Before the Big Bang became scientific dogma

doi:10.1126/science.abj9479

GSTDTAP > 气候变化

DOI	10.1126/science.abj9479
	Before the Big Bang became scientific dogma
	Simon Mitton
	2021-08-20
发表期刊	Science
出版年	2021
英文摘要	The serendipitous detection of the cosmic microwave background radiation in 1964 changed cosmology forever, settling a long-running debate about the origin of the Universe. The radio hiss hinted that the Universe had arisen from an instantaneous fiery beginning, a theory championed by cosmologist George Gamow, who sought to account for the origin of the chemical elements. His rival, Fred Hoyle, who developed the alternative steady-state theory, which posited an infinite Universe, had long insisted that the chemical elements formed continuously in the cores of massive stars. Both cosmic models were falsifiable by solving a simple puzzle: Has the Universe evolved? The feeble whisper detected in 1964 was an undeniable “Yes!” In Flashes of Creation , Paul Halpern presents a scintillating account of the intellectual travails of Gamow and Hoyle, two animated, curious, provocative, and controversial figures in 20th-century physics. In this joint biography, the reader is introduced to the two physicists' theories and their efforts to explain the origin of elements. Gamow, we learn, first encountered cosmology in the early 1920s while studying at the University of Leningrad under Alexander Friedmann, the Russian mathematician who pioneered the idea that the Universe is expanding. In Göttingen and Copenhagen, while a doctoral student in physics, he mingled with pioneers who were working on the new quantum theory. These interactions enabled his breakthrough in 1928, when he showed how an alpha particle could escape from an atomic nucleus by quantum tunneling. Gamow's subsequent realization that quantum tunneling is reversible spurred two colleagues, Robert Atkinson and Fritz Houtermans, to demonstrate that sufficiently energetic protons could penetrate the atomic nuclei often enough to account for the source of stellar energy. Physicist Hans Bethe made the next advance, finding that proton-proton collisions in the cores of stars like the Sun fuse hydrogen to helium. For more-massive stars, he suggested a cycle of nuclear reactions in which carbon, nitrogen, and oxygen catalyze hydrogen to helium. This scheme left open the question that Gamow and Hoyle would confront head on: How did the elements from carbon to uranium come into existence? Hoyle entered the Cavendish Laboratory at the University of Cambridge in 1936 as a doctoral student supervised by Rudolf Peierls. As academics, including Peierls, later fled the Cavendish Laboratory to professorships elsewhere, Hoyle remained at Cambridge until the war years, working alone on extending Enrico Fermi's theory of beta decay. By peacetime, he had developed the steady-state theory and witheringly dismissed Gamow's cosmology as a mere “big bang.” Hoyle could perceive no merit in Gamow's notion that the elements were created in a flash by the eruption of a primeval atom—it violated the conservation laws of physics. His ageless steady-state approach envisaged that new matter trickled continuously into the empty space left by the expansion of the Universe. The buildup of chemical elements then arose as a consequence of the evolution of massive stars, he postulated. When the hydrogen fuel in a star's core became exhausted, it would implode gravitationally, thereby sparking the physical conditions conducive to the rapid assembly of heavier elements. The Gamowian school had considered the role of neutrinos in core collapse, but Hoyle's powerful rebuttal of their model in 1946 was vastly more efficient at building heavy elements. By 1957, Hoyle's team had completed its brilliant synthesis of element building via neutron capture reactions. However, steady-state theory came under relentless attack as report after report by observational astronomers cemented Big Bang cosmology. In 1964, Hoyle reluctantly conceded that “a small residue of Gamow's idea”—the synthesis of light elements in the Big Bang—had merit. Within months, news broke of the discovery of the cosmic microwave background. Hoyle never accepted this as evidence that “the entire cosmos had a start date.” By contrast, Gamow opportunistically seized the moment, claiming primary credit for a neglected prediction of the background temperature made in 1948 by his associates Ralph Alpher and Robert Herman. In the book's closing pages, Halpern sensitively handles with commendable candor the tragic endgames of these two giants. Gamow's alcoholism, we learn, destroyed him and much of his reputation. And while Hoyle commanded great respect after resigning from Cambridge in 1972, his little tweaks to steady-state cosmology failed to find a following. Gamow and Hoyle were friendly rivals who seldom interacted in person. Halpern nonetheless renders their contributions and clashes vividly in this expertly crafted biography of two contentious cosmologists who thrived on ingenious invention.
领域	气候变化 ; 资源环境
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文献类型	期刊论文
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/336018
专题	气候变化资源环境科学
推荐引用方式 GB/T 7714	Simon Mitton. Before the Big Bang became scientific dogma[J]. Science,2021.
APA	Simon Mitton.(2021).Before the Big Bang became scientific dogma.Science.
MLA	Simon Mitton."Before the Big Bang became scientific dogma".Science (2021).