Atmospheric biosignatures are fundamentally evidence of a system existing in a state of chemical disequilibrium.

“I think technically if you want to be physics precise it's not that methane and oxygen are signs of life it's that methane and oxygen are signs of something out of equilibrium and life itself is out of equilibrium”

The coexistence of oxygen and methane in a planet's atmosphere serves as a strong indicator of biological activity.

“when you look at the Earth and try to figure out if there's life on the Earth the combination of oxygen and a reducing gas like methane tells you that something is producing oxygen methane in huge amounts”

Researchers should look for a variety of biosignatures beyond oxygen, including potential industrial pollutants like nitrogen dioxide, as signs of life may evolve or appear in ways that are not immedi

“there's all kinds of things that if they produce life, we might miss it because we don't know how to look for things that aren't familiar to us, but there are lots of interesting signatures of life that we can look for that go beyond oxygen and ozone and methane, right? You can look for nitrogen dio”