A close-up view of Europa's surface shows chaotic patterns, similar to those seen in Earth's artic. (Image: NASA/JPL/University of Arizona)

Two October meetings at SFI aim to dig into some of the trickiest questions about life, both here on Earth, and how we might recognize it elsewhere in the universe.

Life on other worlds might have biochemistries that resemble that of life on Earth, might be built on similar molecular blocks, might behave in ways we’d find familiar. It could look like life as we know it.

Or, it might not.

It’s possible that life on planets beyond our solar system — or even on bodies in our own solar system, like Saturn’s moon, Titan — could host life so different from Earth’s that we wouldn’t recognize it. October 9-10, a working group titled “Towards Truly Agnostic Biosignatures for Astrobiology,” will begin discussing ways that we might identify signs of life that are radically different from the evidence of bacteria, plants, and animals on this planet. 

Life on Earth leaves behind a suite of tell-tale signs, or biosignatures, that we’ve come to recognize. These could be, say, fossils, traces of DNA, or an ocean sediment sample that contains compounds produced during metabolism. But even here at home, recognizing life isn’t always straightforward.

“Detecting life on Earth has its own challenges: you have to rule out the possibility of false-positives where a very chemically complex but abiotic environment could look like what we see in a living world,” says SFI Professor Chris Kempes, who is co-organizing the working group. “For life as we don’t know it, we need to watch for false-negatives — for things that look abiotic but actually have life.”
During this working group, participants will discuss the range of existing methods for identifying biosignatures, then think about how to expand on those to develop more general life-detection methods. “The idea is to get away from any kind of pre-conditioning, so that we’re not completely tied to what we already know about life,” says Kempes.

Another project asking similar questions about how life could originate and the degree of complexity that life could evolve launches with a workshop October 29-30. This will be the first annual meeting for the five-year Research Coordination Network (RCN) on the Exploration of Life’s Origins, funded by the National Science Foundation and organized by Kempes and SFI President David Krakauer.
“Origins of life is one of the most exciting questions out there,” says Kempes. “The goal of these RCN meetings is to address the question: How do you go from a complex but purely abiotic world to the rise of life, and to life that evolves greater complexity over time?” 

Origins of life research draws on a wide range of disciplines, from physics and chemistry to planetary sciences and paleobiology. But to make progress, researchers from these fields need opportunities for deep and meaningful dialogues, say the organizers.

As the expected 30-some workshop participants report on the major accomplishments, critiques and outstanding questions of their respective fields, they will also focus on winding back the clock on one of the most major events in the history of life: translation.
All modern life – life as we know it – has inherited the cellular machinery of translation where information stored in DNA is turned into functional proteins. This “central dogma” is one foundational aspect of biology with widespread agreement among scientists, but we don’t know, necessarily, if translation is essential to the evolution of complex life.

“It becomes equally exciting if you can propose a variety of routes to complex life,” says Kempes. “That begins to expand the possibilities for astrobiology.”