These are my planet and solar system class objects.

planet.rb

@@ -0,0 +1,85 @@
+class Solar_system
+  attr_accessor :planets
+  def initialize(planets)
+    @planets = planets
+  end
+  def find_by_index(index)
+    return @planets[index]
+  end
+  def planet_index(choice)
+    case choice
+    when "mercury"
+      planet  = find_by_index(0)
+    when "venus"
+      planet = find_by_index(1)
+    when "earth"
+      planet = find_by_index(2)
+    when "mars"
+      planet = find_by_index(3)
+    when "jupiter"
+      planet = find_by_index(4)
+    when "saturn"
+      planet = find_by_index(5)
+    when "uranus"
+      planet = find_by_index(6)
+    when "neptune"
+      planet = find_by_index(7)
+    end
+    planet.info_display
+  end
+  def distance_from_other_planets(planet1, planet2)
+
+  end
+end
+
+
+class Planet
+  attr_accessor :name, :mass, :life, :moons, :special_feature
+  def initialize(planet_data)
+    @name = planet_data[:name]
+    @mass = planet_data[:mass]
+    @life = planet_data[:life]
+    @moons = planet_data[:moons]
+    @special_feature = planet_data[:special_feature]
+    @distance_from_the_sun = planet_data[:distance_from_the_sun]
+  end
+  # nicely formats and displays the values for a given planet's attributes
+  def info_display
+    puts "Name: #{@name}"
+    puts "Mass: #{@mass}"
+    if @life
+      puts "IT HAS LIFE!!! WOW!!!"
+    end
+    puts "Number of Moons: #{@moons} moon(s)"
+    puts "Special Feature: #{@special_feature}"
+    puts "Distance from the Sun: #{@distance_from_the_sun} km"
+  end
+end
+
+
+mercury = Planet.new(name: "Mercury", mass: "3.3011×10^23 kg", life: false, moons: 0, special_feature: "smallest", distance_from_the_sun: 57_900_000)
+venus = Planet.new(name: "Venus", mass: "4.8675×10^24 kg", life: false, moons: 0, special_feature: "hottest", distance_from_the_sun: 108_200_000)
+earth = Planet.new(name: "Earth", mass: "5.97237×10^24 kg", life: true, moons: 1, special_feature: "Nutella", distance_from_the_sun: 149_600_000)
+mars = Planet.new(name: "Mars", mass: "6.4171×10^23 kg", life: false, moons: 2, special_feature: "redness", distance_from_the_sun: 227_900_000)
+jupiter = Planet.new(name:"Jupiter", mass: "1.8986×10^27 kg", life: false, moons: 67, special_feature: "biggest", distance_from_the_sun: 778_300_000)
+saturn = Planet.new(name: "Saturn", mass: "5.6836×10^26 kg", life: false, moons: 62, special_feature: "rings", distance_from_the_sun: 1_427_000_000)
+uranus = Planet.new(name: "Uranus", mass: "(8.6810±0.0013)×10^25 kg", life: false, moon: 27, special_feature: "coldest", distance_from_the_sun: 2_871_000_000)
+neptune = Planet.new(name: "Neptune", mass: "1.0243×10^26 kg", life: false, moon: 14, special_feature: "discovered by math", distance_from_the_sun: 5_913_000_000)
+
+planet_list = [mercury, venus, earth, mars, jupiter, saturn, uranus, neptune]
+super_system = Solar_system.new(planet_list)
+
+# loops until user enters "done"
+done = "no"
+until done == "yes" || done == "y"
+  puts "Which planet would you like to learn about?"
+  planet_list.each_with_index do |planet, index|
+    puts "#{index + 1}. #{planet.name}"
+  end
+  choice = gets.chomp.downcase
+  super_system.planet_index(choice)
+  puts "Are you done?"
+  done = gets.chomp.downcase
+end
+
+# solar system method to calculate distance from any other planet