This list of Current Best Estimates is made up of the "defining constants" which are not fixed by convention but measurable and determined by the NSFA Working Group. The NSFA WG will update these constants as and when research produces better values.
Click on one of the following constants to jump to the section with the current best estimate and all the relevant details and references.
Constant of gravitation  G = 6.674 28 x 10^{−11} m^{3}kg^{−1}s^{−2}  G 
Uncertainty:  6.7 x 10^{−15} m^{3}kg^{−1}s^{−2}  
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Average value of 1−d(TCG)/d(TCB) 
L_{C} = 1.480 826 867 41 x 10^{−8}  L_{C} 
Uncertainty:  2 x 10^{−17}  
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Solar mass parameter  GM_{S} = 1.327 124 420 99 x 10^{20} m^{3}s^{−2} [TCBcompatible] GM_{S} = 1.327 124 400 41 x 10^{20} m^{3}s^{−2} [TDBcompatible] 
GM_{S} 
Uncertainty:  1.0 x 10^{10} m^{3}s^{−2} [TCBcompatible] 1.0 x 10^{10} m^{3}s^{−2} [TDBcompatible]  
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Equatorial radius of the Earth  a_{E} = 6.378 1366 x 10^{6} m [TTcompatible]  a_{E} 
Uncertainty:  1 x 10^{−1} m [TTcompatible]  
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Dynamical form factor  J_{2} = 1.082 6359 x 10^{−3}  J_{2} 
Uncertainty:  1 x 10^{−10}  
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Time rate of change in J_{2}  dJ_{2}/dt = −3.0 x 10^{−9} cy^{−1}  dJ_{2}/dt 
Uncertainty:  6 x 10^{−10} cy^{−1}  
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Geocentric gravitational constant  GM_{E} = 3.986 004 418 x 10^{14} m^{3}s^{−2} [TCBcompatible] GM_{E} = 3.986 004 415 x 10^{14} m^{3}s^{−2} [TTcompatible] GM_{E} = 3.986 004 356 x 10^{14} m^{3}s^{−2} [TDBcompatible] 
GM_{E} 
Uncertainty:  8 x 10^{5} m^{3}s^{−2} [TCBcompatible] 8 x 10^{5} m^{3}s^{−2} [TTcompatible] 8 x 10^{5} m^{3}s^{−2} [TDBcompatible]  
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Potential of the geoid  W_{0} = 62 636 853.4 m^{2}s^{−2}  W_{0} 
Uncertainty:  The formal error is 0.02 m^{2}s^{−2}; however, as convention the adopted value is understood free of error.  
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Nominal mean angular velocity of the Earth  ω = 7.292 115 x 10^{−5} rad s^{−1} [TTcompatible]  ω 
Uncertainty:  (see Notes)  
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Ratio mass of the Moon to the Earth  M_{M}/M_{E} = 1.230 003 71 x 10^{−2}  M_{M}/M_{E} 
Uncertainty:  4 x 10^{−10}  
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Ratio of the mass of the Sun to Mercury  M_{S}/M_{Me} = 6.023657330 x 10^{6}  M_{S}/M_{Me} 
Uncertainty:  2.35 x 10^{−1}  
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Ratio of the mass of the Sun to Venus  M_{S}/M_{Ve} = 4.085 237 19 x 10^{5}  M_{S}/M_{Ve} 
Uncertainty:  8 x 10^{−3}  
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Ratio of the mass of the Sun to Mars  M_{S}/M_{Ma} = 3.098 703 59 x 10^{6}  M_{S}/M_{Ma} 
Uncertainty:  2 x 10^{−2}  
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Ratio of the mass of the Sun to Jupiter  M_{S}/M_{J} = 1.047 348 644 x 10^{3}  M_{S}/M_{J} 
Uncertainty:  1.7 x 10^{−5}  
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Ratio of the mass of the Sun to Saturn  M_{S}/M_{Sa} = 3.497 9018 x 10^{3}  M_{S}/M_{Sa} 
Uncertainty:  1 x 10^{−4}  
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Ratio of the mass of the Sun to Uranus  M_{S}/M_{U} = 2.290 295 1 x 10^{4}  M_{S}/M_{U} 
Uncertainty:  1.7 x 10^{−2}  
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Ratio of the mass of the Sun to Neptune  M_{S}/M_{N} = 1.941 226 x 10^{4}  M_{S}/M_{N} 
Uncertainty:  3 x 10^{−2}  
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Ratio of the mass of the Sun to (134340) Pluto  M_{S}/M_{P} = 1.360 5 x 10^{8}  M_{S}/M_{P} 
Uncertainty:  2.1 x 10^{5}  
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Ratio of the mass of the Sun to (136199) Eris  M_{S}/M_{Eris} = 1.191 x 10^{8}  M_{S}/M_{Eris} 
Uncertainty:  1.4 x 10^{6}  
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Ratio of the mass of (1) Ceres to the Sun  M_{Ceres}/M_{S} = 4.72 x 10^{−10}  M_{Ceres}/M_{S} 
Uncertainty:  3 x 10^{−12}  
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Ratio of the mass of (2) Pallas to the Sun  M_{Pallas}/M_{S} = 1.03 x 10^{−10}  M_{Pallas}/M_{S} 
Uncertainty:  3 x 10^{−12}  
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Ratio of the mass of (4) Vesta to the Sun  M_{Vesta}/M_{S} = 1.302 684 6 x 10^{−10}  M_{Vesta}/M_{S} 
Uncertainty:  9 x 10^{−17}  
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Obliquity of the ecliptic at J2000.0  ε_{J2000} = 8.438 1406 x 10^{4} "  ε_{J2000} 
Uncertainty:  1 x 10^{−3} "  
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