SETI Institute Weekly Colloquium - Upcoming Speakers
Interstellar dust grains - small sub-micron-sized particles that pollute the space between the stars - play an important role in the chemistry of the galaxy as well as the star and planet formation process. We glean most information about dust composition in the interstellar medium from infrared spectroscopy. The vibration of molecules making up the dust cause light from a background star to be absorbed at very specific frequencies in the infrared portion of the spectrum. Dust originates in the outflows of old stars and is composed mainly of silicate minerals and carbon particles. In star formation regions, the silicate grains are covered with icy mantles. I will give an overview of the nature of these dust and ice components, with emphasis on our current understanding of the cosmic life cycle of these materials.
Exoplanets discovered to date show a wide range of orbital eccentricities; the angles between their spin equators and orbital planes are still quite unknown, but these "obliquities'' may range widely as well. Both eccentricity and obliquity can have profound effects on a planet's seasons, as well as on its cycle of night and day. Remarkable patterns of insolation occur on synchronously-rotating planets, and on those in other spin-orbit states, with implications for their climates, detectability, and habitability.
Kepler data indicate that there are many planets that could be Earthlike in the sense of having a similar bulk composition. I will explain why such planets are unlikely to be Earthlike in other respects, especially if they are superEarths (three or so Earth masses or more). There are three main points here: (1) SuperEarths will not separate core from mantle because they are likely to be so hot internally that the critical temperature is reached for miscibility of iron alloy and silicate material. (2) Earth is (so far as we know) special in having a water budget that (expressed as an ocean) corresponds to water depths ~ mountain heights.(3) The surface will be hot either from a massive atmosphere or proximity to the parent star.
Abstract: The detection of over 3000 new exoplanets by the NASA Kepler mission has opened up the possibility to infer the occurrence rate of planets in the habitable zones of stars in our galaxy. However, both the characteristics of the detected planets and their occurrence rates crucially depend on our understanding of properties of the stars that were observed. In this talk I will present current efforts to improve our understanding of fundamental properties of Kepler target stars and their planets, in particular using the technique of asteroseismology. I will furthermore discuss the prospects of Kepler’s follow-up mission, K2, for advancing our understanding of exoplanets and stellar astrophysics.
Abstract: The High Resolution Imaging Science Experiment's (HiRISE) imagery of Mars allows for meter scale identification of surface features. In this imagery we can identify boulders clustering on polygonal patterned ground terrains in polar environments on Mars. Previously, terrestrial analogs of Mars were used to explain boulder clustering. However, the Mars environment is distinct from Earth's and the boulders that cluster on Mars are at least 3 - 10 times larger than any found clustering on terrestrial patterned ground terrains. Here, I propose a new mechanism for boulder clustering unique to Mars and use observations of boulder clustering around impact features to place constraints on the timescale of boulder clustering.
Abstract: The Wide Field InfRared Survey Telescope mission is the highest priority large space project recommended by the 2010 Astronomy and Astrophysics Decadal Survey, and it is expected to begin development in 2017 when the James Webb Space Telescope is nearing launch. WFIRST was conceived to conduct wide field, near-infrared surveys for dark energy, exoplanet gravitational microlensing, and general astrophysics using a moderate aperture (~1.3-m) telescope. NASA has recently approved the use of a much larger, Hubble-sized (2.4-m) telescope that was donated by the National Reconnaissance Office. A science definition team is now studying a revamped WFIRST mission concept with this telescope, including a coronagraphic instrument for exoplanet and disk imaging and spectroscopy. This talk will highlight the mission's science potential including brief descriptions of its dark energy and general observer programs with more focus on its exoplanet microlensing survey and coronagraphic imaging and spectroscopy of nearby exoplanetary systems.
The third installment of the SETI Artist in Residence Program speakers series will feature two authors: Edward Frenkel, professor of mathematics at U.C. Berkeley, and Marc Weidenbaum, whose new book, for the 33 1/3 series, is about the Aphex Twin album Selected Ambient Works Volume II. Frenkel will talk about his recent book, Love and Math: The Heart of Hidden Reality (Basic Books), which the New York Times, among others, has praised for its passionate depiction of why "math deserves to be an integral part of our culture." Weidenbaum will describe his development of a globe-spanning network of hundreds of musicians and sound artists who have participated in the Disquiet Junto, his weekly series of compositional prompts that explore restraint as a creative springboard. Frenkel and Weidenbaum will pose questions to each other at the end, and the evening will be moderated by SETI's first artist-in-residence, Charles Lindsay.
