%I M1912 #100 Jan 26 2024 10:18:25

%S 2,9,9,7,9,2,4,5,8

%N Decimal expansion of the SI unit c (speed of light in vacuum), c = 299792458 meters/second.

%C Since 1983, the speed of light has been defined to be exactly 299792458 m/s. - Ron Marcinski (ronmarcinski(AT)hotmail.com), Apr 18 2002

%C From _Stanislav Sykora_, Jun 16 2012: (Start)

%C General context: Within current metrological systems (SI + IAU definitions), several physics constants have been "assigned" immutable values. They thus became metrological reference points, no longer subject to experimental assessment. These should not be confused with "conventional" values of some empirical quantities (such as Josephson's constant) used in applied metrology, but not assigned, and therefore subject to possible future revisions.

%C Assigned metrological constants [before the inception of the 2019 SI, which introduced some changes, see below for references] and some of their combinations that appear in the OEIS include the speed of light (this sequence); magnetic permeability of vacuum (A019694); electric permittivity of vacuum (A081799); characteristic impedance of vacuum (A213610); standard gravity acceleration (A072915), standard atmosphere (A213611), Julian year (A213612), Gregorian year (A213613) and the light-year (A213614), all in basic SI units.

%C (End)

%C Prime factors of this number are 2^1, 7^1, 73^1, 293339^1. - _John W. Nicholson_, Jun 15 2014

%C c is also the speed of gravity. - _Omar E. Pol_, Jun 23 2017

%C In the 2019 SI system of units (see the second BIPM link, and A322415) one of the seven defining constants is c = 299792458 m/s. - _Wolfdieter Lang_, Feb 12 2019 [corrected by _Ivan Panchenko_, May 20 2019]

%D CRC Handbook for Chemistry and Physics, 75th edition, (1994-1995), Page 1-1.

%D H. J. Fischbeck and K. Fischbeck, Formulas. Facts and Constants, Springer-Verlag, NY, 2nd ed., 1987.

%D R. F. Fox and T. P. Hill, An exact value for Avogadro's number, American Scientist, 95 (No. 2, 2007), 104-107.

%D K. R. Lang, Astrophysical Data: Planets and Stars, Springer-Verlag, NY, 1991.

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H BIPM, <a href="https://www.bipm.org/">Bureau International des Poids et Mesures</a>, the historic home of SI units (works jointly with NIST).

%H BIPM, <a href="https://doi.org/10.59161/CGPM2018RES1E">On the revision of the International System of Units (SI)</a>, BIPM, Nov 13-16 2018.

%H G. Bonnet, <a href="http://culturesciencesphysique.ens-lyon.fr/Entree_par_theme/generalites/VLumiere">La vitesse de la lumiere (Text in French)</a> [broken link].

%H IAU, <a href="http://www.iau.org/">International Astronomical Union</a> has accepted SI and added a few definitions of its own.

%H P. J. Mohr, B. N. Taylor and D. B. Newell, <a href="http://dx.doi.org/10.1103/RevModPhys.80.633">CODATA recommended values of the fundamental physical constants: 2006, Rev.Mod.Phys. 80, 2008, 633-730. DOI: 10.1103/RevModPhys.80.633</a>. (This is the hard-core source of what became CODATA 2010.)

%H NIST, <a href="http://physics.nist.gov/cgi-bin/cuu/Value?c">speed of light in vacuum</a>.

%H S. Sykora, <a href="http://www.ebyte.it/library/educards/constants/ConstantsOfPhysicsAndMath.html">Constants of Physics and Mathematics</a>, extensive constant-at-a-glance tables.

%H Eric Weisstein, World of Physics, <a href="http://scienceworld.wolfram.com/physics/SpeedofLight.html">Speed of Light</a>.

%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Speed_of_gravity">Speed of gravity</a>.

%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Speed_of_light">Speed of light</a>.

%H Wikipedia, <a href="https://en.wikipedia.org/wiki/2019_redefinition_of_SI_base_units">2019 redefinition of SI base units</a>

%F c = 299792458 m/s (equals 299792.458 km/s).

%t IntegerDigits[299792458] (* _Michael De Vlieger_, Jun 23 2017 *)

%Y Cf. A224236, A224237, A224238, A070058, A070059, A070060, A070062, A070063, A070064, A322415.

%Y More assigned constants: A003676 (h), A230458 (Δν_{Cs}), A081823 (e), A322578 (N_A), A070063 (k), A021687 (1/K_{cd}); A182999 (c^2), A183000 (c^3), A183001 (c^4), A019694, A081799, A213610, A072915, A213611, A213612, A213613, A213614.

%K cons,nonn,fini,full

%O 9,1

%A _N. J. A. Sloane_