SETI Institute Weekly Colloquium - Upcoming Speakers
Abstract: Recurring Slope Lineae (RSL) are narrow (0.5 to 5 m) dark albedo features that incrementally lengthen down steep slopes and reoccur each year. RSL are well correlated with temperature, as they lengthen as temperature increases and fade as temperature decreases. RSL have been observed within a latitude band from 37°N to 52°S, but tend to cluster in the southern mid-latitudes (SML) in and around Valles Marineris and Chryse Planitia.
In this talk, Dr. Stillman will demonstrate how observations from the ~25 cm/pixel High Resolution Imaging Science Experiment (Hi-Rise) onboard Mars Reconnaissance Orbiter and surface temperature data acquired by three orbital instruments suggest that RSL are caused by subsurface liquid water flows.
The West Antarctic Ice Sheet contains the ice equivalent of 5 meters of sea level and is slowly adding to the rise of global ocean levels. It is now thought that the ice sheet is undergoing irreversible marine ice sheet collapse. The primary cause is bottom melting of coastal ice shelves in the Amundsen Sea sector driven by oceanic and/or atmospheric factors. In addition, the air temperature over the ice sheet interior has risen substantially over the past 50 years at a rate comparable to that recorded on the adjacent Antarctic Peninsula. There are many tropical and high latitude influences at play governing the atmospheric and oceanic behavior in this part of the world. The talk will lay out what is happening to West Antarctica at present and what may happen in the future as worldwide temperatures continue to increase.
In this event, a group of interdisciplinary scientists will participate in a SETI colloquium to summarize and discuss a two-way workshop held to explore nonhuman communication research. Participants for this two-day workshop include scientists who currently work in one of three areas: animal communication, information theory, or astrobiology/intelligence.
The panel will explore and discuss the implications for SETI and astrobiology at this colloquium, including ideas about new tools and techniques that may provide insight into advanced communication systems and intelligence. This summary will be followed by a panel discussion and open to the public for questions.
If we can define complex communication systems on Earth, we may be able to develop tools for potential future assessments of life on other planets. It is expected that this initial workshop and colloquium on nonhuman communication will lead to a working group and future workshops to continue to address this important area of exploration.
We are poised to take advantage of a remarkable confluence of technological advances and scientific opportunity. For the first time, very fast, wide bandwidth, high-gain, low noise near-infrared avalanche photo diode (APDs) detectors are available and reasonably priced. We are designing and constructing a new SETI instrument to search for direct evidence of interstellar communications via pulsed laser signals at near-infrared (900 - 1700 nm) wavelengths. The new instrument design builds upon our past optical SETI work, and is the first step toward a new, more versatile, and more sophisticated generation of very fast optical and near-infrared pulse search devices.
Dr. Wright will discuss the advantages of SETI searches at near-infared wavelengths. She will also present the instrument layout, including an overview of the opto-mechanical design, detector selection and characterization, signal processing, and integration procedure. Finally, Dr. Wright will describe our initial observational setup and search strategies for SETI targets and other astronomical studies.
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.
Abstract: 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.
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.