1. Bruce Buffett: Planetary Magnetic Fields

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    Bruce Buffett presents a public talk at UC Berkeley on July 17, 2010, as part of the Science@Cal Lecture Series described at http://scienceatcal.berkeley.edu/lectures Many of the planets in the solar system have internally generated magnetic fields. All of these fields are produced by the motion of an electrically conducting fluid in the interior, although the details vary from planet to planet. Historical observations of the magnetic field on Earth show that the field is continually changing on time scales as short as a few years. Earth's magnetic field also exhibits spontaneous polarity reversals, which cause the north and south magnetic poles to flip. The mechanism for reversals is not well understood, but geological records suggest that the onset of reversals is accompanied by a sudden reduction in the field strength. A strong field re-emerges from the interior as the new polarity is established. In this presentation I will discuss the origin of planetary magnetic fields. I will also speculate about the current decline in Earth's field, which has prompted some researchers to suggest that the field is entering the next reversal. Bruce Buffett is a Professor of Geophysics in the Department of Earth & Planetary Science at the University of California, Berkeley. He received his PhD in Geophysics from Harvard University and was a Research Fellow at the University of Cambridge. He moved the University of California in 2008 after holding a faculty appointment at the University of Chicago. Videography and editing by Chris Klein. This video is released under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License - http://creativecommons.org/licenses/by-nc-sa/3.0/us

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    • Lucianne Walkowicz: Magnetic Stars, Space Weather and Life: Stellar Activity and its Effect on Planets

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      Lucianne Walkowicz presents a public talk at UC Berkeley on June 19, 2010, as part of the Science@Cal Lecture Series described at http://scienceatcal.berkeley.edu/lectures Sunspots are some of the oldest astronomical phenomena observed by human beings. These "freckles" on the the face of our Sun may look innocuous, but they are actually the footprints of huge magnetic loops that protrude from our star. These loops sometimes twist and snap, causing spectacular solar flares that send radiation and energetic particles hurtling towards Earth. These flares are responsible for beautiful aurorae, but they can also cause the troubling disruption of satellites and other infrastructure. Similar phenomena are observed on many other stars in our Galaxy, with some stellar flares being even more powerful than those of the Sun. What is it like to be a planet around those stars? How do flares and starspots affect a planet's ability to support and sustain life? These are just some of the questions we will explore. Dr. Walkowicz is a Kepler Postdoctoral Fellow in the Astronomy Department at the UC Berkeley. She studies magnetic activity in the atmospheres of cool stars through both observation and theory. She is active in the development of the next generation of ground-based telescopes as Chair of the Transient Working Group for the Large Synoptic Survey Telescope, and is a member of the team working to find earth-sized planets using the new Kepler space telescope. Dr. Walkowicz grew up in New York City, before obtaining her undergraduate degree at Johns Hopkins, and a PhD from the University of Washington. In her spare time, she enjoys drawing and writing comics, and painting. Videography and editing by Chris Klein. This video is released under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License - http://creativecommons.org/licenses/by-nc-sa/3.0/us

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      • Richard Saykally: What Makes Water Wet? The Latest Word on the Most Important Molecule in the Universe

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        Richard Saykally presents a public talk at UC Berkeley on May 15, 2010, as part of the Science@Cal Lecture Series described at http://scienceatcal.berkeley.edu/lectures Water is the third most abundant molecule in the Universe, and the basis for life as we know it. Despite this profound importance, apparent chemical simplicity, and decades of intense study, the nature of water remains incompletely understood. Current debates include the proposed existence of 17 forms of ice and two forms of the liquid, and the nature of water in confined environments, like cells and carbon nanotubes. We have accumulated a wealth of new data characterizing the nature of water via the study of water clusters in the range of dimer through hexamer, using Terahertz Laser Vibration-Rotation-Tunneling spectroscopy, which directly probes the bends and stretches of the hydrogen bonds. These data provide a good start towards “a universal first principles” model for water, that can explain all of its unusual properties. Born in Rhinelander, Wisconsin and educated at UW-Eau Claire and UW-Madison, Saykally has been a professor at the University of California, Berkeley since 1979. Techniques developed by him and his students have permitted the first detailed study of important textbook molecules, including the hydronium (H3O+), hydroxide (OH-) and ammonium (NH4+) ions, as well as small water clusters and carbon clusters. Recent work includes the spectroscopic determination of a universal water force field via the study of water clusters. A co-author of over 360 publications, the recipient of over 60 honors and awards, Saykally is a member of the National Academy of Sciences and the American Academy of Arts and Sciences, and has recently received the E.O. Lawrence Award in Chemistry from the U.S. Department of Energy, the Hinshelwood Lectureship from Oxford University, and Inaugural International Solvay Chair in Chemistry from the Solvay Institutes of Belgium, and the 2009 Peter DeBye Award in Physical Chemistry from the ACS. He is a UC Berkeley Distinguished Teacher, and has been active at the national level in science education. Over 50 students have completed the Ph.D. under his direction. Saykally currently holds The Class of 1932 Chair in the Department of Chemistry. Videography and editing by Chris Klein. This video is released under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License - http://creativecommons.org/licenses/by-nc-sa/3.0/us

