"CURVE OF THE END OF THE WORLD" IN THE HARD-LIFE SCENARIO - by Steno FERLUGA - Common expectations for widespread life in the universe are theoretically supported by the easy-life scenario, which considers biological evolution as a sequence of highly probable transitions, occurring on any habitable planet. On the opposite side, a less popular scientific point of view (yet Copernican) is the hard-life scenario, supposing that the Earth might be a rare case of planetary evolution due to a sequence of low-probability transitions, which we notice only because of the (anthropic) selection effect requiring the presence of observers.
The number of critical evolutionary steps considered in the literature, according to biological and paleontological issues, is generally small (from 5 to 7). A complete conception admits the possibility that the sequence of evolutionary transitions, leading to intelligent life, may include hard and soft steps as well.
In this Poster, it is explained how the hard-life scenario poses a surprising mortgage on the future of the Earth. Computations refer to the general framework, treating together both hard and easy evolutionary steps, which is introduced by the Author in an oral presentation at this Meeting.
A predictive curve is derived, describing the probability that the “End of the World” (egress of the Earth from the Habitable Zone) might occur at a given time in the future, depending on the parameters of the model. The results are displayed in the Figures, showing that hard scenarios with a large number of steps (> 6 or 7) imply uncomfortably short lifetimes for the biosphere. On the other side, the presence of an easy step leading from animals to cognitive intelligence has the effect of lengthening this lifetime expectation.
