Penzias, Arno (1933- )

German-born American astrophysicist

Arno Penzias shared the Nobel Prize for physics in 1978 with Robert Wilson for a discovery that supported the big bang the ory of the universe. The two radio astronomers at what was then American Telephone & Telegraph's (AT&T) Bell Telephone Laboratories were using a 20-ft (6.1-m) horn reflector antenna that year to measure the intensity of radio waves emitted by the halo of gas surrounding the galaxy. The two scientists were bothered by a persistent noise that they could not explain. At first they pinned it on two pigeons that were nesting in the antenna throat. But even after they evicted the birds, the noise continued. Eventually the scientists were able to conclude that the noise came from cosmic background, or microwave, radiation. This came to be widely considered as remnant microwave radiation from the "big bang" in which the universe was created billions of years ago. The Penzias-Wilson discovery came to be considered a major finding in astrophysics.

Arno Allan Penzias was born in Munich, Germany, to Jewish parents Karl and Justine (Eisenreich) Penzias. Hitler's campaign to wipe out the Jews of Europe was well underway when the family escaped in 1940. Arriving in New York, Penzias had to acclimate to a new culture and language and suffer through hard times for his family. Naturalized in 1946, he demonstrated scientific acumen at Brooklyn Technical High School and went on to obtain his B.S. at City College in New York in 1954. He married Anne Pearl Barras that same year; the union produced three children. After a two-year stint in the U.S. Army Signal Corps, Penzias obtained both his master's and Ph.D. degrees at Columbia University. He has said he chose to study physics because he asked a professor if he could make a living in the field and was told, "Well, you can do the same things engineers can do and do them better."

In 1961, Penzias was hired at Bell Labs in Holmdel, New Jersey. AT&T was a telecommunications monopoly at that time and Bell Labs was its research center, attracting the best and brightest scientific minds. In this context, Penzias demonstrated his capabilities early on. Asked to join a committee of older scientists who were trying to devise how to calculate the precise positions of communication satellites by triangulation, young Penzias suggested they use radio stars, which emit characteristic frequencies from fixed positions, as reference points. For his abilities, Penzias rose through the Bell ranks to become director of the facility's Radio Research Laboratory in 1976, and executive director of the Communications Sciences Research Division in 1979. He also took part in the pioneering Echo and Telstar communications satellite experiments of the 1970s.

It was astronomer George Gamow who in 1942 first calculated the conditions of temperature and density that would have been required for a fireball explosion or "big bang" origin of the universe 15 billion years ago. Astronomers Ralph Alpher and Robert Herman later concluded that cosmic radiation would have resulted from this event. This theory was confirmed by Penzias and Wilson. According to the theory, the background radiation resulting from the big bang would have lost energy; it would have essentially "cooled." Gamow and Alpher calculated in 1948 that the radiation should now be characteristic of a perfectly emitting body—or black body— with a temperature of about 5 Kelvin, or −268° C. The scientists said this radiation should lie in the microwave region of the spectrum; their calculations were verified by physicists Robert Dicke and P. J. E. Peebles.

Penzias's and Wilson's contribution to the issue began with a 20-ft (6.1-m) directional radio antenna, the same kind of radio antenna designed for satellite communication. Investigating an irritating noise emitted by the antenna, the two men realized in May of 1964 that what they heard was not instrumental noise but microwave radiation coming from all directions uniformly. Penzias and Wilson calculated the radiation's temperature as about 3.5 K. Dicke and Peebles, who had made the earlier calculations, got reinvolved from nearby Princeton University with a scientific explanation of the Penzias-Wilson discovery. More experiments followed, confirming that the radiation was unchanging when measured from any direction. Even after the duo received the Nobel Prize in 1978 (also awarded that year to Pyotr Kapitsa for unrelated work in physics) they continued to collaborate on research into intergalactic hydrogen, galactic radiation and interstellar abundances of the isotopes.

At the time of the federal lawsuit which led to the breakup of AT&T in 1984, Penzias, who had become vice president of research in 1981, predicted that without the operating companies as a base, Bell Labs would become "a sinking ship." That did not happen. Instead, in September of 1990, Penzias presided over the realignment of Bell Labs into a facility whose research is streamlined and oriented towards the activities of its business units.

While rearranging Bell Labs, Penzias has kept an eye on the outside world, writing Ideas and Information: Managing in a High-Tech World in 1989 and staying involved in the national dialogue regarding the growth of computer technology and international competition. He told Forbes magazine in March of 1989, "You go into Sears, the best cordless telephone you can buy is an AT&T phone. It works better. You try it."

In his personal life, Penzias, who is the proud grandfather of three, is also an avid skier, swimmer, and runner with an interest in kinetic sculpture and writing limericks. Penzias is a member of the National Academy of Sciences and the National Academy of Engineering, as well as the vice-chairman of the Committee of Concerned Scientists, devoted to political freedom for scientists internationally. He has written over 100 articles and collected more than 20 honorary degrees. Penzias holds that technology can be liberating. As he wrote in Fortune magazine in March of 1990: "Everybody is over-stressed…. We've got to stop going to meetings and have them electronically instead…. How far away are we from realizing this dream? My guess is that by the time Fortune marks its 100th anniversary, a lot of this will have happened. In fact, long before I retire, I hope to have at least a multimedia terminal in my office so that I can integrate voice, data, high-definition video, conference video, document access, and shared software… who's going to do all this? I hope it's AT&T. But it could be IBM, Apple—it could be anybody." Penzias officially retired from Bell Labs in the spring of 1998, but continues to serve in a technical advisory role.

See also Cosmic microwave background radiation