CSC/SETI Institute Colloquium Series - Past Lectures

Past lectures' author index

Past Lectures

2007: Nov Dec

2008: Jan Feb Mar Apr May Jun Jul Aug Sep Oct

2007

Nov. 7

Frank Drake

The End of the Habitable Zone: Lessons from the Solar System

 

 

Frank DrakePhenomena in the Solar System have shown that temperatures can be suitable for life at great distances from a star as a result of the action of various forms of  "insulation".   The forms of "insulation" include a solid surface, an ocean, and a greenhouse atmosphere.  It is interesting to note that there appears to be no plausible atmosphere which produces an "anti-greenhouse", a cooling effect.   The existence of insulation greatly extends the habitable zone.  In addition, with regard to the ubiquitous M-stars, the observed large fraction of extrasolar planets with substantial eccentricities suggests, if M-stars have a similar distribution of eccentricities,  that very few will be in synchronous rotation, even though tidally locked, and thus more likely to be habitable.   Insulation in M-stars will extend their habitable zone.   Overall, the lessons from the Solar System suggest that the sizes of habitable zones are much larger than older pictures of habitable zones, greatly increasing the number of habitable planets.

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Nov. 14

Jason Barnes

Titan's Sand Dunes: Window to a New World

 

 

Despite theoretical predictions that Titan would not be able to support sand dunes on its surface, the Cassini orbiter has found an extensive set of sand seas astride the equator.  The dunes are longitudinal in nature and resemble Earth's dunes in Namibia, the Sahara, and Arabia in height and spacing.  Their spectra are consitent with hydrocarbon grains, not water ice as might be expected from erosion of an icy crust. Even with the total dune coverage of ~20%, though, the visible dune sands cannot alone account for the missing hydrocarbons expected to have been produced photochemically from atmospheric methane.  With present understanding of the nature of Titan's surface and the processes that operate there still in its formative stages, the discovery of these familiar forms allows us a window into the global geology of this newly revealed world.

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Dec. 5

Rocco Mancinelli

Extremophiles: What it takes for life to survive beyond the home planet

 

Recently we have come to realize that where there is liquid water on Earth, virtually no matter what the physical conditions, no matter where, there is life.  Environments we previously thought of as having insurmountable physical and chemical barriers to life, such as extremes in temperature, pH, and radiation, are now seen as yet another niche harboring "extremophiles". This realization, coupled with new data on the survival of microbes in the space environment, and modeling of the potential for transfer of life between planets suggests that life could be more common than previously thought. Data from recent Mars missions support the notion that Mars had abundant liquid water on its surface in the past, and has salts in its regolith. It could also have brine pockets that may either be an "oasis" for an extant biota, or the last refuge of an extinct biota. Characteristics that are important to better understand how life may survive conditions on Mars include radiation and desiccation resistance, as well as the ability to survive freeze/thaw cycles. To better understand what it takes to survive these conditions we study microbes and how they live, survive and die from the lagunas in the Bolivian altiplano to the space environment in Earth orbit.  We have shown that terrestrial life can survive away from Earth in a simulated Mars environment and in the space environment.  This research represents the first step in understanding what it takes for life to survive away from its home planet.

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Dec. 19

Devon Burr

Planetary Habitability of Mars and of Titan: A Tale of Two Worlds

 

 

Devon BurrPlanetary geology provides critical information of other worlds, including their astrobiological potential.  By that term, I mean not only their specific potential to harbor life but their more general potential to tell us something about life.  As we expand our understanding of life – where it is, what it is, how it is – beyond Earth, geomorphology complements compositional data in giving us clues as to planet habitability.  Mars is a case in point: the earliest to most recent data show extensive geomorphic evidence of water, the sine qua non for all life that we know.  These remote and (recently) in situ data indicate large volumes of water in the surface, subsurface and atmosphere throughout Mars’ history.  Yet compositional evidence in the spectral data for organic materials is stubbornly lacking.  As a converse example, data of Titan, Saturn’s largest moon, show a near-total lack of liquid water, as expected from its size and position relative to the Sun.  Yet this world is drenched in organic compounds. As part of its hydrocarbon cycle (analogous to Earth’s hydrologic cycle), Titan forms organic molecules in the upper atmosphere, which apparently result on the surface in extensive aeolian (wind-formed) dunes.  Thus, Mars and Titan each provide disparate but important astrobiological information.  In this talk, I will give an overview of some of the most recent geologic discoveries regarding water on Mars and organics on Titan.

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2008

Jan. 2

Bo Thide

On the extraction of all information embedded in radio siganls: Implications for SETI

 

A new idea for utilizing all of the information in photons for communication involves a little-know electromagnetic property: the photon's orbital angular momentum (POAM). The communication and computer industries are actively looking at the possibilities. We will discuss current research and the implications for SETI.

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Jan. 9

Laurance Doyle

Quantum Astronomy: Extending the Weirdness of Modern Physics to Cosmic Scales

 

LAURANCE DOYLEIs the weirdness of aspects of quantum physics confined to the microscopic? Can one trade off information at the detector, thereby changing events that should have already taken place in the past? By increasing ignorance can one actually learn something new that could not have been learned with less ignorance? Does quantum physics recognize time as defined by general relativity, and vice versa? In this seminar we'll discuss how to use the uncertainty principle as a quantum eraser in a cosmic-scale double-slit experiment -- the double-slits being gravitational lenses millions to billions of light years distant. Hopefully by the time of the seminar, our first official paper will have been accepted by The Astrophysical Journal. Anyway, if history can be changed, it won't matter.

