On April 22, 1904, after a difficult labor, a blue-eyed child was born to Julius and Ella Oppenheimer. They named him Robert, but gave him a preceding initial taken from his father, which Robert later said "stood for nothing." Julius Oppenheimer was a Jewish immigrant who had come to the United States from Hanau, Germany, in 1888 to work in a family business importing textiles at the age of seventeen. An ambitious and self-improving man, by his thirtieth birthday he was wealthy with excellent command of the English language and in possession of developed tastes in art and literature; Robert later described him as "one of the most tolerant and human of men." Ella Friedman Oppenheimer was an artist who had studied painting in Paris and whose family had immigrated from Germany in the 1840s. At the time she met Julius, she was teaching art in her own New York studio.
The Oppenheimers lived on the eleventh floor of an apartment building in a well-to-do neighborhood on Riverside Drive, overlooking the Hudson River. In this sheltered atmosphere, Robert grew up surrounded by Van Goghs and fine European furniture in those days more a sign of good taste than wealth.
As a boy, Robert attended the Ethical Culture School, where, in addition to mathematics and science, he was exposed to a variety of subjects ranging from Greek to French literature. Then, as later in his life, Robert pursued science and the humanities with equal ease and pleasure. When Robert was eight, his brother Frank Friedman Oppenheimer was born.
In school he pursued interests in Greek, chemistry, architecture, classics, art, and literature. As a child, he was given a "perfectly conventional tiny collection of minerals" by his grandfather on a visit to Germany. "From then on I became," he recalled, "in a completely childish way, an ardent mineral collector and I had, by the time I was through, quite a fine collection." At age twelve he had been elected an honorary member of the New York Mineralogical Club and delivered a paper at one of its meetings.
Taking a year off before starting college at Harvard due to an attack of colitis, Robert traveled with a former English teacher to New Mexico, where he fell in love with horseback riding and the mountains and plateaus of the American Southwest. He returned reinvigorated.
At Harvard, Robert flourished, pursuing philosophy and French literature along with his science. He was introduced to experimental physics in a course on thermodynamics taught by future Nobel Laureate Percy Bridgman. While only in his first year as an undergraduate, he had applied, on the basis of independent study, for graduate standing in physics, which would allow him to take higher level courses (which he was granted). After three years of college, Robert graduated in 1925 with an A.B. in chemistry, summa cum laude. He was then admitted to carry out advanced work with J.J. Thomson at the Cavendish Laboratory in Cambridge, England. However, Robert was somewhat poor at experimental work, though he was becoming increasingly interested in the theoretical aspects of physics, represented in Cambridge by R.H. Fowler and still in the throes of the revolution started by Planck, Einstein, and Bohr.
Surviving a brief bout of depression, Robert accepted an offer from Max Born to continue his studies at the University of Göttingen in Germany, one of the centers of theoretical physics in Europe. Work at Göttingen was centered around a newly forming field of physics, quantum mechanics, and Robert was in on the ground floor.
During his time at Göttingen, Robert found acceptance and success, despite his relative lack of experience with theoretical physics and his young age he was only twenty-two at the time, and looked much younger. While there he worked with Born, Paul Dirac, Ed Condon, and many others, and he started to gain a very favorable reputation as he began to produce good work and hold his own with any of the other young mathematical physicists. As at Cambridge, there was a steady flow of visiting physicists in Göttingen, and Robert interacted with Werner Heisenberg and Wolfgang Pauli, among many distinguished (and soon-to-be distinguished) others.
In the spring of 1927, Robert was awarded his doctorate with distinction from Göttingen, writing his dissertation on problems concerning the continuous spectrum. He continued to work on the application of quantum mechanics to the problem of scattering, and with Max Born he wrote a joint paper on the quantum theory of molecules, creating the "Born-Oppenheimer approximation," which continues to be used to this day. Robert had arrived in Europe as a somewhat inept and ineffectual laboratory physicist and left as a young maven of mathematical physics. He chose to spend the fall term at Harvard before going to Pasadena to work at the California Institute of Technology, as a National Research Council fellow.
While at Caltech he received numerous invitations for teaching positions ten in the United States and two in Europe and eventually opted for an assistant professorship in physics at the University of California, Berkeley. Berkeley appealed, in his words, because "it was a desert," and yet it was also a fertile place of opportunity. He maintained a joint appointment with Caltech, where he sporadically taught in the spring term, in order to avoid potential isolation. Before his Berkeley professorship began, however, he was diagnosed with a mild case of tuberculosis, and with his now sixteen-year-old brother Frank, spent some weeks at a ranch in New Mexico. They dubbed the location "Perro Caliente," from Robert's exclamation of "Hot dog!" when he found out it could be leased. Eventually he purchased it outright.
Driving west to California, Frank flipped their car over and Robert broke his arm. (There was some debate between them about who was the worse driver, and both had considerable claim to the honor.) To cheer up Frank, Robert chose bright red as the color for his sling, which is what he was wearing when he arrived in Pasadena.
In the fall of 1928, Robert headed back to Cambridge and on to the University of Leiden, Holland, traveling along with Paul Dirac to visit Paul Ehrenfest's institute, where he impressed colleagues by giving lectures in Dutch despite very little experience with the language. They affectionately dubbed him "Opje," which became Americanized as "Oppie." He then spent a month in Utrecht, working with Hendrik Kramers. Robert had planned to head to Copenhagen to work with Niels Bohr, but Ehrenfest instead advised him to go to Zurich, in Switzerland, on the suggestion that Oppenheimer would benefit more from close contact with Wolfgang Pauli, another sharp mathematical physicist, rather than Bohr's more qualitative and cloudy approach. Robert stayed through the spring of the next year, working with Pauli on, among other things, fundamental problems of quantum field theory and the continuous spectrum.