The Goldilocks Zone seemed a remarkably small region of space. It didn’t even include the whole Earth. All life known in those days was confined to certain limits: no colder than Antarctica (penguins), no hotter than scalding water (desert lizards), no higher than the clouds (eagles), no lower than a few mines (deep mine microbes).
In the past 30 years, however, our knowledge of life in extreme environments has exploded. Scientists have found microbes in nuclear reactors, microbes that love acid, microbes that swim in boiling-hot water. Whole ecosystems have been discovered around deep sea vents where sunlight never reaches and the emerging vent-water is hot enough to melt lead.
The Goldilocks Zone is bigger than we thought.