The one critical mistake Alien Hunters keeps making

Photo illustration by Kelly Caminero/The Daily Beast/Getty

Photo 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 further and wider across the vast space for evidence of extraterrestrials.

But it is possible that we are looking for too few signs in too few places. Having evolved on Earth, surrounded by Earth life, we assume that alien life will look and behave like Earth life.

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

Some scientists are trying to fix our Earth’s tilt. In a new study made available for reading on July 27, a team led by Arwen Nicholson, an astrophysicist at the University of Exeter, attacked an assumption that is widespread in astronomy. It is commonly thought that a distant “exoplanet” – a planet outside the solar system – will need a certain amount of oxygen and hydrogen to support life. And these life forms, as they lived and died and evolved, would release methane gas that would build up in the atmosphere.

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

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

Surprise! The tough little organisms hung in there. And yes, they still spewed enough methane to register in astronomical surveys from light years away. “These results help deepen our understanding of interactions between life and the planet,” wrote Nicholson and her co-authors. “It reduces the need to make unnecessary assumptions about alien life based on life on Earth.”

Practically speaking, Nicholson’s study – which has been peer-reviewed and accepted for publication in the Monthly Notices of the Royal Astronomical Society— could expand the list of exoplanets that scientists consider worth probing for signs of life.

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

TRAPPIST-1’s planets are quite far away; it’s not like we’d have a real chance of visiting potential life on these worlds anytime soon. Astronomers aim for them anyway, rather than closer but apparently more barren planets, because the TRAPPIST planets seem to have all the nutrients that Earth life really favors. “Would you prefer relatively poor data about a hard-to-observe, but truly Earth-like, world — or much better data about a nearby nutrient-poor planet?” is how Étienne Artigau, an astrophysicist from 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 has so far appeared somewhat hostile to life.

But the study by Nicholson and her co-authors is still just a push toward a more open-ended approach to the search for ET. She and her team still hypothesize that aliens will share the same basic metabolism common on Earth. Take in oxygen and hydrogen, and release methane. “As we only know about life on Earth, it’s hard not to be influenced by that,” Nicholson admitted.

But at least we can imagine life forms with completely different metabolisms. “For planets it can be very different [from] our own, different metabolisms may be possible than those on Earth, Nicholson said. “Identifying the possible metabolisms will be key to thinking about life on distant planets.”

The problem is that unless and until we discover a life form with a radically different metabolism, it is unlikely that any serious scientists are going to create investigative methods specifically tailored to find signs of that kind of life. It’s kind of a chicken-and-egg problem – you can’t search for something you don’t know you’re looking for. And few scientists seem eager to design investigations around what are currently fictional life forms.

“We are always limited by our imagination, which is governed 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 that reluctance to investigate the totally unknown that keeps us searching alien life so closely related to our understanding of Earth life. The same institutional conservatism can prevent us from recognizing aliens even after we find them.

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

Instead, the scientific community just shrugged as ‘Oumuamua scurried away. And that’s a problem, Loeb said. “Reality has ways of surprising us, so we should simply search for things or behaviors that are unfamiliar to us.” When a mysterious object zooms through the solar system and defies easy categorization, you might worry less about the categories. Investigate with an open mind.

The same applies to planetary surveys. To increase our chances of finding alien life, we could look in places we wouldn’t normally expect life to thrive. It’s a big universe after all. And it only seems stranger every day as our discoveries pile up.

More and more scientists are coming around to the idea that aliens are out there, somewhere. Perhaps more researchers need it also come around to the idea that those aliens can be very strange.

Read more at The Daily Beast.

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