Monday, November 29

NASA prepares to confirm the eventual existence of extraterrestrial life

NASA prepares to confirm the eventual existence of extraterrestrial life

In an article published in the journal Nature, NASA scientists have developed a proposal to make announcements of discoveries related to extraterrestrial life transparent: they propose a scale that would make clear the “level” of certainty of each study, starting with the first signs until finally confirming that we are not alone in the universe.

It is striking that this call for joint work by the entire scientific community, aimed at increasing the certainty in the dissemination of discoveries linked to life outside the Earth, coincides with notable advances in this regard: the launch of the powerful telescope James Webb, which will allow us to know more about exoplanets, or the samples collected by the rover Perseverance on Mars are just a few examples. Are we close to an announcement that will change the destiny of humanity and open us to a greater understanding of the cosmos?

The confidence scale

For the moment, the methodology proposed by the US space agency could be very useful to avoid false hopes or not to give an excessive importance to still primary discoveries. This is what NASA says in a Press release, reinforcing what was expressed in the article signed by James Lauer Green himself, Chief Scientist of the space agency.

If we consider the existing evidence in Mars and on other planets of the Solar System, as well as the large amount of exoplanets confirmed or potential, among which those with notable similarities with the Earth stand out, having a clear scheme to understand the degree of certainty of these discoveries is a tool of great value for scientists, communicators and the general public.

Broadly, the scale developed by the American researchers contains seven levels, which reflect the complicated succession of steps that would culminate in the definitive declaration of the existence of life beyond Earth. The so-called «Life Confidence Screening Scale» (CoLD) It involves evaluating any evidence that can be discovered: each level is a benchmark to meet before moving to the next step.

Related topic: Technosignatures will lead us to meet alien life.

Seven levels to the big announcement

To give a concrete example, if they are discovered biological signatures on an exoplanet in the form of molecules, we would be at level 1. Later, the scientists will try to confirm that the aforementioned life signatures are not the product of some type of contamination with elements originating from the Earth, thus complying with level 2.

The scale would continue with the development of multiple evaluations, such as the study of different scenarios or the completion of complementary tests. If all were exceeded, at level 7 the responsible scientists would indicate that they have discovered some form of extraterrestrial life in complete safety.

It is worth noting that the scale does not mean belittling studies that do not reach the last level: in astrobiology, as in any scientific discipline, these investigations can be used to discover methods that do not work or to know where not to look. At the same time, progress is gradual: a study that reached a certain level can be resumed in the future with new technologies, making further progress possible.

Will this NASA proposal be a way to “set the stage” for a centuries-long anticipated announcement? Apparently, the encounter with our cosmic destiny could be closer than thought.


Call for a framework for reporting evidence for life beyond Earth. James Green, Tori Hoehler, Marc Neveu, Shawn Domagal-Goldman, Daniella Scalice and Mary Voytek. Nature (2021).DOI:

Cover photo: Stefan Keller and Pixabay.

Video and podcast: edited by Pablo Javier Piacente based on elements and sources free of copyright. Video Image Credits: Brian McMahon, Adrian N, MaddiesCreation, Jonas Dücker and Dino Reichmuth on Unsplash. Stefan Keller on Pixabay.

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