Ruby: playing with modules

gistfile1.txt

#!/usr/bin/env ruby
module CoolModule1
  class CoolClass1; end
end

coolmodule2 = Module.new do
  class CoolClass2; end
end

p CoolModule1.constants.any?             # => true
p coolmodule2.constants.any?             # => false   # Why?

p CoolModule1.const_defined? :CoolClass1 # => true
p coolmodule2.const_defined? :CoolClass2 # => true    # wait, what?

# help? :)