Sensational headlines about evidence for life on Mars pop up every time there is the slightest hint of gas or water or tiny pits in a Mar’s rock. But why all the hype?
Methane gas is not unique to life metabolism. Methane gas is abundant on Titan. In fact, methane is a major gas on Jupiter and Neptune and other planets. Other organic molecules such as ethane, acetylene, carbon dioxide, and propane can be found as well.
Methane can be produced geologically by cryovolcanoes, oxidation of iron, and serpentinisation. Olivine is a mineral on Mars that can react with water to form methane.
It is more likely that methane is the product of what is known to be available for its production than from what is not. Methane is evidence that the geochemical process of serpentinisation is occurring. Sure enough, all of the components are present to make it happen. This is not evidence for life except in the biased thoughts of those who want life to be found on Mars.
