Greetings all.
The following is my opinion:
Are the day and night defined? By what?
If the sun defines them, then Day is sunrise to sunset, and night is sunset to sunrise?
Obviously there are different parts of the day and there are different parts of the night.
If I lived in the parts where the sun does not set? I would fast until before I go to bed. Eat and drink ,go to bed( 4/5hours or whatever minimum sleep one requires) Eat when I get up, then carry on with my fast until I next go to bed . My Salat will also follow a similar pattern to the nearest country where the sun is setting. ( Example: Scotland?)
Of course I would try to keep asking GOD for help and guidance, knowing that GOD knows my situation .
God always knows our intention. He is Forgiver most Merciful.
GOD bless you.
Peace.