diff --git a/main.rb b/main.rb
new file mode 100644
index 00000000..6410520d
--- /dev/null
+++ b/main.rb
@@ -0,0 +1,97 @@
+
+require_relative 'planet'
+require_relative 'solar_system'
+
+# Method used if user chooses to add a new planet
+def new_planet
+  puts "What is the name of the planet?"
+  new_planet_name = gets.chomp
+
+  puts "What color is the planet?"
+  new_planet_color = gets.chomp
+    while new_planet_color.empty?
+      puts "How about a color?"
+      new_planet_color = gets.chomp
+    end
+
+  puts "What is the mass?(numbers only)"
+  new_planet_mass = gets.chomp.to_f
+    while new_planet_mass <= 0.0
+      puts "Mass cannot be less than 0. Try again."
+      new_planet_mass = gets.chomp.to_f
+    end 
+
+  puts "What is the distance from the sun?(numbers only)"
+  new_planet_distance = gets.chomp.to_i
+    while new_planet_distance <= 0.0
+      puts "Distance cannot be less than 0. Try again."
+      new_planet_distance = gets.chomp.to_i
+    end 
+
+  puts "What is a fun fact about this planet?"
+  new_planet_fact = gets.chomp 
+  
+  return Planet.new(new_planet_name, new_planet_color, new_planet_mass, new_planet_distance, new_planet_fact)
+end 
+
+# Find all planets within the solar system
+def planet_details(current_planet, solar_system)
+  solar_system.planets.each do |planet|
+    if current_planet == planet.name
+      return planet.summary
+    end 
+  end
+  return "That planet does not exist!"
+end 
+
+# CLI for user with planet details
+def main
+  solar_system = SolarSystem.new("Sun") 
+  solar_system.add_planet(Planet.new("Mercury", "gray", 3.285e23, 57904197.12 ,"Mercury is named after the messenger of the Roman gods."))
+  solar_system.add_planet(Planet.new("Venus", "pale yellow", 4.867e24, 10821.23, "Venus is the second brightest natural object in the sky."))
+  solar_system.add_planet(Planet.new('Earth', 'blue', 5.972e24, 1.496e8, "Only planet known to support life."))
+  solar_system.add_planet(Planet.new("Mars", "reddish brown",6.39e23 , 227883110.4, "Pieces of Mars have been found on Earth."))
+  solar_system.add_planet(Planet.new("Jupiter", "orange", 1.898e27, 778600627.2, "Jupiter has at least 67 moons in satellite around the planet."))
+
+  # Display to user available options to continue
+  puts "Select a number from this COMMAND LIST to continue:
+        1. List all planets
+        2. Display planet details 
+        3. Add a new planet
+        4. exit"
+  input = gets.chomp
+
+  while input != "4"
+    if input == "1"
+      puts solar_system.list_planets
+      puts "Select a number from the orginal command list to continue:"
+      input = gets.chomp
+
+    elsif input == "2"
+      puts "Which planet's details would you like to see?"
+      selected_planet = gets.chomp.capitalize
+      puts planet_details(selected_planet, solar_system)
+      puts "Select a number from the command list:"
+      input = gets.chomp
+      
+    elsif input == '3'
+      solar_system.add_planet(new_planet)
+      solar_system.planets.each do |planet|
+        # puts planet.summary
+      end 
+      puts "Select a number from the orginal command list to continue:"
+      input = gets.chomp
+
+    else
+      puts "Invalid selection type a valid number to continue:
+      1. List all planets
+      2. Display planet details 
+      3. Add a new planet
+      4. exit"
+      input = gets.chomp
+    end 
+  end
+
+end
+
+main()
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diff --git a/planet.rb b/planet.rb
new file mode 100644
index 00000000..7179ddc0
--- /dev/null
+++ b/planet.rb
@@ -0,0 +1,37 @@
+
+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.capitalize
+    @color = color
+    @mass_kg = valid_mass(mass_kg)
+    @distance_from_sun_km = valid_distance(distance_from_sun_km)
+    @fun_fact = fun_fact
+  end
+
+  # Check that planet's mass is no less than 0
+  def valid_mass(mass_kg)
+    if mass_kg <= 0 
+      raise ArgumentError "0 is an invalid input"
+    else 
+      mass_kg.to_s
+    end
+  end
+
+  # Check that planet's distance to the sun is not less than 0
+  def valid_distance(distance_from_sun_km)
+    if distance_from_sun_km <= 0
+      raise ArgumentError "0 is an invalid input"
+    else
+      distance_from_sun_km.to_s
+    end
+  end
+
+  # Display the planet's details
+  def summary
+    return "\nThe planet's name is #{@name}, it has a recognizable #{@color} color. 
+    It weighs about #{@mass_kg} kilograms and is #{@distance_from_sun_km} kilometers from the sun. 
+    Fun fact about #{@name}: #{@fun_fact}.\n"
+  end
+end
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diff --git a/solar_system.rb b/solar_system.rb
new file mode 100644
index 00000000..94d3a0fe
--- /dev/null
+++ b/solar_system.rb
@@ -0,0 +1,34 @@
+
+class SolarSystem
+
+  attr_reader :star_name, :planets
+
+  def initialize (star_name)
+    @star_name = star_name
+    @planets = []
+  end
+
+  # Add planet to list of planets
+  def add_planet(planet)
+    @planets << planet
+  end
+
+  # List that displays all available planets and their star
+  def list_planets
+    puts "Planets that orbit the #{self.star_name} are:"
+    @planet_list = self.planets.each_with_index.map{ |planet, i| " #{i += 1}.#{planet.name} " }
+    return @planet_list
+  end
+
+  # Locate planet by name
+  def find_planet_by_name(planet_name)
+    input = planet_name.capitalize
+    @planets.each do |planet|
+      if input == planet.name
+        return planet
+      end
+      return "Planet not found"
+    end
+  end
+
+end
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