ABSTRACT

A key goal in astrobiology is to search for life and signs of life (biosignatures) beyond our own planet, yet we are confronted with this challenge - how do we search for signs of life that may use an unknowable, unfamiliar biochemistry? Current strategies for biosignature detection rely mainly on identification of well-established and widely accepted features associated with contemporary life, such as particular classes of molecules and isotopic signatures, enantiomeric excesses, and patterns within the molecular weights of fatty acids or other lipids. As we begin to explore farther out in the Solar System, where a common heritage with Earth is less likely, it becomes more necessary to design agnostic life detection approaches based on fundamental features and mechanistic models of biological systems. It also becomes much more important to incorporate knowledge of the abiotic chemical, physical and geologic processes that provide environmental context for our observations. For example, the diverse organic chemistry of extraterrestrial materials could be interpreted as false positives for biomolecules on other planets. Agnostic life detection methods require a more complete assessment of these sources in order to deconvolve abiotic inputs, account for alteration processes, and expand to include less specific search criteria focused on evidence of energetic input.

About the Speaker:

Dr. Heather Graham is a research physical scientist in the Astrochemistry Laboratory at Goddard Space Flight Center. An organic geochemist by training, they received an AB in Chemistry from Occidental College and a PhD in Geocsciences and Biogeochemistry from the Pennsylvania State University. With a diverse background in biology, analytical chemistry, paleontology, and statistical modeling Graham combines their expertise in the expression and preservation of chemical biosignatures with an understanding of the unique constraints of space flight instrumentation.