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Jan. 16

Jill Tarter

The Allen Telescope Array: A Wide-angle, Panchromatic Radio Camera for SETI and Radio Astronomy

 

Jill TarterAccording to Jerry Ostriker (Plumian Professor, Cambridge; Professor of Astrophysics, Princeton; Provost, Princeton), "Surveys aren’t just something that astronomers do, they are the only thing astronomers do." These words are understandable, given Prof. Ostriker’s intimate association with the Sloan Digital Sky Survey that is presently transforming our view of the optical universe. The ability to systematically survey one quarter of the sky, with the dynamic range and spatial resolution to zoom in to study individual objects, is providing us with the first truly 3-dimensional map of the nearby cosmos. The optical portion of the spectrum unveils the moderately energetic and hot components of the universe, but the physics of the cool constituents is probed at radio wavelengths. [New Paragraph] The Allen Telescope Array (ATA) of 350 telescopes, each 6.1 m in diameter, will do for the radio sky what the Sloan Digital Sky Survey has done for the optical sky. And it will do it so rapidly that it will also provide the first systematic look at the transient radio universe. The ATA provides simultaneous access to any frequency between 500 MHz and 11.2 GHz, with four separate frequency channels feeding a suite of signal processing backends that can produce wide-angle radio images of the sky in 1024 colors, and at the same time, study up to 32 point sources of interest within its large field of view. This new approach to commensally sharing the sky allows SETI (the Search for ExtraTerrestrial Intelligence) and traditional radio astronomical science to both use the telescope nearly all the time: our tools are beginning to be commensurate with the size of the vast explorations of the radio sky that we wish to undertake. [New Paragraph] This talk will put the ATA into context with the rest of the SETI activities around the world and describe the initial SETI observations we intend to conduct.

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Jan. 18

Francis Nimmo

Geodynamics of Icy Satellites

 

 

francis nimmoThere are at least 37 objects in this solar system with masses greater than 1020 kg, two thirds of which have surfaces made primarily of water ice. The handful of icy bodies studied by spacecraft have revealed an enormous diversity of bizarre and unanticipated features, from geysers on Triton and Enceladus, to the peculiar shapes of Iapetus and 2003 EL61. I will discuss three aspects of icy body geodynamics: using surface observations to constrain their thermal evolution; the role of tidal heating; and their potential to undergo reorientation.

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Jan. 23

Adrian Brown

CRISM Observations of the seasonal recession of the Martian southern polar cap

 

Adrian BrownIn this, the International Polar Year 2007-2008, it is a satisfying time to consider our understanding of Extraterrestrial Polar environments. On Mars, they're celebrating summertime in the austral hemisphere, and have just gone through a big defrosting known as the 'spring recession'. Luckily, we humans had an emissary there to catch all the action. [New Paragraph] Dr. Adrian Brown reports on the latest results back from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) and explains how the unanticipated discovery by CRISM of small ephemeral water ice deposits, common in winter areas on Earth, are of vital interest to Mars polar science.

For more information, go to: http://abrown.seti.org

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Jan. 30

Ashok Srivastava

Anomaly Detection in Data Streams and its Implications for Radio Astronomy and SETI

 

Recent advances in data mining have enabled the detection of anomalies in massive time series data sets. These techniques range from analysis of individual time series to multidimensional analysis of streaming data. [New Paragraph] A key issue in anomaly detection is characterizing the expected signal from the unexpected signal. In many situations, these characterizations can be made based on a physical understanding of the data generating process. In the context of SETI@home, the software searches for spikes in the power spectra, Gaussian rises and falls in transmission power, triplets, and pulsing signals. While these signals are well motivated based on our current knowledge of communications systems, we discuss methods of anomaly detection that do not rely on strong assumptions of the data generating process. [New Paragraph] This talk will cover recent algorithmic developments in anomaly detection with applications to SETI.

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Feb. 6

Ross Beyer

HiRISE views of Martian Strata and Slope Streaks

 

 

Ross will give a brief overview of the HiRISE instrument and then discuss how its high-resolution color imaging is contributing to an improved understanding of the geologic history of Mars as exposed in its layered outcrops. Ross will also discuss recent work regarding the enigmatic streaks observed on many slopes on Mars, and possible hypotheses regarding how these streaks change from dark to bright, and then fade away.

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Feb. 8

Paul Gazis & Creon Levit

Viewpoints: a Fast, Interactive, Multi-platform Visualization Tool for Exploring Large Multivariate Data Sets

 

Finding effective ways to visualize of large multivariate data sets has become a significant challenge as data volumes have grown. Modern astrophysical data sets can easily exceed millions of samples that involve hundreds or thousands of variables. While it may be possible to plot subsets of these data using scripted languages sch as MATLAB or IDL, this presupposes that one already knows what one wishes to plot. This is rarely the case during the initial phases of data exploration.