Abstract: Like the Earth, Mars experiences seasonal cycles due to its ~25-degree
axial tilt. Unlike the Earth, polar winter on Mars brings temperatures
cold enough to freeze out the atmosphere, in the form of carbon dioxide
surface frosts and snowfalls. The ice caps of Mars grow and shrink in
response to seasonal changes in the polar heat balance. Since 2006, we
have been monitoring the martian polar regions with multi-spectral thermal
infrared measurements acquired by the Mars Climate Sounder (MCS). From
these data, we retrieve vertical profiles of temperature and aerosol
opacity, as well as surface properties such as ice granularity and dust
content. This dataset provides an unprecedented view of the rich and
complex ice caps and polar atmosphere. In this talk, I will highlight the
dynamic polar processes at the heart of the martian CO2 cycle, as revealed
by MCS. We will see evidence for striking inter-annual repeatability,
diverse thermal and precipitation regimes, and intense localized
snowstorms. In light of these new observations, we will explore the
implications for the present and past climate of Mars.
The International Space Station is a US taxpayers investment estimated at about $70 billion spent over 30 years (with an overall price tag of $100 billion by all member nations), thus it is natural to ask about the ISS’s Return on Investment to justify its continuous operation and existence its scientific payoff. While this is not a trivial financial question, a more appropriate measure for the ISS would be the Return on Innovation phrased from the perspective of: “What is the cost of NOT innovating and NOT exploring in microgravity?” This simply correlates with the otherwise-not-accessible-knowledge, the number of unique “lessons learned” and discoveries, especially those that enable humanity to pursue solutions for global critical problems and open up new avenues in areas at big impasse. To add to it, maybe space is the necessary step that humanity will have to undertake to progress, to change consciousness and awareness and to encourage creative cooperation coupled with a communitarian view of Earths future.
ISS is a top engineering achievement in space harboring a myriad of outstanding fundamental scientific investigations. There is a growing interest in highlighting the ISS achievements especially from the perspective of their impact on terrestrial technologies and by being the source of a cascade of accomplishments and developments ranging from the seed scientific discoveries to direct applications, many of them serendipitous in nature. The ultimate goal is to build upon these successes to increase the potential of commercialization and to create a stable, self-sustainable space based market. An overview of already identified microgravity benefits to material and life sciences will be given as well as examples highlighting the breadth of these scientific investigations and the aforementioned serendipitous effects. The value of a space-based novel initiatives will be explored with specific examples in the works.
The talk will also touch upon the need for a customized on-demand payload return from the ISS to augment the current payload downmass to Earth and increase the ISS commercialization potential. The existing transportation infrastructure is correlated with the current ISS utilization demands in terms of bulk downmass and schedule frequency and it is operated by the SpaceX Dragon Capsule and the Russian Soyuz with a combined frequency of about three to seven times per year. Based on previous experience with commercial partners it appears that a customized on-demand payload return system better meets the customers' needs and directly encourages potential emerging markets of ISS users. The talk will briefly step through the rationale behind defining a metric (requirements and design functions) that identifies/assigns quantifiable system level parameters to capture the various aspects of the need for a customized on-demand payload return from the ISS.
ISS is the first platform of its kind that enabled long term human presence in space, long term exploration of skills needed to survive the extreme environment, long terms exposure of basic scientific experiments to the microgravity environment. No matter what angle we look at it, the ISS is first and foremost a learning platform. As such its primary role is to help answer fundamental questions about living and working in space and help figure out the capabilities we need that we don’t have to ensure a future sustainable human exploration: one facet oriented towards the depths of space, the other towards Earth.
Abstract: Sona Hosseini will report on progress toward development of a tunable spatial heterodyne spectrometer (TSHS) at the fixed focus of the Coudé Auxiliary Telescope (CAT) in the Shane Telescope at Lick Observatory (Khayyam). Spatial Heterodyne Spectrometer (SHS) instruments are a class of interferometric sensor capable of providing a combination of large étendue, high resolving power (R=λ/dλ~ 105) and wide field of view (FOV~0.5 degree) at Optical and NUV wavelengths in a compact format.
The TSHS implementation addresses the bandpass limitation of the basic SHS through controlled rotation of pilot mirrors in the interferometer. The use of a single grating as both a dispersing and beam-splitting element in the all reflective SHS greatly relaxes the precision required in the alignment of the other optical elements relative to a more typical scanning Fourier Transform Spectrometer and allows the TSHS implementation to be accomplished with low cost commercial rotation stages. The new design builds on a previous design originally tested in 2007, and will address several issues identified with the input beam, output imaging, and grating efficiency. Here she will discuss the design considerations going into this new system and the initial results of the installation and testing of the TSHS and the future plans.
Following completion of the ground based TSHS version (Khayyam), the longer term goals of the TSHS project are to provide in flight testing on a sounding rocket platform that Sona’s research group is developing and then ultimately a translation to satellite applications.