The book of Enoch explains all of this. This was a known and accepted as Canon in the days of Jesus and even quoted in the Bible. This was not accepted in the Bible because of its violent and disturbing content and now there are various versions of it so it may not be completely accurate word for word.
UFOS and aliens are not the great delusion.
I am sorry but it was never accepted as canon. The book of Enoch is NOT quoted in the Bible.
I have always thought Islam was the great delusion.
I’ve been considering reading the book of Enoch simply out of curiosity. I think one needs to be careful though and keep everything through the lens of the Bible.
The Book of Enoch is not included in the KJV of the Bible, so many Christians are not acquainted with it.