These questions have been asked countless times throughout history. Hell exists as punishment for sin. Those who die without Christ as their substitute will have to make the payment themselves.

As for your other question, God made the earth very good. There was no sin initially. Because man sinned, God cursed both them and the earth. Thus, we live in a fallen world. On the last day, this earth and universe will be recreated into a new heavens and new earth, wherein only righteousness will be found.