Is Anyone There?
A new way to search for life on other planets
The search for extraterrestrial life has long fascinated scientists—and Dr. Sara Seager is no exception. As a planetary scientist with a focus on exoplanets (planets outside our solar system), she dreams of the landmark moment we find it. But when scientists search for signs of life on planets beyond our solar system, they don’t have a ton of information to go on. Here at home, the signs are everywhere—from vast forests to sprawling cities. In exoplanets, the signs are likely to be much subtler: perhaps a greater atmospheric concentration of the gases that organisms breathe out, for example. Discovering exactly what those signs could be is the focus of Dr. Seager’s research project.
Currently, when scientists are assessing an exoplanet’s potential to support life, they limit their consideration to the amount of oxygen (or a handful of other gases) in the atmosphere. Dr. Seager proposes to develop an extensive database of the molecules that life creates and how commonly they are made, enabling scientists to employ a new set of rules for detecting the existence of extraterrestrial life. Her research team determined that about one quarter of the small molecules on earth composed of certain elements are produced by life, but that other molecules made from these same building blocks are in fact rarely or never produced or utilized by living things. The database will enable Dr. Seager and her team to analyze the interactions between chemistry and life, and to map out “motifs” of biochemical spaces—certain combinations of molecules that make it easier or harder, more or less likely, for life to exist.
Establishing a new research area combining biology, chemistry, computer science, and physics
Funding for multidisciplinary research is difficult to secure, and traditional funding sources are hesitant to take a risk on an entirely new line of speculative research. Dr. Seager’s project defies disciplinary siloes, and the data organization, research techniques, and infrastructure required to complete it have yet to be created. Furthermore, there’s a chance that the motifs and chemical patterns her team uncovers will be too complex or abstract to be used in practical exoplanet research. But Dr. Seager remains undaunted. She says, “My intuition from all my years of experience is that this is going to be big. You can feel when you’re onto something momentous—but you can’t write that in a proposal to the NSF.”
This work is completely outside my mainstream research but I am so convinced of its value I am willing to invest substantial time pursuing it. This effort is an example of a high-risk high-reward kind of research—the kind of reward that could revolutionize our understanding of the universe and our place in it.”
Proof that we’re not alone
The motifs that Dr. Seager’s research will reveal have the potential to redefine the way we search for life on other planets—and may serve as our best strategy for finding it. Such a discovery would fundamentally transform our understanding of the universe and our place within it. Closer to home, she imagines her team using these motifs as a framework for exploring life on earth, leveraging this knowledge to understand the chemical structures at play in biological processes such as metabolism, toxicity, and drug absorption. Dr. Seager envisions the database as a novel tool for examining chemical biology wherever it is found. “Our plans remain open ended,” she says, “because we have the opportunity to examine life everywhere through the lens of this new telescope, the occurrence database.”