diff --git a/lib/main.rb b/lib/main.rb
new file mode 100644
index 00000000..de5d5f33
--- /dev/null
+++ b/lib/main.rb
@@ -0,0 +1,114 @@
+require_relative 'planet'
+require_relative 'solar_system'
+
+def user_choice
+  puts "\nWhat would you like to do? Choose from the following options:"
+  puts "List Planets\nPlanet Details\nAdd Planet\nGet Distance\nExit"
+  choice = gets.chomp.downcase
+  until choice == "list planets" || choice == "exit" || choice == "planet details" || choice == "add planet" || choice == "get distance"
+    puts "NOT A VALID OPTION\n\n"
+    choice = user_choice
+  end
+  return choice
+end
+
+def planet_details(planet, solar_system)
+  which_planet = solar_system.find_planet_by_name(planet)
+  return which_planet.summary
+end
+
+def pre_existing_planets(solar_system)
+  return solar_system.list_planets
+end
+
+def add_planet(solar_system)
+  print "Please enter the new planet name: "
+  new_planet = gets.chomp.downcase
+  check_planet = solar_system.find_planet_by_name(new_planet)
+
+  if check_planet == nil
+    print "What is planet's color? "
+    new_color = gets.chomp
+
+    print "What is planet's mass (in Kg)? "
+    new_mass = gets.chomp.to_f
+
+    print "What is planet's distance from the Sun (in Km)? "
+    new_distance = gets.chomp.to_i
+
+    print "Add a fun fact about #{new_planet}: "
+    new_fact = gets.chomp
+
+    brand_new = Planet.new(new_planet.capitalize, new_color.capitalize, new_mass, new_distance, new_fact)
+    solar_system.add_planet(brand_new)
+
+    puts "New planet added: #{brand_new.name}.\n"
+    puts brand_new.summary
+  else
+    puts "This planet is already listed in the Solar System."
+  end
+  return brand_new
+end
+
+def get_distance(solar_system)
+  distant_planets = []
+  2.times do
+    print "Please enter one planet: "
+    plan1 = gets.chomp
+    check_plan1 = solar_system.find_planet_by_name(plan1)
+    if check_plan1.nil?
+      puts "This planet is not listed in the Solar System"
+      return
+    else
+      distant_planets << plan1
+    end
+  end
+  return solar_system.distance_between(distant_planets[0], distant_planets[1])
+
+end
+
+def main
+  earth = Planet.new("Earth", "Blue", 5.972e24, 1.496e8, 'Only planet known to support life')
+  mars = Planet.new("Mars", "Red", 6.41693e23, 230e8, 'Carries the name of the Roman God of War')
+  jupiter = Planet.new("Jupiter", "Yellow", 1.898e27, 817e6, 'The largest planet in the Solar System.')
+  saturn = Planet.new("Saturn", "Pale yellow", 5.69e26, 1.5e9, "Has rings made of ice mixed with dust and other chemicals.")
+  uranus = Planet.new("Uranus", "Blue-green", 8.68e25, 3e9, 'The coldest of the planets.')
+
+  solar_system = SolarSystem.new('Sun')
+  solar_system.add_planet(earth)
+  solar_system.add_planet(mars)
+  solar_system.add_planet(jupiter)
+  solar_system.add_planet(saturn)
+  solar_system.add_planet(uranus)
+
+  #CLI
+  keep_going = true
+
+  while keep_going
+    choice = user_choice
+    if choice == "exit"
+      puts "Good-bye"
+      return
+    elsif choice == "list planets"
+      puts pre_existing_planets(solar_system) + "\n"
+    elsif choice == "planet details"
+      puts pre_existing_planets(solar_system) + "\n"
+      print "Choose a Planet and I will tell you about it: "
+      chosen_planet = gets.chomp
+      check = solar_system.find_planet_by_name(chosen_planet.downcase)
+
+      if check.nil?
+        puts "It looks like #{chosen_planet} is not in this Solar System"
+      else
+        puts planet_details(chosen_planet, solar_system) + "\n"
+      end
+
+    elsif choice == "add planet"
+      puts add_planet(solar_system)
+
+    elsif choice == "get distance"
+      puts get_distance(solar_system)
+    end
+  end
+end
+main
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diff --git a/lib/planet.rb b/lib/planet.rb
new file mode 100644
index 00000000..19bdfe1b
--- /dev/null
+++ b/lib/planet.rb
@@ -0,0 +1,38 @@
+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
+
+    #wave1 - optional // error checking
+    if @mass_kg.is_a?(Float) == false && @mass_kg.is_a?(Integer) == false
+      raise ArgumentError.new("Expected number, got #{@mass_kg}.")
