No it is not an ether.
Why not? An invisible, odorless realm that affects gravity and light. Whys it not an ether?
If it isn't an ether, is it an ester? Maybe a ketone?
I don't really "get" dark matter. Having spent time in caves, I don't consider normal matter "luminous", unless excited.
Is it not just 'regular' matter that is cold, as in near or at zero K?
Can you enlighten?