package space // Planet name type Planet string // seconds in Earth year const year = 31557600 // scale year duration compared to Earth var scale = map[Planet]float64{ "Earth": 1.0, "Mercury": 0.2408467, "Venus": 0.61519726, "Mars": 1.8808158, "Jupiter": 11.862615, "Saturn": 29.447498, "Uranus": 84.016846, "Neptune": 164.79132, } func Age(seconds float64, p Planet) float64 { factor, ok := scale[p] if !ok { return 0.0 } return seconds / year / factor }