Despite lacking in Earth’s conditions, bacteria have been shown to grow in space. Although, it is still not fully understood how organic life has it’s origins in space, is it theorized that the first organic microorganisms were transmitted to earth by hitchhiking on a comet or via an asteroid that impacted the Earth. Considering that all basic ingredients for life have been created and exist in space, it is possible that early organic microorganisms formed elsewhere in the universe prior to transportation to Earth. The life cycles of stars create the basic ingredients for life, as well as UV light. The two have been shown to ‘effectively promote photochemical processes in interstellar ice that have led to the formation of organic molecules.’ (Meierhenrich et al., 2011) The ‘photochemistry of interstellar ices [could have been incorporated] in cometary dust.’ (Meinert et al., 2012) which could have promoted spontaneous development and spread of early organic microorganisms in space through panspermia resulting in the introduction of early microscopic life on Earth.
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Meierhenrich, C. M. (2011). Photochirogenesis: Photochemical models on the absolute asymmetric formation of amino acids in interstellar space. Physics of Life Reviews, 307-330.
Meinert, C. F.-J. (2012). N-(2-Aminoethyl)glycine and Amino Acids from Interstellar Ice Analogues. . ChemPlusChem, 186-191.
Shih, I. (2016, March 24). Bacteria found to thrive better in space than on Earth. Retrieved from phys.org: https://phys.org/news/2016-03-bacteria-space-earth.html