;;; astronomical-constants.el - Physical constants for astronomical calculation.
;;; Created: November 11, 2008
;;; Author:  David Meyer

;; Size and distance (km)
(defconst Re 6.371e3)    ; Mean radius of Earth
(defconst Rm 1.738e3)    ; Mean radius of Moon
(defconst Rs 6.96e5)     ; Mean radius of Sun
(defconst Rem 3.84401e5) ; Mean Earth-Moon distance
(defconst AU 1.496e8)    ; Astronomical Unit (Mean Earth-Sun distance)
(defconst ly 9.46053e12) ; Light year
(defconst parsec 3.0852e13) ; Parallax second

;; Mass (kg)
(defconst Me 5.974e24)   ; Mass of Earth
(defconst Mm 7.348e22)   ; Mass of Moon
(defconst Ms 1.989e30)   ; Mass of Sun

;; Gravitational constant (G) times mass of ... (m^3/s^2)
(defconst GMe 3.986e14)  ; ... Earth
(defconst GMm 4.903e12)  ; ... Moon
(defconst GMs 1.327e20)  ; ... Sun

;; Speed (m/s)
(defconst c 2.99792458e8) ; Speed of light in vacuum

;; Acceleration (m/s^2)
(defconst gn 9.80665)    ; Standard gravity