Sara Seager
Massachusetts Institute of Technology
Professor of Planetary Science
Professor of Physics
Professor of Aeronautics and Astronautics
 Author: The Smallest Lights in the Universe: A Memoir

How will humanity first discover ET Life?
Best guess: Via biosignature gases on exoplanet atmospheres
Details: Within the next two decades we will have the capability to observe gases on rocky exoplanet atmospheres

Caveat #1
There will be only a handful of ideally suitable planets for observation, because studying gases on small exoplanets is very challenging
Take a guess at the odds with the Seager equation: 
Credit: Information is beautiful

Caveats #2 and #3
If we do not find what we are looking for with concepts being developed for the next few decades, we will need a new paradigm, such as in-space manufacturing and assembly
Biosignature gases are signs of life, nothing more. We will not be able to 100% guarantee a suspect gas is produced by life

We want to be able to take our children and grandchildren, 
nieces and nephews to a dark site and point to a sun-like star and tell them, 
“That star has a planet like Earth.”  Credit: S. Seager

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