The Scriptural expression "heaven and earth" means all that exists, creation in its entirety. It also indicates the bond, deep within creation, that both unites heaven and earth and distinguishes the one from the other: "the earth" is the world of men, while "heaven" or "the heavens" can designate both the firmament and God's own "place" - "our Father in heaven" and consequently the "heaven" too which is eschatological glory. Finally, "heaven" refers to the saints and the "place" of the spiritual creatures, the angels, who surround God.
Source: Catechism of the Catholic Church (Vatican.va)