littleguru said:
But the important fact, which is not vague, is that methane is a volatile gas which quickly gets destroyed in the Martian atmosphere... So, some process is putting it in the atmosphere at rates that suggest it still exists... Geologic or Biologic, something is going on deep inside Mars that is surprising. What I don't understand is how spectroscopic analysis of the Martian atmosphere missed this. Why now? What about 20 years ago?