Discovering Extraterrestrial Life Would Be Slow and Uncertain

What would it be like to find signs of life beyond Earth?
What would it be like to find signs of life beyond Earth? (Image credit: NASA)

Scientists have spent long enough looking for proof of alien life that the little buggers, if they do exist, probably aren't going to be easy to identify.

Instead, experts thinking about how to spot life beyond Earth are realizing that they may put humanity in an uncomfortable place of uncertainty. Initial data may raise eyebrows and prompt speculation of alien life, but it likely won't be definitive enough to settle the matter on its own.

"It's probably something that's going to be a slow discovery, not like the little green humanoids arriving here on Earth scaring everybody," Sara Seager, an astronomer at the Massachusetts Institute of Technology who focuses on detecting exoplanets, said during a panel held last month at the International Astronautical Congress in Washington. "It's probably going to take a long time." Seager added that she thinks that a slow discovery could make it easier for people to process it, and its significance.

Related: The Most Fascinating Exoplanets of 2018

But the uncertainty could be difficult for humans to deal with, Kathyrn Denning, an anthropologist at York University in Canada who thinks extensively about these scenarios, told during the conference. "Humans, we're not good with holding spaces open," Denning said. "We just fill them with whatever's available."

And, in the case of potentially detecting life, plenty of what's available could trigger fear and other negative emotions, she said. Speculations about contact scenarios with extraterrestrial life, even those imagined by scientists, are often less than cheerful. Modern information circulation patterns favor negativity and inaccuracy.

So, Denning worries that a detection of life that isn't definitive could leave humans to fill in the blanks on their own, regardless of the lack of evidence. That scenario is particularly concerning if the discovery is of some sort of extraterrestrial intelligence, but scientists don't have any details about its capacities, technologies or intentions. "That would be so exciting scientifically," she said. "But for many people, it just creates a space on which to project."

To prepare, we should spend our time practicing dealing with uncertainty, Denning said, and having conversations that make us more confident in humanity's ability to navigate such a discovery.

Seager sees the uncertainty as a challenge for scientists as well, albeit in a different way. She described the possibility that as exoplanet studies continue to develop, different communities' understanding of the certainty of life beyond Earth may diverge. Scientists may still lack what they deem sufficient evidence to truly identify such life.

But, gather enough unconfirmable yet seemingly legitimate possibilities, and the picture can look a little different, especially when you aren't responsible for writing peer-reviewed papers. "If we see all the signs — it's not for this audience, but enough to just know that there's life out there somewhere." Seager said. "I know this is an unsatisfying answer."

Email Meghan Bartels at or follow her @meghanbartels. Follow us on Twitter @Spacedotcom and on Facebook. 

All About Space Holiday 2019

Need more space? Subscribe to our sister title "All About Space" Magazine for the latest amazing news from the final frontier! (Image credit: All About Space)

Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at:

Meghan Bartels
Senior Writer

Meghan is a senior writer at and has more than five years' experience as a science journalist based in New York City. She joined in July 2018, with previous writing published in outlets including Newsweek and Audubon. Meghan earned an MA in science journalism from New York University and a BA in classics from Georgetown University, and in her free time she enjoys reading and visiting museums. Follow her on Twitter at @meghanbartels.