Meet J. Robert Oppenheimer, father of the atomic bomb and the first director of Los Alamos National Laboratory.
Nestled high on the Pajarito Plateau, Project Y brought together Oppenheimer’s two great loves: “physics and New Mexico.” Here, Oppenheimer is pictured at his property near Pecos, New Mexico. Photo: Niels Bohr Library & Archives.
In 1943, at 38 years old and with no previous administrative experience, physicist J. Robert Oppenheimer accepted responsibility for a national security mission of unprecedented scale.
His charge, handed down by Manhattan Project director General Leslie Groves, was to lead a team of the world’s foremost scientific minds in developing the first nuclear weapon. Under Oppenheimer’s leadership, more than 6,000 scientists, engineers, and other personnel lived and worked at a top-secret lab in Los Alamos, New Mexico, and completed their task in only 27 months. Weeks later, they delivered the world’s first two nuclear bombs to the U.S. military. World War II ended shortly thereafter.
Long before joining the Manhattan Project, Oppenheimer had a personal connection to northern New Mexico. Prone to illness in his youth, an 18-year-old Oppenheimer spent a restorative and formative summer at Los Piños ranch near Santa Fe. He returned often to the area in adulthood, even as a busy academic teaching physics at the University of California, Berkeley and the California Institute of Technology.
The treacherous road “up the hill” to Los Alamos helped Oppenheimer’s wartime laboratory remain fairly isolated during the Manhattan Project.
The fall of 1942 found Oppenheimer back in New Mexico touring a potential site—Jemez Springs—for Project Y, the wartime codename for what would eventually become Los Alamos National Laboratory. Both Oppenheimer and Groves found Jemez Springs unsuitable, and Oppenheimer proposed a nearby alternative: Los Alamos, which he had once visited during a horse-packing trip. There, a few homesteads and a boys’ boarding school sat on an isolated, nearly inaccessible plateau—the perfect location for a secret lab.
Within a few months, the federal government had acquired 50,000 acres of land, including the boy’s school, which rushed to graduate its oldest students by January 1943. That spring, crews broke ground on the additional buildings necessary for a full-scale nuclear research laboratory.
Oppenheimer’s badge photo was taken in 1943 as he began his directorship at the top-secret lab in northern New Mexico.
Even before the construction dust settled, in March 1943, Oppenheimer and Groves began assembling a team of the world’s brightest scientific minds. Oppenheimer, of course, was brilliant himself. An accomplished theoretical physicist, intellectual jack-of-all-trades, and a deep thinker well-read in Eastern philosophy, Oppenheimer was a guiding force in asking and answering the research questions that led to groundbreaking innovations at the Lab.
Though he had no shortage of expert advisors and team leaders, including more than a dozen current or future Nobel laureates, Oppenheimer bore the responsibility of making critical scientific and personnel decisions to keep the Lab on track and on schedule. Many who worked with Oppenheimer said that there was no other man for the job. His profound understanding of both nuclear physics and human nature made Oppenheimer a natural leader of his technical staff and an able keeper of the specialized research underway across the Lab’s four divisions.
Oppenheimer’s counsel continued to pave the way as Los Alamos reached a crossroads in mid-1944. Atomic bomb design had been progressing along two lines: a gun-type uranium device called Little Boy and a gun-type plutonium device called Thin Man. After a series of failed experiments that were attributed to an incompatibility between the gun-type mechanism and plutonium fuel, Oppenheimer gave the order to abandon the Thin Man design. He then raised two new divisions divisions—Explosives and Weapons Physics—to design and build a complex and unproven imploding weapon. On July 20, 1944, he declared at an administrative board meeting that “all possible priority should be given to the implosion program.”
Oppenheimer’s McKibbin card (as Laboratory personnel cards were called in reference to their issuer, Dorothy McKibbin) notes his date of final departure from Los Alamos. The cards were employment verification and were issued to every Lab employee during the Manhattan Project era.
The Little Boy and Fat Man atomic bombs were released above Japan on August 6 and 9, respectively. Japan surrendered shortly thereafter, and World War II officially ended on September 2, 1945.
The Manhattan Project was complete. On October 16, 1945, the Army-Navy E Award for excellence in war production was bestowed upon Oppenheimer and the scientists, engineers, military personnel, and others at the Lab whose patriotism “helped our country along the road to victory.” On the day of this capstone event, Oppenheimer announced his resignation.
