Astronomical Constants
Radius of the Moon R = 1.74 × 10 cm = R / 4
Radius of Mars R = 3.40 × 10 cm = R / 2
Radius of the Earth R = 6.37 × 10 cm
Radius of Jupiter R = 7.14 × 10 cm =   10 × R
Radius of the Sun R = 6.96 × 10 cm = 100 × R
Astronomical Unit AU = 1.50 × 10 cm = 200 × R
Parsec pc = 3.09 × 10 cm = 3.26 light-years
Light-year ly = 9.46 × 10 cm
Earth mass M = 5.98 × 10 gm
Solar mass M = 1.99 × 10 gm
Solar luminosity L = 3.90 × 10 erg s
Solar temperature T = 5.78 × 10 K
Density of water = 1 gm cm
Density of rock = 3 gm cm
Density of steel = 8 gm cm

Astronomical Calculator (constants built in)