3 Our Lord Jesus Christ, then, comes from heaven; and He comes with glory at the end of this world, in the last day. For of this world there is to be an end, and this created world is to be re-made anew. For since corruption, and theft, and adultery, and every sort of sins have been poured forth over the earth, and blood has been mingled with blood in the world, therefore, that this wondrous dwelling-place may not remain filled with iniquity, this world passes away, that the fairer world may be made manifest.
And would you receive the proof of this out of the words of Scripture? Listen to Esaias, saying, And the heaven shall be rolled together as a scroll; and all the stars shall fall, as leaves from a vine, and as leaves fall from a fig-tree . The Gospel also says, The sun shall be darkened, and the moon shall not give her light, and the stars shall fall from heaven . Let us not sorrow, as if we alone died; the stars also shall die; but perhaps rise again. And the Lord rolls up the heavens, not that He may destroy them, but that He may raise them up again more beautiful.
Hear David the Prophet saying, You, Lord, in the beginning laid the foundations of the earth, and the heavens are the work of Your hands; they shall perish, but You remain. But some one will say, Behold, he says plainly that they shall perish. Hear in what sense he says, they shall perish; it is plain from what follows; And they all shall wax old as does a garment; and as a vesture shall Thou fold them up, and they shall be changed. For as a man is said to “perish,” according to that which is written, Behold, how the righteous perishes, and no man lays it to heart, and this, though the resurrection is looked for; so we look for a resurrection, as it were, of the heavens also. The sun shall be turned into darkness, and the moon into blood. Here let converts from the Manichees gain instruction, and no longer make those lights their gods; nor impiously think, that this sun which shall be darkened is Christ. And again hear the Lord saying, Heaven and earth shall pass away, but My words shall not pass away; for the creatures are not as precious as the Master's words.
Source: Catechetical Lectures (New Advent)