SETI Institute Weekly Colloquium - Upcoming Speakers

Tuesday, July 22 2014 - 12:00 pm, PDT

The Diversity of Habitable Zones and the Planets

Stephen Kane
San Francisco State University

habitable zoneThe field of exoplanets has rapidly expanded from the exclusivity of exoplanet detection to include exoplanet characterization. A key step towards this characterization is the determination of which planets occupy the Habitable Zone (HZ) of their host stars. As the Kepler data continues to be processed, the orbital period sensitivity is increasing and there are now numerous exoplanets known to occupy the HZ of their host stars. In this talk Dr. Kane will describe the properties of the HZ, the dependence on the spectral type properties, and the current state of exoplanet detections in the HZ. Along the way Dr. Kane will attempt to dispel some common misconceptions regarding the Habitable Zone. Dr. Kane will relate HZ results to the calculation of eta_Earth and eta_Venus. Finally, Dr. Kane will present several case studies of HZ Kepler planets, including circumbinary planets for which the HZ is a time-dependent function.

Eventbrite - The Diversity of Habitable Zones and the Planets

Tuesday, July 29 2014 - 12:00 pm, PDT

Khayyam: A Tunable Spatial Heterodyne Spectrometer for Broadband Observation of Diffuse Emission Line Targets

Sona Hosseini

Shane telescope at Lick ObservatoryAbstract: 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. 

Eventbrite - Khayyam: Spectrometer for Observation of Diffuse<br />
Emission Line Targets

Tuesday, August 05 2014 - 12:00 pm, PDT

Our Galactic Center

Reinhard Genzel
MPI for Extraterrestrial Physics, Garching and University of California, Berkeley

milky way galaxy illustrationAbstract: Evidence has been accumulating for several decades that many galaxies harbor central mass concentrations that may be in the form of black holes with masses between a few million to a few billion time the mass of the Sun.

Dr. Genzel will discuss measurements over the last two decades, employing adaptive optics imaging and spectroscopy on large ground-based telescopes that prove the existence of such a massive black hole in the Center of our Milky Way, beyond any reasonable doubt. These data also provide key insights into its properties and environment. Most recently, a tidally disrupting cloud of gas has been discovered on an almost radial orbit that reached its peri-distance of ~2000 Schwarzschild radii in 2014, promising to be a valuable tool for exploring the innermost accretion zone. Future interferometric studies of the Galactic Center Black hole promise to be able to test gravity in its strong field limit.

 Eventbrite - Our Galactic Center (SETI Talks)

Tuesday, August 12 2014 - 12:00 pm, PDT

Investigations of strange, linear features on Mars (AKA playing with dry ice blocks in the Utah desert)

Serina Diniega
Jet Propulsion Laboratory

matian duneAbstract:
Comparative geomorphology is a standard and highly useful approach in determining the origin of features seen on planetary surfaces. However, this approach sometimes can point interpretations into the wrong direction - the specific and sometimes highly unique conditions found on another planet cannot be neglected in the analysis! In particular, long, narrow grooves found on the slopes of martian sand dunes have been cited as evidence of liquid water via the hypothesis of melt-water initiated debris flows.

Dr. Diniega and her team proposed an alternative hypothesis: blocks of CO2 ice (AKA dry ice) blocks that form naturally on the dune surfaces each winter may fall onto and slide down the dune slope, carving out features such as those observed. To test this hypothesis, they experimented with dry ice blocks on terrestrial dunes and then compared the expected behavior of blocks on the Earth and Mars via a theoretical model. Their results demonstrated that CO2 blocks can move as natural "hovercrafts" on dune slopes on both Earth and Mars, and that such blocks on Mars can naturally create the unique features we see on Mars.

Eventbrite - Investigations of strange, linear features on Mars (SETI Talks)

Tuesday, August 19 2014 - 12:00 pm, PDT

SETI Institute/NSF REU Students Final Talks

SETI Institute

REU class of 2014Abstract: The REU class of 2014 will give their final public presentations. In a series of 5 minute talks, the students will discuss the projects they have conducted with their SETI mentors this summer.

Tuesday, August 26 2014 - 12:00 pm, PDT

Laser-based exploration of planetary surfaces: lab, field, and mission instruments and concepts

Pablo Sobron
SETI Institute

Tuesday, September 09 2014 - 12:00 pm, PDT

Earth-Sized Planets in the Habitable Zones of Cool Stars

Elisa Quintana
SETI Institute

Abstract: A primary goal of the Kepler mission is to determine the frequency of Earth-sized planets in the habitable zones of other stars. M dwarfs, stars that are smaller and cooler than the Sun, comprise more than 70% of the stars in our galaxy. Finding that Earth-sized planets around M dwarfs are common, therefore, has big implications for determining the frequency of other Earths.

