diff --git a/main.rb b/main.rb
new file mode 100644
index 00000000..7bcfa7f5
--- /dev/null
+++ b/main.rb
@@ -0,0 +1,59 @@
+# main.rb
+
+require_relative "planet.rb"
+require_relative "solar_system.rb"
+
+# option menu
+def options
+  return "
+  Options available to you...
+  1. See a LIST of all the planets on file
+  2. See a specific planet's DETAILS
+  3. ADD a planet
+  4. EXIT\n
+  Please enter your option:"
+end
+
+def main
+  solar_system = SolarSystem.new("Omicron")
+
+  vulcan = Planet.new("Vulcan", "brown & reddish", 546700, 8426000, "Has no moon")
+  solar_system.add_planet(vulcan)
+  shoreleave = Planet.new("Shore Leave Planet", "green", 492600, 8634000, "Created as an amusement park")
+  solar_system.add_planet(shoreleave)
+  nibiru = Planet.new("Nibiru", "reddish & green", 734500, 3264000, "Home to chalk-skinned aliens")
+  solar_system.add_planet(nibiru)
+  vendikar = Planet.new("Vendikar", "red & grey", 236300, 284200, "Very rocky!")
+  solar_system.add_planet(vendikar)
+
+  # Welcome message
+  puts "Welcome to the PlanetDex!"
+
+  # user input time
+  # fencepost loop
+  puts options
+  option = gets.chomp
+
+  loop do
+    if option.include?("list") || option == "1"
+      puts solar_system.list_planets
+    elsif option.include?("detail") || option == "2"
+      puts "Which planet would you like to learn about?"
+      planet = gets.chomp.downcase
+      puts solar_system.find_planet_by_name(planet).summary
+    elsif option.include?("add") || option == "3"
+      puts solar_system.new_planet
+    elsif option.include?("exit") || option == "4"
+      puts "Thank you for using the PlanetDex!"
+      exit
+    else
+      puts "That is not a valid option."
+      puts "Please re-enter your option:"
+    end
+
+    puts options
+    option = gets.chomp
+  end
+end
+
+main
diff --git a/planet.rb b/planet.rb
new file mode 100644
index 00000000..fb45c984
--- /dev/null
+++ b/planet.rb
@@ -0,0 +1,41 @@
+# planet.rb
+
+require "terminal-table"
+
+class Planet
+  attr_reader :name, :color, :mass_kg, :distance_from_sun_km, :fun_fact
+
+  def initialize(name, color, mass_kg, distance_from_sun_km, fun_fact)
+    @name = name
+    @color = color
+    @mass_kg = mass_kg
+    @distance_from_sun_km = distance_from_sun_km
+    @fun_fact = fun_fact
+  end
+
+  def mass_kg
+    pretty_mass = @mass_kg.to_s.reverse.gsub(/(\d{3})(?=\d)/, '\\1,').reverse
+    return pretty_mass
+  end
+
+  def distance_from_sun
+    pretty_distance = @distance_from_sun_km.to_s.reverse.gsub(/(\d{3})(?=\d)/, '\\1,').reverse
+    return pretty_distance
+  end
+
+  def summary
+    table = Terminal::Table.new do |t|
+      t << ["Name:", @name]
+      t << :separator
+      t << ["Color:", @color]
+      t << :separator
+      t << ["Mass:\n(kilograms)", mass_kg]
+      t << :separator
+      t << ["Distance from the sun:\n(kilometers)", distance_from_sun]
+      t << :separator
+      t << ["Fun Fact:", @fun_fact]
+    end
+
+    return table
+  end
+end
diff --git a/solar_system.rb b/solar_system.rb
new file mode 100644
index 00000000..bfdc1bfc
--- /dev/null
+++ b/solar_system.rb
@@ -0,0 +1,52 @@
+# solar_system.rb
+
+require "terminal-table"
+
+class SolarSystem
+  attr_reader :star_name, :planets
+
+  def initialize(star_name, planets = [])
+    @star_name = star_name
+    @planets = []
+  end
+
+  def add_planet(planet)
+    @planets << planet
+  end
+
+  def list_planets
+    table = Terminal::Table.new do |t|
+      @planets.each_with_index do |planet, index|
+        t << ["#{index + 1}.  ", planet.name.capitalize]
+      end
+    end
+
+    return table
+  end
+
+  def new_planet
+    puts "What is the planet's name?"
+    name = gets.chomp
+    puts "What is the planet's color?"
+    color = gets.chomp
+    puts "What is the planet's mass (kg)?"
+    mass = gets.chomp
+    puts "What is the planet's distance from the sun (km)?"
+    sun_distance = gets.chomp
+    puts "Please enter  a fun fact about the planet!"
+    fun_fact = gets.chomp
+
+    name = Planet.new(name, color, mass, sun_distance, fun_fact)
+    add_planet(name)
+
+    return "Successfully added new planet!"
+  end
+
+  def find_planet_by_name(planet_string)
+    find_planet = @planets.find(ifnone = nil) do |planet|
+      planet.name.capitalize == planet_string.capitalize
+    end
+
+    return find_planet
+  end
+end