ABC2019 wrote:a star does not lead to a maximum production of entropy, precisely, otherwise it would explode instantly! This happens sometimes in the case of supernovae, but it is precisely because there are no longer any stable structures possible.
We must remain vigilant in the correlation between words and their transcription to physical phenomena and avoid too direct extrapolations.
In everyday language, thePigmentation refers to the most important possibilities that can be brought into play.
For example in running the maximum corresponds to a sprint of 30,50,100 m according to the physical possibilities of the runner.
Applied to a star it could therefore, as you mention, correspond in our imagination to a supernovæ type explosion (energy sprint). The problem is that such an explosion is simply not possible for an accreting gas cloud, any more than a human embryo could run the 100m!
Prerequisites are needed, in particular an evolution of the different constituents of the star to arrive, depending on its mass, at a white dwarf type evolution or for larger masses of novae, super novae, etc.
When we speak of maximum entropy production, we are referring to the maximum level that the energy flows can reach with regard to the state of the system considered, not a reasoning extrapolated to the absolute.
For example, in the earth's atmosphere, currents are formed, these correspond to the temperature differences between the poles and the equator, resulting in air movements that will self-organize, which will cause currents of air from the equator towards the poles leading at the same time to a temperature balancing of the air masses and a reduction in the yield of mechanical energy production.
Pass a stage therefore, the currents stop increasing, we consider that they have reached their maximum values:they are then in a state of maximum entropy production.
This does not mean that there should be a single one-second gale at 3000km / h.
except that the lichen will have "temporarily" slowed down the entropy flow a bit, and eventually store some negentropy in fossil form. But he will not have accelerated the production of entropy, he will have used it.
The principle of maximum entropy production is still respected in the living world.
Your lichen does not accelerate thermal entropy stricto sensu but it accelerates it informally over time, which anyway amounts to increasing the entropy to a level higher than a pebble.
Cyanobacteria dissipate about 10 mW / Kg, the various plants 100 mW / Kg, the first animals dissipate 1 W / Kg, Man dissipates 3 W / Kg (at rest), etc.
Eric Chaisson for example demonstrated that a human being dissipates 10 times more energy per unit mass than the solar equivalent!
[url] https://lweb.cfa.harvard.edu/~ejchaisson/reprints/Springer_complexity_ (exobio) _final_review.pdf
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