The heaven exists too, and for mankind. The gravity pushing down on the world holds it in place, and likewise keeps mankind in place. Gravity is meant to keep mankind from the heavens and knowing all that is beyond. That was made clear when the Tower of Babel was destroyed. There are some things mankind need not know because it raises doubt.
The thought that life might exist in the heavens causes doubt of God. Why so? The world was made for mankind, but ironically the world is mankind's enemy. The world is for mankind to have tribulation (John 16:33). That is accentuated by mankind (Adam and Eve) being cast out into the world from Paradise (Gen 3:23-24). They were safe in Paradise from tribulation and even death. Outside of safety they were unsafe, and even non-accommodated. Whereas Paradise was easy (dress and keep God; Gen 2:15), the world outside was harsh (Gen 3:15-19). Paradise was for mankind and the world against him!
Although the world is mankind's enemy just as God so loved the people of the world (John 3:16), the people love the world:
Do not love the world or the things in the world. If anyone loves the world, the love of the Father is not in him. For all that is in the world—the desires of the flesh and the desires of the eyes and pride in possessions—is not from the Father but is from the world. And the world is passing away along with its desires, but whoever does the will of God abides forever.(1 John 2:15-17 ESV).Life condenses to which people love the most: God or the world. Adam soon found that he loved God more than the world because God offered eternal life and the world offered only death (Gen 3:7) soon after he realized what he had done! If you do not understand, Adam was emancipated from God by doing what he wanted to do. He usurped God's authority.
Love of the world displaces love for God. Endeavoring to love the world and God is counterproductive, and cannot be done (Mat 6:24). In effect, those who sin anoint the Devil as ruler of their life (John 8:44). Loving the world anoints Lucifer as prince of it, a contender for the throne. (Ephes 2:2).
God, by loving the world, loves its people; people by loving the world love Satan - the prince's new title. Therefore Christianity is letting loose of the world by looking up to God! The Word - Jesus - in Paradise covered our forebears' sins because covering their own was not effectual. That was merciful of God and an innocent life died that their sins were covered. That's what the Word later suffered Himself for all mankind once and for all (Heb 7:27; 9:26).
The land in the world was Eden. The Garden of Eden in the East, was safety from the world. Once mankind was out of the safety of God and on his own, there was one gate back into the Garden Paradise, and it was guarded by cherubim with flaming swords (Gen 3:24). There was only one way back in and no backdoor. The path out of Paradise was man's pathway back in. It is the Way of the Word:
Enter ye in at the strait gate: for wide is the gate, and broad is the way, that leadeth to destruction, and many there be which go in thereat: Because strait is the gate, and narrow is the way, which leadeth unto life, and few there be that find it. (Mat 7:13-14; KJV).The gate to Hell is wide and the way into Hell is broad. On the other hand, the gate, the one guarded by cherubim is straight (the Doctrine of Christ), and the Way is narrow (by the propitiated blood of Christ - the Word). The Garden, just as the Word was later to do, ascended into Heaven. The Kingdom of God was there for Christ's ascension. It's foundation remains on earth, physically, I believe, in Jerusalem. Why so? When Jesus descends again forever, New Jerusalem will return to its foundation after the world is cleansed in preparation:
And I saw a new heaven and a new earth: for the first heaven and the first earth were passed away; and there was no more sea. And I John saw the holy city, new Jerusalem, coming down from God out of heaven, prepared as a bride adorned for her husband. And I heard a great voice out of heaven saying, Behold, the tabernacle of God is with men, and he will dwell with them, and they shall be his people, and God himself shall be with them, and be their God. (Rev 21:1-3; KJV)
The world outside the Garden was unclean and troublesome. It once was washed by water to no avail since sin soon returned. In the end, the world will be washed by fire just as the sins of man were burnt as a sin offering in patriarchal times!
Whereby the world that then was, being overflowed with water, perished: But the heavens and the earth, which are now, by the same word are kept in store, reserved unto fire against the day of judgment and perdition of ungodly men. (2 Pet 3:6-7; KJV).People put too much emphasis on the world: "the desires of the flesh and the desires of the eyes and pride in possessions." The world, as scripture says, is temporal, at least in its present iniquitous state. We so love the world, but the world which we know will soon be gone. Jesus said, "surely I come quickly" (Rev 20:22).
The world is the kingdom of Satan who uses the world to tempt mankind, ultimately to diminish God. People belong to God but followed their own hearts which they gave to Satan. Thinking they were true to themselves they were being put in chains by Satan! "The flesh" is not only the person's material but also the wills, desires, behaviors, and emotions of people. The joy of pleasure is the peak experience of sinful men. Born-again is the same for spiritual men!
To overcome the world (John 16:33) is to put aside the lusts of the eyes, the lusts of the flesh, and the pride of life. Christians are to willingly crucify themselves of those things. Scripture calls that circumcision of the heart (Rom 2:29) which is the willingness to overcome the world with its lusts!
Christians are at liberty to sin or not (Gal 5:100). Obligation and intimidation to not sin is bondage! However, our willingness not to sin is the sweet aroma which God savors! God doesn't want to force mankind to be righteous. Christians are to appreciate God's sacrifice so intensely that they worship by doing His will! That is how Christians demonstrate their love for God (John 14:21). What God wants is His creatures' wills. We are to submit our will to God as a living sacrifice (Rom 12:1). That is harmonizing what we desire with what God wants. Christians, if they truly are, should want not to sin (Mat 26:41). Liberty is a choice of whether to sin or not. The Pharisees missed out on that doctrine. They tried to force people to live rightly, and increased wrongness! God isn't that way.
I want my family and friends to be righteous. I even want my enemies to be likewise so that they won't go to Hell. Christians are inclined to be good Pharisees by forcing right-living on those who prefer the world. Christians mandate love, and anyone should know that love cannot be forced on people. By being too forceful that others meet my personal standards, even which I fail to meet, I alienate those who I love. I want that none should perish but they must want that too. They must want eternal life enough that they choose God over the world.
I want that others overcome the world so much that I tend to enforce God's standards. I can teach them but others must have a desire to do God's will. They are free to choose the world over God if they don't mind going to Hell. The problem is that sinners don't believe in the reality of Hell enough to be right with God. The world is real. We know that. Christians have been spiritually informed of the reality of Hell. We know Hell is so real, that we desire never to perish; so much that we put aside lusts and pride and overcome the temptations of the world... at least we are willing to! Of course we often fail.