Objection 1. It would seem that Christ did not ascend above all the heavens, for it is written (Psalm 10:5): "The Lord is in His holy temple, the Lord's throne is in heaven." But what is in heaven is not above heaven. Therefore Christ did not ascend above all the heavens.
Objection 2. [This objection with its solution is omitted in the Leonine edition as not being in the original manuscript.]
Further, there is no place above the heavens, as is proved in De Coelo i. But every body must occupy a place. Therefore Christ's body did not ascend above all the heavens.
Objection 3. Further, two bodies cannot occupy the same place. Since, then, there is no passing from place to place except through the middle space, it seems that Christ could not have ascended above all the heavens unless heaven were divided; which is impossible.
Objection 4. Further, it is narrated (Acts 1:9) that "a cloud received Him out of their sight." But clouds cannot be uplifted beyond heaven. Consequently, Christ did not ascend above all the heavens.
Objection 5. Further, we believe that Christ will dwell for ever in the place whither He has ascended. But what is against nature cannot last for ever, because what is according to nature is more prevalent and of more frequent occurrence. Therefore, since it is contrary to nature for an earthly body to be above heaven, it seems that Christ's body did not ascend above heaven.
On the contrary, It is written (Ephesians 4:10): "He ascended above all the heavens that He might fill all things."
I answer that, The more fully anything corporeal shares in the Divine goodness, the higher its place in the corporeal order, which is order of place. Hence we see that the more formal bodies are naturally the higher, as is clear from the Philosopher (Phys. iv; De Coelo ii), since it is by its form that every body partakes of the Divine Essence, as is shown in Physics i. But through glory the body derives a greater share in the Divine goodness than any other natural body does through its natural form; while among other glorious bodies it is manifest that Christ's body shines with greater glory. Hence it was most fitting for it to be set above all bodies. Thus it is that on Ephesians 4:8: "Ascending on high," the gloss says: "in place and dignity."
Reply to Objection 1. God's seat is said to be in heaven, not as though heaven contained Him, but rather because it is contained by Him. Hence it is not necessary for any part of heaven to be higher, but for Him to be above all the heavens; according to Psalm 8:2: "For Thy magnificence is elevated above the heavens, O God!"
Reply to Objection 2. [Omitted in Leonine edition; see Objection 2] A place implies the notion of containing; hence the first container has the formality of first place, and such is the first heaven. Therefore bodies need in themselves to be in a place, in so far as they are contained by a heavenly body. But glorified bodies, Christ's especially, do not stand in need of being so contained, because they draw nothing from the heavenly bodies, but from God through the soul. So there is nothing to prevent Christ's body from being beyond the containing radius of the heavenly bodies, and not in a containing place. Nor is there need for a vacuum to exist outside heaven, since there is no place there, nor is there any potentiality susceptive of a body, but the potentiality of reaching thither lies in Christ. So when Aristotle proves (De Coelo ii) that there is no body beyond heaven, this must be understood of bodies which are in a state of pure nature, as is seen from the proofs.
Reply to Objection 3. Although it is not of the nature of a body for it to be in the same place with another body, yet God can bring it about miraculously that a body be with another in the same place, as Christ did when He went forth from the Virgin's sealed womb, also when He entered among the disciples through closed doors, as Gregory says (Hom. xxvi). Therefore Christ's body can be in the same place with another body, not through some inherent property in the body, but through the assistance and operation of the Divine power.
Reply to Objection 4. That cloud afforded no support as a vehicle to the ascending Christ: but it appeared as a sign of the Godhead, just as God's glory appeared to Israel in a cloud over the Tabernacle (Exodus 40:32; Numbers 9:15).
Reply to Objection 5. A glorified body has the power to be in heaven or above heaven. not from its natural principles, but from the beatified soul, from which it derives its glory: and just as the upward motion of a glorified body is not violent, so neither is its rest violent: consequently, there is nothing to prevent it from being everlasting.
Source: Summa Theologica (New Advent)