Where does the matter of the universe come from? The first question to answer is what matter really is. Matter is really “frozen” or condensed energy, like a ray of light that’s wrapped up upon itself like a phone cord SNAFU. Energy comes in two forms: kinetic, and potential.
One form of kinetic energy exists as the free wave/particle dual entities we call photons, which in empty space can only travel at exactly the speed of light relative to all other observers. This means photons can never exist confined in atoms.
Another form of kinetic energy is bound up as particles with mass, which always travel below the speed of light. Under certain conditions particles are formed from the kinetic energy of the collision of other particles.
Kinetic energy is momentum, and momentum is mass times velocity. So whatever excess energy is left over after the creation of these particles is carried away in the velocity of the resultant particles, which we experience as the heat of a nuclear reactor, for example. Heat is really motion.
Potential energy is stored by the relative position of two particles within each other’s gravitational field. It is a negative number that exactly equals the kinetic energy that would be released if the particles were allowed to collide. If you have a rock on the top of
a hill, it has potential energy, and when it rolls down the hill and strikes a wall, the force it delivers is a positive number exactly equal to the negative potential energy that rock had when it was sitting up there on the hill. So the sum of these two energies is zero.
Now if you add up all the kinetic energy of the universe which is in the form of light, matter, and the motion of that matter, and then subtract all the potential energy from the gravitational fields of all that stuff, the total sum of the energy of the universe is zero. That is, NOTHING!
The universe is nothing, it comes from nothing, and if we see something it is only a temporary blip, like a vacuum fluctuation but on a much larger scale.