Science might be redefining what “life out there” really means.
How Do We Find Aliens? Maybe Unlearn What We Know About 'Life' First
Clara Moskowitz: This is Clara Moskowitz and you're listening to the Science Quickly podcast from Scientific American. Today, we're talking about life as we don't know it.
Sarah Scoles just wrote a piece for us in our February magazine on that very subject. Sarah, hi.
Sarah Scoles: Hi, Clara. How are you?
Moskowitz: I’m great. Thanks for joining us.
Scoles: Thanks for having me.
Moskowitz: So what exactly is life as we don't know it or as you brilliantly call it in the story: LAWDKI.
Scoles: Yes, So I'm glad we like the that acronym that I just made up, but I think it's a talk about life as we don't know it, it's important first to talk about life as we do know it, because we really only think about life as life. Biology as biology.
But life as we do know it is really just a specific instance of one kind of biology that could exist, you know, where most things kind of breathe oxygen, rely on DNA, and RNA as genetic material and kind of share a common what they call what scientists call biochemistry.
And so that is life as we know it and life as we don't know it ... I guess I'm procrastinating saying what it is, because the point is that we don't know what it is. It is something that is biological but does not necessarily rely on the same elements, and compounds are ways of transferring information. It's just something that's not ... it's not physics, chemistry, but it's biology, but we don't know anything about it, really.
Moskowitz: Right. It actually kind of hurts your brain to try to imagine something that you've never encountered or never thought about or never seen before. So as we talk about looking out into the universe for life, are most searches for extraterrestrial life these days, searches for life as we know it, or life as we don't know it?
Scoles: Right now, and historically, most searches have been for life as we do know it, because it's the only example of life that we have. So it kind of makes sense as a place to start. One analogy that the scientists I talked to use is, you know, if you lose your keys out of the streets of where the first place you might look is under a streetlamp because there's light there, you'll be able to see it. You'll be able to recognize it as keys.
But if you're just fumbling around in the dark, even if your keys are there, it's a lot harder. And so it makes sense to me scientifically that that is where scientists would start. And so they look for things like essentially fingerprints out in the universe that life kind of like us or like other animals on earth might create if we saw them somewhere else.
But now that we've been kind of doing that for a little while, scientists are starting to get a little more creative and think about ways that you might try to find life as we don't know it, which is very hard because, as you said, we don't know anything about it. It's unfamiliar and unimaginable, I think, is what one of the sciences said to me. And where do you even begin with that?
Moskowitz: Right? Totally. So what are some of their ideas? How do they go about looking for life as we don't know it?
Scoles: Right. Good question. And they have given it a lot of thought. The general idea is to figure out what fundamentally makes something that's alive different from something that is just relying on like physics or chemistry. Like what, fundamentally, makes something biological and how would you look for a signature of that? And some of the things that they have come up with so far are looking for compounds, molecular compounds that are complex that nature would be unlikely to just produce on its own unless something alive was kind of forcing it to.
Another thing is looking for maybe concentrations of molecules like that, like little dots of complication on another planet or on on a moon of a planet in the solar system or something.
A third thing is evidence that that energy is kind of flowing from one place to another, like things in nature generally like to be in equilibrium. So, if you see something that's not an equilibrium where energy is kind of flowing in and being used, that that could be an indication of life. But these are also essentially just guesses. They don't they don't really, though, it's kind of another sort of streetlamp.
Moskowitz: Huh. It's cool to think about, though.
So you touch on an important point, though. What is life anyway? How do you define being alive?
Scoles: Everyone would like to know the answer to that question. And in general, scientists don't totally agree on the definition of life and what makes something alive. There are dozens of different definitions that are kind of equally and differently valid. But there was one scientist who wrote a paper kind of bringing together all those different definitions and trying to distill them down into the essence of what it means to be alive.
And at least in his opinion, when you get right down to it, it's just life is self reproduction with variation. So essentially something that can make more copies of itself, but copies that are just clones, but that are a little different. That's it, I guess. Although you could probably ask five different scientists and get five different definitions.
Moskowitz: That certainly works to describe my three year old and my five-year-old.
Scoles: Not clones of you, exactly?
Moskowitz: Not even close. So do you personally think that some form of extraterrestrial life must be out there somewhere?
Scoles: You know, for most of my life, I have thought that there's just got to be something out there. The universe is so big. We know now that there are so many planets with so many different conditions. A lot of which, you know, could be habitable to life like us. And so kind of in the past, I just thought like, yeah, statistically, sure, of course, there has to be life out there.
But as I've learned more and worked on articles like this and talked to people who are biologists and not just astronomers, they're a little more hesitant. You know, life arose here from physics and chemistry became biology. And it's we don't actually know how that happened. And so we don't know how hard it is. We don't know how likely it is.
And so even if there's trillions of planets in the universe, we don't actually know that the chances of of life arising are more than, you know, one in 10 trillion or something like that. So my new stance is that I don't know and I'm not making any guesses. I'm going to wait for people like these researchers to gather some more data and then reform my conclusion.
What do you think?
Moskowitz: That sounds very wise and prudent. I, I mean, I still hear the echoes of Jodie Foster's character in “Contact” saying if there isn't someone out there, it's just an awful waste of space. So I. I hope so. I feel like I'm hopeful for life. But as you point out, you know, it's sort of it's fascinating either way.
I mean, if we were the only example that that would just be incredible. But thinking about what life out there might actually look like also feels incredible.
Scoles: Yeah. Yeah. I think either answer is really pretty awe-inspiring. I would kind of prefer to have some alien cousins, but if they're not out there, I can kind of get on board with being alone in the universe, also.
Moskowitz: Agreed. Well, thank you so much for joining us, Sarah, and and for writing the awesome article. So, I encourage everybody to go read that for a lot more interesting details.
Scoles: Thank you.
Moskowitz: For Scientific American’s Science. Quickly, I'm Clara moskowitz.
Science Quickly is produced by Kelso Harper, Tulika Bose and Jeff DelViscio. Our theme music was composed by Dominic Smith.
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