Evidence of God

In Alma 30 (http://scriptures.lds.org/en/alma/30) the prophet Alma
provides evidence of God.  He confronts Korihor who has been teaching
that God does not exist and that Christ will not come.  In verse 44
Alma says to Korihor:

Will ye say, Show unto me a sign, when ye have the testimony of all
these thy brethren, and also all the holy prophets? The scriptures are
laid before thee, yea, and all things denote there is a God; yea, even
the earth, and all things that are upon the face of it, yea, and its
motion, yea, and also all the planets which move in their regular form
do witness that there is a Supreme Creator.

In addition, if this is not enough, we can pray to God and ask for a
witness to our souls.  Here is what the prophet Moroni
(http://scriptures.lds.org/en/moro/10) counseled:
 4 And when ye shall receive these things, I would exhort you that ye
would ask God, the Eternal Father, in the name of Christ, if these
things are not true; and if ye shall ask with a sincere heart, with
real intent, having faith in Christ, he will manifest the truth of it
unto you, by the power of the Holy Ghost.
 5 And by the power of the Holy Ghost ye may know the truth of all things.

As I have read the scriptures and prayed about them, I have received a
confirmation from the Holy Ghost that they are true. In fact each time
I read the scriptures I get a feeling that confirms to my soul that
they are true witnesses of God's existence and of the divinity of
Jesus Christ.  I use the same process when I do scholarly studies. I
read as much as I can.  I ponder (or think) about what I'm studying.
I may draw a word map. Or write about what I'm reading.  Things fit
together. And then my mind confirms this is true. I believe that is
how the Holy Ghost inspires and bears witness.

Picture: Astronomy Picture of the Day, Pinwheel Galaxy