Age converter for some planets I was wondering if it is better to use:

    double onJupiter() {
     return AgeInSeconds / (jupiterOrbitalInEarthYears * ageInEarthSeconds);
    }

    double onMars() {
     return inputAgeInSeconds / (marsOrbitalInEarthYears * ageInEarthSeconds); 
 }


Or:

  double onJupiter() {
        return onEarth() / JUPITER_ORBIT_RATIO;
    }

  double onMars() {
    return onEarth() / MARS_ORBIT_RATIO;
  }


In the second option, notice I called the onEarth() method twice. Does calling onEarth() create a brand new Stack (a bit like in recursion), hence it is not good to use? Because if I have a bunch of methods like onMars(), onMercury etc and they all call onEarth(), then would I end up creating a lot of new stacks?

Here are the Java classes in question:

Class 1:

class SpaceAge {

    private final double AgeInSeconds;
    private static final double ageInEarthSeconds = 31557600;
    private static final double marsOrbitalInEarthYears = 0.2408467;
    private static final double jupiterOrbitalInEarthYears = 11.862615;

    SpaceAge(double seconds) {
        this.AgeInSeconds = seconds;
    }

    double getSeconds() {
        return AgeInSeconds;
    }

    double onEarth() {
        return AgeInSeconds / ageInEarthSeconds;
    }

    double onJupiter() {
        return AgeInSeconds / (jupiterOrbitalInEarthYears * ageInEarthSeconds);
    }


    double onMars() {
        return AgeInSeconds / (marsOrbital * ageInEarthSeconds);
    }

}


Class 2:

class SpaceAge {

    private static final double EARTH_YR_IN_SECS = 31557600;
    private static final double MARS_ORBIT_RATIO = 1.8808158;
    private static final double JUPITER_ORBIT_RATIO = 11.862615;


    private final double ageInSeconds;

    SpaceAge(final double seconds) {
        this.ageInSeconds = seconds;
    }

    double getSeconds() {
        return this.ageInSeconds;
    }

    double onEarth() {
        return this.ageInSeconds / EARTH_YR_IN_SECS;
    }

    double onJupiter() {
        return onEarth() / JUPITER_ORBIT_RATIO;
    }

    double onMars() {
        return onEarth() / MARS_ORBIT_RATIO;
    }
}
Don't care about that. Unless you can prove that it creates a bottleneck, just stick with whatever seems the most readable and maintainable option. 
 prefer the latter.

I'd also rename the methods. onEarth is too generic. What exactly on onEarth? Weeks? Months? Years? If it's years, call it getYearsOnEarth or something like this.