Viewpoints is a fast interactive visualization and analysis tool for large, complex, multidimensional data sets. It runs on most common platforms and operating systems to produce multiple linked scatterplots that can be changed, rescaled, modified, and processed in real time in a variety of powerful and informative ways. It was originally developed for internal use by the informal ARC Cluster Group to examine data from the Sloan Digital Sky Survey, but as requests for the package arrived from a growing number of outside users, we discovered that it had considerable potential as a data exploration tool for applications ranging from aeronautical engineering, quantum chemistry, and computational fluid dynamics to virology, computational finance, and aviation safety. It should also have considerable potential for use by members of the SETI community.

We will present a brief overview of viewpoints, followed by a live hands-on demonstration. We invite you to bring your own data sets (as conventional ASCII flat files) for the latter. Copies of viewpoints are also available from the project WWW site at http://astrophysics.arc.nasa.gov/~pgazis/viewpoints.htm.

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Feb. 13

Elisa Quintana

Terrestrial Planet Formation and Habitability in Binary Star Systems

 

Most stars reside in binary/multiple star systems. Perturbations from a companion star can disrupt the formation and long-term stability of planets. More than 40 extrasolar planets have been detected in binary star systems, including 3 with stellar separations of only ~20 AU, well within the region spanned by planets in our Solar System. I will present results from a large suite of numerical simulations that explore the final stages of terrestrial planet formation in main sequence binary star systems. Planetary accretion is examined around one star of widely separated (> 5AU) binary stars, and also around both members of close (< 0.5 AU) binary stars, in order to determine whether/where Earth-like planets can form. I will also review the dynamics of planetary habitability via the delivery of volatiles, and examine the likelihood of a habitable world with two Suns.

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Feb. 20

Baruch Blumberg

Hepatitis B Virus. Discovery, the Present, and the Future.

 

Baruch BlumbergThe Trustees of SETI have interesting and varied careers in addition to their activities with the Institute. This is the first in a series of presentations to be given by Board members on their work.

Hepatitis B virus was discovered as a result of a basic science project on inherited biochemical variation related to disease susceptibility. It was not, initially, directed to the discovery of hepatitis B virus (HBV), the development of a vaccine, and the prevention of a common cancer. It is an example of non-targeted basic research leading to important clinical and business outcomes.

HBV is one of the most common and deadly viruses. About 400 million people worldwide are currently infected. Infection can lead to acute disease, chronic hepatitis, and primary cancer of the liver. The vaccine was invented in 1969 using an unusual process in which the vaccine protein was isolated from the blood of HBV< carriers. It is now one of the most widely used vaccines worldwide and has resulted in a striking decrease in infection and in a reduction in the incidence of liver cancer. It is the first cancer prevention vaccine and has encouraged the development of another vaccine to prevent cancer of the cervix. It is also possible to greatly decrease the risk of cancer and life-shortening chronic liver disease by the use of antivirals. There are likely to be many cancers that can be prevented and/or treated in a similar manner that could, in time, greatly decrease the burden of human cancer.

The virus also has non-pathological effects; the ratio of males to females among offspring is related in a complex manner to the response of parents to infection with HBV.

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Feb. 27

Javiera Guedes

Formation and Detectability of Planets around Alpha Cen B

 

 

We simulate the formation of planetary systems around Alpha Centauri B. The N-body accretionary evolution of a 1/r disk populated with 400-900 lunar-mass oligarchs is followed for 200 Myr. All simulations lead to the formation of multiple-planet systems with at least one planet in the 1-2 Msun mass range at 0.5-1.5 AU. We examine the detectability of our simulated planetary systems by generating synthetic radial velocity observations including noise based on the radial velocity residuals to the recently published three planet fit to the nearby K0V star HD 69830. Using these synthetic observations, we find that we can reliably detect a 1.8 Msun planet in the habitable zone of Alpha Centauri B after only three years of high cadence observations. We also find that the planet is detectable even if the radial velocity precision is 3 m/s, as long as the noise spectrum is white. Our results suggest that the most significant barrier to a characterization of the Alpha Cen system is the degree of frequency dependence exhibited by the noise.

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Mar. 5

Mate Adamkovics

Condensed-phase methane and tropospheric meteorology on Titan

 

 

Methane is near its triple point at Titan’s surface. On the icy-cold moon of Saturn this hydrocarbon is a fluid analog of water on Earth. Transitions among the phases of methane give rise to various meteorological phenomena that can intimately link the atmosphere and surface. Despite the evidence for solid and liquid methane in Titan’s atmosphere, spectroscopic retrievals of aerosol haze opacities, cloud properties, and surface reflectivities have not included opacity due to condensed-phase methane. I will describe how a significant discrepancy between observations and radiative transfer models of near-IR spectra can be resolved by a rudimentary treatment of large methane droplets or solid methane particles. I will present observations from VLT/SINFONI, Keck/OSIRIS, and Cassini/VIMS, while explaining a technique for enhancing contrast in haze-obscured and surface-contaminated images of the lower atmosphere. Ongoing work regarding the interaction of clouds and precipitation will be cautiously presented with a handful of speculations regarding Titan’s weather patterns.

