The Question
Fueled by powerful new telescopes and the discovery of thousands of exoplanets — planets that orbit stars other than the sun — the search for life beyond Earth is accelerating. Yet whether in the solar system or on distant exoplanets, finding life may require a broadened perspective. Could life exist in Venus’ acidic clouds, on airless planets or in other extreme environments once considered uninhabitable?
Many known exoplanets are too warm for surface liquid water and therefore considered inhospitable to life. Liquid is a fundamental requirement for life as we understand it, but whether that liquid must be water is not known.
Groundbreaking experiments in Sara Seager’s lab have shown that some key building blocks of life remain stable in sulfuric acid — the main component of Venus’ clouds — challenging conventional thinking. Beyond Venus, the researchers suggest that ionic liquids — special nonevaporating liquids that can be hospitable to biomolecules — can form and exist naturally, perhaps even on planets without atmospheres.
“My research expands the definition of habitability, offering new pathways to detect life on planets once dismissed as inhospitable. At a deeper level, it speaks to a universal human desire to understand our place in the cosmos — and the aim to discover that we are not alone. While driven by pure scientific curiosity, this work can occasionally lead to practical spinoffs, especially through the development of hardware for space missions, as my team is actively doing.”
— Sara Seager
The Approach
The project From Lab to Cosmos aims to expand the definition of habitability by conducting laboratory experiments that study biomolecules’ chemistry in sulfuric acid for Venus missions; explore biomolecules in ionic liquids as exotic solvents; and predict signs of life based on planets that could sustain life in extreme environments.
The most transformative potential of this research lies in its implications for the origin of life. By examining exotic solvents and rejecting water as the sole prerequisite for biology, we gain access to a wider chemical space — one that may encompass the primitive pathways by which life began. These pathways, now erased from Earth’s surface record, may still be active elsewhere, and exploring them could redefine our understanding of life’s beginnings and its potential distribution across the cosmos.
From Lab to Cosmos: Rethinking Habitability and the Search for Life Beyond Earth is being led by Sara Seager at the Massachusetts Institute of Technology (MIT) in Cambridge, US.
Feature image: Left photo courtesy of Sara Seager; center photo by JAXA; right photo by NASA