He would go on to serve in important advisory roles as the United States debated the future of nuclear research and the wartime lab at Los Alamos. ★
Dorothy McKibbin (left) had an office at 109 East Palace Avenue in Santa Fe, New Mexico. There, she should greet new arrivals to the Manhattan Project and send them on their way to the Secret City. She became known as the “gatekeeper to Los Alamos” and came to know Oppenheimer quite well. “I never met a person with a magnetism that hit you so fast and so completely,” McKibbin once said of Oppenheimer. “I knew anything he was connected with would be alive.” The letter J in Oppenheimer’s first name is still a mystery. Most sources—including Oppenheimer’s own birth certificate and a 1944 letter from the War Department granting Oppenheimer his security clearance—state that Oppenheimer’s first name was Julius. Numerous other people, though—including Oppenheimer himself— insisted the J didn’t stand for anything at all. In a 1946 letter to the U.S. Patent Office (pictured), Oppenheimer wrote: “This is to certify that I have no first name other than the letter J, and that my full and correct name is J Robert Oppenheimer.”Before his arrival at Los Alamos, Oppenheimer recorded some thoughts about the challenges of Project Y on the back of a letter from his bank.An early organizational chart of the secret Los Alamos laboratory shows four technical divisions. The Theoretical division still exists at Los Alamos National Laboratory today.In 1929, a log and stone cottage was built at 1967 Peach Street in Los Alamos. Part of the Los Alamos Ranch School, the house was called Master’s Cottage #2. During the Manhattan Project, the Oppenheimers occupied the house from April 1943 to October 1945. In 2020, the house became part of the Los Alamos Historical Society, which is working to restore the structure and open it to the public. Learn more.
Oppenheimer often wore a brown porkpie hat (size 6 and 7/8, according to The New York Times). In May 1948, Oppenheimer’s hat was featured on the cover of Physics Today.Shortly after the end of World War II, General Groves called Oppenheimer a genius. “Why, Oppenheimer knows about everything,” he said. “He can talk to you about anything you bring up. Well, not exactly. I guess there are a few things he doesn’t know about. He doesn’t know about sports.”Oppenheimer’s charm is widely noted. Scientist Robert Christy remembered when Oppenheimer asked Christy to join him at the secret Los Alamos Lab. “I said I would be delighted because like most of his students, I would more or less follow him to the ends of the earth.”
Oppenheimer and physicist Ernest Lawrence.In a 1967 interview, Oppenheimer recalled meeting General Leslie Groves for the first time: “The first meeting with Groves was at the house of the president of the University for California. ... I said, ‘This thing will never get on the rails unless there is a place where people can talk to each other and work together on the problems of the bomb. And this could be at Oak Ridge [Tennessee], it could be some California desert, but someplace, there has got to be a place where people are free to discuss what they know and what they do not know and to find out what they can.’ And that made an impression on him.”This sketch of Oppenheimer’s wartime office at Los Alamos is from the collections of the National Security Research Center, which houses the Lab’s classified archives along with unclassified legacy materials. This sketch is the only known imagery of Oppenheimer's wartime office.Oppenheimer smoked for most of his life and died in 1967 from throat cancer at the age of 62. One of Oppenheimer’s physics students at the University of California—Berkeley recalled that “the most distinctive feature of his lectures [was] his chain smoking. He spoke quite rapidly, and puffed equally rapidly. When one cigarette burned down to a fragment he no longer could hold, he extinguished it and lit another almost in a single motion.” Groves once told his secretary that Oppenheimer (third from left) “has the bluest eyes I’ve ever seen. He looks right through you. I feel like he can read my mind.”Metallurgist Eric Jette, mathematical physicist Charles Critchfield, and Oppenheimer.Oppenheimer’s military-issued chair was made by the B.L. Marble Company and is currently on display in the National Security Research Center. The chair, available in catalogs from 1930 to 1943, was typically offered in a stained birch color. Oppenheimer’s chair, however, is green, which means the color was likely customized. Here, Oppenheimer sits in the chair during a visit to Los Alamos in 1964. This photo appeared in the June 1964 issue of The Atom magazine with the caption: “The famed scientist…tried the old executive chair he used as Laboratory Director. Oppenheimer noted that it was ‘still very hard.’”Dorothy McKibbin, Oppenheimer, and Victor Weisskopf enjoy a party at the Oppenheimer house.
