The One Critical Mistake Alien Hunters Keep Making

Photographic illustration by Kelly Caminero / The Daily Beast / Getty

Our search for alien life is getting serious. With better telescopes and a growing scientific consensus that we are probably not alone in the universe, we are starting to look farther and farther into the vastness of space for evidence of extraterrestrials.

But it is possible that we are looking for few signals in few places. Having evolved on Earth, surrounded by terrestrial life, we assumed that alien life would look and behave like terrestrial life.

What if we’re wrong? What if ET is out there waiting to be discovered by the first astronomer willing to open their minds to the possibility that, to us, alien life might seem very strange?

Some scientists are trying to correct our Earth bias. In a new study that was made available for reading on July 27, a team led by Arwen Nicholson, an astrophysicist at the University of Exeter, attacked a widely held assumption in astronomy. There is a common line of thinking that a distant “exoplanet” – a planet outside the solar system – would need a certain amount of oxygen and hydrogen to support life. And these life forms, as they lived and died and evolved, would excrete methane gas that would accumulate in the atmosphere.

Methane is one of the big things astronomers look for when it comes to evidence of alien life. They call this a “biosignature”. But with more than 5,000 confirmed exoplanets on the official list and only so many telescopes powerful enough to survey them, astronomers tend to exclude planets that appear to be nutrient-poor – lacking, say, the concentration of hydrogen we have here. Earth.

To examine this assumption, Nicholson and his team built a sophisticated computer model of a roughly Earth-like planet, populated it with simple simulated microbes, and began extracting hydrogen. The goal: to see if the microbes would survive and if they would still excrete detectable levels of methane as they struggled on their low-resource planet.

Surprise! The small resistant organisms resisted. And yes, they still spewed out enough methane to be recorded in astronomical surveys light-years away. “These results help deepen our understanding of planet-life interactions,” Nicholson and his co-authors wrote. “This reduces the need to make unnecessary assumptions about alien life based on life on Earth.”

In practical terms, Nicholson’s study – which was peer-reviewed and accepted for publication in Monthly notices from the Royal Astronomical Society— could expand the list of exoplanets that scientists consider worth searching for signs of life.

Astronomers are lining up to use NASA’s new James Webb Space Telescope to inspect planets for biosignatures. The priority in this first year of JWST operations is the seven possible Earth-sized planets in the TRAPPIST-1 star system, 40 light-years from Earth.

TRAPPIST-1’s planets are far away; it’s not like we have a real chance to visit any potential life on these worlds anytime soon. Astronomers are targeting them anyway, rather than closer, but apparently more barren planets, because TRAPPIST planets seem more likely to have all the nutrients that life on Earth actually favors. “Would you prefer relatively poor data on a hard-to-observe but truly Earth-like world — or much better data on a nearby nutrient-poor planet?” this is how Étienne Artigau, an astrophysicist at the Université de Montréal who was not involved in Nicholson’s study, described the surveyors’ dilemma.

If Nicholson’s model gains traction, however, astronomers may be willing to risk their precious telescope time on a closer planet that until now has seemed a little hostile to life.

But the study by Nicholson and his co-authors is still just a push toward a more open approach to the search for ETs. She and her team are still assuming that aliens would share the same basic metabolism that is common on Earth. Ingest oxygen and hydrogen and excrete methane. “Because we only know life on Earth, it’s hard not to be influenced by it,” Nicholson admitted.

But we can at least imagine life forms with totally different metabolisms. “For planets that can be very different [from] our own different metabolisms may be possible than Earth’s,” Nicholson said. “Identifying these possible metabolisms will be key to contemplating life on distant planets.”

The problem is that unless and until we discover some form of life with a radically different metabolism, it is unlikely that any serious scientist will devise research methods specifically tailored to find signs of this type of life. It’s a chicken-and-egg problem—you can’t look for something you don’t know you’re looking for. And few scientists seem eager to design research into what are currently fictional life forms.

“We are always limited by our imagination, which is guided by our experience,” Avi Loeb, a Harvard physicist who was also not involved in Nicholson’s study, told The Daily Beast. For all their intelligence, curiosity, and training, scientists tend to be extremely conservative when it comes to weird things.

It is this reluctance to probe the totally unknown that keeps our search for abroad life so closely tied to our understanding of Earth life. The same institutional conservatism could prevent us from recognizing aliens even after finding them.

Take ‘Oumuamua. That’s the name astronomers have given to a very strange oblong object, up to 3,000 feet long and bright, that passed through our solar system in 2017. No one is quite sure what it was. Likewise, no one should say with certainty what was not. But despite ‘Oumuamua behaving as we would expect an alien spacecraft to behave, very few scientists – Loeb is one of them – are asking their colleagues to at least consider the possibility that the strange object was an opportunity for first contact. .

Instead, the scientific community just shrugged it off as ‘Oumuamua walked away. And that’s a problem, Loeb said. “Reality has ways of surprising us, so we should simply look for things or behaviors that are unfamiliar to us.” When a mysterious object approaches the solar system, defying easy categorization, perhaps you care less about categories. Investigate with an open mind.

The same goes for planetary surveys. To increase our chances of finding alien life, we could look in places we wouldn’t normally expect life to thrive. After all, it’s a big universe. And it just seems weirder every day that our discoveries pile up.

More and more scientists are coming to the idea that aliens are out there somewhere. Perhaps more scientists need also come to the idea that these aliens might actually be weird.

Read more at The Daily Beast.

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