Der Exoplanet K2-18b ist 124 Lichtjahre von der Erde entfernt und gilt als Kandidat für ausserirdisches Leben.Bild: hycean.group.cam.ac.uk
09.02.2026, 18:0009.02.2026, 18:00
The search for habitable planets beyond our solar system just got more focused, thanks to new research pinpointing the critical chemical elements needed for life to emerge. A study led by researchers at ETH Zurich sheds light on why some planets may be more conducive to life than others and why Earth represents a fortunate combination of circumstances.
The research, led by postdoctoral researcher Craig Walton at the Centre for Origin and Prevalence of Life at ETH Zurich, and ETH Professor Maria Schönbächler, demonstrates that sufficient quantities of phosphorus and nitrogen are essential for the development of life on a planet. This discovery refines the parameters scientists use when evaluating the potential for life on exoplanets, moving beyond simply looking for the presence of water.
Phosphorus is indispensable for building DNA and RNA, which store and transmit genetic information, and is crucial for cellular energy processes. Nitrogen, the study explains, is a vital component of proteins, essential for the structure and function of cells. Without these two elements, the development of life from non-living matter is impossible, according to ETH Zurich.
The study reveals that the availability of sufficient phosphorus and nitrogen is largely determined during the planet’s core formation. “Crucially, during core formation, there needs to be just the right amount of oxygen so that phosphorus and nitrogen remain on the planet’s surface,” Walton stated.
Earth: A Chemical Fortunate Event in the Universe
Approximately 4.6 billion years ago, Earth experienced precisely these conditions, making it a chemical anomaly in the universe. This finding underscores the delicate balance of elements required for a planet to support life.
Through numerous simulations, Walton and his co-authors demonstrated that both phosphorus and nitrogen remain in sufficient quantities within the mantle only within a surprisingly narrow range of average oxygen ratios – a so-called “chemical Goldilocks zone.”
ETH Zurich emphasizes that these new insights could reshape the search for life in the universe. Previously, the focus has primarily been on whether a planet has water. However, Walton and Schönbächler argue that this approach is too limited. The research highlights the increasing sophistication of astrobiological investigations, moving beyond simple habitability metrics.
Astronomers can indirectly measure these fundamental chemical prerequisites when observing distant solar systems with large telescopes. Planets with chemical compositions significantly different from our solar system are unlikely candidates for harboring life, Walton explained. (sda)
