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Summary of Constants



Physical Constants
(ref. Physics Today, Aug. 1995 pg. BG9)

AU = astronomical unit = 1.4960 · 1013 cm
c = speed of light = 2.99792458 · 1010 cm/s
G = 6.67259(85) · 10-8 dyne cm2/gm2
h = Planck's constant = 6.626075(40) · 10-27 erg sec
k = Boltzmann's constant = 1.380658(12) · 10-16 erg/K
Na = Avogadro's number = 6.0221367(36) · 1023 /mole
sigma = Stefan-Boltzmann constant = 5.67051(19) · 10-5 erg/s/cm2/K4
S0 = 1.37 · 106 erg/cm2
Runiv = Na · k = 8.3143 · 107 erg/mole/K
<mw>H2O = 18.016 gm/mole
<mw>O3 = 47.9982 gm/mole

Earth Constants

Req = 6378.388 km
Mearth = 5.975 · 1027 gm
<mw>dry air = 28.964 gm/mole
Rg = 0.28705 · 107 erg/gm/K
N0 = Loschmidt's number = 2.686763(23) · 1019 molecules/cm3
gs = Standard surface gravity = 980.665 cm/s
Ps = Standard surface pressure = 1.01325 · 106 dyne/cm2
cp = 1.006 · 107 erg/gm/K at stp
cv = 0.718 · 107 erg/gm/K at stp
gamma = cp/cv = 1.401 at stp

Unit Conversion

1 knot = 1 nautical mile/hour = 1.151555 mile/hour = 1.853248 Km/hr
1 megaton = 4.2 · 1022 erg = 4.2 · 1015 Joule
1 AU = 1.495 · 108 Km = 8.31 light minutes