Rare Chemical Fluke May Have Made Earth Habitable

Got story updates? Submit your updates here. ›

A new study published in Nature Astronomy suggests that the precise balance of phosphorus and nitrogen during Earth's formation was crucial for the development of life. Researchers found that the formation of Earth's core required a specific amount of oxygen, and too much or too little would have resulted in either phosphorus being locked away in the core or nitrogen being lost to space. This narrow 'Goldilocks zone' allowed both elements to remain accessible in the planet's mantle and crust, enabling the chemical processes necessary for life.

Why it matters

This discovery shifts the focus in the search for extraterrestrial life, suggesting that habitability requires more than just the right temperature and distance from a star. The chemical composition of the star itself, and the resulting oxygen levels during planet formation, are now seen as critical factors. Identifying solar systems with stars similar to our sun could be a more effective strategy for finding potentially habitable planets.

The details

The new research highlights the importance of phosphorus as a 'biosignature' - a substance that could indicate the presence of past or present life. Phosphorus is fundamental to DNA, cell membranes, and energy transfer processes. Nitrogen also plays a dynamic role in planetary ecosystems, with recent observations showing nitrogen fixation occurring under declining Arctic sea ice.

• The new study was published in Nature Astronomy in February 2026.

What’s next

Researchers now believe that identifying solar systems with stars similar to our sun could be a more effective strategy for finding potentially habitable planets.