Before the world began, God was telling a story. When he created the universe, his space and our space completely overlapped, but when sin entered the world, we were separated from God. So God sent his Son Jesus Christ to live a perfect life, save us from sin, and reunite Heaven and earth. Because of the resurrection of Jesus, we look forward to the day when we are reunited with God perfectly. Until then, we live and pray in for things on earth to be as in heaven.
Watch the video, "Learn Where Heaven and Earth Overlap," by the Bible Project.