In his book "Seeing Further: The Story of Science and the Royal Society," Bill Bryson explores the intriguing notion that some microbes found on Earth may originate from distinct biogenesis events, potentially classifying them as ‘alien organisms.’ This idea suggests the existence of a 'shadow biosphere' where life forms arose independently from those we currently recognize.

This perspective challenges our understanding of life on Earth by proposing that the microbial world may be more diverse and complex than previously thought. It raises questions about the origins of life and the possibility of coexisting forms of life that may not fit within the traditional parameters of biology. Bryson effectively presents this thought-provoking concept, encouraging readers to reconsider what we define as life.