Catálogo de publicaciones - libros

The prospect of engineering a planetary climate raises a multitude of issues associated with climatology, engineering on truly macroscopic scales and indeed the ethics of such ventures. Depending on personal views, such large-scale engineering is either an obvious necessity for the deep future, or yet another example of human conceit. In this chapter a simple climate model will be used to assess the possibility of engineering the Earth’s climate (geo-engineering) using large orbiting reflectors. Two particular cases will be considered: active cooling of the climate to mitigate against anthropogenic climate change due to a doubling of the carbon dioxide concentration in the Earth’s atmosphere and active heating of the climate to mitigate against an advance of the polar ice sheets of a magnitude comparable to that induced by the Milankovitch cycles. These two cases will be used as representative scenarios to allow the scale of the engineering challenge to be determined. In addition, even more visionary applications of solar reflectors to slowly manipulate the Earth’s orbit will be investigated. While, engineering on such scales appears formidable at present, emerging capabilities to process lunar and asteroid material will allow such ventures to be considered in the future. This chapter aims to provide a foretaste of such future possibilities

A stellar engine is defined in this chapter as a device that uses the resources of a star to generate work. Stellar engines belong to class A and B when they use the impulse and the energy of star’s radiation, respectively. Class C stellar engines are combinations of types A and B. Minimum and optimum radii were identified for class C stellar engines. When the Sun is considered, the optimum radius is around 450 millions km. Class A and C stellar engines provide almost the same thrust force. A simple dynamic model for solar motion in the Galaxy is developed. It takes into account the (perturbation) thrust force provided by a stellar engine, which is superposed on the usual gravitational forces. Two different Galaxy gravitational potential models were used to describe solar motion. The results obtained in both cases are in reasonably good agreement. Three simple strategies of changing the solar trajectory are considered. For a single Sun revolution the maximum deviation from the usual orbit is of the order of 35 to 40pc. Thus, stellar engines of the kind envisaged here may be used to control to a certain extent the Sun movement in the Galaxy

We consider the problem of detectability of macro-engineering projects over interstellar distances, in the context of Search for ExtraTerrestrial Intelligence (SETI). Freeman J. Dyson and his imaginative precursors, like Konstantin Tsiolkovsky, Olaf Stapledon or John B. S. Haldane, suggested macro-engineering projects as focal points in the context of extrapolations about the future of humanity and, by analogy, other intelligent species in the Milky Way. We emphasize that the search for signposts of extraterrestrial macro-engineering projects is not an optional pursuit within the family of ongoing and planned SETI projects; , the failure of the orthodox SETI thus far clearly indicates this. Instead, this approach (for which we suggest a name of ‘‘Dysonian’’) should be the front-line and mainstay of any cogent SETI strategy in future, being significantly more promising than searches for directed, intentional radio or microwave emissions. This is in accord with our improved astrophysical understanding of the structure and evolution of the Galactic Habitable Zone, as well as with the recent wake-up call of Steven J. Dick to investigate consequences of postbiological evolution for astrobiology in general and SETI programs in particular. The benefits this multidisciplinary approach may bear for macro-engineers are also briefly highlighted