TERZO CLASSICO: GUERRE STELLARI

Empire of the stars: Obsession, friendship, and betrayal in the quest for
black holes

On January 11, 1935, an event that was, in the words of author Arthur Miller,
“singular in the annals of modern science,” took place at a meeting of the Royal
Astronomical Society (RAS) at Burlington House, Piccadilly Square, London. In an
elegant presentation lasting only fifteen minutes, a very young Indian astrophysicist,
Subrahmanyan Chandrasekhar (now known universally as simply Chandra) presented
his startling theory about the fate of stars which have consumed their basic fuel.
Chandra believed his theory, which predicted that stars not much larger than the sun
would collapse into compact objects now known as either neutron stars or black
holes, would solve a critical problem posed by the doyen of British astrophysics,
Sir Arthur Stanley Eddington. In a vitriolic response that immediately followed,
however, Eddington demolished Chandra’s paper. Eddington’s rhetorical flurry of
denial that such objects could possibly exist was to have lasting consequences for
both individuals. Those consequences form the basis for the remainder of this very
readable and interesting book.
Born into a Brahmin family of high intellectual achievement (his uncle C. V.
Raman was the first Indian to receive a Nobel Prize in Physics), Chandra exhibited
prodigious mathematical talent as a child. His ability was widely recognized and led
to a scholarship for graduate studies at Cambridge University, where he chose
astrophysics as an emerging field of science rather than pure mathematics. While
in transit to Britain from India, Chandra made the discovery that would plague him
for the remainder of his life, as he calculated the maximum mass of a star that could
remain stable as a white dwarf, recognizing in the process that any larger star would
collapse under the influence of its own gravity. The mathematical details of the
whole process were only worked out by Chandra after his arrival in Cambridge.
During that working out of the details, Chandra was pleased that Eddington would
visit him in his office on a frequent basis to learn about the progress of Chandra’s
work; he felt certain, on that basis, that Eddington would support his paper when
it was presented to the RAS. Thus, Eddington’s vehement attack on the paper was
a stunning surprise to all present in the RAS audience, but most of all to Chandra.
Almost as disappointing to Chandra was the failure of others like A. E. Milne who
had befriended Chandra, James Jeans who opposed Eddington on nearly everything,
and others who seemed sympathetic to Chandra’s scientific conclusions to publicly
Williams, JAAVSOVolume35, 20062
challenge Eddington. In effect, the British astrophysical community was completely
cowed by its acknowledged éminence grise.
Unfortunately for Chandra, in two subsequent opportunities when he presented
his theory in international forums, the outcome was the same—Eddington’s
vehement denial of the possibility of the collapse of a white dwarf into any smaller
body accompanied by surprising condescension to Eddington’s position by senior
astrophysicists. At the last of these occasions, an International Astronomical
Union meeting in Paris, the reluctance of those assembled to challenge Eddington
was all the more surprising in that in that same meeting Gerard Kuiper had already
presented observational evidence that tended to support Chandra’s theoretical
proposition.
Several decades passed, during which Chandra relocated to the University of
Chicago, first at Yerkes Observatory and eventually to the main campus in Chicago.
His work also moved on to demonstrate his theoretical prowess in a succession of
book length theoretical explorations, first of stellar structure, then radiative transfer,
hydrodynamics, and finally a series of papers exploring the application of general
relativity to astrophysical problems, culminating in a book on the mathematical
theory of black holes.
Progress on Chandra’s original problem, the collapse of white dwarfs of more
than 1.4 solar masses (now known as the Chandrasekhar Limit) was slow, and came
from a surprising quarter. Work on supernovae proceeded observationally from the
1930s and on with little understanding of the theoretical mechanisms involved. It
remained for physicists who were interested in high temperature nuclear reactions
to sort out the mechanisms involved. They worked under the urgent pressure to
understand the physics of thermonuclear explosions necessary for nuclear weapons
development. Supernovae and superbombs thus developed apace in both the
United States and in the Soviet Union under the pressure of cold-war geopolitics.
The story abounds with the names and personalities of well known figures from this
period like Oppenheimer, Teller, Bethe, and Fermi. Astrophysicists also made their
own contributions; thus Baade, Zwicky, Gamow, Hoyle, Gold, and Wheeler enter
the story at appropriate points. Miller also adds interesting glimpses into the
personalities and workings of astrophysics and nuclear physics in the Soviet Union,
including biographical information on Russian scientists like Landau and Zel’dovich.