NASA Scientists Propose New Scale for “Evidence of Alien Life”



As the search for alien life intensifies, scientists may need to step up their reporting game a bit.

Researchers are expected to report evidence of alien life on a scale similar to the technological readiness scale commonly used to assess the readiness of space flight components, according to a new article. The aim is to make the search for life less “binary” – life or no life – and to express it more precisely in terms of agreed scientific uncertainty.

The newly proposed Evidence of Alien Life Scale was described in a study published online Oct. 27 in the journal Nature led by NASA Chief Scientist Jim Green. The scale includes seven levels, which may change depending on the type of environment concerned and the reaction of the scientific community.

For a mission to Mars, for example, finding clues to a life signature would register at level 1 on the scale, and showing that the find was not due to contamination by terrestrial life would raise it to Level 2. Higher levels include checking for signs of life with multiple instruments (Level 6) and at different locations on a world (Level 7).

Related: 5 bold claims of alien life

“So far, we have led the public to believe that there are only two options: it’s life or it’s not life,” said Mary Voytek, co-author of the study. , head of NASA’s astrobiology program at NASA headquarters, in a statement. “We need a better way to share the excitement of our findings and to demonstrate how each discovery builds on the next, so that we can bring the public and other scientists on the journey.”

NASA expects the new scale to have a special resonance when it comes to Mars, as there have been several high-level debates about the potential signs of life on the Red Planet. In 1996, for example, a team of researchers suggested they had found convincing signs of life on Mars in a Martian meteorite called Allan Hills 84001 (ALH84001). The report remains controversial 25 years later.

Another debate was sparked in 2015, when data collected by NASA’s Mars Reconnaissance Orbiter suggested that the signature of hydrated salts was associated with intriguing and seasonal dark streaks on the Red Planet, known as slope lines. recurrent (RSL). Some scientists believe these salts result from the evaporation of brackish water, but others say RSL is more likely caused by dry landslides.

Although NASA did not allude to previous research to describe the new scale in the press release, the agency stressed that astrobiology – as well as all science – is a process that includes “asking questions , propose hypotheses, develop new methods, look for clues and exclude any alternative explanation. ”

“Any individual detection may not be fully explained by a biological process and must be confirmed by follow-up measures and independent investigations,” agency officials said in the statement. “Sometimes there are issues with the instruments themselves. Other times the experiments give nothing at all but still provide valuable information on what is not working or where not to look.”

NASA officials stressed that the scale is meant to stimulate discussion in the community. The scale is also likely to change as large agency missions begin later in the 2020s, including a planned Mars sample return mission and the launch of Europa Clipper to a potentially habitable moon of Jupiter.

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