class Date

# File lib/geoeras.rb, line 174
def self.geologic_present
  Date.new(1950,1,1)
end

# File lib/geoeras.rb, line 178
def self.million_years_ago(years)
  Date.geologic_present - (years*365*1000000).to_i
end

# File lib/geoeras.rb, line 188
def after_dinosaurs?
  self > Date.million_years_ago(65)
end

# File lib/geoeras.rb, line 182
def in_geologic_time_range?(million_years_start, million_years_end)
  time_period_start = Date.million_years_ago(million_years_start)
  time_period_end = million_years_end == 0 ? Date.today : Date.million_years_ago(million_years_end)
  (time_period_start..time_period_end).cover?(self)
end