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Extraterrestrial Life May Well Be Purple

EnolaGaia

I knew the job was dangerous when I took it ...
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Now that we're starting to develop tactics for analyzing exoplanet reflected light to find hints of possible life, we should give some attention to the purple portion of the spectrum ...

Extraterrestrial Life Could Be Purple
Alien life might be purple. ...

That's the conclusion of a new research paper that suggests that the first life on Earth might have had a lavender hue. In the International Journal of Astrobiology, microbiologist Shiladitya DasSarma of the University of Maryland School of Medicine and postdoctoral researcher Edward Schwieterman at the University of California, Riverside, argue that before green plants started harnessing the power of the sun for energy, tiny purple organisms figured out a way to do the same.

Alien life could be thriving in the same way, DasSarma said.

"Astronomers have discovered thousands of new extrasolar planets recently and are developing the capacity to see surface biosignatures" in the light reflected from these planets, he told Live Science. There are already ways to detect green life from space, he said, but scientists might need to start looking for purple, too. ...

FULL STORY: https://www.livescience.com/63883-purple-alien-life.html
 
Purple retinal pigments. Hmmm. with red encompassing one end of the visible light range and blue at the other, wouldn't this be expected? A sort of undifferentiated light-sensitive ability that "averages out" the visible spectrum and resolves it as a uniform purple...
 
Purple retinal pigments. Hmmm. with red encompassing one end of the visible light range and blue at the other, wouldn't this be expected? A sort of undifferentiated light-sensitive ability that "averages out" the visible spectrum and resolves it as a uniform purple...

A clarification ... In this context 'retinal' is the name of a particular biochemical compound (aka retinaldehyde):

https://en.wikipedia.org/wiki/Retinal

... rather than an allusion to the retina of an eye.
 
But will they eat people?

Retinal-based (purple) photosynthesis is dependent on a narrower range of light wavelengths than chlorophyll-based (green) photosynthesis, so it's likely to be less efficient in supporting larger and more complex organisms.

In any case ... If an organism is photosynthetic it probably isn't configured for predation.
 
Ah, got it. Went down the wrong path on "retinal" and thought "cones and rods". Thanks!
 
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