> (A jab at searches for extraterrestrial life that maintain oxygen as a key criteria) I am not aware of any searches that have oxygen as a necessary condition

> (A jab at searches for extraterrestrial life that maintain oxygen as a key criteria) I am not aware of any searches that have oxygen as a necessary condition for life and I doubt they exist. It is not even considered a very good biosignature[1][2] because there are potential abiotic process that can replenish it, but it can be used as a biosignature, but that would work for life even if the life does not use oxygen, so using oxygen as a biosignature is not saying that life needs oxygen. [1]: https://en.wikipedia.org/wiki/Biosignature#False_positives https://en.wikipedia.org/wiki/Biosignature#False_positives [2]: https://www.liebertpub.com/doi/full/10.1089/ast.2017.1727 https://www.liebertpub.com/doi/full/10.1089/ast.2017.1727