The second Person of the Trinity became man on earth as a member of the human race. Angels are intelligent beings one of whose works is to enforce the natural law, therefore, including the laws of planetary motion and the stars.
If there were intelligent life in addition to angels they would have no relation to Our Lord Jesus Christ. They would have no relation to His Blessed Mother. They would be aliens if they were to be admitted to heaven, not being subjects of the King and Queen of heaven.
It seems impossible that there could be intelligent beings composed of body and soul that are not descendants of Adam.
OBJECTION: Fr. Faber speculates in one of his books, title forgotten, that there could be many planets with intelligent beings in space.