Science

Where the Universe Began

On a field just below the summit of Crawford Hill, the highest point in Monmouth County, N.J., almost within sight of the skyscrapers of Manhattan, sits a cluster of shacks and sheds. Next to them is the Holmdel Horn Antenna, a radio telescope somewhat resembling the scoop of a giant steam shovel: an aluminum box 20 feet square at the mouth and tapering to an eight-inch opening, through which the radio waves are funneled into the “cab,” a wooden hut on stilts. From a distance, the whole site could be mistaken for an old mining camp you might come across in Montana or Idaho.

What it once mined was the sky. While listening with the antenna in May 1964, two young radio astronomers, Arno Penzias and Robert Wilson, picked up an eerie and persistent hum from the heavens. For a long time, they thought it was caused by pigeon droppings that had accumulated in the horn. Instead, they eventually learned, they had detected the beginnings of space and time. They were listening to the last sigh of the Big Bang, which birthed the universe 13.8 billion years ago and is detectable now only as a faint, omnipresent hiss of microwave radiation.

Up until then, scientists had debated whether the universe even had a beginning; maybe it was timeless. That question was now settled. As important, the discovery brought the beginning of time into the lab, where it could be pinched, squeezed and dissected. Encoded in that microwave fuzz are vestiges of events that occurred when the cosmos was less than one-trillionth of a second old and brimming with energies far beyond the capacity of modern particle colliders.

The cosmic microwave background offered a new window into the nature of reality, one into which astronomers have been peering intently ever since. In 1978, Dr. Penzias and Dr. Wilson were awarded the Nobel Prize in Physics for their discovery, and in 1988, the antenna was designated a National Historic Landmark, a symbol of humankind’s ingenuity, curiosity and persistence, and of nature’s ability to surprise and humble us.

Dr. Wilson, now 87, lives in Holmdel and still has the keys to the telescope. When he offered an invitation to visit this spring, I jumped at the chance. The antenna was at the center of a real estate dispute: The new owner of the site wanted to build a senior housing development there and possibly displace the antenna. The neighbors and various citizen groups were in an uproar. As a photographer and I made our way to Dr. Wilson’s house, we passed lawn sign after lawn sign: “Save Crawford Hill,” they said. “Save the Horn Antenna.”

Dr. Wilson lives a few blocks from the antenna and still has the keys to the telescope.

The trouble with pigeons

The Holmdel Horn was built in 1959 by Bell Laboratories for an experiment called Project Echo, which aimed to send messages from one place on Earth to another by bouncing microwaves off giant aluminized balloons. When the project was done, Bell turned the antenna over to two young astronomers: Dr. Penzias, who had left Nazi Germany before the Holocaust and earned a Ph.D. from Columbia, and Dr. Wilson, a radio whiz from Houston with a Ph.D from the California Institute of Technology.

The beginning of time was the last thing on their minds; they wanted to measure the brightness of galaxies. Astronomers often characterize the brightness of their sources by the temperature that a warm body — a so-called blackbody — would have to have in order to produce the same amount of radiation. To accurately measure the galaxies of interest, Dr. Penzias and Dr. Wilson first had to calibrate the antenna by studying sources whose brightness or temperatures were known.

“On May 20, 1964, we got it all together,” Dr. Wilson said when I caught up to him in Holmdel; he was lanky and soft-spoken, with a meticulous manner and an imposing dome of a forehead. But, he recalled, there had been a troublesome surprise — a persistent hiss wherever they pointed the telescope. “The sky was too warm,” he said. “It should have been colder.”

Arno Penzias, right, checking the inside of the horn antenna with Dr. Wilson (on ladder); a mess of wires in one of the antenna’s rooms; Dr. Wilson at the seven-meter antenna, a defunct telescope likely to be demolished.Credit…Nokia Bell Labs

The intrusive noise corresponded to a temperature of about 3.5 kelvin, barely yet clearly above the absolute zero that they had expected from empty space. It was present no matter in what direction they pointed the antenna. Try as they might, they could not get rid of the extra heat.

“And we, of course, were worried — ‘what’s wrong with this system?’” Dr. Wilson said.

On the long list of potential wrongs were two pigeons that had roosted in the narrow end of the antenna and the “white dielectric material,” as Dr. Penzias called it, that they had left behind. “And they had decorated it the way they decorate various statues,” Dr. Wilson said.

The pigeons were sent away. “A couple of days later, they were right back,” Dr. Wilson said. A more permanent eviction was arranged. But even after cleaning the telescope, the buzz remained, eluding all explanation for nearly a year. “We were at wit’s end,” Dr. Wilson said.

