What about this Christian thing, the Trinity?  They say they have one God.  "Trinity" isn't in their book, The Bible.

This is true that the word isn't in The Bible, but the concept is.  Let me explain.
1.  There is one God
2.  God in heaven is God, of course.
3.  The Holy Spirit of God accepts worship as god and is the creator of the universe.
4.  The Angel of the Lord, who was later known as Jesus the Messiah, accepted worship as god and forgives sins.
5.  The three of them interacted with each other and supported each other.  Thus they were called, the "triple unity" or "trinity" for short.

This is nonsense.  Do you have one God or three gods?

Bear with me.  There are three different aspects of the same one God.  I can be a man with my woman, a father to my children, a businessman and a protector of my family.  But I am still one man.  So it is with God.

Wait a minute, how could Jesus die on the cross and the universe keep running if he was god?

There's another matter you haven't considered.  God is free of time; we are slaves to time.  God can go anywhere and anywhen as often as he likes.  We are dragged through time like a car being dragged through an automatic carwash.  We have no other experience.

God can indwell each Christian currently on Earth with no problem.  He just goes to the place and time he or she received Jesus as their Lord and savior and remain with him or her for the rest of their lives.  And go back in time to do the same thing for the next Christian.  And so on.

This is why Jesus could be dying on the cross, the Holy Spirit could be keeping the universe going and God the Father could be presiding over the whole thing -- all at the same time.  And there still is only one God.

I dunno ... this is weird.