Monday, April 27, 2009

04/15/2009 - The Dynamic Lunar Environment

Jasper Halekas, UC Berkeley Space Sciences Laboratory

The lunar environment, serene and unchanging to the naked eye, seethes with plasma and electromagnetic activity. Plasma, photons, micrometeorites and energetic particles constantly bombard the lunar surface, producing a tenuous exosphere and a dynamic wake region, and charging the surface to electrostatic potentials reaching kilovolts, producing surface electric fields large enough to affect lunar ions and dust. Meanwhile, plasma interacts directly with crustal magnetic fields, producing perhaps the smallest magnetospheres in the solar system. Dr. Halekas will talk about how the Moon provides an ideal laboratory to study a variety of fundamental physics processes which are both interesting in their own right, and potentially applicable to Mars and other planets in the solar system.

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Wednesday, April 15, 2009

4/8/2009 - Convergent evolution of our own and extra-terrestrial intelligence

John McCarthy, Professor Emeritus, Computer Science Stanford University

Convergent evolution is the phenomenon of two or more species of widely different origins evolving extremely similar features in response to the same environmental opportunity. Our intelligence and that of aliens with whom we might communicate are likely to have converged considerably and to converge further in the future. Much of this future convergence is likely to be artificial, i.e. electronic. Professor McCarthy will discuss some possibilities.

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Wednesday, April 8, 2009

04/01/2009 - Weathering on Icy Satellites: Probing the Near Surface Using Infrared Spectroscopy

Rachel Mastrapa, NASA Ames Space Sciences Division and SETI Institute

Infrared spectra of icy satellites contain information about the surface composition and the phase state of those materials. For example, the phase of H2O-ice can be used to interpret the temperature and radiation history of an icy surface. Optical constants derived from laboratory data are needed to create model spectra for comparison to observations and may lead to a new understanding of surface processes.

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Wednesday, April 1, 2009

03/18/2009 - Discovery of Strong Cycles in Fossil Diversity

Richard Muller, Lawrence Berkeley Laboratory, UC Berkeley

Richard Muller and his collaborators have recently analyzed the most complete record of marine animal fossils ever compiled, the "Compendium" of Jack Sepkoski, which lists all known fossil marine animal genera back 542 million years. When the fossil diversity (number of distinct genera) is plotted, it shows a very strong 62 Myr cycle. The cycle is particularly evident in the species that endured for relatively short times, as shown in the diagram below (published in Nature, vol 434, 208-210, 10 March 2005).

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