How can a non-physical God create a physical universe? I was just curious on how God could create a universe of physical matter when God is a non-physical being to begin with. How can a non-physical being create physical matter? Thanks if anyone can answer this question ;)
Your question is a creative one and as humans we tend to think in human terms. 

In our day however we have a greater capacity of understanding how such things could even be possible. 

I'm going to use the example of computer games as what might be a humanly relatable comparison. I'm usually not one to use elaborate world-oriented illustrations, but this time I will.

Think of a programmer, and a computer. Perhaps even a game, with a character in it.

The environment is completely virtual, and yet its perfectly possible for it to reflect any system or idea the programmer may wish to present. On a very simple level we can emulate reality through  a game, or even invent our different realities. We can interact with it through a window (monitor or television), and yet even that requires a high level of abstraction and visualization. 

If humans can do this with a machine, we could even present the idea that we are ourselves in an environment created by a master programmer, complete with laws of cause and effect, intelligent characters locked into the game, and even characters separate from it, controlled from the outside. Our human characters have the capacity to experience the world in pre-programmed ways through our senses (and really, our senses are just translators for environmental events, which are little more than information).

This idea is not too far fetched:

Psalm 139:16


  Your eyes saw my unformed body; all the days ordained for me were
  written in your book before one of them came to be.


Some believe this could even loosely refer to matters of DNA, but it implies a design by a higher authority on both events and physical matters.

Luke 10:20


  However, do not rejoice that the spirits submit to you, but rejoice
  that your names are written in heaven."


Luke 12:7


  Indeed, the very hairs of your head are all numbered. Don't be afraid;
  you are worth more than many sparrows.


You can look through a technological window (the television or monitor) and see the character's gaming world just how it should be perceived. We could speculate that the spiritual realm (where God himself resides) can see us the same way, and even interact with it, the same as many might interact in an online game. Thus we have stories of angels materializing, and things such as miracles (and even sorceries)...created by higher beings who understand the programming, and even have the capacity to exploit it for better or worse. 

Creation is in a way a giant program of cause and effect, the programming of which we ourselves know we can alter. Thus even in the bible, you have the stories of the nephilim: Genesis 6:4 where wicked angels corrupted God's creation to an extreme. 

So from even our human understanding shows that its perfectly possible to create one realm from another realm as in my gaming example.



Origin of physical matter...

In my personal opinion its easier to picture the creation of a physical realm from a spiritual realm, than a spiritual realm from a physical one.

We know that God resides in a source of light so powerful it can't be approached:
1 Timothy 6:16


  who alone is immortal and who lives in unapproachable light, whom no
  one has seen or can see. To him be honor and might forever. Amen.


By way of comparison today, we know that when matter decays it takes the form of electromagnetic radiation, and we know light is a visible spectrum of electromagnetic radiation. So we know that the source of matter is energy (we could loosely refer to as "light"), and we know that God is the source of energy itself, and is often associated with light. 

Even modern day "big bang" theory has energy as the dominant player, creating the rest of the physical world and reality we know. So its not hard to put an intelligent director (and source) behind that energy that defines our universe. 

And yet our universe we can see is only a small part of the bigger picture: 


  26:14 -  Behold, these are but the outskirts of his ways, and how
  small a whisper do we hear of him! But the thunder of his power who
  can understand?”