‘Boys, we’ve been scooped’

The Bell Labs Holmdel Complex in May.

A few miles away, Robert Dicke, a physicist at Princeton, and his students had begun looking into the conditions under which the universe could have begun, if indeed it had a beginning. They concluded that any such Big Bang must have been hot enough to sustain thermonuclear reactions, at millions of degrees, in order to synthesize heavy elements from primordial hydrogen.

That energy should still be around, they realized. But as the universe expanded, the primeval fireball would have cooled to a few kelvin above absolute zero — which, they calculated, would put the cosmic radiation in the microwave region of the electromagnetic spectrum. (The group did not know, or had forgotten, that the same calculation had been made 20 years earlier by the physicist George Gamow and his collaborators at George Washington University.)

Dr. Dicke assigned two graduate students — David Wilkinson, a gifted instrumentalist, and James Peebles, a theorist — to try to detect these microwaves. As the group was meeting to decide on a plan of action, the phone rang. It was Dr. Penzias. When Dr. Dicke hung up, he turned to his team. “Boys, we’ve just been scooped,” he said.

The two teams met and wrote a pair of papers, which were published back-to-back in the journal Physical Review Letters. The Bell Labs group described the radio noise, and the Princeton group proposed that it could be leftover heat from the Big Bang — “probably each side thinking, Well, what we’ve done is correct but the other may not be,” Dr. Wilson said.

“I think both Arnold and I wanted to leave open the idea that there was some other source of this noise,” he added. “But, of course, that didn’t work out.”

Dr. Wilson and Dr. Penzias in 1978; an artist’s concept of the Cosmic Background Explorer satellite; Robert Dicke of Princeton in the 1960s.Credit…Associated Press; NASA; Bettmann/Getty Images

Over the next decades, other astronomers and physicists joined and competed in the quest to measure the cosmic microwave background at different frequencies and to fill in its electromagnetic spectrum. The effort migrated from Crawford Hill to mountaintops, the South Pole, balloons and space, where instruments could study the microwaves unfiltered by Earth’s atmosphere.

In 1990, the Cosmic Background Explorer satellite, or COBE, reported that the temperature of the microwave background was a consistent 2.7 kelvin — 2.7 degrees Celsius above absolute zero — in every direction. The result pleased Dr. Wilson since it was close to his and Dr. Penzias’s original estimate. COBE also found that the microwave universe was not as uniform as it appeared: It was mottled with spots a few hundred-thousandths of a kelvin hotter or cooler than average. Astronomers now think these spots are the seeds of the galaxies and galaxy clusters that now dot the sky.

The COBE results produced two more Nobel Prizes, for John Mather of the Goddard Space Flight Center in Greenbelt, Md., and George Smoot of the University of California, Berkeley.

Continuing studies of the cosmic microwaves, along with regular astronomy, have cemented a view of what is sometimes called “a preposterous universe,” of which atomic matter — the stuff of stars and people — composes only 5 percent by weight. By analyzing the relative sizes and frequencies of these spots and ripples, astronomers have been able to describe the birth of the universe to a precision that would make the ancient philosophers weep. It now seems that the universe is 13.8 billion years old and consists, by mass, of 4.9 percent ordinary matter like atoms, 27 percent dark matter and 68 percent dark energy.

Dr. Wilson in his basement.

The microwaves detected by Dr. Penzias and Dr. Wilson date from 380,000 years after the Big Bang, when the entire universe was as hot as the surface of the sun and the first atoms formed, releasing light in the process. That is as far back as optical and radio telescopes can reach.

But the patterns within these microwaves date from less than one-trillionth of a second into the Big Bang. Cosmologists speculate that in that tiny moment, the universe experienced a brief, violent burst of hyper-expansion known as inflation. Such a wrenching outburst would have left ripples — gravitational waves — imprinted on the microwave background. In 2014, astronomers operating a sensitive experiment called Bicep2 claimed to have detected those ripples, but they had been fooled by interstellar dust. So far, the smoking gun of inflation has not been detected.

A cosmic time capsule

Scientists continue to try to crack this cosmic time capsule open.

Suzanne Staggs, an astrophysicist at Princeton, points out that as the cosmic microwaves have traveled 14 billion light-years to our detectors, they have passed through all of cosmic history — through all of the galaxies and clusters of galaxies that have ever existed. Along the way, the microwaves would have been warped and distorted by the gravity of all of those massive objects through a process called gravitational lensing.

