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Astrobiologists continue to work towards determining which biosignatures might be best to look for when searching for life on other worlds. The most common idea has been to search for evidence of plants that use the green pigment chlorophyll, like we have on Earth. However, a new paper suggests that bacteria with purple pigments could flourish under a broader range of environments than their green cousins. That means current and next-generation telescopes should be looking for the emissions of purple lifeforms.<\/p>\n
\u201cPurple bacteria can thrive under a wide range of conditions, making it one of the primary contenders for life that could dominate a variety of worlds,\u201d said L\u00edgia Fonseca Coelho, a postdoctoral associate at the Carl Sagan Institute (CSI) and first author of \u201cPurple is the New Green: Biopigments and Spectra of Earth-like Purple Worlds,\u201d published in the Monthly Notices of the Royal Astronomical Society: Letters.<\/p>\n
<\/p>\n According to NASA\u2019s Exoplanet Archive, 5612 extrasolar planets have been found so far, as of this writing, and another 10,000 more are considered planetary candidates, but have not yet been confirmed. Of all those, there are just over 30 potentially Earth-like worlds, planets that lie in their stars\u2019 habitable zones where conditions are conducive to the existence of liquid water on surface.<\/p>\n But Earth-like has a broad meaning, ranging from size, mass, composition, and various chemical makeups. While being within a star\u2019s habitable zone certainly means there\u2019s the potential for life, it doesn\u2019t necessarily mean that life could have emerged there, or even if it did, the life on that world might look very different from Earth.<\/p>\n \u201cWhile oxygenic photosynthesis gives rise to modern green landscapes, bacteriochlorophyll-based anoxygenic phototrophs can also colour their habitats and could dominate a much wider range of environments on Earth-like exoplanets,\u201d Coelho and team wrote in their paper. \u201cWhile oxygenic photosynthesis gives rise to modern green landscapes, bacteriochlorophyll-based anoxygenic phototrophs can also colour their habitats and could dominate a much wider range of environments on Earth-like exoplanets.\u201d<\/p>\n \n