Purple Earth Hypothesis
Encyclopedia
Purple Earth hypothesis is an astrobiological
hypothesis that life forms of early Earth were retinal
-based rather than chlorophyll
-based thus making Earth appear purple rather than green. An example of a retinal-based organism today is the photosynthetic microbes called halobacteria
.
Astrobiology
Astrobiology is the study of the origin, evolution, distribution, and future of life in the universe. This interdisciplinary field encompasses the search for habitable environments in our Solar System and habitable planets outside our Solar System, the search for evidence of prebiotic chemistry,...
hypothesis that life forms of early Earth were retinal
Retinal
Retinal, also called retinaldehyde or vitamin A aldehyde, is one of the many forms of vitamin A . Retinal is a polyene chromophore, and bound to proteins called opsins, is the chemical basis of animal vision...
-based rather than chlorophyll
Chlorophyll
Chlorophyll is a green pigment found in almost all plants, algae, and cyanobacteria. Its name is derived from the Greek words χλωρος, chloros and φύλλον, phyllon . Chlorophyll is an extremely important biomolecule, critical in photosynthesis, which allows plants to obtain energy from light...
-based thus making Earth appear purple rather than green. An example of a retinal-based organism today is the photosynthetic microbes called halobacteria
Halobacteria
In taxonomy, the Halobacteria are a class of the Euryarchaeota, found in water saturated or nearly saturated with salt. They are also called halophiles, though this name is also used for other organisms which live in somewhat less concentrated salt water...
.
External links
- Colorful Worlds: Plants on Other Planets Might Not Be Green
- http://adsabs.harvard.edu/abs/2006AAS...209.0605S 2007 AAS/AAPT Joint Meeting, American Astronomical Society Meeting 209, #06.05; Bulletin of the American Astronomical Society, Vol. 38, p. 901
- http://www3.interscience.wiley.com/journal/120697717/abstract?CRETRY=1&SRETRY=0 BR Green, E Gantt - J Phycol, 2000 - interscience.wiley.com
- http://news.softpedia.com/news/Early-Earth-Was-Purple-51653.shtml Softpedia article
- http://www.foxnews.com/story/0,2933,265378,00.html Fox News article