I feel like I’ve been neglecting the literary side of this blog for a while now and will remedy that in the near future. However, today I want to address a conceptual problem in the (often theistic) claim that the universe could not have appeared out of nothing because that is a violation of physical laws. Well, guess what? It’s not.
I’ll try keep this post short and easy to understand, so just keep in mind there are decades of scientific study and evidence going into this, and it is in no way as simple as I can make it seem. Let’s start from the beginning.
Matter, antimatter, and photons all consist of positive energy. However, this energy is exactly balanced out by the negative gravitational energy of the everything in the universe. Essentially, we have a universe where the total energy is zero (J.M. Pasachoff and A.V. Filippenko, 2001). If you remember Einstein’s famous equation, you’ll know this means all matter is also equal to zero. Basically, we live in nothing, but fortunately, the nothing is separated into the positive and negative parts. To use Stephen Hawking’s analogy, it’s like a man building a pile of dirt on a flat land. As he digs up dirt, the pile of dirt is exactly the same size as the hole he is digging. They balance each other out.
Now to see why gravitational potential energy is considered negative because potential energy is considered negative by convention in science. A quick explanation for you guys would be to consider this: an object at rest an infinite distance away from a source of gravity will be said to have zero kinetic energy (as it is resting) and zero gravitational energy (as it is infinitely far away, so it does not experience gravity). As the object gets closer to the gravitational source, it gains kinetic energy (by moving towards it due to the attraction), but this energy is exactly balanced out by the negative gravitational energy. This energy is negative because to counteract the energy of the system, you would have to put in more energy (to push the object away from the gravitational source). If you have to add more energy to get back to zero, then the potential energy of the attraction is obviously negative.
Together, this is known as a zero-energy universe and, along with inflation, suggests that all that is needed is a tiny volume of energy to get things started and the universe will experience inflationary expansion without creating net energy. So essentially, the universe is still nothing, just in positive and negative states (where we live in the positive state).
Well, those of you that are sharp enough to pick up on the details will be asking “where did this tiny volume of energy to get things started come from?” which would lead you back to the original question, how to get that little something from nothing? Here comes the Heisenberg Uncertainty Principle. This is a long established scientific law that allows for particles and antiparticles to appear out of nothing and then annihilate each other without violating conservation of energy. These pairs are known as virtual particles and appear in a process known as quantum fluctuation. Studies have shown quantum fluctuations to appear everywhere at all times, so really, something is appearing out of nothing all around us. Although the virtual particles annihilate each other, they leave a very real effect on the energy levels of atoms. Originally, the Uncertainty Principle (part of quantum theory) was to help account for experimentally measure energy levels disagreeing with predicted levels, and introduced quantum fluctuation, which had to be accounted for to arrive at correct answers.
Again, the smart ones will see where I’m going, and it’s almost done. If we understand that energy can appear out of nothing, then it is entirely possible and even likely that our universe appeared out of “nothing”. There’s possibly one last argument that can be made – the Uncertainty Principle only applies to tiny particles. Well, let’s not forget the singularity that exploded in the Big Bang was, by definition of singularity, an infinitely small point. As Hawking has said, the universe is the “ultimate free lunch”. We got it out of nothing without violating any laws of physics.
Here’s a little bonus to add on to the concept of a zero-energy universe where the positive and negative are separated. Scientists at the University of Michigan developed a mathematical model allowing a super-high-energy electron laser to rip apart nothingness (a vacuum) into its matter and antimatter components (http://ns.umich.edu/new/releases/8167). Basically, what we call “nothing” is actually a perfect balance of positive and negative components – our universe could essentially just be an expanding “nothingness” caused by quantum fluctuation.