Habitable zone
The habitable zone may also be called the "life zone", "comfort zone", "green belt" or "Goldilocks zone". One in five stars has an Earth-sized planet in the habitable zone.<ref>[https://www.bbc.co.uk/news/science-environment-24824007 One in five suns has habitable world. BBC News Science & Environment]</ref> However, it is not known what proportion would have conditions suitable for life.