Our planet earth is really a tiny bit of astronomical dust circulating around a little star called the sun, which in turn is whirling around the outer rim of our galaxy called the Milky Way. Our immense Milky Way galaxy, which has a huge black hole in its center, is about to be crashed into by another nearby galaxy called Andromeda, which is hurling toward us at about 700,000 miles an hour. However, Andromeda is still about 750,000 light years away, and therefore the crash is scheduled to occur around 12 billion years from now. When the crash occurs, however, there is not much of our planet expected to be left, especially when the black hole of Andromeda merges with our own Milky Way's black hole.
Someday the world as we know it is going to end. Either this could happen in a natural way, perhaps with the Andromeda crash, or with our earth's having a life-killing collision with a meteorite, or with human madmen exploding nuclear or thermonuclear weapons, or with a shift in the polar tilt, or with a major movement of the tectonic plates, etc., or it could happen otherwise in a supernatural and miraculous way. But, end someday it shall (2 Peter 3:12-13). It might occur tomorrow or the next day or it might happen millions of years from now. The main feature, of course, at the end of the world will be the return of Christ to be our Judge (Matthew 25:31-46). For this coming of His, our divine Master has warned us always to be ready and prepared (Luke 21:25-36; John 12:48; Acts of the Apostles 24:15).
At the end of the world just as at the end of our lives, Jesus, our Savior, will come to us. Each year in the weeks before Christmas, in the season called Advent, as we prepare to welcome Christ to be born by grace anew in our souls on the Solemnity of His Nativity, we also are invited most appropriately by the Church's liturgy to prepare for his definitive return at the end of our earthly existence and at the end of time. At each Mass, although we say that "we await with joyful hope" His coming in the future, professing also in the Creed our belief that "He will come again in glory to judge the living and the dead", we are able to experience as well, in sacramental reality here and now, a true anticipation and genuine foretaste of that Parousia, that end-time. Each Holy Communion is a "pledge of future glory" (John 6:55), when Christ, Who will come one day in the clouds of heaven accompanied by His angels, comes now to us, and "through our lips which utter sin, the King of glory enters in."
Speaking of Advent and of the final "coming" of the Lord, the Catechism of the Catholic Church says, "The last judgment will come when Christ returns in glory. Only the Father knows the day and the hour. Only He determines the moment of its coming (Mark 13:32-33). Then, through His Son, Jesus Christ, He will pronounce the final word on all history. We shall know the ultimate meaning of the whole work of creation and of the entire economy of salvation and understand the marvelous ways by which His providence led everything towards its final end. The last judgment will reveal that God's justice triumphs over all the injustices committed by His creatures and that God's love is stronger than death. (Song of Songs 8:6)."
Preaching one time in Advent on verses 12 and 13 of Psalm 95, the Great Doctor and Bishop of Hippo in North Africa, Saint Augustine, said, "The Lord has come the first time, and He will come again. Previously He came through His preachers and He filled the whole world. Let us not resist His first coming so that we will not dread His second. What then should a Christian do? He ought to use this world but not become its slave. What does this mean? It means having as though not having (1 Corinthians 7:29-31)."
He goes on to say, "He who is without anxiety waits without fear until His Lord comes. For what sort of love of Christ is it to fear His coming? Brothers, do we not have to blush with shame? We love Him, yet we fear His coming. Are we really certain that we love Him or do we love our sins more? Therefore, let us hate our sins and love Him Who will exact punishment for them. He will come whether we wish it or not. Do not think that because He not coming just now, He will not come at all. He will come you know not when, and provided He finds you prepared, your ignorance of the time of His coming will not be held against you."
The Saint says further, "These are the (Advent) sacrifices most pleasing to God: mercy, humility, praise, peace, and charity. Such as these, then, let us bring and, free from fear, we shall await the coming of the Judge, Who will judge the world in equity and the peoples in His truth."
Pope Benedict XVI says, "Advent is a Latin word that can be translated as ‘presence' or ‘coming'. In the ancient world it was a technical term, denoting the arrival of a person of high office such as a king or an emperor. It could also indicate the coming of a deity, in which case the god's advent was his emerging from concealment and making his presence known in power or else having it solemnly celebrated in an act of worship. Christians took over this word in order to express their particular relationship with Jesus Christ. For them He was and is their King Who has entered their wretched province, the earth, and enables it to celebrate His visit." The Holy Father notes that for a Christian Advent should be a time "of great joy, a personal Advent, preparing for a visit from God Who wants to enter my life and turn toward me… when, through faith, hope, and love, He wants His light to shine over and over again in the night of this world."
Saint Andrew of Crete preaching about Advent said, "He is coming Who is everywhere present and pervades all things. He is coming to achieve in you His work of universal salvation. He is coming Who came to call to repentance not the righteous but sinners, coming to recall those who have strayed into sin. Do not be afraid. Receive Him with open, outstretched hands, for it was on His own hands that He sketched you. Receive Him Who laid your foundations on the palms of His hands. Receive Him, for He took upon Himself all that belongs to us except sin, to consume what is ours in what is His. Be glad and fear not. Glorify Him for His mercy…. Rejoice exceedingly.. sing and leap for joy…"
Remember the closing words of the Holy Bible: "Come Lord Jesus. The grace of our Lord Jesus Christ be with all. Amen." Don't worry about Andromeda!