02 May 2016

Trappist-1, nearby (40 ly) brown dwarf with "Earthlike" planets?

I can never resist commenting on this sort of thing. Geek alert! If you aren't interested in life in the universe in its broadest sense, turn the page!

http://www.space.com/32761-three-alien-planets-trappist-1-s…

There are three issues the articles about this fail to cover adequately. 1. Brown dwarfs, to remain hot enough to warm even quite nearby planets to Earthlike temperatures, are likely to be quite young. Young celestial bodies translate to insufficient time for the evolution of complex life, which took several billion years on Earth. 2. Complex life insofar as we have any grasp of how it does or might possibly come into existence, requires photosynthesis. Chemoautotrophic life could exist, but no examples of such life developing sufficient energetics to evolve into complex microscopic organisms, are known on Earth, and there are pretty good theoretical reasons for concluding that the "engineering" of such organisms simply would not support that. And, as a corollary, the peak of the light curve of a dim star like this is so far in the infrared that the chemistry of photosynthesis, no matter how liberal you are in allowing for variations, simply DOES NOT WORK. There just isn't enough energy in the photons for the quantum states in the atoms involved in the reactions to change. No one can even suggest how photosynthetic reactions using infrared light might be made to work. And, again, there are pretty good theoretical reasons to believe this JUST DOES NOT HAPPEN, anywhere, at any time.

Artificial habitats in such places might be made to work; there is energy and matter. But it's highly unlikely that complex life (beyond the most rudimentary heterotrophs and chemoautotrophic bacteria-like organsims) could evolve there naturally.

 

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