In April 2014 we announced the discovery of Kepler-186f, the first definitive Earth-sized planet found to orbit in the habitable zone of a star other than our Sun.  We will discuss our methods of combining ground-based observations with transit modeling to confirm this system, and will present our theoretical studies on the formation and habitability of this planet. We will also present updates on several promising multi-planet systems that have Earth-sized, and possibly sub-Earth-sized, candidates in the habitable zones of cool low-mass stars in the Kepler field-of-view.

Tuesday, September 16 2014 - 12:00 pm, PDT

Mars: Periglacial morphology and ice stability

Jennifer Heldmann
NASA Ames Research Center


At the Mars Phoenix landing site and in much of the martian northern plains, there is ice-cemented ground beneath a layer of dry permafrost. Unlike most permafrost on Earth, though, this ice is not liquid at anytime of year. However, in past epochs at higher obliquity the surface conditions during summer may have resulted in warmer conditions and possible melting.  This situation indicates that the ice-cemented ground in the north polar plains is likely to be the most recently habitable place on Mars as near-surface ice likely provided adequate water activity ~5 Myr ago.  The possibility of life on Mars is important both for Mars science (Science Mission Directorate (SMD) and Mars Exploration Program Analysis Group (MEPAG) goals and objectives) as well as preparation for human exploration (Human Exploration and Operations Mission Directorate (HEOMD) and Strategic Knowledge Gaps (SKGs) pertaining to biohazards and planetary protection).

The high elevation Dry Valleys of Antarctica provide the best analog on Earth of martian ground ice. These locations are the only places on Earth where ice-cemented ground is found beneath dry permafrost. The Dry Valleys are a hyper-arid polar desert environment and in locations above 1500 m elevation, such as University Valley, air temperatures do not exceed 0°C. Thus, similarly to Mars, liquid water is largely absent here and instead the hydrologic cycle is dominated by frozen ice and vapor phase processes such as sublimation.  These conditions make the high elevation Dry Valleys a key Mars analog location where periglacial processes and geomorphic features can be studied in situ.

This talk will focus on studies of University Valley as a Mars analog for periglacial morphology and ice stability. We will discuss observations revealing a unique trend as the depth to ice-cemented ground varies linearly from near zero at the head of the valley to over 80 cm deep 1.5 km away at the valley mouth. This setting provides a natural gradient in physical permafrost properties, water vapor transport, and ice stability. We will also discuss geomorphic ramifications of this ground ice distribution as polygon size is shown to increase down the length of the valley and is correlated with increasing ice depth. Since polygons are long-lived landforms and observed characteristics indicate no major fluctuations in the ice-table depth during their development, the University Valley polygons have likely developed for at least 104 years to achieve their present mature-stage morphology, and the ice-table depth has been stable for a similar length of time. In addition, we will discuss geomorphic features (e.g., rock weathering and erosion, thermal contraction, sublimation till) as possible diagnostics for subsurface ice type.  Finally, we will review a landing site selection study encompassing this information gleaned from the Antarctic terrestrial analog studies plus Mars spacecraft data analysis to identify candidate landing sites for a future mission to search for life on Mars.

Eventbrite - Mars: Periglacial morphology and ice stability

Tuesday, September 23 2014 - 12:00 pm, PDT

Are you living in a simulation?

Silas Beane
University of Washington

virtual lake landscapeAbstract: Philosophers have long considered the possibility that we live in an artificial or simulated reality. Dr. Beane will give a short overview of some of the simulation arguments/scenarios that he personally finds most compelling.
Dr. Beane will then attempt to frame the simulation argument in the context of science. In particular, he will discuss recent work which suggests various observational tests of the hypothesis that we are currently living in a simulated universe. These include studies of the cosmic microwave background, high-energy cosmic rays, and high-precision terrestrial experiments.

Eventbrite - Are you living in a simulation?

Tuesday, October 14 2014 - 12:00 pm, PDT

Inflationary Cosmology with BICEPs

Chao-Lin Kuo
Stanford University


How did the universe begin ? This is one of the deepest mysteries in science. I will describe the BICEP program, a series of South Pole-based experiments aiming to answer this question by studying the polarization of cosmic microwave background radiation. This whole enterprise is an amazing combination of big ideas (inflation, general relativity, and quantum gravity) and cutting edge technology (superconductors, quantum electronics, microwave engineering, and advanced materials). In March 2014, the second experiment of the series BICEP2 has announced a detection of degree-scale B-mode polarization that is consistent with having an inflationary origin. I will describe what this measurement means and how we are going to follow up on it.

