Bell Labs Scientists Proved the Big Bang Theory

“How did we get here?”

That existential question about the universe has captivated humankind for centuries. Many scientists have attempted to answer it, including the Rev. Georges Lemaître, a Belgian cosmologist and Catholic priest. In 1927 he theorized that the universe was created from a single particle he called the “primeval atom.”

That atom later disintegrated in an explosion, LeMaître figured, creating space, time, and an ever-expanding universe, according to the American Museum of Natural History.

LeMaître’s idea likely sounds familiar, as it is now known as the big bang theory. Direct evidence for the theory wasn’t found until almost four decades later, entirely by accident.

Bell Labs researchers Arno Penzias and Robert Woodrow Wilson were conducting radio astronomy experiments in 1964 using a horn antenna located on the company’s campus in Holmdel, N.J. The reflector antenna was the most sensitive in the world at the time. It was constructed to pick up weak radio signals from space for Project Echo, NASA’s experimental 1960 satellite communications program. The project successfully did so twice, first in 1961 through the passive Echo communication satellite, and a second time in 1963 through the active Telstar communications satellite.

While Penzias and Wilson were using the Holmdel antenna to map radio signals from the Milky Way, it picked up a mysterious buzzing noise that wouldn’t go away despite their attempts to eliminate it.

The signals, which persisted day and night, turned out to be cosmic microwave background radiation that permeates the universe—a remnant from the creation of the cosmos—that helped confirm the big bang theory. The accidental breakthrough earned Penzias and Wilson the 1978 Nobel Prize in Physics.

Project Echo, Telstar, and the discovery of the cosmic microwave background radiation were recognized as an IEEE Milestone at a ceremony held on 25 May in Holmdel at Wilson Park, where the horn antenna is located.

Penzias and Wilson’s evidence for the big bang theory shaped “our understanding of this universe and our place in it,” Thomas Coughlin, 2024 IEEE president, said in a news release about the dedication.

“Cosmic background radiation, one of the most transformative discoveries in the second half of the 20th century, has also led to non-terrestrial communication innovations that address some of the world’s greatest needs, including disaster relief aid,” Coughlin said.

Building the world’s most sensitive antenna

After the Soviet Union in 1957 launched Sputnik, the world’s first artificial satellite put into low Earth orbit, the U.S. government increased its efforts to fund the development of non-terrestrial communication innovations, as detailed in an Engineering and Technology History Wiki entry.

Government and industry worked together on initiatives at laboratories around the country. One of the first programs was Project Echo, which aimed to achieve two-way voice communication between NASA’s Jet Propulsion Laboratory in Goldstone, Calif., and Crawford Hill in Holmdel, 5 kilometers from the Bell Labs complex.

Langley engineers (from right): Norman Crabill, Edwin Kilgore, and an unidentified man take a peek inside the vast balloon during inflation tests of the Echo 1 Satellite in Weeksville, N.C.NASA

To make the communication possible, project leads developed and built the horn antenna on the Bell Labs site. The antenna was 15.24 meters long by 6.1 meters wide, weighing in at 16,329 kilograms. It funneled radio waves in or out of the horn shape, and the reflector bounced the waves into a single focused beam—similar to a huge metal megaphone pointing into a curved mirror. Despite its large size, the machine could be precisely aimed.

Unlike other antennas that are tuned to only one frequency, the Holmdel antenna worked across a wide band of frequencies, so it could pick up several types of radio signals. It also could handle radio waves moving in linear or circular paths.

The design accounted for the potential need to eliminate unwanted noise from the environment.

The receiver was placed at the horn’s apex, eliminating the need for a connecting line, which could result in external noise and signal loss.

The antenna allowed Project Echo to complete the first high-quality long-distance voice circuit in 1961 through its namesake’s passive communication satellite, Echo. A similar experiment was successfully completed two years later through the Telstar satellite, according to the proposal for the IEEE Milestone.

In 1964 Penzias and Wilson began using the Holmdel antenna to perform their own radio astronomy experiments.

What’s that buzzing sound?

The duo was trying to map weak radio signals from the Milky Way. They took pains to eliminate external noise from the ground, the environment, and the antenna itself so that their readings would not be affected. They even suppressed interference from the receiver on the antenna by cooling it with liquid helium to -269 °C—only 4 degrees above absolute zero, the theoretical temperature at which all motion stops.

Yet they kept hearing a persistent buzz. It was low, steady, and 100 times more intense than the researchers would expect for interference noise—and it was coming from all directions in space.

Penzias and Wilson redoubled their efforts to eliminate the interference, painstakingly retesting their equipment.

Penzias and Wilson’s evidence for the big bang theory shaped “our understanding of this universe and our place in it.” —Thomas Coughlin, 2024 IEEE president

“They went so far as to take rags and detergents to carefully wash the antenna from the droppings of a pair of pigeons that had nested there,” Leonardo Colletti told IEEE Spectrum in a 2023 article about the discovery. Colletti is a physics professor at the Free University of Bozen-Bolzano, in Italy.

But even after all the duo’s work, the mysterious buzz continued.

After Penzias and Wilson had accounted for everything, including the pigeon poop, they concluded that the radiation they detected could not have come from the Earth, the sun, or anything else in the galaxy.

They later learned that researchers and astrophysicists Robert H. Dicke, P. James Peebles, and David Todd Wilkinson at Princeton University predicted the existence of cosmic microwave background noise, which “they believed would have resulted from the big bang,” according to an entry on the Nokia Bell Labs website.

“As it turned out,” the article says, “the radiation detected by Penzias and Wilson was a perfect match for what the Princeton researchers had predicted.”

Saving the horn antenna

In 1989 the Holmdel antenna was named a national historic landmark. But in 2021 Nokia, which had acquired Bell Labs, sold the 43-acre area to technology entrepreneur Rakesh Antala.

The following year, the Holmdel planning board voted to undertake a study to consider reclassifying the site as an area in need of redevelopment.

[From left] Holmdel Deputy Mayor Kim LaMountain, former Bell Labs researcher Giovanni Vannucci, and 2024 IEEE President Tom Coughlin celebrating the Milestone dedication in front of the Horn Antenna in Holmdel, N.J.Bala Prasanna

That put the landmark at risk of being demolished, IEEE Spectrum reported.

The local community banded together, launching a publicity campaign and an online petition to save the antenna. The township ultimately secured ownership of the horn antenna site following an extensive legal process. Last year it dedicated the site as Dr. Robert Wilson Park, honoring it as the place where “we gained a critical understanding of the birth of our universe.”

A plaque recognizing the IEEE Milestone designation is displayed in the lobby of the AT&T Labs Science and Technology Center in Middletown, N.J., which is about 7 kilometers from Crawford Hill. The plaque reads:

In 1959–1960, NASA and AT&T developed a satellite Earth station in Holmdel, N.J., including a novel tracking horn-reflector antenna, maser preamplifier, and FM demodulator. The Earth station demonstrated the first high-quality long-distance voice circuit via the Echo passive communication satellite in 1960–1961, and via the active Telstar communications satellite in 1962–1963. Experiments conducted in 1964–1965 provided the first indication of the cosmic background radiation associated with the Big Bang.

The IEEE New Jersey Coast Section and the IEEE Photonics Society sponsored the nomination.

Administered by the IEEE History Center and supported by donors, the Milestone program recognizes outstanding technical developments around the world.