On November 01, 1950, Pope Pius XII issued the Apostolic Constitution "Munificentisimus Deus" which officially declared the dogma of the Assumption of Mary: "We proclaim and define it to be a dogma revealed by God that the Immaculate Mother of God, Mary ever Virgin, when the course of her earthly life was finished, was taken up body and soul into the glory of heaven."
In using the phrase, "when the course of her earthly life was finished", the dogma leaves open the question of whether or not the Blessed Virgin died before her assumption. Many Catholics over the centuries believed she did not die, but just fell asleep. That is why they use the term "Dormition of the Theotokos". Still many others believe she died but was miraculously resurrected before being taken up to heaven. Both views may be considered valid and legitimate, but whether Mary had a physical death has not been dogmatically defined.
Death, in the strict sense as a consequence of punishment of sin, cannot be applied to the Blessed Mother. Being the Immaculate Conception, she is free from any stain of sin, original and personal. However, since her body is also of mortal nature, and in conformity with her Jesus, her Son, it is also subject to the general law of death. Pope St. John Paul II said that since she was united with her Son in His suffering on the cross, the logical conclusion is that she also followed Him through her own death as well, "so that she might be the more fully conformed to her Son."
God, however, cannot allow her body to undergo corruption. The first reason is because she is free from all sins. And so her body is not subject to the consequences of sin, which includes physical death and corruption. The second reason is, her body is absolutely holy and perfectly pure, having been prepared by God from all eternity to bear and nurse the Divine Redeemer. God cannot allow such a perfect and most holy body, the "New Ark of the Covenant" that carried His Eternal Son, to suffer corruption.
Hence, her body, whole and intact, is taken up into heaven together with her soul. That is why, there is not a single a relic that is said to be of Mary's actual body. The dogma of the Assumption of Mary, together with that of the Immaculate Conception, naturally and logically arises from her role as Theotokos, the Mother of God.
We may ask: what does the Assumption of the Blessed Mother mean for us? The Preface of today's Mass answers this question: "Today the Virgin Mother is taken up into heaven to be the beginning and the pattern of the Church, and a sign of hope and comfort for your people on their pilgrim way."
Mary is the beginning of the Church, for from her came forth the Savior of mankind, Jesus her Son. And being the first and most perfect disciple of Jesus, she is also the pattern of the Church. As her children, we are expected to model ourselves after the example of her holiness and complete obedience to the will of God.
Secondly, she is the 'sign of hope and comfort' for all of us on our pilgrim way to our heavenly home. Mary's Assumption should be seen, not as abandonment, but an assurance of her unceasing motherly care for all of her children. Being now with God in heaven, she has complete powers to come to our assistance at all times. As Pope Benedict XVI said: "precisely because Mary is with God and in God, she is very close to each one of us. While she lived on this earth she could only be close to a few people. Being in God, who is actually 'within' all of us, Mary shares in this closeness of God." The Catechism confirms this: "In giving birth you kept your virginity; in your Dormition you did not leave the world, O Mother of God, but were joined to the source of Life. You conceived the living God and, by your prayers, will deliver our souls from death."
Finally, the Assumption of Mary is a preview of our future glory. The Catechism states: "The Assumption of the Blessed Virgin is a singular participation in her Son's Resurrection and an anticipation of the resurrection of other Christians." Mary has shown us that heaven is our final destination. In God's time, we will all share in the glory and victory of God's children in heaven.
Let us, therefore, strive to be close to Mary while we are still in this world. Pope St. John Paul II assures us: Our Lady "knows our hearts, can hear our prayers, can help us with her motherly kindness. She always listens to us and, being Mother of the Son, participates in the power of the Son and in His goodness. We can always entrust the whole of our lives to this Mother."