>What are Islam's views on aliens, other planets and the possibility of life existing outside of Earth?
Allah is the Lord of ALL that exists, including aliens, planets, worlds, dimensions, multiverses, alternate realities etc etc that theoretically may or may not exist outside of the scope of man's perception and earth.
So it doesn't matter if an alien race light years away believe in some space deity or religion, if Islam is presented to them and they submit, they are Muslim and if they reject it, they are kufaar.
The same would apply to another human living in another dimension or multiverse, the race/species is irrelevant, the location is irrelevant.
The created being in their respective world(s) and existence is one of two types Muslim or Kaafir (which means any and all things other than Islam).