The Bible doesn't tell us exactly where heaven is; it simply tells us that heaven is real, and is far more beautiful and glorious than anything we'll ever experience in this life. The Bible says, "No eye has seen, no ear has heard, no mind has conceived what God has prepared for those who love him" (1 Corinthians 2:9).
This indicates heaven isn't a part of anything our satellites or telescopes will ever see, nor is it a place our rockets or spacemen will ever visit. This doesn't mean heaven isn't real -- because it is. But when we get to heaven, we'll be experiencing life on a whole new level -- life that will never end, because sickness and death will be destroyed. We'll even be given new bodies (like that of Jesus after His resurrection) which will never get tired or sick.
But an even more important truth about heaven is that we will be with God, and with Jesus Christ. Think of it: We will be with God! The Bible says, "The throne of God and of the Lamb (Jesus) will be in the (heavenly) city, and his servants will serve him" (Revelation 22:3).
The most important fact about heaven, however, is this: We can go there! Sin separates us from God -- but Jesus Christ came to take away our sin and open heaven's door for all who believe in Him. My prayer is that you will ask Jesus to come into your heart today -- and that some day you and I will meet in heaven.