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Mar. 12

LPSC No Colloquium

 

Mar. 19

Tori Hoehler

The Energetics of Habitability

 
  Energy is required by all living things. Known organisms exhibit two distinct requirements, analogous to the voltage and power requirements of electrical devices, which must be met simultaneously in order to support metabolism. Quantification of these requirements, and of their sensitivity to environmental factors and organismal specifics, establishes energetic boundary conditions on ‘habitability’. These constraints are likely among the chief determinants of the possible distribution of life in the deep subsurface and in other energy-starved systems. The biochemistry of energy metabolism has largely been understood through laboratory models, but quantification of the minimum biological requirements for energy must rely on study of natural populations that are adapted to chronic energy starvation. This talk will present a general energy-balance formulation of habitability and describe the quantification of microbial minimum free energy requirements in a natural ecosystem.

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Mar. 21 (Friday)

Fred Sharpe

Humpback Whales and the Social Intelligence Hypothesis

 
  The Drake Equation predicts a positive correlation between a silent cosmos and a tendency for intelligent life to self extinguish. Alternatively, we simply may not be able to detect or recognize intelligence life in the cosmos --or on planet earth. Humpback whales provide interesting test case, as they appear to exhibit high levels of social intelligence. In Alaska, groups of non-kin form large hunting teams with enduring bonds, specialized tasks, tool use, and gender equity. Their haunting songs and social chatter also suggest that an un-deciphered intelligence echoes through our oceans. Dr. Fred Sharpe of the Alaska Whale Foundation has teamed up with Dr. Laurance Doyle of the SETI Institute, and Dr. Brenda McCowan and Sean Hanser at the University of California, Davis. This team brings the signal processing prowess developed for interstellar inquiry to focus on the phonations of these ocean dwelling societies. We seek to define universal rules of communication and understand how humpback whales fit into the Drake Equation. We also seek to understand how intelligent societies endure or self-extinguish by balancing beneficent behaviors with bellicosity.

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Mar. 26

Jay Melosh

Redox Chemistry in Large Impacts and the Origin of Life

 
  All material affected by close proximity to large impacts, for example, tektites and microkrystites, is chemically reduced compared with the starting material. In her PhD research, Abby Sheffer demonstrated that this chemical reduction is the inevitable consequence of the high temperature equilibrium between liquid and gas phases in the hot vapor plume. In parallel work on his PhD, Matt Pasek demonstrated that only the reduced form of Phosphorous can participate in aqueous reactions that lead to the precursors of life. Although Pasek sought the source of this reduced Phosphorous in the relatively rare mineral Schreibersite, I will argue that the conditions for reduction are far more general. In this talk I will discuss the thermodynamic conditions that exist in an impact vapor plume, show how reduction occurs and argue that the principal source of reduced Phosphorous on the early earth was probably material vaporized in large impacts and globally distributed in the fast distal ejecta of large impact events. All life on earth may thus owe its birth to the capacity of large asteroid impacts to perform chemical reduction.

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Apr. 2

Art Weber

Sugars as the Source of Energized Carbon for the Origin of Life

 
  art weberWhat were the chemical processes that started life on Earth?  Biochemist Art Weber is trying to answer this question by studying prebiotically plausible chemical reactions in the lab – reactions that might have been responsible for biogenesis.

Art’s experiments have shown that sugars are unsurpassed in their ability to undergo spontaneous self-transformation reactions in water.  Consequently, for the past decade he’s been investigating the prebiotic synthesis of sugars and their subsequent reactions in the presence of ammonia that yield a complex mixture of chemical products whose activities are essential to the origin of life, and even combine to form semi-solid microspherules that could have provided a primitive cell-like, catalytic environment. The ultimate goal of his research effort is to develop a model, self-replicating system that resembles the birth of life on Earth, and can be artificially evolved to a more dynamic and complex state.

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Apr. 9

Tom Pierson

SETI Institute - History, the Institute Today, and Plans for the Future

 
  tom piersonThe Colloquium Series changes pace from our normal scientific discussions as SETI Institute CEO Tom Pierson invites everyone to join in a conversation. How did the Institute spring to life? What events punctuated its evolution? Why does the Institute have a Carl Sagan Center? What is the state of the Institute today? And what might the future bring?

From humble beginnings in a trailer at Ames Research Center, to modern facilities on Whisman Road in Mountain View, the SETI Institute truly has evolved over the past 24 years. From the beginning, the Institute’s mission has been to conduct, support, and encourage a broad range of research and educational activities intended to improve humankind’s understanding of the nature, prevalence, and distribution of life in the universe. This work encompasses SETI, astrobiology, and science education efforts funded from a wide variety of public and private sources.

Tom will survey the past and present of the SETI Institute, and also provide some thoughts on how he sees the future, highlighting some of the things that senior management and the Board of Trustees are focusing on. It is hoped that this colloquium will truly be a conversation with the plenty of audience participation. All SETI Institute staff and interested supporters or collaborators are welcome and encouraged to attend.

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Apr. 11
(Friday)

Claudio Maccone

The Statistical Drake Equation

 
  claudio macconeWe provide the statistical generalization of the Drake equation.

