I love astronomy, but haven't enough time to spend for it.
I have an assumption regarding sky.
The density of the universe determines its shape. It could be spherical, saddle-shaped or flat.
so,the universe could be of different shapes. if the universe is dome shaped, sky would be dome too.
but here ibn taimiya said that,sky is round and it's the opinion of the majority https://islamqa.info/en/118698
before qiyamah solid sky will break down and fragments of it will reach earth through worm-holes or such portals,as space -time will be severely distoryed.and may be we will be able to see rifts on sky then,because light can pass through worm-hole too.
however, sometimes it seems that,human has already encountered a rift https://www.youtube.com/watch?v=hdqZLYyKF0g