21 -- The Habitable Galaxy: Variation in Space and Time

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TUESDAY, April 15, 2008: MORNING

Adrian Melott
University of Kansas
Lawrence, KS, USA


The concept of a galactic habitable zone has recently been broadened, and may also include dynamical considerations which will be relevant to the Terrestrial Planet Finder. There should be differences in the suitability of planetary life with time and position dependence in the galaxy. Examples include sufficient element abundance for rocky planet formation, the rate of supernovae which can damage biospheres, exposure to extragalactic cosmic rays, and sufficient time for evolution of life. These processes can cause extinctions or possibly stimulate biodiversification--a fundamental research topic in paleontology and evolutionary biology--and so have bearing on the probability that life has emerged elsewhere and the broader context for life. On Earth, evidence is emerging that there are large and correlated fluctuations in origination and extinction rates on timescales ranging from 10-100 My. These periodicities may be related to galactic forcing. Research on the galactic habitable zone is interdisciplinary, integrating paleontology with broader geophysical and astrophysical inputs, and has only begun to be integrated with astrobiology. This session invites contributions on such topics with the goal of developing an integrated picture of "habitable galactic phase space".


9:45           21-04-O. The Galactic Habitable Zone and the Age Distribution of Complex Life

                  in the Milky Way [invited]   C. Lineweaver

10:15         21-08-O. Cycles of Fossil Diversity [invited]    R.A. Muller

10:45         BREAK

11:00         21-06-O. Distribution of Cosmic Rays in the Galaxy–a Link to Biodiversity Cycles

                  [invited]   M. Medvedev

11:30         21-07-O. Further Aspects of Periodicity in Terrestrial Biodiversity   A. Melott

11:45         21-01-O. Using Climate Models to Investigate the Cause of Mass Extinction Events                   G. Feulner


21-02-P.     Dynamics of Populations Subjected to Fast Depletions   D. Galante, J.E. Horvath

21-03-P.     Dynamics of Planetary Systems in Different Galactic Environments  

                   J.J. Jimenez-Torres, B. Pichardo

21-05-P.     Astroecology, Directed Panspermia, and the Cosmological Future of Life  

                   M. Mautner

21-09-P.     Were Galactic Cosmic Rays Responsible for Global Cooling Associated with

                   Three Major Paleozoic Mass Extinction Events?   D. Petrizzo, P. Jogi, B. Runnegar


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