Typical Climate Perturbations Unlikely to Disrupt Gaia Hypothesis. (arXiv:1906.01112v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Alcabes_O/0/1/0/all/0/1">Olivia D. N. Alcabes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Olson_S/0/1/0/all/0/1">Stephanie Olson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Abbot_D/0/1/0/all/0/1">Dorian S. Abbot</a>
The Gaia hypothesis postulates that life regulates its environment to be
favorable for its own survival. Most planets experience numerous perturbations
throughout their lifetimes such as asteroid impacts, volcanism, and the
evolution of a star’s luminosity. For the Gaia hypothesis to be viable, life
must be able to keep the conditions of its host planet habitable, even in the
face of these challenges. ExoGaia, a model created to investigate the Gaia
hypothesis, has been previously used to demonstrate that a randomly mutating
biosphere is in some cases capable of maintaining planetary habitability.
However, those model scenarios assumed that all non-biological planetary
parameters were static, neglecting the inevitable perturbations that real
planets would experience. To see how life responds to climate perturbations to
its host planet, we created three climate perturbations in ExoGaia: one rapid
cooling of a planet and two heating events, one rapid and one gradual. The
planets on which Gaian feedbacks emerge without climate perturbations are the
same planets on which life is most likely to survive each of our perturbation
scenarios. Biospheres experiencing gradual changes to the environment are able
to survive changes of larger magnitude than those experiencing rapid
perturbations, and the magnitude of change matters more than the sign. These
findings suggest that if the Gaia hypothesis is correct, then typical
perturbations that a planet would experience may be unlikely to disrupt it.
The Gaia hypothesis postulates that life regulates its environment to be
favorable for its own survival. Most planets experience numerous perturbations
throughout their lifetimes such as asteroid impacts, volcanism, and the
evolution of a star’s luminosity. For the Gaia hypothesis to be viable, life
must be able to keep the conditions of its host planet habitable, even in the
face of these challenges. ExoGaia, a model created to investigate the Gaia
hypothesis, has been previously used to demonstrate that a randomly mutating
biosphere is in some cases capable of maintaining planetary habitability.
However, those model scenarios assumed that all non-biological planetary
parameters were static, neglecting the inevitable perturbations that real
planets would experience. To see how life responds to climate perturbations to
its host planet, we created three climate perturbations in ExoGaia: one rapid
cooling of a planet and two heating events, one rapid and one gradual. The
planets on which Gaian feedbacks emerge without climate perturbations are the
same planets on which life is most likely to survive each of our perturbation
scenarios. Biospheres experiencing gradual changes to the environment are able
to survive changes of larger magnitude than those experiencing rapid
perturbations, and the magnitude of change matters more than the sign. These
findings suggest that if the Gaia hypothesis is correct, then typical
perturbations that a planet would experience may be unlikely to disrupt it.
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