Available energy for life on a planet with or without stellar radiation

Sertorio, L. and Tinetti, G. (2001) Available energy for life on a planet with or without stellar radiation. Il nuovo cimento C, 24 C (3). pp. 421-444. ISSN 1826-9885

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The quest for life in the Universe is often affected by the free use of extrapolations of our phenomenological geocentric knowledge. We point out that the existence of a living organism, and a population of organisms, requires the existence of available energy or, more precisely, available power per unit volume (sect. 1). This is not a geocentric concept, but a principle that belongs to the foundations of thermodynamics. A quest about availability in the Universe is justified. We discuss the case in which power comes from mining (sect. 2), and from thermal disequilibrium (sect. 3). Thermal disequilibrium may show up in two ways: on planets without a star (sect. 4), and on planets where the surface thermal disequilibrium is dominated by the incoming photon flux from the nearest star (sect. 6). In the first case we study the availability by simulating the structure of the planet with a simple model that contains the general features of the problem. For the first case we show that the availability is in general very small (sect. 5). In the second case we show that the availability is in general large; the order of magnitude depends first of all on the star’s temperature and the planet’s orbit, but is also controlled by the greenhouse gases present on the planet.

Item Type: Article
Uncontrolled Keywords: Nonequilibrium and irreversible thermodynamics ; Ecology and evolution ; Heat flow; geothermy
Subjects: 500 Scienze naturali e Matematica > 550 Scienze della Terra
Depositing User: Marina Spanti
Date Deposited: 10 Mar 2020 18:38
Last Modified: 10 Mar 2020 18:38
URI: http://eprints.bice.rm.cnr.it/id/eprint/14299

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