According to the popular Big Bang theory, the universe existed as a very tiny, super compressed something called the singularity that popped and released the ever expanding universe from within.
According to recent Quantum theory, the universe that we thing is so solid, is actually just a big hologram.
So when you combine the two, you get the idea that the singularity was a light that suddenly got switched on.  Leaving the obvious questions:
What was the light?
Who or what switched it on?

Of course, if there never was a singularity, than we come up with something very different.  Then we have spiritual light from spiritual dimensions such as heaven, suddenly being split, or lowered in frequency, and descending to form a lower dimension of existence, the material universe.  And the cause of it happening was what we know of as "the fall", when Lucifer and his followers decided to create on their own rather than follow God's plan.  So now we have a place for the light to come from and a reason that it happened.  Two thing missing in the current scientific theory.