Here's a thought.. Window, or Gate like when the waters above pored down after God opened the Firmament to flood the whole earth. The edges may have a bit of frost, or frozen waters that remained after the flood gate was shut.. IMHO I asked God, about this so called rift, and the answer I gave is what the spirit gave me. Ever heard of frozen O², its light blue when frozen solid, maybe that is what the firmament is made of?. That's what I think..