The truth is out there: Scientists want a new mission to hunt for life beyond Earth

Independent

08-04-2025

Scientists want a new mission to hunt for life beyond Earth and the solar system.
The Swiss university ETH Zurich's international Large Interferometer for Exoplanets mission would send telescopes to investigate the diversity of other worlds.
The so-called LIFE mission would study the atmospheres of dozens of exoplanets with a similar temperature, radius and mass to Earth for signs of water and oxygen.
"A single positive detection would change everything," physicist Dr. Daniel Angerhausen explained in a statement, "but even if we don't find life, we'll be able to quantify how rare — or common — planets with detectable biosignatures really might be."
The mission concept is detailed in a new study published in The Astronomical Journal.
The study reviews what astronomers could learn if there's 'no life detected' in future exoplanet surveys, relying on a 'Bayesian' statistical analysis to establish the minimum number of exoplanets that should be observed to get meaningful answers about the frequency of possibly inhabited worlds. Bayesian statistics has to do with determining the probability of an outcome based on other known probabilities, according to Space.com.
There are currently more than 5,800 confirmed exoplanets that exist beyond our solar system. Most of them orbit other stars and the majority of those that have been discovered are in our Milky Way galaxy. But, NASA believes that billions exist.
The research found that if scientists examined between 40 and 80 exoplanets finding no life, they could conclude that fewer than 10 to 20 percent of similar planets host life. They said those conclusions would enable researchers to place an upper limit an estimated prevalence of life in the universe.
'This kind of result would be a turning point,' said Angerhausen, the study's lead author. 'Even if we don't find life, we'll finally be able to quantify how rare — or common — planets with detectable biosignatures really might be.'
Still, they acknowledge that every observation comes with a certain level of uncertainty. For example, the mission could result in false negatives thanks to missed signs of life.
The study authors say specific and measurable questions are necessary to address uncertainty, including 'which fraction of rocky planets in a solar system's habitable zone show clear signs of water vapor, oxygen, and methane.'
"It's not just about how many planets we observe — it's about asking the right questions and how confident we can be in seeing or not seeing what we're searching for," Angerhausen said. "If we're not careful and are overconfident in our abilities to identify life, even a large survey could lead to misleading results."