The prophecy as mentioned above speaks of things descending from space upon the Earth and not falling upon the Earth. Falling of things that invoke such fear and dread could only indicate a Comet or Asteroid on a collision path with Earth. However it is not Falling, but Coming which the prophecy speaks of, so what other than a Comet could possibly come to the Earth; Aliens, Alien Spaceships, Alien Landing, Alien Invasion.
The other possible interpretation could be that about Inter Continental Ballistic Missiles carrying nuclear warheads or warplanes carrying nuclear warheads. However most prophecies; including those from the Bible and Nostradamus describe warplanes as birds of prey and missiles as comets with a long tail or as a spark in the sky or in such similar terms. They also describe them as coming from the skies and not as coming or landing upon the Earth from space.
There are numerous other Bible and Nostradamus Prophecies relating to and descriptive of Aliens which I have earlier described before. Nevertheless, this one looks like an obvious prediction about an upcoming Alien Landing. This could even be the same prophecy of Nostradamus about the discovery of the thing that lies hidden being uncovered.
The timing of this yet to be fulfilled prophecy has to be decoded and decoding is not that simple, this could be an event, which comes without any warning, and right out of the blue. The world learns about these things just as they are about to land on Earth.