Testing Origin-of-Life Theories with the Habitable Worlds Observatory (HWO)

TL;DR

The paper discusses how the Habitable Worlds Observatory can test different origin-of-life theories by observing biospheres on exoplanets, with implications for understanding abiogenesis and the environmental factors influencing life's emergence.

Contribution

It categorizes origin-of-life theories and proposes how HWO observations can empirically test and distinguish among them using statistical analysis.

Findings

Large sample sizes are needed to constrain abiogenesis theories effectively.

Detection or nondetection of biospheres can support or falsify specific theories.

Correlations with planetary parameters can test environmental hypotheses of life's origin.

Abstract

The Habitable Worlds Observatory (HWO) aims to telescopically constrain the frequency and abundance of biospheres in the solar neighborhood. Origin-of-life theories vary in their predictions for the environmental requirements and the expected frequency of abiogenesis, meaning that constraints on the frequency and distribution of life on exoplanets from HWO can in principle directly test theories of abiogenesis. We categorize origin-of-life theories into three broad classes and discuss how HWO could potentially test them. Nondetection of biology on a large sample of habitable planets would provide prior-independent evidence in favor of the class of abiogenesis theory which holds that the origin of life is a contingent, vanishingly unlikely event, whereas detection of event a single biosphere would falsify this class of theories. Correlations of candidate biospheres with planetary parameters such as UV irradiation, the presence of oceans, and the presence of continents can test specific origin-of-life theories. Simulated surveys with Bayesian analysis are required to quantify the ability of HWO to execute this science case. However, a clear theme from the limited such studies that have already been conducted is the need for large sample sizes ($\gtrsim50$ planets characterized) to provide meaningful constraints on abiogenesis theories, favoring a larger design sample for HWO.