We can get a good feel for what the Final Earth/Heaven might be like by simply looking around at what the current Earth is like.

What does Revelation 6 teach us about life in the Current Heaven?

God is spirit, but sometimes takes on human form - especially in the person of Jesus.  And the bible often uses physical descriptions of those in the Current Heaven.  Could it be a physical place?

Heaven is where God dwells.  But the Heaven that believers in Jesus go to now is not the Final Heaven.  So what happens when we die then?

True Christian theology teaches that for a person to go to hell, no change of course is required.  Jesus teaches more about hell than anyone else, because He truly loves people and wants them to know the truth.

All people have a fear of death.  Jesus gives the answer to that fear promising eternal life with Him by grace through faith.  Heaven is where God dwells - but what is it like.  The Bible gives good pictures of heaven - it is good to try to imagine it and hope for it. 

Jude concludes his letter by giving some good safeguards against the false teachers.

The Apostles and many OT Prophets warned about future false teachers that would come.  Jude concludes they do not have the Holy Spirit and warns that they are self-serving, causing division.

Jude continues to show examples of the character of false teachers and the punishment they will undergo for their teachings that do not line up with true doctrine about God

Jude, James and Jesus' brother, writes his inspired letter to combat false teachers and contend for the faith once for all delivered to God's people.