I believe it's as literal as it could be for people's understanding at the time...
these events are comparable to our modern understanding of natural disasters and astrological phenomenon (i.e. black sun = eclipse; falling stars = meteor shower; mighty wind = hurricane/tornado; etc.)
but rather than a single disaster at once, they'll all be occurring at the same time...
Yes.. But the stars falling from the sky i believe is a large meteorite shower..
I believe the trigger for all these signs will be the impact of a large meteor in the sea. the energy of the impact will kick up tons of debris into space that will return to earth in the form of a massive meteorite shower.. This meteor is called in the Bible a great mountain falling into the sea burning with fire..
Revelation 8:8 "And the second angel sounded, and as it were a great mountain burning with fire was cast into the sea: and the third part of the sea became blood;"
I agree with @wildbill83 It's literal but maybe not exactly as we would understand it today. The human authors used what language and knowledge that they had to write down the revelations.
@newjaninev2 Stole my thunder. Well that many headed and horny beast that ariseth from the nether world will obey every command out of the mouth of this ho, as Satan unleashes his unholy daughter. Do not gaze upon this ho lest ye turn into a pillar of NaCl.
Earlier I said that it was literal but I might add that the Bible always contains some degree of allegory but it must all be read in context of the entire book. Its still a revelation of future truth.