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When you see a headline with “biosignature” or “technosignature” (or just “aliens”), does it make your eyes open just a little wider?
Then you read the rest of the article and realize that no actual evidence of extraterrestrial creatures has been found. The truth may be out there, but it hasn’t been found, and all that could really be confirmed was that those water molecules on an exoplanet were possible biosignatures and that weird X-ray signal was a possible technosignature. It can be a letdown for the Mulder and Scully in all of us — but no aliens doesn’t mean no progress.
NASA chief scientist James Green wants to believe just as much as anyone. He led a study, recently published in Nature, which proposes the CoLD (Confidence of Life Detection) scale, a new framework for measuring just how close we are to finding something that spawned somewhere other than Earth.
“We created the CoLD scale as an example of what NASA would like to use when discussing progress that has been made in life detection research to not only other scientists but also to the public,” he told SYFY WIRE.
The CoLD scale is based on NASA’s Technology Readiness Level (TRL) scale that is used to tell scientists how ready upcoming missions are before they can be launched into space. Lucy, which recently took off, was subject to the rigorous testing this scale demands, and so were DART and the James Webb Space Telescope, both of which will be launching later this year. Passing every level of the TRL scale assures scientists that the spacecraft and instruments will be able to pull off the observations they are meant for. CoLD is the equivalent when it comes to astrobiology.
Determining whether something really is alive, or that a signal is being zapped to Earth by living beings, is and will continue to be a complex process. CoLD uses seven levels to evaluate how far along an investigation is in that process. This scale is meant to provoke discussion among scientists, and studies carried out on Earth that supplement the search for live beyond our planet will also be factored into how far a particular search for life has progressed. It is also open to change and will continue to evolve as astrobiological research advances.
Green also wants to make sure this scale will inform journalists how to interpret these findings, so “aliens” in a headline won’t set off an instant freakout.
“The CoLD scale is an example we would like for the science community to consider, to debate and to change as necessary,” he said. “The paper has done exactly what we wanted, which was to create a science community discussion for reporting evidence for life beyond Earth.”
Whether such a scale was even necessary was brought up for discussion as the study was being peer-reviewed in July. The committee on Astrobiology and Planetary Sciences (CAPS) of the National Academies of science will be meeting on November 10 to further discuss CoLD and how scientists have been reacting to it. This could eventually influence how the public could react to progress in astrobiology, so rumors of aliens won’t go viral—which in itself ends up misinforming people—every time a potential biosignature or technosignature shows up.
Take Mars as an example. Now that Perseverance is on the scene, especially since the evidence it found on Jezero crater led scientists to confirm the crater was once a huge lake, anything could be associated with aliens. That doesn’t mean there were actually life-forms on Mars. Finding out that a barren crater was once a body of water is the type of thing that would fall on the first level of the CoLD scale. There is prevailing idea among alien enthusiasts that something is either life or not life, but being able to gauge how close we are to finding life may change that.
“We recognize that the public would really like a yes or no answer as to whether an exoplanet or other body had life,” Green said. “CoLD gives us the opportunity to report when clear progress has been made and to discuss what those next steps would be to move up the scale. To me, showing progress is also important.”
Does that mean you should deny anything that may or may not be a sign of aliens? Not necessarily. Keep following that particular study, and hang on to the suspense until something new emerges.