From a simple product of seven positive numbers, the Drake equation is now turned into the product of seven positive random variables. We call this “the Statistical Drake Equation”. The mathematical consequences of this transformation are then derived. The proof of our results is based on the Central Limit Theorem (CLT) of Statistics. In loose terms, the CLT states that the sum of any number of independent random variables, each of which may be ARBITRARILY distributed, approaches a Gaussian (i.e. normal) random variable. This is called the Lyapunov Form of the CLT, or the Lindeberg Form of the CLT, depending on the mathematical constraints assumed on the third moments of the various probability distributions. In conclusion, we show that:

  1. The new random variable N, yielding the number of communicating civilizations in the Galaxy, follows the LOG-NORMAL distribution. Then, as a consequence, the mean value of this log-normal distribution is the ordinary N in the Drake equation. And the standard deviation of this N log-normal random variable is found also.
  2. In the classical Drake equation one adds the constraint N ≥ 1 because Humans exist. But in our statistical Drake equation this N ≥ 1 fact is just a mathematical consequence of the logs. In fact, ln(N) = Gaussian, and the Gaussian density can never be equal to zero, except for the limiting case where its variance tends to infinity. So, it must be N ≥ 1.
  3. The seven factors in the ordinary Drake equation now become seven positive random variables. The probability distribution of each random variable is ARBITRARY. The CLT in the so-called Lyapunov or Lindeberg forms (that both do not assume the factors to be identically distributed) allows for that. In other words, the CLT “translates” into our statistical Drake equation by allowing an arbitrary probability distribution for each factor. This is both physically realistic and practically very useful, of course.
  4. An application of our statistical Drake equation then follows. The average distance between any two neighboring and communicating civilizations in the Galaxy may be shown to be inversely proportional to the cubic root of N. Then, in our approach, this average distance becomes a new random variable. We derived the relevant probability density function, apparently a previously unknown probability distribution.   
  5. DATA ENRICHMENT PRINCIPLE. Please notice that ANY positive number of random variables in the Statistical Drake Equation is compatible with the CLT. So, our generalization allows many more factors to be added in the future as long as more refined scientific knowledge about each factor will be known by the scientists. This capability to make room for more future factors in the statistical Drake equation we call the “Data Enrichment Principle”, and it is the key to more profound future results in the field of Astrobiology.

Finally, a practical example is given of how our statistical Drake equation works numerically. We work out in detail the case where each of the seven random variables is uniformly distributed around its own mean value and has a given standard deviation. For instance, the number of stars in the Galaxy is assumed to be uniformly distributed around (say) 300 billions with a standard deviation of (say) 100 billions. Then, the resulting log-normal distribution of N is computed numerically by virtue of a MathCad file that the author has written. This shows that the mean value of the log-normal random variable N is actually of the same order as the classical N given by the ordinary Drake equation, as one might expect from a good statistical generalization.

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Apr. 16

AbSciCon No Colloquium

 

Apr. 23

Norm Sleep

Anoxygenic photosynthesis, evolution, and the origin of continents and cyanobacteria

 
  norm sleepPre-photosynthetic niches were meager with productivity << 10-4 of modern photosynthesis. Serpentinisation, arc volcanism, and ridge-axis volcanism reliably provided H2. Methanogens and acetogens reacted CO2 with H2 to obtain energy and make organic matter. These skills preadapted a bacterium for anoxygenic photosynthesis, probably starting with H2 in lieu of an oxygen acceptor. Use of ferrous iron and sulphide followed as abundant oxygen acceptors, allowing productivity to approach modern levels. The “photo-bacterium” proliferated rooting much of the bacterial tree. Land photosynthetic microbes faced a dearth of oxygen acceptors and nutrients. A consortium of photosynthetic and soil bacteria aided weathering and access to ferrous iron. Weathering led to formation of shales and, and ultimately to granitic rocks. Already oxidized and Fe-poor sedimentary rocks and low-Fe granites provided scant oxygen acceptors. So did fresh water in their drainages. Cyanobacteria evolved di-oxygen production that relieved them of these vicissitudes. They did not immediately dominate the planet. Eventually anoxygenic and oxygenic photosynthesis oxidized much of the Earth’s crust and supplied sulphate to the ocean. Anoxygenic photosynthesis remained important until there was enough O2 in downwelling seawater to quantitatively oxidize massive sulphides at ridge axes.

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Apr. 30

Stefanie Milam

Following Carbon's Evolutionary Path from Nucleosynthesis to the the Solar System

 
  stephanie milamObservations at millimeter/submillimeter wavelengths of various species can be used to trace the cyclic nature of molecular material, specifically carbon-based, throughout stellar evolution. Studies have shown that the carbon isotopic composition of the interstellar medium suggest a strong dependence upon nearby evolved stars and distance to the Galactic center. However, this can also be affected by the chemical composition, carbon-rich or oxygen-rich, and evolutionary status of these old stars. Observations have recently shown that oxygen-rich circumstellar envelopes have a more complex carbon-chemistry than once considered and may have played a role in interstellar carbon enrichment. As large stars evolve into planetary nebulae, molecular material shed from these objects has been shown to endure this highly destructive phase. Additionally, matter may survive from planetary nebulae into the diffuse interstellar medium as the inventories of both regions are now converging. Once gas and dust condense into new stars and planetary systems, the material is potentially recycled in a molecular form and on some level preserved. This is traced by the pristine composition of comets, meteors, and interplanetary dust particles. It has also been shown that comets undergo fragmentation events that release organic material into the solar system and may potentially “seed” planets for prebiotic chemistry. I will present some of these observational results and discuss laboratory experiments underway to help trace interstellar/cometary chemistry.