+    elsif @mass_kg < 0
+      raise ArgumentError.new("Expected value greater than zero, got #{@mass_kg}.")
+    end
+
+    if @distance_from_sun_km.is_a?(Float) == false && @distance_from_sun_km.is_a?(Integer) == false
+      raise ArgumentError.new("Expected number, got #{@distance_from_sun_km}.")
+    elsif distance_from_sun_km < 0
+      raise ArgumentError.new("Expected value greater than zero, got #{@distance_from_sun_km}.")
+    end
+  end
+
+  def summary
+    summary = "
+     - Planet: #{@name}
+     - Color: #{@color}
+     - Mass (in Kg): #{@mass_kg}
+     - Distance from the sun (in Km): #{@distance_from_sun_km}
+     - Fun Fact: #{@fun_fact}"
+
+    return summary
+  end
+
+
+end
\ No newline at end of file
diff --git a/lib/solar_system.rb b/lib/solar_system.rb
new file mode 100644
index 00000000..0a4b7cf6
--- /dev/null
+++ b/lib/solar_system.rb
@@ -0,0 +1,38 @@
+class SolarSystem
+
+  attr_reader :star_name, :planets
+
+  def initialize(star_name)
+    @star_name = star_name
+    @planets = []
+  end
+
+  def add_planet(planet)
+    @planets << planet
+  end
+
+  def list_planets
+    str_planets = "Planets orbiting #{self.star_name}:"
+    @planets.each_with_index do |planet, i|
+      str_planets += "\n#{i+1}.  #{planet.name}"
+    end
+    return str_planets
+  end
+
+  def find_planet_by_name(planet_name)
+    @planets.each do |planet|
+      if planet_name.upcase == planet.name.upcase
+        return planet
+      end
+    end
+    return nil
+  end
+
+  def distance_between(planet_name1, planet_name2)
+    planet1 = find_planet_by_name(planet_name1)
+    planet2 = find_planet_by_name(planet_name2)
+
+    return (planet1.distance_from_sun_km - planet2.distance_from_sun_km).abs
+  end
+
+  end
\ No newline at end of file
diff --git a/rakefile.rb b/rakefile.rb
new file mode 100644
index 00000000..fb007c61
--- /dev/null
+++ b/rakefile.rb
@@ -0,0 +1,9 @@
+require 'rake/testtask'
+
+Rake::TestTask.new do |t|
+  t.libs = ["lib"]
+  t.warning = true
+  t.test_files = FileList['test/*_test.rb']
+end
+
+task default: :test
\ No newline at end of file
diff --git a/test/planet_test.rb b/test/planet_test.rb
new file mode 100644
index 00000000..d2cff7ac
--- /dev/null
+++ b/test/planet_test.rb
@@ -0,0 +1,46 @@
+require 'minitest'
+require 'minitest/spec'
+require 'minitest/autorun'
+require 'minitest/reporters'
+require 'minitest/pride'
+
+require_relative '../lib/planet'
+
+Minitest::Reporters.use! Minitest::Reporters::SpecReporter.new
+
+#wave 1
+
+describe 'Planet' do
+
+  it 'raises ArgumentError if mass_kg is not a number' do
+
+    expect {
+      weird_planet = Planet.new("Weird Planet", "Purple", "Ada Lovelace", 20, 'It exist in my dreams')
+    }.must_raise ArgumentError
+
+  end
+
+  it 'raises ArgumentError for mass_kg smaller than 0' do
+
+    expect {
+      weird_planet = Planet.new("Weird Planet", "Purple", -4, 20, 'It exist in my dreams')
+    }.must_raise ArgumentError
+
+  end
+
+  it 'raises ArgumentError if distance_from_sun_km is not a number' do
+
+    expect {
+      weird_planet = Planet.new("Weird Planet", "Purple", 800, "Giraffe", 'It exist in my dreams')
+    }.must_raise ArgumentError
+
+  end
+
+  it 'raises ArgumentError for distance_from_sun_km smaller than 0' do
+
+    expect {
+      weird_planet = Planet.new("Weird Planet", "Purple", 600000, -3, 'It exist in my dreams')
+    }.must_raise ArgumentError
+
+  end
+end
\ No newline at end of file