Dr. Staggs is the principal investigator on a multinational collaboration called the Atacama Cosmology Telescope, which is at an altitude of 17,000 feet in Chile and consists of dozens of telescopes and thousands of individual microwave sensors. For the last decade, the research team has used this lensing effect to map the distribution of matter, including dark matter, in the universe.

The South Pole Telescope; a small aperture telescope for the Simons Observatory that is under construction in Chile; the Atacama Cosmology Telescope.Credit…Daniel Luong-Van/National Science Foundation; Simons Observatory Collaboration; Giulio Ercolani/Alamy

Recently, astronomers using the South Pole Telescope, another multinational effort, used a similar technique to “weigh” an entire cluster of galaxies that existed some 12 billion years ago, at the dawn of time. And a worldwide collaboration of scientists and experiments operating under the name CMB-S4 is gearing up for the deepest dive yet into the cosmic microwave sea: a seven-year search over the next decade for even fainter patterns within patterns. If found, these could bear testimony to the forces that prevailed at the beginning of time.

The effort will include the Simons Observatory, now under construction next door to the Atacama Cosmology Telescope, and other experiments at the South Pole and elsewhere. It will cost its sponsors, the Department of Energy and the National Science Foundation, half a billion dollars. “As with any big projects, it has many gates to get through before the construction funding is secure,” said John Carlstrom, an astrophysicist at the University of Chicago and project scientist for the CMB-S4.

Lyman Page, a physicist at Princeton who has spent his career investigating the cosmic microwaves, added: “It’s just great physics.”

The sounds of creation

Dr. Wilson, left, with Rakesh Antala, a property owner with Crawford Hill Holdings, LLC. “I suppose that Rakesh will keep lawyers employed on both sides,” Dr. Wilson said.

Dr. Wilson retired from Bell Labs in 1984 and joined the Center for Astrophysics Harvard & Smithsonian as a senior scientist. Dr. Penzias retired as the vice president and chief scientist of Lucent Technologies, which had absorbed Bell Labs, in 1998, and is now living in California. At the suggestion of a colleague, Dr. Wilson has signed up to be one of the 459 members of the CMB-S4 collaboration, though he doesn’t yet have specific research plans.

In the meantime, Dr. Wilson was in the middle of the fight to save the horn antenna. He has maintained cordial relations with Rakesh Antala, the new property owner, and credits him with allowing access to the antenna and protecting it.

“I’d like it to stay where it is,” he said, referring to the horn. “And I think the idea of making it into a park is a good one.” He noted that the antenna had suffered some vandalism, including broken windows. “So it needs some protection,” he said.

In June, Holmdel’s township committee voted to take the first step toward invoking eminent domain and claiming at least part of the 43 acres, including the antenna, as a park, citing “a ground swelling of public support for preservation of the Crawford Hill property.” Dr. Wilson said that he approved, but that it would be a long process. “I suppose that Rakesh will keep lawyers employed on both sides,” he said.

He unlocked a gate to the antenna, then led the way up a short flight of stairs into the hut at the tapered end of the horn. He pointed out the mechanism for aiming the antenna — not gears, but what looked like an oversize bicycle chain. “It was built in a hurry to get ready for the Echo satellite,” Dr. Wilson said. “There was no time to forge gear teeth.”

Gears for turning the antenna; an old page from a Bell Labs phone book; a map of the housing development plan for Crawford Hill; an abandoned shed that was once part of the Holmdel Horn Antenna complex.

At one time, the hut had been full of radio equipment, set to receive data from the tail end of the horn. Now it was empty, and the floor was suspect. The eight-inch opening to the horn, and to the cosmos at large, was covered by a wooden plate to keep birds from flying in. A broken window looked out into the woods.

Dr. Wilson picked up a piece of paper that was nearly ripped in half; it bore the names and phone numbers of Bell Labs employees, circa 1964, his among them. A few lines above his was Dr. Penzias’s name and number. Dr. Wilson tucked it away to take home. He took another piece of paper hanging on a wall and frowned; it had lists and columns of numbers relating voltages and temperatures. “I don’t know what this is,” Dr. Wilson said.

Hanging above that was a hair dryer that had been used for warming up equipment that had been cooled in liquid helium. Dr. Wilson left it where it was.

“The past is never dead,” William Faulkner famously wrote in the novel “Requiem for a Nun.” “It’s not even past.” The sounds of creation are still ringing, if you have the ears to hear them.

Bir yanıt yazın

E-posta adresiniz yayınlanmayacak. Gerekli alanlar * ile işaretlenmişlerdir

time