Are we the only beings in the Universe? NASA demands a new protocol to announce alien life.

How can we interpret the importance of fresh scientific findings in the hunt for life? When will we be able to claim with certainty that alien life has been discovered?

NASA scientists are urging the scientific community to develop a new paradigm for putting results relevant to the hunt for life into perspective. They suggest constructing a scale for analysing and merging multiple lines of evidence in the journal Nature, which might eventually lead to an answer to the ultimate question: Are we alone in the universe?

A NASA group proposes a sample scale to use as a starting point for talks among anybody who would utilise it, such as scientists and communicators, in a new essay lead by Jim Green, the agency’s top scientist.

They foresee a scale based on decades of astrobiology research, a science that studies the origins of life on Earth and the potential for life beyond.

“Having a scale like this will help us understand where we are in terms of the search for life in specific locations, as well as the capabilities of missions and technologies that can assist us in that search,” Green said.

The scale has seven levels, which represent the meandering, hard path that scientists must take to declare they’ve discovered life beyond Earth. Green and colleagues utilise the Technology Readiness Level scale, a mechanism used inside NASA to determine how ready a spacecraft or technology is to fly, as an example. Innovative technology, like the Mars helicopter Ingenuity, starts as concepts and grows into carefully proven components of history-making space missions along this spectrum.

The authors expect that, in the future, scientists would mention how their new astrobiology findings fit within this scale in published publications. Journalists might use this paradigm to establish public expectations in reports about new scientific findings, ensuring that tiny steps do not seem to be enormous leaps.

“Until now, we’ve led the public to believe there are only two options: life or death,” said Mary Voytek, co-author of the report and chief of NASA’s Astrobiology Program at NASA Headquarters in Washington. “We need a better way to communicate the excitement of our discoveries and show how each one builds on the previous one so that the public and other scientists can join us on our journey.”

Each time a rover or orbiter discovers evidence that water previously flowed on Mars, it’s thrilling. Each new discovery shows that Mars’ ancient environment was comparable to Earth’s, implying that the red planet previously supported life.

But it doesn’t show there was ever any life there, or that there is anything there today. Discoveries of rocky planets circling stars other than our Sun, particularly those with liquid water on their surfaces, are exciting, but they are not evidence of life beyond Earth. So, how do we interpret these findings considering their context?

All of science is asking questions, formulating hypotheses, devising new techniques for locating clues, and excluding all other possibilities. Any single finding may not be totally explained by a biological activity, and several measurements and examinations must validate it. There are issues with the instruments themselves from time to time. Experiments that don’t provide any results might provide useful information about what doesn’t work or where not to search.

Astrobiology is no exception. The discipline investigates some of the most fundamental questions about our origins and location in the cosmos that anybody might have. Scientists may develop and refine technology to uncover comparable clues elsewhere as they understand more about the signals linked with life in various places on Earth.

While the scale’s specific parameters will change as more scientists, communicators, and others weigh in, the Nature publication serves as a beginning point for dialogue.

Scientists would report evidence of a hallmark of life, such as a physiologically relevant chemical, at the first step of the scale, “level 1.” A future measurement of a chemical on Mars that may be connected to life would be an example. As scientists go to “level 2,” they will confirm that devices that have been corrupted on Earth do not affect the detection.

They would show how this biological signal is discovered in an analogue habitat, such as an old lakebed on Earth comparable to the landing location of the Perseverance rover, Jezero Crater, at “level 3.”

Scientists would augment those first detections with information on whether the environment could sustain life and rule out non-biological sources to add evidence to the centre of the scale. Samples returning from Mars, in particular, might aid in this type of advancement. Perseverance will soon begin collecting and storing samples, hoping to return them to Earth on a future trip.

Because multiple teams on Earth would be able to independently verify signs of life in Mars samples using a range of tools, the evidence might reach “level6,” the second highest step on the scale. However, in this case, an extra expedition to a different portion of Mars may be necessary to satisfy level 7, the criteria by which scientists would be most certain they had identified life on Mars.

The authors add, “Achieving the highest levels of confidence requires the active participation of the broader scientific community.”

This scale would also apply to discoveries made outside of our solar system. Exoplanets, or planets beyond our solar system, are thought to outnumber the Milky Way’s 300 billion stars. Small, stony planets are more difficult to observe from afar than gas giants. It would require future expeditions and technology to investigate the atmospheres of Earth-size planets with Earth-like temperatures and enough starlight to support life as we know it.

The James Webb Space Telescope, which will launch later this year, will be the next significant step forward in this field. However, detecting the mix of chemicals that would suggest life would certainly need an even more sensitive telescope.

Detecting oxygen in an exoplanet’s atmosphere, which is a planet beyond our solar system, would be a key step in the hunt for life. We link oxygen with life because plants produce it and we breathe it, but geological processes also produced it, so it is not evidence of life.

To proceed up the scale, a mission crew might show that Earth-reflected light did not corrupt the oxygen signal and investigate the chemistry of the planet’s atmosphere to rule out a geological explanation. Additional evidence of a life-supporting environment, such as an ocean, would reinforce the hypothesis that this hypothetical planet is populated.

Exoplanet researchers are hoping to locate both oxygen and methane, a mix of gases found in Earth’s atmosphere that shows life. Finding both would be a crucial “level 4” milestone since both gases would generate reactions that cancel each other out unless biological sources of both are present.

A second, independent identification of some evidence of life, such as global photos of the planet with hues indicative of forests or algae, would be required to attain level 5. To be confident they had discovered life on an exoplanet, scientists would require more telescopes or longer-term monitoring.

The scale should not be seen as a race to the top, according to the study’s authors. The scale underscores the necessity of laying the framework for many NASA missions that do not immediately detect probable life signs, such as assessing conditions on other planetary bodies.

Future missions like Europa Clipper, an orbiter that will study Jupiter’s ice moon Europa later this decade, and Dragonfly, an octocopter that will explore Saturn’s moon Titan, will give crucial knowledge on the settings in which life may one day be discovered.

“We learn more about both biological and nonbiological planetary processes with each measurement,” Voytek added. “The hunt for life beyond Earth requires widespread scientific engagement and a wide range of observations and experiments. We can be more effective in our search for signs that we are not alone if we work together.”