Scientists At NASA's Nexus For Exoplanet System Science Evaluate How To Distinguish Life On Other Planets

Over just a short span of the last 10 years, scientists have detected thousands of other planets that may host life outside of our solar system, yet the question many of them are asking themselves is whether they would be able to spot this potential life if it was actually there.

To try and determine the best way in which to seek out life on other planets, scientists working in the fields of geology, astronomy, and biology have formed the new NASA research group known as Nexus for Exoplanet System Science (NExSS), as Universal Sci reports. Their lofty goal is to learn how best to distinguish life on other planets that may be vastly different from that which we know.

NExSS recently published five different papers in which they addressed subjects such as the significance of detecting and interpreting biosignatures on other planets, as the discovery of these could point to life, whether in the distant past or present.

Scientists working with this NASA group are also keen to learn about the different instruments that would be the most useful for detecting life in other worlds, which would certainly come in handy for future government missions.

However, since we are not currently heading to other planets right now, all scientists have to go on are telescopic observations of light outside our solar system. Studying the gases that lurk in the atmosphere of distant planets and observing whether these change over time is the main way in which scientists can presently learn whether other planets have the potential to host life.

While scientists can certainly search for specific biosignatures for possible life on other planets while on Earth, it is important to remember that the vast majority of these planets will be orbiting stars that are much cooler than our sun, and the light from these stars will show up in the infrared spectrum.

As NASA microbiologist and astrobiologist Mary Parenteau put it, researchers will need to keep an open mind when examining the potential for life in other worlds.

"What does a living planet look like? We have to be open to the possibility that life may arise in many contexts in a galaxy with so many diverse worlds — perhaps with purple-colored life instead of the familiar green-dominated life forms on Earth, for example. That's why we are considering a broad range of biosignatures."
And while searching for oxygen on other planets may appear to be one of the best indicators of life, a discernible lack of oxygen would not necessarily preclude life from existing, as University of Washington astronomer Victoria Meadows explained.
"On early Earth, we wouldn't be able to see oxygen, despite abundant life. Oxygen teaches us that seeing, or not seeing, a single biosignature is insufficient evidence for or against life — overall context matters."
Getty Images | NASA

NASA scientists at the Nexus for Exoplanet System Science believe that rather than just looking at one specific trait for alien life, researchers should instead be focusing on a large number of these traits. They aim to create a framework that will distinguish how good the odds are that a planet is capable of hosting life.

According to NASA astrobiologist Shawn Domagal-Goldman, while it would be impossible for scientists to give a definitive yes or no answer as to whether a planet holds life, by careful observations scientists should at least be able to have a high degree of assurance of this possibility.

"We won't have a 'yes' or 'no' answer to finding life elsewhere. What we will have is a high level of confidence that a planet appears alive for reasons that can only be explained by the presence of life."
The five papers on the hunt for life on other planets by NASA's Nexus for Exoplanet System Science have been published in the journal Astrobiology.