Quote Originally Posted by Elias0returned
The Day of the Lord (Malachi 4:5) is to be preceded by the Three Days of Darkness; they are related but separate occurrences.
"The prophecy of three days of darkness is not in the Book of Revelation but in the revelations of the end times provided by Catholic prophets St. Caspar del Bufulo, Blessed Anna Maria Taigi, Blessed Elizabeth Canori-Mora and Blessed Mary of Jesus Crucified. These holy Catholics of the 19th century, the last two of whom Pope John Paul II beatified".
(from one of the search links you provided)

I am completely uninformed on such "prophets" so I will politely refrain myself from further discussion on the subject.

However, this:

Quote Originally Posted by snoop
How can one tell that the Heavens have shaken? The earth can shake sure, but how can you tell whether the sky shakes or not? Seems kind of like an impossible thing to begin with. If you interpret it as the earth shaking, making the sky look like it's shaking, then why don't all earthquakes count?
I find more interesting.
No, it is not earthquake in question, but "heaven-quake".
Imagine this, really not hard considering lines the scinece has gone: let's say someone overheat ionosphere: what would happen to the skies?

I could give you several more ideas, completely different (like kind of ionospheric overheating or wrecking havoc overthere by scientific means, or some strange kind of "collective merging" of dream and real-outer world awareness-perception, like dreaming (awake?) dreams or seeing (awake) visions... etc.), but I will ask only this instead, more down-to-earth: let's say you live a milenia ago and someone teleports you into todays world, into your city here for example. As night approaches, you will for the first time find yourself below the "fallen sky" - so little stars in urban area had never been seen (yes, we call it light pollution), and to someone from previous centuries - all (almost) the stars from heaven had fallen down to earth: they cannot be seen in the sky because all on earth is so much lighted-up. Ok, I am aware that this explanation can be thought of as oversimplifyed, but it cannot hurt to put oneself in the shoes of people who wrote these things and the times they wrote it.

As I've sad, you posed an interesting (and really, in my mind, not so unimportant) question. . .