“We usually say that nothing can be created out of nothing because we think it would violate the law of conservation of energy,” a hallowed principle in physics holding that energy can neither be created nor destroyed, Vilenkin explains. So how could you create a universe with matter in it, where there had been nothing before?
“The way the universe gets around that problem is that gravitational energy is negative,” Vilenkin says. That’s a consequence of the fact, mathematically proven, that the energy of a closed universe is zero: The energy of matter is positive, the energy of gravitation is negative, and they always add up to zero. “Therefore, creating a closed universe out of nothing does not violate any conservation laws.”
What Came Before the Big Bang? | DiscoverMagazine.com
“The way the universe gets around that problem is that gravitational energy is negative,” Vilenkin says. That’s a consequence of the fact, mathematically proven, that the energy of a closed universe is zero: The energy of matter is positive, the energy of gravitation is negative, and they always add up to zero. “Therefore, creating a closed universe out of nothing does not violate any conservation laws.”
What Came Before the Big Bang? | DiscoverMagazine.com