Transparent atmosphere link to intelligent life?
Posted 06 August 2013 - 06:29 PM
Before I started my astrophysics graduate degree, my first field of study was paloeanthropology, evolutionary psychology of hominid species. There is indeed a link between observing and intelligence, and the evidence lay off the southern tip of Africa, When the Sahara pump failed and Africa became barren, H. Sapiens moved to the southern tip, driven by drought and famine. By observing the moon, they were able to predict lunar tides, and thus the cycle of lower ocean levels. They then began the first harvesting of crab near the Cape of Good Hope South Africa.
This was the impetus of advancement in intelligence known as regional determinism.
I hope that helped.
Posted 07 August 2013 - 12:16 AM
Hi all, it's been a while.
I'd say a transparent atmosphere is necessary for photosynthesis, the basis for a sustained 'global metabolism' of our planet, which occurs in the visible.
I'don't know if IR-or longer wavelenght-based-photosynthesis
would be energetic enough to sustain hydrocarbon synthesis, probably not, and in the UV and shorter wavelenght, there is probably no 'molecular antenna' strong enough to do the job, i.e, a chlorophyle system working in the UV would be destroyed by the UV photon (could anybody confirm that?). So, i suppose hydrocarbon sysnthesis using an organic antenna works best between IR and UV and so the atmosphere had to be transparent in this part of the spectra.
The link to intelligent life is that only photosynthesis generates enough biomass to sustain 'higher' lifeforms. Also, since the energy gathered by the molecular antenna in grren plants or cyanobacterias goes all the way down to the photolysis of water, to release protons and oxygen (O2 as a byproduct), it's a good thing that organic photosynthesis released a byproduct transparent for organic photosynthesis.
There would have been no future for photosynthesis, had the photolysis of water opacified the atmosphere.
Even if the primitive earth atmosphere was not as transparent as today's, there still must have been enough transparency to initiate the process.
I partly agree and partly don't. Pretty much all you said is true for life on Earth. Hypothetically, though, a planet that's not Earth could under the right circumstances power a robust and energy-rich living community without photosynthesis. Under the right circumstances, I think that a planet more massive than Earth can retain its internal heat longer, pump out more of it over a longer period, and sustain an ecosystem based on chemotrophs. Alternatively, the internal heat of an Earth-sized planet can be sustained tidally, as in Io, by the gravitational influence of a close massive companion.
And, back to the OP's point and yours, an atmosphere can be translucent enough to allow sufficient light for photosynthesis while still remaining hazy enough that distant details are obscured. In none of these cases is the evolution of intelligence necessarily precluded, unless I'm missing something.
Posted 07 August 2013 - 09:08 AM
Posted 14 August 2013 - 05:37 PM
Posted 15 August 2013 - 10:45 PM
To me, a transparent sky (not just our atmosphere but our region of space, relatively free of dust clouds) provided humans with a much deeper environment in terms of information. Time keeping, calendar making, predication of regular events, navigation, and then to the modern day revlelations of phsyics and astronomy, humanity has been challenged and rewarded by a night sky full of stars.
Since I think humans are in a different phase of evolution than saw the initial rise of intelligence, the incredible effect of the night sky on human thinking has played a role in our evolution, from the ancient times to the present day.
Douglas Adam's plotline for the planet Krikkit was one of the first things I thought of when I read the first post on this thread...