Tikalon Blog by Dev Gualtieri

J. Robert Oppenheimer and Black Holes

April 24, 2017

Most languages allow the construction of compound words; so, in English, we have words such as backpack, searchlight, and railroad. The German language seems to take this concept to excess, building extremely long words. Mark Twain wrote in his essay, "The Awful German Language," published as an appendix to the second volume of "A Tramp Abroad," that "Some German words are so long that they have perspective".[1]

A few of the smaller compound German words are in common use among English speakers. The prime example of this is "schadenfreude," the enjoyment attained from seeing someone else's misfortune. The word even appeared in an episode (Episode 3, Season 3, "When Flanders Failed") of The Simpsons. In that episode, Lisa Simpson defines the word for Homer Simpson, who is reveling in the misfortune of his neighbor, Ned Flanders.[2]

I've never had occasion to use the word, schadenfreude. Scientists are good-natured people who share information and want their competitor's experiments to succeed. I'm sure that there were cheers at Fermilab when the the Higgs boson was discovered in 2012 at CERN, but no cheers when the Large Hadron Collider exploded in 2008. One compound German word that I enjoy using is putzfimmel, the word for cleaning mania. I don't like vacuum cleaner noise. To write a blog like this, you need "sprachgefühl," a "feeling for language."

Putzfimmel

An illustration by Charles Keene (1823–1891), from a book by Douglas William Jerrold, "Mrs Caudle's curtain lectures," page 193.

This was a comic strip originally published in Punch magazine.

(Modified Wikimedia Commons image.)

Physicist, Freeman Dyson, has used the German word, "sitzfleisch," to describe American physicist, J. Robert Oppenheimer (1904-1967).[3] Sitzfleisch is the ability to sit still and work quietly. As I write this I'm reminded of Daya's song, "Sit Still, Look Pretty."[4] In a lengthy article in 2013 in the New York Review of Books, Dyson writes that Oppenheimer was not able to sit long enough to finish a difficult calculation. As a consequence, his calculations contained many errors.

This lack of sitzfleisch extended to Oppenheimer's seminars, in which he would be in constant motion, incessantly smoking.[3] Dyson also writes about Oppenheimer's "pathological" interest in everything, a personality trait that he shared with Richard Feynman, who decided he needed to know why a thrown dinner plate wobbled the way that it did.[5] Dyson comments that Oppenheimer's personality traits prevented his becoming a great scientist, and the only significant problem that he solved was the gravitational collapse of massive stars into black holes.[3]

With the discovery at LIGO of gravitational waves arising from the merger of black holes, black holes are very much in the news. Three papers from 1938-1939, co-authored by Oppenheimer, discuss the existence of black holes.[6-8] Dyson writes that Oppenheimer's papers on black holes were his "only revolutionary contribution to science."[3] Interestingly, Oppenheimer didn't think the work was significant, and he placed the most importance on his early research on the positron.

J. Robert Oppenheimer, smoking a cigarette, at the Guest Lodge, Oak Ridge, February 1946.

This was nearly twenty years before the 1964 Surgeon General report on smoking. Oppenheimer died from throat cancer on February 18, 1967, at the young age of 62.

(DOE Digital Archive Image 2017659, photograph by Ed Westcott, via Wikimedia Commons, modified for artistic effect.)

The starting point for a black hole is a neutron star. Oppenheimer and post-doc Robert Serber published the paper, "On the stability of stellar neutron cores,"in 1938.[6] The next year, Oppenheimer and his graduate student, George Volkoff, published the paper, "On Massive Neutron Cores," in which they calculated the mass above which a star should collapse into a neutron star.[7] All this was long before neutron stars were detected in 1967.

Oppenheimer and Hartland Snyder, another of his students, published the 1939 paper, "On Continued Gravitational Attraction", that predicted the existence of black holes; or, as they wrote, objects for which "an observer co-moving with the matter would not be able to send a light signal from the star; the cone within which a signal can escape has closed entirely."[8] It wasn't until 1967 that John Archibald Wheeler (1911-2008) coined the term, "black hole."

Oppenheimer and Snyder found that static solutions of stellar collapse were impossible, but solutions where the object continued to change in time were allowed; that is, the object would continually contract.[8-9] Finally, "The star thus tends to close itself off from any communication with a distant observer; only its gravitational field persists."[8-9]

Most physicists thought that nature would not allow such infinite collapse. Russian physicist and eventual Nobel Laureate, Lev Landau, thought that something in quantum mechanics would disallow such a thing.[9] The paper, and the idea of the black hole was essentially ignored until Wheeler and other physicists revived the concept decades later.[9]

A team of physicists from the School of Physics of the University of Costa Rica (San José, Costa Rica) have just published an article on arXiv examining a few historical aspects of Oppenheimer's black hole paper, including its neglect by both Oppenheimer and the physics community.[10] They undertake to answer the following questions:

• Whether the Oppenheimer paper was considered good science according to the standards of the time.

• Whether the work was ignored because Oppenheimer was not preeminent among scientists in the field.

They conclude that the paper was good science, and that Oppenheimer had a good standing in physics. It was just an idea before its time.[10]

NASA - Artist's conception of a black hole

The hole may be black, but its surrounding accretion disk is anything but.

(NASA image, via Wikimedia Commons.)

J. Robert Oppenheimer and Black Holes

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