Astronomical Constants


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Quantity Value
astronomical unit (A.U.) 149,597,870,660(20) m
light year (ly) 9.460 536 207 ~ 1015 m = 63,240 A.U.
parsec (pc) 3.085 677 580 7(4) ~ 1016 m = 206,265 A.U. = 3.2616 ly
sidereal year 365.256 36 days
31 558 149.8 s
tropical year 365.242 19 days
31 556 925.2 s
Gregorian year 365.242 50 days
Earth mass 5.974(9) ~ 1024 kg
Sun mass 1.988 9(30) ~ 1030 kg = 332,980 ~ Earth
mean Earth radius 6.378 140 ~ 106 m
Sun radius 6.962 65 ~ 108 m = 109 ~ Earth
Sun luminosity 3.827~ 1026 watts


Earth Parameter
Distance from the Sun (Semimajor axis of orbit):
149,597,890 km
1 A.U.

Mean Equatorial Radius:
6,378.14 km

Mass:
5.9742 x 1027 g

Density:
5.515 gm/cm3

Surface Gravity:
980 cm/s2

Escape Velocity
11.18 km/s

Sidereal Rotation Period:
0.99726968 day

Sidereal Orbit Period (Earth years)
0.99997862


Mean Orbit Velocity
29.7859 km/s

Orbit Eccentricity
0.01671022

Orbit Inclination to Ecliptic
0.00005 degree

Inclination of Equator to Orbit
23.45 degrees

Mean Temperature at Solid Surface (in Kelvin)
288 to 293 K

Atmospheric Temperature (at level with pressure = 1 bar)
288 K

Major Atmospheric Constituents
N2, O2

Natural Satellites
1. The Moon 
   
 
            



 

This page is updated  by MS .