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May 7

Rusty Schweickart and Ed Lu

The NEO Challenge: Technology and Politics

 
  astronautEd & Rusty will respectively give an overview of the challenge of protecting the Earth from asteroid impacts from the perspectives of both the technical capability to deflect them (and provide other mitigation options) and the international political challenge in defining and agreeing to take such actions.

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May 14

Diane Wooden

Probing the Meteorology of our Protoplanetary Disk with Cometary Mineralogy

Our planetary system formed out of a rotating accretion disk of gas and dust, often called the solar nebula. In the outer disk where temperatures were cold enough to harbor ices and interstellar materials, comet nuclei accreted. Yet, comets also accreted Mg-rich crystalline silicate mineral grains that formed in the hot inner disk close to the young Sun. Hence, cometary Mg-rich crystalline silicates are the touchstone for radial transport of grains that formed in the inner protoplanetary disk out to the comet-forming zone.

Mg-rich crystalline silicate minerals are the expected condensates from the "arid" canonical solar nebula, i.e., condensates from a gas of solar composition. In comparison to Mg-rich crystalline silicates, Fe-rich crystalline silicates are recently discovered in Stardust Mission return samples from comet 81P/Wild 2 and in the Deep Impact coma of comet 9P/Tempel 1. We discuss how Fe-rich crystalline silicates, as well as phyllosilicates (aqueous minerals) can form in more "humid" weather conditions (higher oxygen fugacity) than Mg-rich crystalline silicates. The inward migration of cometesimals (small icy bodies) can raise the humidity of the solar nebula and allow these more oxidized minerals to condense. By comparing the relative abundances of Mg- and Fe-rich crystalline silicates in comets with those in chondrites (asteroidal samples), and by looking at recent dating of chondrules, we derive a picture of the solar nebula as initially arid that then suffers fluctuating epochs of humid weather by 0.6 Myr to 3Myr after the formation of the first condensates. Cometary mineralogy probes the meterology of the solar nebula.

This idea that fluctuating solar nebula "weather" caused the formation of a variety of recently discovered cometary materials challenges recent assertions that cometary Fe-rich crystalline silicates, carbonates, and phyllosilicates are aqueously altered asteroidal materials (selective tiny bits of asteroids that were accreted by comets), or products of selective aqueous alteration on submicron scales in comet nuclei. Instead, if comets do not contain aqueous alteration products from asteroids, then cometary dust grains that formed in the disk are pre-accretionary with respect to asteroids. If comets contain pre-accretionary nebular grains then comets indeed probe the earliest planet-forming processes. Comets contain both the interstellar ingredients for and the products of transmutation in the inner nebula.

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May 21

Sienny Shang

Jets and Outflows from Young Stars: How They Help Shape the Early Solar System

Jets and outflows from young forming stars are among the most spectacular and energetic phenomena in the night sky. They are ubiquitous in star forming regions, and signal the birth of stars like our own. Similar phenomena exist around new higher massive stars, compact objects, and even black holes. They may differ in dynamics, energetics or emission mechanisms, yet they share the striking similarities in their highly-collimated appearance and high-velocity outflowing motion of gas.

Jets and outflows play important roles in the early lives of a newborn star and help shape the early evolution of a young forming planetary system. We review status of theoretical modeling from the point of view of young stellar objects, and the multiwavelength observations of the outflow phenomena. We discuss emission mechanisms of jets and the formation of molecular outflows at the interface of theoretical interpretation and observational confrontations. We present synthetic images from the X-Wind models at the highest-angular resolution as an atlas for future planning of observations. We will touch on the connection of the highly collimated jets to the earliest processing of planetary material, and the large-scale transportation and mixing events that have been inferred to exist from the Stardust return mission.

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May 28

William S. Marshall

An Insider's View of NASA Ames Lunar Skunkworks

will marshalNASA Ames was recently announced as the center for development of the Lunar Atmosphere and Dust Environment Explorer (LADEE) mission, to be launched in 2011. Dr. Marshall arrived at NASA Ames in 2006 and since then has been at the forefront of NASA Ames small satellites development program. Dr. Marshall will discuss the work that has already taken place to develop a common bus architecture for the LADEE Mission and beyond.

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June 2008

June 4

Robert Smith

Liverpool Telescope: Development and science results from a fully autonomous common-user telescope

Robert SmithThe Liverpool Telescope is a fully autonomous robotic telescope at the world-class observatory site on La Palma in the Canary Islands, owned and operated by Liverpool John Moores University (UK). Robert will summarize the original motivation for building such a facility and the design features of telescope, instrumentation and control software which enable its unusual operating mode. The unique facility that it provides has enabled or facilitated exciting scientific results in a wide range of solar system, Galactic and extra-Galactic astrophysics and Robert shall present recent results from some of the diverse research projects performed on the telescope, concentrating on the now proven usefulness of large-aperture robotic telescopes.

