There could be beings from other planets somewhere. That would be God's business. God knows that our limited brains are incapable of figuring out Revelations, muchless other things (of His) that are beyond our reach and comprehension. So maybe, He doesn't share things He knows we are incapable of understanding. Because of humanity's inherent pride and self-centeredness, we tend to assume that we should know everything. We try to minimize God's realm in order for our little brains to understand it.