During the Manhattan Project, Oppenheimer often hosted parties and informal gatherings at his Los Alamos home. One guest, Pat Sherr, remembered, “He served the most delicious and coldest martinis.” Oppenheimer’s martini recipe was four ounces of gin and a dash of vermouth; the rim of the chilled glass was dipped in honey and lime juice. Oppenheimer is pictured here in 1946 at a party at his Los Alamos home (he had moved out of it by then).Oppenheimer oversees final assembly of the Gadget.Oppenheimer’s copy of Bhagavad-Gita, translated from Hindu to English by Arthur W. Ryder, is part of the collections at the Lab’s Bradbury Science Museum. Oppenheimer’s handwritten initials appear in the upper right corner of the front endpapers. After the successful Trinity test, Oppenheimer was said to have recalled the line: “Now I am become death, destroyer of worlds.”Tucked inside Oppenheimer’s personal copy of the Bhagavad Gita — a 700-verse holy scripture central to Hindu religion — is a four-leaf clover. The clover is taped to a card on which “Mrs. Robert Oppenheimer” is printed. The patent application for the Fat Man bomb lists J. Robert Oppenheimer as the inventor.A recently rediscovered 149-page classified manual includes detailed drawings that show how to assemble the Fat Man bomb. The manual is the only known copy of the 25 originals that still exists.
In his November 2, 1945, speech to the Association of Los Alamos Scientists, Oppenheimer said of making the world’s first atomic devices: “…when you come right down to it the reason that we did this job is because it was an organic necessity. If you are a scientist you cannot stop such a thing. If you are a scientist you believe that it is good to find out how the world works; that it is good to find out what the realities are; that it is good to turn over to mankind at large the greatest possible power to control the world and to deal with it according to its lights and its values.”
On May 18, 1964, Oppenheimer returned to Los Alamos for the first time since 1945. In addition to visiting the Laboratory, he gave an evening lecture at the Civic Auditorium in Los Alamos High School. According to the June 1964 issue of The Atom magazine, “Oppenheimer received a standing ovation as he approached the lectern and again when he finished his speech.” He spoke about Danish physicist Niels Bohr, winner of the 1922 Nobel Prize in Physics. Norris Bradbury (left) and J. Robert Oppenheimer both served as directors for what is now known as Los Alamos National Laboratory. They are pictured here in 1964.
Nearly a decade after his security clearance was revoked, Oppenheimer received the Enrico Fermi Award from the Atomic Energy Commission on December 2, 1963. The award recognized Oppenheimer’s “unique role in the development of physics in the United States, as a teacher, as an originator of several fundamental concepts and as the administrator under whose leadership the atomic bomb was successfully developed at Los Alamos Scientific Laboratory during World War II” and came with $50,000.
“One of President Kennedy's most important acts was to sign the Enrico Fermi Award for Dr. Oppenheimer for his contributions to theoretical physics and the advancement of science in the United States of America,” explained President Lyndon Johnson, who presented the award to Oppenheimer in the wake of Kennedy’s death just 10 days prior.
Upon receipt of the award, Oppenheimer said: “I think it just possible, Mr. President, that it has taken some charity and some courage for you to make this award today. That would seem to be a good augury for all our futures.”
Oppenheimer’s obituary, which was published in The New York Times, explains that “J. (for nothing) Robert Oppenheimer lived the remainder of his life [after the 1945 Trinity test] in the blinding light and the crepusculine [sic] shadow of the world’s first manmade atomic explosion, an event for which he was largely responsible.”Oppenheimer died at his New Jersey home February 18, 1967, after unsuccessful treatments for throat cancer. He was 62, survived by his wife, Kitty, and their two children. Kitty spread his ashes near their simple beach home in the U.S. Virgin Islands (pictured), following a memorial service at Princeton University. Photo: Kitty Oppenheimer and J. Robert Oppenheimer Memorial CommitteeEmilio Segre Archives
In 1962, Manhattan Project leader General Leslie Groves wrote to Oppenheimer to ask about the origins of the name Trinity. According to a copy of the letter that is a part of the collections of the Lab’s National Security Research Center, Oppenheimer said, “Why I chose the name is not clear, but I know what thoughts were in my mind. There is a poem of John Donne, written just before his death, which I know and love.” Oppenheimer then quoted the sonnet “Hymn to God, My God, in My Sickness” about a man unafraid to die because he believed in resurrection. Oppenheimer continued, “That still does not make a Trinity, but in another, better known devotional poem Donne opens, ‘Batter my heart, three person’d God.’ Beyond this, I have no clues whatever.”
