The Earth will be destroyed by a Supernova
Two destruction's' of the earth are described in the Bible, one past and one yet to come. The first destruction came when the Flood covered the earth in the days of Noah, sparing only eight righteous persons (Gen. 6:8). In one of the best-known promises in the Old Testament, however, signified by the rainbow, God promised Noah that He would never again destroy the earth by a flood. Nevertheless, two passages in the Bible predict that God will yet again destroy the earth.
Destruction will come by fire, after which He will restore all things (judgement day). 2 Peter 3: 10-12 says "But the day of the Lord will come like a thief. The heavens will disappear with a roar; the elements will be destroyed by fire, and the earth and everything done in it will be laid bare. Since everything will be destroyed in this way, what kind of people ought you to be? You ought to live holy and godly lives as you look forward to the day of God and speed its coming. That day will bring about the destruction of the heavens by fire, and the elements will melt in the heat."
The only thing capable of destroying the heavens, the atmosphere, and totally stripping the earth bare would be a supernova. An asteroid or comet would not be capable of accomplishing all that was mentioned; no life-form or vegetation survives, no oxygen to breath, no water to drink, nothing at all left but the sphere we call Earth.
But notice how Isaiah 65:17-25 speaks of a restored earth, one that is restored after the judgement day.
“See, I will create new heavens and a new earth. The former things will not be remembered, nor will they come to mind. But be glad and rejoice forever in what I will create, for I will create Jerusalem to be a delight and its people a joy. I will rejoice over Jerusalem and take delight in my people; the sound of weeping and of crying will be heard in it no more.
Never again will there be in it an infant who lives but a few days, or an old man who does not live out his years; the one who dies at a hundred will be thought a mere child; the one who fails to reach a hundred will be considered accursed. They will build houses and dwell in them; they will plant vineyards and eat their fruit. No longer will they build houses and others live in them, or plant and others eat. For as the days of a tree, so will be the days of my people; my chosen ones will long enjoy the work of their hands. They will not labor in vain, nor will they bear children doomed to misfortune; for they will be a people blessed by the Lord,
they and their descendants with them. Before they call I will answer; while they are still speaking I will hear. The wolf and the lamb will feed together, and the lion will eat straw like the ox, and dust will be the serpent’s food. They will neither harm nor destroy on all my holy mountain, says the Lord."
Because it is God's plan for humankind to inhabit the earth forever in fulfillment of His promises, after He does away with this planet as we know it, He will create a new heaven and a new earth, better than anything this world has ever known, including the Garden of Eden. And Revelation 21:1-4 describes what this restored Earth will be like: "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, “Look! God’s dwelling place is now among the people, and he will dwell 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.”
The new earth will be the Christian's heaven.
"Now the dwelling of God is with men, and he will live with them" (Rev. 21:3). Another characteristic of this new city is that God's Tabernacle will no longer be in the third heaven, for He will move His headquarters to the new earth and will literally take up His abode in the New Jerusalem. Whenever we read about heaven in the Bible, we should keep in mind that there are three heavens: the atmospheric heaven around the earth, the stellar heaven, which contains the great galaxies that we view on a starry night, and the third heaven, or the throne of God (see 2 Cor. 12:2 and Rev. 4:5)
So when will all this happen?
Matthew 24:36-41
“But about that day or hour no one knows, not even the angels in heaven, nor the Son, but only the Father. As it was in the days of Noah, so it will be at the coming of the Son of Man. For in the days before the flood, people were eating and drinking, marrying and giving in marriage, up to the day Noah entered the ark; and they knew nothing about what would happen until the flood came and took them all away. That is how it will be at the coming of the Son of Man. Two men will be in the field; one will be taken and the other left. Two women will be grinding with a hand mill; one will be taken and the other left."
Why would He take one person and not the other? Because one was an "elect" (a believer whom He often referred to as sheep) and the other was not. Matthew 25:31-33 says, “When the Son of Man comes in his glory, and all the angels with him, he will sit on his glorious throne. All the nations will be gathered before him, and he will separate the people one from another as a shepherd separates the sheep from the goats. He will put the sheep on his right and the goats on his left."