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June 11

Prof. Donald A. Glaser, UC Berkeley (Nobel Prize in Physics, 1960 for the invention of the "bubble chamber")

The Role of Cortical Noise in Brain Function

GlaserProfessor Glaser will show some visual dynamic and static visual illusions and the effects of ethanol and marijuana on these illusions. He will speculate that ET's may experience a different set of illusions related to their own brain structures and functions. Could their language and visual imagery depend on these cerebral features and therefore be difficult for us to "understand" or appreciate? Do you assume in your work that their physics is the same as ours?

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June 18

Mario Parente, Department of Electrical Engineering, Stanford University and SETI Institute

Exploratory data analysis of planetary hyperspectral datasets - use of
statistics to enhance mission science return

mario parenteMario Parente will describe the latest developments in statistical
analysis of hyperspectral images, describing his efforts to enhance the
science return of the CRISM infrared spectrometer using a multi-stage
denoising technique. He will describe how it is possible to model the
CRISM instrument and efforts currently ongoing that involve
investigations of surface minerals at Juventae Chasma and Mawrth Valles
on the surface of Mars.

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June 25

Jon Rask and Erin Tranfield:

Toxicological effects of moon dust - how humans will react in the lunar environment

author imagesDuring the Apollo era, lunar regolith was commonly brought into the lunar module via dirty spacesuits and as a result, the cabin surfaces and the cabin atmosphere became contaminated. Based on detailed technical debriefs of the Apollo astronauts, it was apparent during the missions that respiratory effects, skin effects and potential ocular effects of lunar dust needed to be evaluated. Although these areas of concern were recognized, short mission duration and rapid mission succession prevented a detailed analysis of the medical problems associated with lunar dust. Erin and John will report on their investigations into the biological effects of lunar dust to understand potential skin effects, inhalation toxicity, and ocular effects that may result from long duration human habitation of the Moon.

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July 2008

July 2

Greg Delory, Space Sciences Laboratory, UC Berkeley

An Electromagnetic Sounder to Detect Subsurface Liquid Water on Mars: Field Test Results

Passive, low frequency electromagnetic soundings of the subsurface can identify salinated liquid water at depths ranging from tens of meters to ~10km in an environment such as Mars. With support from NASA planetary and Mars instrument programs, Greg Delory and his colleagues have developed an autonomous sensor platform that has demonstrated magnetotelluric soundings over one kilometer deep at field test sites in the upper Snake River Plain region of southeastern Idaho. Greg will discuss his latest field test results, compare them with previous measurements of subsurface properties in the region, and demonstrate the applicability of this technique on a variety of potential future missions to the surface of Mars.

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July 9

Jessica Marquez, NASA Ames Research Center

People and Automation: Implications for Long Duration Lunar and Planetary Exploration

jessica marquezFuture long duration lunar and planetary missions will require that astronauts leverage automated systems to a far greater extent than has ever been experienced. Dr. Jessica Marquez will outline the latest research on automated mobility systems that future astronauts will need and potential pitfalls that may be encountered if too much automation is used.

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July 16

Eli Silver, UC Santa Cruz, Earth and Planetary Sciences

Creation and Destruction of Continental Crust at Subduction Zones

eli silverDr. Eli Silver of UC Santa Cruz will outline some of the latest research on plate tectonics. Presently, continental crust is being created in subduction zone settings (sites where tectonic plates converge) such as the Aleutians and Sumatra, due to both magmatic addition to the crust and to tectonic off-scraping. Other subduction zones (Central America, Tonga, Mariana, Peru, northern Chile, northern Japan, Kuriles) are undergoing crustal destruction through the process of subduction erosion. Global estimates indicate thmagmatic addition plus sediment accretion slightly exceeds the combined rates of subductionat erosion and sediment subduction, leaving the Earth slightly positive in terms of the growth of continental crust.

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July 30

Josh Emery, SETI Institutejosh emery

Spitzer Thermal Emission Spectra of Asteroids: Implications for the Formation and Evolution of Planetary Systems

The Infrared Spectrograph (IRS) on Spitzer has observed more than 120 asteroids, several Centaurs and Kuiper Belt objects (KBOs), and satellites of the giant planets. As capabilities continue to improve, direct observations of small body populations in other systems and inter-comparisons between systems will foster significant insights into the formation and evolution of planetary systems. In this talk, Josh will present an overview of the IRS observations of small Solar System bodies, with a few representative objects highlighted for detailed discussion.

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Aug. 6

alfonso davilaAlfonso F. Davila, NASA Ames Space Sciences Postdoctoral Researcher

Life in a cold and dry planet - Lessons for the Phoenix Mission

The Atacama Desert (Chile) ranks as the driest desert on Earth, and is considered a good analog to the extremely arid conditions on Mars. Alfonso will show how photosynthetic bacteria in the hyper-arid core of the Atacama are almost exclusively found within hygroscopic salts, which favor the condensation of water at relative humidity levels that otherwise hinder the occurrence of liquid water on the surface. The resulting saturated solutions are challenging to life, but the habitability of some salts is enhanced at temperatures close to the eutectic. Hygroscopic minerals provide one of the last habitable niches when liquid water is no longer stable or possible, on the surface of a planet that transitions into extreme hyper-aridity and freezing temperatures. Life in dry and cold planets will likely follow similar survival strategies and adaptations

 

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Aug. 20

alfonso davilaDr. Rosalind Grymes, UC Santa Cruz and NASA Ames Advanced Studies Laboratory

The Advanced Studies Laboratory - A unique linkage between UCSC and NASA Ames

Dr. Rose Grymes is the inaugural director of the Advanced Studies Laboratory (ASL), a NASA Ames and UC Santa Cruz strategic partnership created last year and currently based in Building 239 of NASA Ames. The ASL is developing a shared-use, open-access environment and engages projects as Affiliates which join the ASL consortium. The current membership, eight Affiliates, has focal interests linking advanced materials science and technology to planetary exploration, particularly astrobiology. In this presentation, Rose will describe the founding ideals and operational strategy of the new laboratory and the hopes for its future.

