Anyone Out There? New Report Says We Need to Look for Life in Other Places
According to a new report by the National Academies of Sciences, Engineering, and Medicine (NASEM), we need to review our approach to the search for extraterrestrial life. Traditionally, habitability has been associated with terrestrial, Earth-like planets at a certain distance from the sun that would allow liquid water to exist on the surface.
The report, issued this week, says that we need to go underground. Recently, an lake has been discovered beneath the surface on Mars. On Jupiter and Saturn’s moons, subsurface oceans are suspected to exist. Could life really exist underground?
NASEM recommends that NASA search these disregarded worlds for signs of life. With the recent discovery of an underground lake on Mars and suspected subsurface oceans on Jupiter and Saturn’s moons, the committee of scientists behind the report think that studying all sorts of environments, not just those that mimic Earth’s, could uncover life in unexpected places.
NASEM is a collective scientific national academy of the United States, founded in 1863. It brings together top professionals in the field — in this case, astronomers research scientists, biologists, earth scientists and others — to answer questions of national importance. In this case, NASA asked NASEM to conduct an independent and objective analysis of the agency’s space exploration strategy. The final report’s most important conclusion: to find signs life outside our planet, NASA needs to incorporate astrobiology into every mission and begin probing planets and moons that were previously thought not conducive to life.
“The more that we can integrate the astrobiology lens and astrobiology thinking from the beginning of missions, the more that we can capitalize on the fantastic discoveries that are going on with missions that are out there now,” said Barbara Sherwood Lollar, NASEM Chair and an Earth science professor at the University of Toronto. “But by embedding the astrobiology thinking early in the process, we may be able to do even more.”
Astrobiology studies how organisms form and evolve on Earth. With this in mind, space missions generally search for worlds with liquid water on the surface. They also look for biosignatures that were made by living things that resemble those on Earth — specific atmospheric gases and molecules, or specific ecosystem patterns.
The future telescope instruments — such as the James Webb Telescope — should also be able to suppress the sunlight of stars to allow scientists to take a new, closer look at exoplanets and exomoons to search for biosignatures.
But the report says that the current strategy is too narrow: it operates under the assumption that life is born only in environments similar to Earth’s. Therefore, NASA could be overlooking other sources and markers of life.
“We need to make sure that our toolbox of biosignatures is universal enough that it encompasses both our ability to recognize life as we know it, but also our ability to recognize life as we don’t know it,” said Lollar.
And if organisms do exist in these new environments such as underground bodies of water, their biosignatures will likely go against our understanding of life on Earth. NASEM recommends strategies for broadening the search for biosignatures, such as molecular pairings that do not occure naturally, or chemicals that seem out of place.
NASEM thinks that there is a distinct possibility that the recently discovered Mars’ underground lake and the potential oceans within Jupiter and Saturn’s moons could be habitable. To give more credibility to their new theory, they point out that more and more ecosystems are being discovered below Earth’s surface.
Probing the surface isn’t enough, the report says. The subsurfaces should also be probed in the search for life. “Drilling technologies get a lot of interest, absolutely,” Loller said. “But they’re not the only means to go subsurface. Seismic, ground-penetrating radar, orbital scans, all of these things will actually give us information about the subsurface.”
The future telescope instruments — such as the James Webb Telescope — should also be able to suppress the sunlight of stars to allow scientists to take a new, closer look at exoplanets and exomoons to search for biosignatures.
NASEM’s report concludes that for successful outcomes of the project, it needs to be a collaboration between NASA and other international governmental and private organisations. To focus on astrobiology, the report says, is to increase our chances of finding extraterrestrial life.
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