## Astronomy and Astrophysics

`GSL_CONST_MKS_ASTRONOMICAL_UNIT`
  The length of 1 astronomical unit (mean earth-sun distance), au.
`GSL_CONST_MKS_GRAVITATIONAL_CONSTANT`
  The gravitational constant, G.
`GSL_CONST_MKS_LIGHT_YEAR`
  The distance of 1 light-year, ly.
`GSL_CONST_MKS_PARSEC`
  The distance of 1 parsec, pc.
`GSL_CONST_MKS_GRAV_ACCEL`
  The standard gravitational acceleration on Earth, g.
`GSL_CONST_MKS_SOLAR_MASS`
  The mass of the Sun.