Comets are an ideal vehicle for sustaining and transporting a variety of microbes, including viruses, from planet to planet and even from solar system to solar system. In consequence, when these organisms are deposited on a world already thriving with life, genes may be exchanged, the evolution of new species may ensue, or conversely contagion may be unleashed, and disease, death, and plague may spread throughout the land.
Comets and Contagion: Evolution and
Diseases From Space, 2010
by Rhawn Joseph, neuropsychologist
and Chandra Wickramasinghe, astrobiologist
Stage I
EMERGENCE