Nothing 
 
Nothing is the absence of anything, a particular thing  or the inactivity of a thing or things. "Nothingness" is a philosophical term for the general state of nonexistence, sometimes reified as a domain or dimension into which things pass when they cease to exist or out of which they may come to exist. God is understood to have created the universe ex nihilo, "out of nothing"

What is this Nothingness? By definition nothing contains literally "no things" at all. In order to achieve nothingness, you'll have to get rid of every fundamental constituent of matter. Every quantum of radiation has to go. Every particle and antiparticle, from the ghostly neutrino to whatever dark matter is, must be removed.

If you could somehow remove them all — each and every one — you could ensure that the only thing that was left behind was empty space itself. With no particles or antiparticles, no matter or radiation, no identifiable quanta of any type in your Universe, all you'd have left is the void of empty space itself. To some, that's the true scientific definition of "nothingness."

 In order to achieve nothingness, you'll have to get rid of every fundamental constituent of matter. Every quantum of radiation has to go. Every particle and antiparticle, from the ghostly neutrino to whatever dark matter is, must be removed.

If you could somehow remove them all — each and every one — you could ensure that the only thing that was left behind was empty space itself. With no particles or antiparticles, no matter or radiation, no identifiable quanta of any type in your Universe, all you'd have left is the void of empty space itself. To some, that's the true scientific definition of "nothingness."

When scientists talk about nothing, there is no consensus. Language is ambiguous, and the concept of nothingness means different things to people in different contexts. "Something from nothing" can be a situation where something fundamentally arises where it wasn't there before, but not everyone will agree that "nothing" is what it arose from.

If we start with true nothingness, how does anything come into being? It would seem to be impossible. Yet things do exist. Therefore the universe could not have come out of nothing, even though there is no other explanation.

Well, there is one other explanation of sorts. That is: God is consciousness (physically that is nothing) and this conscousness created the universe witin the nothingness of its consciousness.