- Red edge
Red edge refers to the region of rapid change in reflectance of
chlorophyll in thenear infrared range. Vegetation absorbs most of the light in the visible part of the spectrum but is strongly reflective at wavelengths greater than 700 nm. The change can be from 5% to 50% reflectance between 680 nm to 730 nm. This is an advantage to plants to avoid overheating duringphotosynthesis .The phenomenon accounts for the brightness of foliage in
infrared photography . It is used inremote sensing to monitor plant activity and could be useful to detect light-harvesting organisms on distant planets.References
* Seager, S., Turner, E. L., Schafer, J., & Ford, E. B. (2005) ``Vegetation's Red Edge: A Possible Spectroscopic Biosignature of Extraterrestrial Plants" Astrobiology, Volume 5, Issue 3, pp. 372-390. ( [http://dx.doi.org/10.1089/ast.2005.5.372 link] and [http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005AsBio...5..372S&link_type=PREPRINT&db_key=AST preprint] )
ee also
*
Purple Earth Hypothesis
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