Researchers from ETH Zurich, SETI Institute, and other institutions have developed a new statistical model to help scientists understand how many exoplanets they should observe before declaring that life beyond Earth is common or rare. The study suggests that observing 40-80 planets without finding signs of life can confidently conclude that fewer than 10-20% of similar planets harbor life.
The findings have significant implications for upcoming missions like NASA’s Habitable Worlds Observatory and the European-led Large Interferometer for Exoplanets, which will study dozens of Earth-like planets. However, the study highlights the importance of carefully accounting for uncertainties and biases in observations to ensure statistically meaningful results.
According to Dr. Daniel Angerhausen, lead researcher on the project, “Even a single positive detection would change everything — but until then, we need to make sure we’re learning as much as possible from what we don’t find.” The study’s key insight is that uncertainties in individual observations can significantly affect conclusions, emphasizing the need for careful consideration of confidence levels and biases.
The new model provides a framework for scientists to quantify the prevalence of life in the Universe, which has not been possible until now. With this information, scientists may be able to put a meaningful upper limit on how common or rare life is among planets with detectable biosignatures.
Source: https://www.sci.news/astronomy/future-exoplanet-habitability-biosignature-surveys-13806.html