“Are We Alone?” Asks an Exoplanet Scientist at NASA


In just ten years, scientists have discovered thousands of exoplanets, learning that there are many worlds in our galaxy, but are they able to host life? And if they are, could we recognize it if we see it?

A team of researchers in astronomy, biology and geology work at NASA’s Nexus for Exoplanet System Science, or NExSS to find many of the unanswered questions.

Martin Still, is an exoplanet scientist at NASA Headquarters (Washington):

“We’re moving from theorizing about life elsewhere in our galaxy to a robust science that will eventually give us the answer we seek to that profound question: Are we alone?”

NExSS Published Five Papers on Biosignatures

NExSS scientists published five review papers last week in the scientific journal Astrobiology, each talking about promising signs of life. Among the authors of the papers, there are four scientists from NASA’s Jet Propulsion Laboratory (JPL, Pasadena, California).

Scientists interpret the presence of signs of life, called biosignatures. They searched for a way to interpret them if we detect them on faraway planets. The first issue is distinguishing a living world from a barren one that looks like its alive.

The first biosignatures will be spotted with the help of complicated instruments on the Giant Magellan Telescope and the Extremely Large Telescope and with the help of NASA’s James Webb Space Telescope.

Scientists working with NExSS also aim to find the best approach to detect potential life to help with NASA’s flagship missions in the future. They plan to detect atmospheric signatures of some habitable planets by 2030, but after that, in-depth studies will have to be done to see if those planets have life or are habitable.

What does a living planet look like?

Mary Parenteau is an astrobiologist and microbiologist at NASA’s Ames Research Center (Silicon Valley) and a co-author of the study:

“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.”

Victoria Meadows is an astronomer at the University of Washington (Seattle) and the lead author of one of the five papers, explaining that some planets could harbor life, even if there are no traces of oxygen:

“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.”


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