For sure !
And maybe life could exist and be based on methane, or be even more complex and have a complete different form such as global consciousness based on things that have a complete different form.
I very like halo universe and comparing to, there was a species that was very advanced, they are called forerunner, they look like a bit a mix between a human and a reptile. The forerunner made the halo (A technology to ~kill life in universe). But they where destruct by the flood, a specie that is composed by individual specie that form a kind of a global consciousness a bit like an anthill.
What i like the most in Halo, is the complete story about, a long time ago, human where more a lot more advanced than now and had a war against the forerunner, but humanity has lost against these human/reptiles aliens so they decided to reduce humanity to homo-sapiens evolution level.
What i like is the completeness of the story.
But from that point humanity has revolved and between this time forerunner have been destroyed by the flood. (The story suggest that we cloud have been made from theses forerunner).
So after humanity revolved they had a problem against the covenant alliance, that is a group of some species containing elites and other species such as the grunts that lives on a methane based planet.
But the covenant alliance has lost due the internal conflict they had, a lot of elite joined human to fight against the alliance that was very hierarchical and where they would destruct all life.
Apparently flood are a transformation from a very peaceful species that where so advanced that they haven't a physical body or where nearly without constraints, after some unknown event they turned into a species with a physical body often an host and at the inverse became not peaceful and conquerable.
Apparently these flood where they was advanced and peaceful where a lot more clever than forerunner and so advanced that they have saw/created forerunner and human, they where the creator/destructor of the universe.
Some illustrations:
Forerunner (Pre-Human ?)
Flood (As destructor statement )
Grunt (Methan based specie forcefully added to the covenant alliance)
Ancient humanity (before have been destructed/reduced by forerunner)
Forerunner planet
Human planet(s)
A Halo
Earth planet (humanity)
Reach planet (humanity)
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Halo universe has a lot inspired me, for sure it's fiction but some things are nearly more realistic if we search deeper and i find the universe awesome, it has a lot open my imagination.