What Is Photosynthesis? From Light Energy to Chemical …
Chemistry for Biologists: Photosynthesis
Depending on a main sequence star's spectral type, even a planet with 's atmospheric composition may be colored differently. In general, larger and more massive, main-sequence ("dwarf") stars have hotter surface temperatures than our Sun, , and so they radiate more photons, particularly towards the more energetic, bluish end of the spectrum. As a result of their greater luminosity, Earth-like planets would orbit farther away from hotter dwarf stars to avoid getting scorched, but their skies would still appear bluish due to of abundant bluish photons. Around smaller, less massive and dimmer dwarf stars, however, planets would have to orbit closer in order to sustain a surface temperature that is warm enough to keep water liquid and so the star would appear larger in the sky. In addition, stars with surface temperatures of 3,300 kelvins or lower (red dwarfs of spectral type M2.5 such as , or redder) would emit so fewer photons towards the bluish wavelengths compared to Sol that the sky would appear whitish down to reddish to Human eyes (more from ). If comparatively more bluish or reddish light reaches a planet's surface than on Earth, photosynthetic plant-type life may may not be greenish in color, because such life will have evolved to different pigments in order to optimize their use of available and so color the appearance of the planet's land surfaces accordingly.
Chlorophyll | Causes of Color - WebExhibits
Extraterrestrial photosynthetic plant-type life may look quite look different in color because they will have evolved their own pigments based on the colors of light reaching their surfaces. of NASA's Goddard Institute for Space Sciences has modelled the light reaching the surfaces of Earth-sized worlds orbiting their host stars at distances hospitable to Earth-type life, where liquid water could exist on a planetary surface, where depending on the star's brightness (and color) and the planet's atmosphere. Kiang found that "plants" on Earth-like planets orbiting stars somewhat brighter and bluer than the Sun might look yellow or orange, and even look bluish by reflecting a dangerous overabundance of more energetic blue light. On the other hand, plants on planets orbiting stars much fainter and redder than the Sun might look black. Hence, astrobiologists seeking signs of life on planets outside the Solar System may want to look for colors reflected by planetary vegetation that is colored differently than the green wavelengths found on Earth (NASA/GSFC ; Spitzer ; ; ;; and ).