Astrobiology

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

What 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.

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.

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.

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.

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.

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

The 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.

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".

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