The agency on Wednesday recapped the contents of a new article published in Nature. The article was led by NASA’s chief scientist Jim Green.
The group said that creating a scale for evaluating and combining different lines of evidence would help to provide context for findings related to the search for life.
The scale presented contains seven levels that NASA said are “reflective of the winding, complicated staircase of steps that would lead to scientists declaring they’ve found life beyond Earth.”
Green and the team used NASA’s Technology Readiness Level scale as an example.
“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 in a statement.
At the first level of the scale, scientists would report hints of a signature of life. Next, they would ensure that detection was compromised or influenced by the instruments having been contaminated on Earth. For the tertiary step, scientists would show how the biological signal is found in an analog environment.
Initial detections would be supplemented with information regarding whether the environment in question could support life and rule out non-biological sources at the fourth level and additional and independent detection would be required to reach level five.
Level six, the authors say, includes future observations that rule out alternative hypotheses that were proposed following the original announcement.
Level seven, the highest level on the scale, would include independent follow-up observations of predicted biological behavior in the environment in question.
“With each measurement, we learn more about both biological and nonbiological planetary processes,” Mary Voytek, a study co-author and head of NASA’s astrobiology program, said. “The search for life beyond Earth requires broad participation from the scientific community and many kinds of observations and experiments. Together, we can be stronger in our efforts to look for hints that we are not alone.”
One of the goals of the agency’s presence on Mars this year is the search for signs of ancient microbial life, and NASA’s Chandra X-ray Observatory announced this week that astronomers had found evidence of what would be the first planet seen to transit a star outside of the Milky Way.
NASA noted that all of science is a process, including astrobiology, and said that scientists can create and improve upon the technologies needed to find signs of life off Earth.
“Until now, we have set the public up to think there are only two options: it’s life or it’s not life,” Voytek noted. “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.”
NASA’s upcoming missions include the Europa Clipper orbiter and the Dragonfly octocopter that will explore Saturn’s moon Titan.