Proof of Life: Searching for living signals in a noisy universe

17 May, 5:30 pm, Cosmos Hall

Are humans really alone in this incomprehensively vast universe?  It seems unlikely but how will we really know?  In our age of social media, memes, cult beliefs and AI imagery, many people are convinced they know already. But how can we apply science to really learn the answer?  

Since Earth is the only planet known to have life, how can we be sure we are searching for the right signs elsewhere? How do we even define life in a way that does not merely reflect our terrestrial biases? When we are exploring other planets in our own solar system with spacecraft, or peering at distant exoplanets through space telescopes, and we find something we don’t expect or understand, how can we distinguish a genuine alien detection from an unknown geologic or atmospheric phenomenon?

To sort this out, astrobiologists have worked hard to define a set of “standards of evidence” – a series of questions we pose when making a discovery:  Can we confirm that the signal is real? Are there nonbiological ways to explain it?  What further observations can we make that will confirm if we’ve found a real biosignature, and so on.

As an astrobiologist who has led NASA’s efforts in this area and served on the recent (first ever) NASA study of UAP (unidentified anomalous phenomena), David Grinspoon will give an insider’s perspective on the science of these rapidly progressing questions:  How will we know alien life when we find it? And, in the meantime, how can we communicate about these efforts in a way that helps, rather than hinders, public understanding?