Oxygen is a promising exoplanet biosignature, but several scenarios exist in which a lifeless, rocky planet could evolve to have non-biological oxygen in its atmosphere.
![Oxygen biosignature alone does not indicate life on other planets](https://www.advancedsciencenews.com/wp-content/uploads/2021/04/daniel-olah-dFA5XycbhoQ-unsplash.jpg)
Oxygen is a promising exoplanet biosignature, but several scenarios exist in which a lifeless, rocky planet could evolve to have non-biological oxygen in its atmosphere.