Planetary SecurityAre We Alone in the Universe? NASA Calls for New Framework

By Elizabeth Landau

Published 28 October 2021

NASA scientists are encouraging the scientific community to establish a new framework to provide context for findings related to the search for life in the universe. They propose creating a scale for evaluating and combining different lines of evidence that would ultimately lead to answering the ultimate question: Are we alone in the universe?  

How do we understand the significance of new scientific results related to the search for life? When would we be able to say, “yes, extraterrestrial life has been found?” 

NASA scientists are encouraging the scientific community to establish a new framework that provides context for findings related to the search for life. Writing in the journal Nature, they propose creating a scale for evaluating and combining different lines of evidence that would ultimately lead to answering the ultimate question: Are we alone in the universe?   

In the new Nature article  led by Jim Green, the agency’s chief scientist, a NASA group offers a sample scale to use as a starting point for discussions among anyone who would use it, such as scientists and communicators. They envision a scale informed by decades of experience in astrobiology, a field that probes the origins of life on Earth and possibilities of life elsewhere.  

“Having a scale like this will help us understand where we are in terms of the search for life in particular locations, and in terms of the capabilities of missions and technologies that help us in that quest,” Green said. 

The scale contains seven levels, reflective of the winding, complicated staircase of steps that would lead to scientists declaring they’ve found life beyond Earth. As an analogy, Green and colleagues point to the Technology Readiness Level scale, a system used inside NASA to rate how ready a spacecraft or technology is to fly. Along this spectrum, cutting-edge technologies such as the Mars helicopter Ingenuity begin as ideas and develop into rigorously tested components of history-making space missions.  

The authors hope that in the future, scientists will note in published studies how their new astrobiology results fit into such a scale. Journalists could also refer to this kind of framework to set expectations for the public in stories about new scientific results, so that small steps don’t appear to be giant leaps.   

“Until now, we have set the public up to think there are only two options: it’s life or it’s not life,” said Mary Voytek, head of NASA’s Astrobiology Program in at NASA Headquarters in Washington and study co-author. “We need a better way to share the excitement of our discoveries, and demonstrate how each discovery builds on the next, so that we can bring the public and other scientists along on the journey.”