diff --git a/lib/main.rb b/lib/main.rb
new file mode 100644
index 00000000..bb5796d2
--- /dev/null
+++ b/lib/main.rb
@@ -0,0 +1,87 @@
+require_relative "planet"
+require_relative "solar_system"
+
+def main
+  solar_system = SolarSystem.new("Sol")
+
+  mercury = Planet.new("Mercury", "grey", 0.33e24, 57.9e6, "it has ice in craters that never receive sunlight.")
+  solar_system.add_planet(mercury)
+
+  venus = Planet.new("Venus", "yellow", 4.87e24, 108.2e6, "it probably had a moon, but collided with it after another impact reversed the planet's spin.")
+  solar_system.add_planet(venus)
+
+  earth = Planet.new("Earth", "blue", 5.97e24, 149.6e6, "it has more life than the rest of the known universe, as far as we know.")
+  solar_system.add_planet(earth)
+
+  mars = Planet.new("Mars", "red", 0.64e24, 227.9e6, "it has liquid water.")
+  solar_system.add_planet(mars)
+
+  jupiter = Planet.new("Jupiter", "orange", 1898e24, 778.3e6, "its gravity breaks apart many comets.")
+  solar_system.add_planet(jupiter)
+
+  saturn = Planet.new("Saturn", "gold", 569e24, 1427e6, "it's not known how or when its rings formed.")
+  solar_system.add_planet(saturn)
+
+  uranus = Planet.new("Uranus", "blue", 86.8e24, 2871e6, "it also has large storms in its atmosphere, like Jupiter.")
+  solar_system.add_planet(uranus)
+
+  neptune = Planet.new("Neptune", "blue", 102e24, 5913e6, "the wind can go as fast as 1,700 km/hr - faster than the speed of sound.")
+  solar_system.add_planet(neptune)
+
+  continue = true
+
+  while continue == true
+    puts "What would you like to do next?"
+    puts "list planets | planet details | add planet | distance between planets | exit"
+    get_input = gets.chomp
+    if get_input == "exit"
+      puts "See ya!"
+      return continue == false
+    elsif get_input == "list planets"
+      puts solar_system.list_planets
+    elsif get_input == "planet details"
+      puts "Which planet would you like to learn about?"
+      input_name = gets.chomp
+      puts solar_system.find_planet_by_name(input_name)
+    elsif get_input == "add planet"
+      solar_system.add_new_planet
+      puts "Planet added to the solar system!"
+    elsif get_input == "distance between planets"
+      puts "What's the first planet you're interested in?"
+      planet1_name = gets.chomp
+      puts "Sweet, what's the second planet?"
+      planet2_name = gets.chomp
+      puts solar_system.distance_between(planet1_name, planet2_name)
+    else
+      puts "Invalid prompt."
+    end
+  end
+end
+
+puts "Welcome to the solar system!"
+main
+
+# Moved to solar_system.rb for now
+
+# def add_new_planet
+#   puts "Okay, what's the name of the planet we're missing?"
+#   name = gets.chomp
+#   puts "Cool, what color is it?"
+#   color = gets.chomp
+#   puts "What about its mass in kilograms?"
+#   mass_kg = gets.chomp
+#   until mass_kg.to_f > 0
+#     puts "Must be a number greater than zero."
+#     mass_kg = gets.chomp
+#   end
+#   puts "Now I need its distance from the sun in kilometers."
+#   distance_from_sun_km = gets.chomp
+#   until distance_from_sun_km.to_f > 0
+#     puts "Must be a number greater than zero."
+#     distance_from_sun_km = gets.chomp
+#   end
+#   puts "And finally, what's a fun fact about this planet?"
