Timberwoof wrote:
In article ,
John Harshman wrote:

Who says water is an indicator of life? It's only claimed to be
necessary for life. Methane, as far as I know, is never mentioned.
Oxygen is the indicator of life, and if you want to suggest an inorganic
process that can make a lot of free oxygen in an atmosphere, feel free.

Only oxygen?

Yeah... it's common and it does some handy chemical reactions. But
similar arguments can be made for water.

No they can't. Unlike water, free oxygen is not common anywhere that I
know of except on earth, where it's made by life. Water is all over, a
product of inorganic chemistry.