s almost 20 years later.”

For those 20 years, and the three decades before them, Wilson has lived—literally and metaphorically—under the shadow of the horn receiver on Crawford Hill. In late May he had an opportunity to return to the hill one more time and meet up with his former partner, Arno Penzias, at a Bell Labs event celebrating the golden anniversary of their discovery of the CMB. (Penzias, 81, is now a venture capitalist living in California’s Silicon Valley.)

Typically, Wilson’s response to the gala—and the achievement it lauded—is modest to the point of self-effacement. “The whole thing is amazing,” he says, “that what we were doing 50 years ago is providing so much information about the universe we live in. I’m awed and proud about that.”

Leslie Garisto Pfaff, a longtime contributor, ponders the cosmic questions from her own pocket-universe in Nutley.

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