fine-structure constant concept from the Astronomy knowledge base

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fine-structure constant
(α, α)

subject fact

fine-structure constant has symbol α 2001-09-27 09:33:08.0
has symbol α
has value 7.297352533 × 10^-3 has URL: http://physics.nist.gov/cgi-bin/cuu/Value?eqalph, 2001-09-27 09:33:08.0
has equation
has uncertainty 0.000000027 × 10^-3
has definition A "coupling constant," e² / h bar c, approximately 1/137, that measures the strength of an interaction between a charged particle and the electromagnetic field. It gives a rough measure of the relative importance of relativistic and spin effects in the spectra of atoms. has source: Hopkins, J. 1976 Glossary of Astronomy and Astrophysics, University of Chicago Press, 2001-09-27 09:33:08.0
has definition A parameter that measures the strength of the electromagnetic force. The fine-structure constant is a combination of other fundamental constants of nature - the electrical charge of the electron, the speed of light, and Planck's constant of quantum mechanics. has source: Lightman, A., Brawer, R. 1990 The Lives and Worlds of Modern Cosmologists, Harvard University Press, 2001-09-27 09:33:08.0
has definition A coupling constant e² / h bar c, approximately equal to 1/137 (where e is the electron charge, h bar is Plancks constant, and c is the speed of light), that measures the strength of the interaction between a charged particle and the electromagnetic field. has source: Silk, J. 1990 The Big Bang, W. H. Publishers, New York, 2001-09-27 09:33:08.0
is an instance of atomic constant

fundamental physical constant has accuracy 2001-09-27 09:32:59.0
has unit

fine-structure constant	has symbol α
	has symbol α
	has value 7.297352533 × 10^-3
	has equation
	has uncertainty 0.000000027 × 10^-3
	has definition A "coupling constant," e² / h bar* c, approximately 1/137, that measures the strength of an interaction between a charged particle and the electromagnetic field. It gives a rough measure of the relative importance of relativistic and spin* effects in the spectra of atoms.
	has definition A parameter that measures the strength of the electromagnetic force. The fine-structure constant is a combination of other fundamental constants of nature - the electrical charge of the electron, the speed of light, and Planck's constant of quantum mechanics.
	has definition A coupling constant e² / h bar* c, approximately equal to 1/137 (where e is the electron charge, h bar* is Plancks constant, and c is the speed of light), that measures the strength of the interaction between a charged particle and the electromagnetic field.
	is an instance of atomic constant
fundamental physical constant	has accuracy
fundamental physical constant	has unit