How to find out magnitude of translation

    /// <summary>
     /// Get the current distance between a planet and a sphere.
     /// </summary>
     /// <param name="planet">The position of planet the sphere is orbiting.</param>
     /// <param name="sphere">The position of a sphere orbiting the planet.</param>
     /// <returns></returns>
     float GetTranslationMagnitude(Vector3 planet, Vector3 sphere)
     {
         Vector3 offset = planet - sphere;
         return Vector3.Magnitude(offset);
     }
 
     /// <summary>
     /// Set the distance between a planet and a sphere.
     /// </summary>
     /// <param name="planet">The planet the sphere is orbiting.</param>
     /// <param name="sphere">A sphere orbiting the planet.</param>
     /// <returns></returns>
     void SetTranslationMagnitude(Transform planet, Transform sphere, float distance)
     {
         Vector3 offset = planet.position - sphere.position;
         sphere.position = planet.position + offset.normalized * distance;
 
     }