2 Corinthians 12:2 English Standard Version (ESV) I know a man in Christ who fourteen years ago was caught up to the third heaven—whether in the body or out of the body I do not know, God knows.

Paul speaks to the issue of the third heaven. Where are the first and second heavens?

Revelation 21:1 English Standard Version (ESV) Then I saw a new heaven and a new earth, for the first heaven and the first earth had passed away, and the sea was no more.

So the first heaven is connected to the first earth. We at one time looked up into the sky and understood the blue sky to be a heaven.

Matthew 3:16 English Standard Version (ESV) And when Jesus was baptized, immediately he went up from the water, and behold, the heavens were opened to him, and he saw the Spirit of God descending like a dove and coming to rest on him;

The sense of the heavens opening up might have been seen as the clouds parting.

The second heaven might well be defined in Matthew 24.

Matthew 24:29 English Standard Version (ESV) “Immediately after the tribulation of those days the sun will be darkened, and the moon will not give its light, and the stars will fall from heaven, and the powers of the heavens will be shaken.”

The celestial bodies which we know as the universe comprised of an untold number of galaxies would be the second heaven.

In verse 3 Paul declares that the third heaven is paradise. We can assume that this is a reference to the Garden of Eden where God walked with Adam and Eve. Interestingly Paul declares that in this place he hears things that cannot be shared, verse 4. This is a place where great secrets are kept.

Why not share those great secrets with us in the first heaven?