NASA scientists call for a new framework of seven steps to verify claims of extraterrestrial existence. 

NASA’s chief scientist Jim Green created the seven-step scale. It can be used by anyone to start the search for life, even scientists. 

It would be easier to search for life using seven steps than it is to rate a spacecraft’s readiness to fly.

“Until now, we have set up the public to believe there are only two choices: it’s either life or it is not life,” said Mary Voytek (head of NASA’s Astrobiology Program), in a statement. 

“We need a better method to share the excitement of our discoveries and show how each discovery builds on another, so we can bring the public along on the journey with other scientists.”

NASA scientists are calling for a new seven-step framework on how to corroborate claims of life beyond Earth

NASA scientists propose a seven-step framework for corroboration of claims of life beyond Earth.

The scale can be used as a starting point in the search for life by anyone. Using seven points would make the search for life more akin to rating 'how ready a spacecraft or technology is to fly'

Anyone can use this scale to help them in their search for meaning. The search for life would be more like rating ‘how ready a technology or spacecraft is to fly’ with seven points.

The framework, also known as the confidence of life detection (CoLD) scale lists its seven steps in this manner:

  • Detection a signal that is known to be a result of biological activity
  • Contamination ruled out
  • Demonstration of or prediction of biological production in the environment for detection
  • All known non-biological signals have been proven to be impossible in that environment.
  • Additional, independent signal detected from biology
  • Future observations will rule out alternative hypotheses that were suggested after the original announcement
  • Independent follow-up observations of predicted biological behaviour in the environment    

The scale was created from ‘decades worth of experiences’ in Astrobiology, a field best equipped to look for life elsewhere in the universe as well as the origins on Earth.

Green stated in a statement that ‘having a scale such as this will help us understand our position in terms search for life in specific locations and in terms the capabilities of missions, technologies that aid us in that pursuit.’ 

Mars is used as an example. To achieve a Level 7, it’may require investigations on Mars where these results would predict specific signs and life’, the authors wrote in their study.

The scale will likely have a huge role in NASA's missions to Mars, especially in light of the fact there have been controversial announcements that life has been found on Mars

NASA’s Mars missions will likely be influenced by the size of the spacecraft, especially given recent controversy surrounding claims that life may have been discovered on Mars. 

NASA’s Mars missions will be dominated by the scale of the mission, especially considering recent controversial announcements about life on Mars.

1996: Researchers studying the Martian meteorite ALH84001 found evidence of life in the 4.5 billion year-old meteorite.

Although the 25-year-old findings remain controversial, researchers of the new study claim that the older research could have benefited by the proposed seven-point scale.

“The report of evidence of life in the 4.5-billion year old Martian meteorite ALH8400111 illustrates the challenges inherent with communicating results in a binary fashion and the benefits associated with a progressive scale,” they wrote in their study.

They discovered that meteorite could contain “possible biomolecule residues” such as carbonate molecules and magnetite particles. These could indicate that it was formed by microbes. 

The meteorite might have been formed in liquid at temperatures between 0 and 80 degrees Celsius on Martian surface that was ‘probably’ habitable. However, 1996 researchers also believed that the findings were evidence of early Mars life. 

The researchers said that they had published their results and made them public. This led to the community working together to establish a stronger case for the abiotic source of the features in a collective set. 

“The consensus is that features found in ALH84001 may not be indicative of real life.

Researchers believe that humanity is ready to find evidence of life beyond Earth’s surface, and the seven-step scale is an imperative.  

The abstract of the study stated that “As space-detection goals become more prominent in space sciences,… it is essential to open an informal community dialogue about how to communicate information in a subject matter which is diverse, complex and has a high potential for being sensationalized.” 

“Establishing best practice for communicating about the detection of life can serve to set reasonable expectation on the early stages a hugely difficult endeavor, attach values to incremental steps along that path, and build trust by making clear to the public that false starts and dead end are an expected and possible productive part of the scientific method.  

Jupiter's ice moon Europa (pictured) is thought to have an ocean capable of supporting life

Saturn's ice moon Titan (pictured) is thought to have an ocean capable of supporting life

The scale applies to discoveries made in the solar system, potentially from Jupiter’s ice moon Europa or Saturn’s moon Titan, which are both thought to be candidates to host life, but exoplanets as well

The scale refers to discoveries made within the solar system, potentially from Jupiter’s ice moon Europa, or Saturn’s moon Titan. These moons are thought to be candidates to host human life, but also exoplanets..  

NASA’s mission to Titan, known as Dragonfly, will fly more than 100 miles around the celestial satellite. It was originally scheduled to launch in 2026. However, the COVID-19 pandemic delayed the launch date to 2027.

NASA’s Europa Clipper, which will be launched in 2024, is scheduled to reach the moon in 2030. 

NASA released that the detection and analysis of oxygen in an exoplanet would be a significant step in the search for life.

The authors point out that the scale is part of the groundwork that NASA missions have done even though they have yet to detect biological signals on other celestial bodies. 

Voytek stated that each measurement reveals more about both the biological and non-biological processes of the planet. 

“The search to find life beyond Earth requires broad participation of the scientific community with many types and types of observations and experimentation. We can work together to discover clues that we’re not the only ones looking for them.

The paper was recently published by Nature.