error message.txt

C:\.....\SpaceAge.hs:14:10: error:
    * No instance for (Ord Planet) arising from a use of `fromList'
    * In the expression:
        fromList
          [(Mercury, 0.2408467), (Venus, 0.61519726), (Earth, 1),
           (Mars, 1.8808158), ....]
      In an equation for `orbits':
          orbits
            = fromList
                [(Mercury, 0.2408467), (Venus, 0.61519726), (Earth, 1), ....]

space_age.hs

module SpaceAge (Planet(..), ageOn) where
import Data.Map.Strict as Map

data Planet = Mercury
            | Venus
            | Earth
            | Mars
            | Jupiter
            | Saturn
            | Uranus
            | Neptune

orbits :: Map Planet Float
orbits = fromList [(Mercury, 0.2408467), (Venus, 0.61519726), (Earth, 1), (Mars, 1.8808158), (Jupiter, 11.862615), (Saturn, 29.447498), (Uranus, 84.016846), (Neptune, 164.79132)]

ageOn :: Planet -> Float -> Float
ageOn planet seconds = seconds / (31557600 * orbits ! planet)