+#   fun_fact = gets.chomp
+
+#   return new_planet = Planet.new(name, color, mass_kg, distance_from_sun_km, fun_fact)
+# end
diff --git a/lib/planet.rb b/lib/planet.rb
new file mode 100644
index 00000000..ee3d8899
--- /dev/null
+++ b/lib/planet.rb
@@ -0,0 +1,15 @@
+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 summary
+    return "#{@name} is a #{@color} planet that weighs #{mass_kg} kilograms and orbits #{@distance_from_sun_km} kilometers from the sun.  A cool fact about #{@name} is that #{fun_fact}"
+  end
+end
diff --git a/lib/solar_system.rb b/lib/solar_system.rb
new file mode 100644
index 00000000..fa7a9e80
--- /dev/null
+++ b/lib/solar_system.rb
@@ -0,0 +1,74 @@
+require_relative "planet"
+
+class SolarSystem
+  attr_reader :star_name, :planets
+
+  def initialize(star_name)
+    @star_name = star_name
+    @planets = []
+    @planet_print = ["Planets orbiting #{star_name}"]
+    #@new_planet
+  end
+
+  def add_planet(planet)
+    @planets << planet
+  end
+
+  def add_new_planet
+    print "Okay, what's the name of the planet we're missing?\n"
+    new_name = gets.chomp
+    print "Cool, what color is it?\n"
+    new_color = gets.chomp
+    print "What about its mass in kilograms?\n"
+    new_mass_kg = gets.chomp.to_f
+    until new_mass_kg > 0
+      print "Must be a number greater than zero.\n"
+      new_mass_kg = gets.chomp.to_f
+    end
+    print "Now I need its distance from the sun in kilometers.\n"
+    new_distance = gets.chomp.to_f
+    until new_distance > 0
+      print "Must be a number greater than zero.\n"
+      new_distance = gets.chomp.to_f
+    end
+    print "And finally, what's a fun fact about this planet?\n"
+    new_fun_fact = gets.chomp
+
+    new_planet = Planet.new(new_name, new_color, new_mass_kg, new_distance, new_fun_fact)
+    add_planet(new_planet)
+  end
+
+  def list_planets
+    @planets.each_index do |index|
+      @planet_print << "#{index + 1}. #{@planets[index].name}"
+    end
+    return @planet_print
+  end
+
+  def find_planet_by_name(input_name)
+    @planets.each do |each_planet|
+      if each_planet.name.casecmp(input_name) == 0
+        return each_planet.summary
+      end
+    end
+    return "Invalid planet."
+  end
+
+  def find_planet_distance_by_name(planet)
+    @planets.each do |each_planet|
+      if each_planet.name.casecmp(planet) == 0
+        return each_planet.distance_from_sun_km
+      end
+    end
+    return "Invalid planet."
+  end
+
+  def distance_between(planet1_name, planet2_name)
+    planet1_position = find_planet_distance_by_name(planet1_name)
+    planet2_position = find_planet_distance_by_name(planet2_name)
+    if planet1_position.is_a?(Float) == false || planet2_position.is_a?(Float) == false
+      return "Invalid planet entered."
+    end
+    return "#{(planet2_position - planet1_position).abs} kilometers"
+  end
+end
diff --git a/specs/planet_spec.rb b/specs/planet_spec.rb
new file mode 100644
index 00000000..9626f1f0
--- /dev/null
+++ b/specs/planet_spec.rb
@@ -0,0 +1,25 @@
+gem "minitest", ">= 5.0.0"
+require "minitest"
+require "minitest/spec"
+require "minitest/autorun"
+require "minitest/reporters"
+require "minitest/pride"
+
+require_relative "../lib/planet"
+
+describe "Planets tests" do
+  it "Tests mass is greater than zero" do
+    mercury = Planet.new("Mercury", "grey", 0.33e24, 57.9e6, "it has ice in craters that never receive sunlight.")
+    expect(mercury.mass_kg).must_be :>, 0
+  end
+
+  it "Tests distance is greater than zero" do
+    mercury = Planet.new("Mercury", "grey", 0.33e24, 57.9e6, "it has ice in craters that never receive sunlight.")
+    expect(mercury.distance_from_sun_km).must_be :>, 0
+  end
+
+  it "Test planet variable assignment and summary" do
+    mercury = Planet.new("Mercury", "grey", 0.33e24, 57.9e6, "it has ice in craters that never receive sunlight.")
+    expect(mercury.summary).must_equal "Mercury is a grey planet that weighs 3.3e+23 kilograms and orbits 57900000.0 kilometers from the sun.  A cool fact about Mercury is that it has ice in craters that never receive sunlight."
+  end
+end
diff --git a/specs/solar_system_spec.rb b/specs/solar_system_spec.rb
new file mode 100644
index 00000000..3653be4f
--- /dev/null
+++ b/specs/solar_system_spec.rb
@@ -0,0 +1,17 @@
+gem "minitest", ">= 5.0.0"
+require "minitest"
+require "minitest/spec"
+require "minitest/autorun"
+require "minitest/reporters"
+require "minitest/pride"
+
+# require_relative "../lib/planet"
+require_relative "../lib/solar_system"
+
+describe "Solar system tests" do
+  it "Tests planet finding" do
+    solar_system = SolarSystem.new("Sol")
+    @planets = ["earth", "mars"]
+    expect(solar_system.find_planet_by_name("mars2")).must_match "Invalid planet."
+  end
+end