What is the difference between the old heaven/old earth and the new heaven/new earth?

First, let’s look at verses that tell us this is going to happen. We’ve read them before, but they’re worth repeating. At the beginning of Revelation 21, we read this: Then I saw a new heaven and a new earth, for the first heaven and the first earth had passed away, and there was no longer any sea. I saw the Holy City, the new Jerusalem, coming down out of heaven from God, prepared as a bride beautifully dressed for her husband. And I heard a loud voice from the throne saying, “Now the dwelling of God is with men, and he will live with them. They will be his people, and God himself will be with them and be their God. He will wipe every tear from their eyes. There will be no more death or mourning or crying or pain, for the old order of things has passed away”—Revelation 21:1-4. The Greek word for new in this case is KAINOS (kahee-nos^), and it means: new, as opposed to old or former, and hence also implying better; also meaning renewed, made new, and therefore superior, more splendid—the sense in which it is being used here. It is the same word that is used by Paul when he says, Therefore, if anyone is in Christ, there is a new creation; the old has gone, the new has come!—Paul, II Corinthians 5:17. And the Bible teaches that this is necessary. When sin entered into the world, not only did mankind fall; the whole of creation fell. That created two very different realities: the perfect spirituality of heaven and the fallen sinfulness of earth. Those two are now separated as a result of sin. Sin also brought death—not only to man but to the planet as well. Plants die, as do animals. In fact, Paul said it this way when speaking of nature: The creation waits in eager expectation for the sons of God to be revealed. For the creation was subjected to frustration, not by its own choice, but by the will of the one who subjected it, in hope that the creation itself will be liberated from its bondage to decay and brought into the glorious freedom of the children of God. We know that the whole creation has been groaning as in the pains of childbirth right up to the present time—Paul, Romans 8:19-22. That creation includes the entire universe. What does that “groaning” look like? How about weather—hurricanes and tornadoes, blizzards, droughts, flooding rains? What about earthquakes and volcanoes? All these are pictures of a creation that is groaning, which in the Greek is SUSTENAZO (soo-ten-ad^-zo), which literally means to moan jointly, to experience a common calamity. When Paul mentioned that I declare to you, brothers, that flesh and blood cannot inherit the kingdom of God, nor does the perishable inherit the imperishable. . . . For the perishable must clothe itself with the imperishable, and the mortal with immorality—Paul, Romans 15:50, 53, he was referring to more than just us. The entirety of creation must be changed—and it will!