A recent study by ETH Zurich researchers has tackled the question of what happens when scientists come up empty-handed in their search for life on other planets. The research team, led by Dr. Daniel Angerhausen and affiliated with the SETI Institute, explored how many exoplanets scientists should observe before declaring that life beyond Earth is either common or rare.
Using advanced statistical modeling, the team found that if scientists examine 40-80 planets and find no signs of life, they can confidently conclude that fewer than 10-20% of similar planets harbor life. However, this depends heavily on how certain we are about each observation.
This study has direct implications for upcoming missions like NASA’s Habitable Worlds Observatory (HWO) and the European-led Large Interferometer for Exoplanets (LIFE). The team emphasizes that even if future surveys don’t find evidence of extraterrestrial life, they will still provide valuable insights into how rare or common habitable conditions are in the universe.
The key to meaningful results lies not just in observing a large number of planets but also in carefully accounting for uncertainties and biases. The study highlights the importance of framing the right questions and asking specific and measurable ones, such as “Which fraction of rocky planets in the conservative habitable zone show clear signs of water vapor, methane, and oxygen?”
Ultimately, this work serves as a reminder that science isn’t just about finding answers but also about asking the right questions and embracing uncertainty as part of the journey.
Source: https://www.seti.org/press-release/what-if-we-find-nothing-our-search-life-beyond-earth