Finding aliens: Is there a ‘theory of everything’ for life? | Sara Walker | Big Think

Finding aliens: Is there a ‘theory of everything’ for life?
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This video was produced in partnership with John Templeton Foundation.

What, should it exist, is the universal law that connects all living things? To even dream of answering that question, and to one day find alien life elsewhere in the cosmos, humans must first reconcile the fact that our definition of life is inadequate.

For astrobiologist Sara Walker, understanding the universe, its origin, and our place in it starts with a deep investigation into the chemistry of life. She argues that it is time to change our chemical perspective—detecting oxygen in an exoplanet's atmosphere is no longer sufficient enough evidence to suggest the presence of living organisms.

"Because we don't know what life is, we don't know where to look for it," Walker says, adding that an unclear or too narrow focus could result in missed discoveries. Gaining new insights into what life on Earth is could shift our quest to find alien life in the universe.
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SARA WALKER:

Sara Walker is an astrobiologist and theoretical physicist interested in the origin of life and how to find life on other worlds. Walker is the deputy director of the Beyond Center for Fundamental Concepts in Science, associate director of the ASU-Santa Fe Institute Center for Biosocial Complex Systems, and assistant professor in the School of Earth and Space Exploration at Arizona State University. She is also co-founder of the astrobiology-themed social website SAGANet.org.

Read Sara Walker's book "From Matter to Life (Information and Causality)" at https://amzn.to/3pm9S7r
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TRANSCRIPT:

SARA WALKER: We have, through science over the last 400 years, come to have a really deep understanding of the natural world. But so far that deep understanding doesn't include us. It's really important in an age when we're being faced with existential threats on a regular basis to understand our place in the cosmos. And I think unless we actually really address the question of 'What is life?' we're not really gonna understand ourselves in the context of the systems that we live in.

Because we don't know what life is, we don't know where in the universe to look for it. My biggest worry is that we might just completely miss discovering it because we actually don't really have an idea what we're looking for. And we're thinking about the definitions of life the wrong way.

I'm Sara Walker and I'm an astrobiologist. What that means is that I'm really interested in understanding if there's life elsewhere in the universe, but I'm also really interested in just understanding ourselves. And so most of my work is really focused on understanding the origin of life on Earth. To do that, my group is building ensembles of thousands of organisms and thousands of ecosystems and looking at properties of their chemistry.

NARRATOR: On Earth, we're surrounded by life, but we have no idea how common or rare living systems are in the universe. We have no idea how many different forms life can take, no notion of what limits there are to its size or the timescales it operates on. We might've encountered alien life already and not recognized it.

WALKER: There's this assumption that we make that because we are alive, we actually recognize life when we see it, or we understand what life is, and I think that's actually a really flawed viewpoint. For a long time, it was thought if we see oxygen in the atmosphere of an exoplanet, that is a sign of life, and we will be able to claim victory that we have discovered aliens. But as scientists thought about it a little bit more, it turns out you can make atmospheric oxygen pretty easily with simple models that don't even contain life. We really need a more general definition for life that doesn't depend on the specific chemistry that life on Earth uses but is more characteristic of what life is as a process that organizes chemistry and does all of the wonderful things that we associate with living matter.

So I, for example, have a very broad definition of life that includes things like technology. Part of the reason for that is if you found a phone on Mars, you might not think that you discovered life, but you certainly would think you discovered evidence of life. Because the likelihood of that phone being there is zero without a living process putting it there. Life is literally the physics of creativity. It's the creative process in the universe. It's not an individual in that process...

Read the full transcript at https://bigthink.com/john-templeton-foundation/alien-life?