 

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Aug. 27

Professor Lynn Cominsky, Department of Physics and Astronomy, Sonoma State University

Exploring the Extreme Universe with GLAST

NASA's Gamma-ray Large Area Space Telescope (GLAST) mission was launched into orbit on June 11, 2008. GLAST's mission is to explore the most energetic and exotic objects in the cosmos: blazing galaxies, intense stellar explosions and super-massive black holes. All the instruments on board are working well, and details of the hardware for Large Area Telescope and the GLAST Burst Monitor are described, along with opportunities for ground-based astronomers to get involved with GLAST. Professor Cominsky will present the first exciting results from the mission.

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Septempber 2008

Sep. 10

Professor Charles Townes, UC Berkeley (1964 Nobel Prize winner for Physics for the invention of the laser)

Science in my life, and the unpredictability of discovery

Professor Townes is the 1964 Nobel prize winner for fundamental work in the field of quantum electronics, which has led to the construction of oscillators and amplifiers based on the maser-laser principle. He is a former member of the SETI Institute board. His presentation will focus on the fact that many of the most important discoveries have been unpredicted surprises, hence we need to search intensely and hopefully. He will illustrate this with his own personal history, and other interesting examples that he knows well.

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Sep. 17

bruce macDr. Bruce Macintosh, Lawrence Livermore National Laboratory

Direct detection of extrasolar planets and the Gemini Planet Imager

The next frontier in the study of extrasolar planets is direct (imaging) detection of the planets themselves. Such direct detection is sensitive to planets inaccessible to current radial-velocity surveys and allows spectral characterization of the planets, shedding light on planet formation and the structure of other solar systems. We are constructing the Gemini Planet Imager, combining advanced adaptive optics, coronagraphy, and an integral field spectrograph/polarimeter to detect and characterize giant planets and circumstellar dust disks around nearby stars. Dr. Macintosh will present an overview of the science, design, and capabilities of this instrument and briefly discuss science possibilities for future observatories such as the Thirty Meter Telescope.

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Sep. 24

Prof. Roger Blandford, Stanford Linear Accelerator and Physics, Stanford University

Black Holes: End of Time or a New Beginning?

Black holes are popularly associated with death and destruction (excluding romances dealing with the redemptive properties of wormholes). However, their conventional astrophysical role is now seen as regenerative and they play a major role in the formation and evolution of galaxies stars and, arguably, organic molecules. Some possible ways in which they may impact the research of the SETI Institute will be discussed and ways in which they may have played a role in the history of our solar system will be briefly discussed.

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October 2008

Oct. 1

Dr. Jeff Cuzzi (NASA Ames), Dr. Mark Showalter (SETI Institute) and Dr. Stuart Pilorz (JPL/SETI Institute)

What's hot in Saturn's Rings?

Dr. Jeff Cuzzi (NASA Ames), Dr. Mark Showalter (SETI Institute) and Dr. Stuart Pilorz (JPL/SETI Institute) are outer planets scientists working on the currently ongoing Cassini mission to Saturn. All three are experts on Ring systems, and have used the instruments of Cassini to learn more about the most dazzling Rings in our Solar System. They will address the new information that has come back to us from Cassini, the old questions that have been answered, and the new questions that have arisen in the course of this mission. The panel will tell us what's hot in the icy rings of Saturn.

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Oct. 8

Greg LaughlinGreg Laughlin, UC Santa Cruz

The Galactic Planetary Census

During the past decade, over three hundred planets have been discovered orbiting stars beyond the Sun. The catalog of planets is rapidly pushing down to ever-lower masses, and the discovery of potentially habitable planets is likely no more than a year or two away. In this talk, Greg will focus on how the emerging and distinct population of "Super Earth" type planets is giving an advance indication of both the frequency of occurrence and the mechanisms of formation for terrestrial-mass planets in the local galactic neighborhood.

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Oct. 22

dr. shenoyDr. Sachindev Shenoy

MIPSGAL: MIPS/Spitzer Survey of the Galactic Plane

MIPSGAL is a survey of the Galactic plane at 24 and 70 microns using Multiband Imaging Photometer for Spitzer (MIPS) Space Telescope. This is one of the most sensitive survey in the mid-infrared of our Galactic plane. In this talk, Dr. Shenoy shall describe the science requirements, strategies, and data reduction of the survey program. He will outline some of the science topics that can be explored by the community using his team's data. In particular he will talk about the discovery of over 8000 Debris Disk candidates in the Galactic plane using the MIPSGAL 24 micron point source catalog.

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