Tuesday, October 28 2014 - 12:00 pm, PDT

Extending the search for ETI communication to near-infrared wavelengths

Shelley Wright
University of Toronto

Tuesday, November 04 2014 - 12:00 pm, PST

Lakes, Fans, Deltas, and Streams: Geomorphic Constraints on the Hydrologic History of Gale Crater, Mars

Marisa Palucis
UC Berkeley


It has been proposed that in Gale Crater, where the Curiosity rover landed in August 2012, lakes developed to various depths after the large central mound (informally referred to as Mt. Sharp) had evolved to a form close to its current topography. Using a combination of CTX and HiRISE imagery and CTX, HiRISE and HRSC topography, we have documented a sequence of rising and falling lake levels, thereby providing a possible relative timeline of the hydrologic events within Gale crater. Assuming that the entrance canyon deposits (the canyon which the Curiosity rover will ascend once it reaches Mt. Sharp) records a back-stepping sequence of fans and deltas, then a corresponding hydrologic sequence is suggested. After the formation of a gilbert-type delta exiting an 84-km long incised valley (Farah Vallis) that drains 270,000 km2 to the south of Gale, and a corresponding lake with an average depth of 700 meters, the inflow of water from Farah Vallis fell or ceased. The lake level dropped considerably, to an elevation at least below the entrance canyon deposits. At a later time, local precipitation drove gully erosion of the Gale rim, and amplified by renewed Farah Vallis runoff, caused a rising lake level that produced deltas on the western rim of Gale and the entrance canyon deposits on Mt. Sharp. This hydrologic system shut down sufficiently abruptly that the deltas did not cut down as the lake evaporated. The time gap between these two lake forming events, perhaps driven by different hydrologic systems, is not yet established. Fan deposition around Gale crater, including the Peace Vallis fan near the rover’s landing site, likely occurred after these large lakes disappeared. This has implications for understanding regional paleo-climates on Mars after the Noachian, as well as providing context for the geology and sedimentology along the Curiosity rover traverse.

Tuesday, November 11 2014 - 12:00 pm, PST

A link between meteoritic organic compounds and the homochirality of life?

George Cooper

Eventbrite - A link between meteoritic organic compounds and the<br />
homochirality of life?

Tuesday, November 18 2014 - 12:00 pm, PST

Rise of the Machines: Mining the Kepler Data for Astrobiology

Lucianne Walkowicz
Princeton University

Kepler space telescopeAbstract: Since its launch in 2009, NASA's Kepler Mission has transformed our knowledge of exoplanetary system demographics. Kepler's primary mission goal-- to quantify the occurrence rate of habitable zone Earth-size planets around Sun-like stars-- has a clear connection to astrobiology. However, in addition to its planet-finding capabilities, the Kepler data may also be used to study other questions of astrobiological interest. In this talk, I will discuss my work on two such ongoing projects: the quantification of the stellar flare rate, which influences planetary habitability through its influence on atmospheric photochemistry and escape; and the detection of anomalous stellar variability as a form of signal-agnostic optical SETI. Both of these lines of research employ machine learning techniques, making them applicable to the current and future large datasets that now dominate the astronomical landscape.

Eventbrite - Rise of the Machines: Mining the Kepler Data for Astrobiology (SETI Talks)

Tuesday, January 20 2015 - 12:00 pm, PST

A new model for the origin of life: Coupled phases and combinatorial selection in fluctuating hydrothermal pools

Bruce Damer and Dave Deamer
UC Santa Cruz


Abstract: Hydrothermal fields on the prebiotic Earth are candidate environments for biogenesis. We propose a model in which molecular systems driven by cycles of hydration and dehydration in such sites undergo chemical evolution and selection in a dehydrated surface phase followed by encapsulation and combinatorial selection in a hydrated phase. This model is partly supported by recent science, and lies partly in the realm of speculation including a hypothesized pathway for the parallel evolution of the functional machinery of life. Complex models like this present challenges for science in the 21st century and we will describe a new technology to enable the simulation of such models.

Tuesday, March 03 2015 - 12:00 pm, PST

Going to the Ends of the Earth to Glimpse the Beginnings of Time

Brian Keating
UC San Diego