Lecture 12 Flashcards
What is/are examples for possible biosignatures?
The seasonal variation in Earth’s atmospheric CO2 abundance
The seasonal variation in Mars’s atmospheric methane abundance
The large abundance of free oxygen in Earth’s atmosphere
The characteristic change in surface reflectivity due to the presence of vegetation
Our best hope for determining that life on an extrasolar world lies in
Obtaining spectra that allow us to determine atmospheric composition
Why do most astronomers think that the search for biosignatures - and not SETI - will more likely lead to the first detection of probably extraterrestrial life?
Because even life on Earth was microbial for most of its time
Examples of possible biosignatures
the fact that we detect large amounts of free oxygen (O2 or O3) in the atmosphere of an Earth-like exoplanet
the fact that we detect seasonal changes in the methane abundance in the atmosphere of an Earth-like exoplanet
the fact that we observe changes in the reflectivity of an exoplanet’s surface that indicate pigments
Different types of biosignature
Gaseous, Temporal, and Surface
