But lots of life on Earth does not rely on oxygen, and for the majority of time that life existed on Earth it also didn’t rely on oxygen. This was about two years of work on top of my many years of work investigating phosphine as a biosignature. The odds that we find life beyond Earth from a booming, unambiguous, intelligent signal from the heavens is very slim. SOUSA-SILVA: Life is very resilient and very resourceful on Earth and there’s no reason to think that’s some special characteristic of life on Earth rather than of life itself. Life on Earth came to be in a huge diversity of forms, and life changed Earth’s atmosphere many times.