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        • Michael Silver: How Attention Affects What You See

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          Michael Silver presents a public talk at UC Berkeley on March 20, 2010, as part of the Science@Cal Lecture Series described at http://scienceatcal.berkeley.edu/lectures We are continuously bombarded with an enormous amount of information entering our eyes. How do our brains extract the most relevant parts of this fire hose of information? Attention is one way the brain selects certain aspects of the environment for enhanced processing. Prof. Silver discusses the effects of attention on visual perception and summarize what we know about the underlying brain mechanisms. A better understanding of the effects of attention on perception would be relevant for a wide variety of activities, including setting policy for cell phone use while driving, improving performance of airport luggage screeners, and optimizing teaching methods in the classroom. Michael Silver is a member of the School of Optometry and the Helen Wills Neuroscience Institute. The research in his group is focused on the neural bases of perception, attention, and learning in the human visual system. The Silver laboratory employs brain imaging methods to track the flow of information through brain areas. His group also conducts drug studies to investigate the functions of specific neurotransmitters in vision. Other research projects include the study of visual processing in patients with schizophrenia and changes in visual perception and brain organization associated with retinal degeneration. Videography and editing by Chris Klein. This video is released under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License - http://creativecommons.org/licenses/by-nc-sa/3.0/us

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          • John Harte: Predicting Climate Change on a Green Planet: The Daunting Challenge

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            John Harte presents a public talk at UC Berkeley on February 20, 2010, as part of the Science@Cal Lecture Series described at http://scienceatcal.berkeley.edu/lectures Ecosystems and Climate are linked by feedback mechanisms that can hugely influence future global warming. Prof. Harte reviews results from analysis of past climate change, from ongoing climate manipulations in ecosystems, and from observations of ecosystems along climate gradients, and shows that climate-ecosystem feedbacks are often large and positive. Because current IPCC projections do not include many of these feedbacks, future warming is likely to be considerably more intense than is currently anticipated. Unfortunately, there are huge gaps in our current understanding of future ecosystem responses to global warming, and therefore in our understanding of climate change itself. Prof. Harte’s research focuses on the effects of human actions on, and the linkages among, biodiversity, ecosystem structure and function, and climate. He aims to understand the nature and causes of patterns in the distribution and abundance of species. He also studies the interaction between ecosystems and the process of climate change, and how the health of ecosystems impacts human well-being. Prof. Harte has received the Leo Szilard prize from the American Physical Society, the UC Berkeley Graduate Mentorship Award, and a Miller Professorship. He has served on six National Academy of Sciences Committees and has authored overed 170 scientific publications, including six books, on topics including biodiversity, climate change, biogeochemisty, and energy and water resources. Videography and editing by Chris Klein. This video is released under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License - http://creativecommons.org/licenses/by-nc-sa/3.0/us

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            • Bethany Cobb: From Failure to Triumph - The Story of the Hubble Space Telescope

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              Bethany Cobb presents a public talk at UC Berkeley on January 16, 2010, as part of the Science@Cal Lecture Series described at http://scienceatcal.berkeley.edu/lectures Released into orbit in 1990, the highly anticipated Hubble Space Telescope quickly became a major embarrassment for NASA. Despite two decades of development and testing, the telescope's main mirror had been shaped incorrectly, leaving the telescope out of focus. The telescope also suffered from a design flaw that caused the telescope to shake! Despite these troubles, HST was still a powerful astronomical instrument thanks to its orbit above Earth's atmosphere. With a series of delicate space repairs in 1993, HST finally reached its full potential and has been a revolutionary instrument ever since. This talk describes HST's history and future and highlights some of the telescope's groundbreaking astronomical observations. Bethany Cobb is a National Science Foundation Astronomy and Astrophysics Postdoctoral Fellow at UC Berkeley. She works on the explosive deaths of massive stars as gamma ray bursts. She enjoys communicating her love of astronomy to the public, whether teaching at the Osher Lifelong Learning Institute, providing astronomical information for "The Old Farmer's Almanac", participating in the astronomy department's International Year of Astronomy Lecture Series, or developing an astronomy-themed dance performance with choreographer Kathryn Roszak. Videography and editing by Chris Klein. This video is released under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License - http://creativecommons.org/licenses/by-nc-sa/3.0/us

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