The most common question I’m asked when describing the history of the Universe is: “what came before the Big Bang?” This is a wonderful question, and it is from questions like these that we now have a sharp picture of our cosmic evolution; however, I have found that this question is rooted in a flawed understanding of the nature of the Universe.
I should clarify that I’m not talking about “what was going on prior to the Inflationary scale,” but “how can we get our Universe from nothingness.” The answer is simple: There is no such thing as nothing!
The lonesome crowded cosmos
We think of space as being empty. To some extent, that’s accurate. If we look out into the vastness of space, we see around one atom per cubic centimeter. Not exactly a party. However, if we look for radiation left over from the Big Bang, we see that there are over 400 photons (discrete light particles) per cubic centimeter (on average). There are even ~300 neutrinos (very light particles that travel close to the speed of light) per cubic centimeter everywhere. The vacuum of empty space is teeming with stuff! Much like physicists at a party, these particles don’t interact much and therefore aren’t terribly interesting out there.
The spaces between galaxies are also full of mysterious Dark Matter and Dark Energy, which are exciting unknowns in our standard model that physicists love to use to garner more hits on their blog posts (fingers crossed!).
But these examples aren’t what I mean when I say that there’s no such thing as nothing. This is meant to show an example of how we can mis-classify space as being empty based on our mind’s bias towards things we can touch, taste, hear, smell, and see. To really see nothing in a new light, we need to get quantum, baby.
Quantum of Solace
Quantum mechanics is really a triumph of human understanding. (Nice work everyone, beers are on me.) We no longer think of particles as being discrete objects but probabilities. That last sentence should cause a furrow on your brow. The scales described by quantum mechanics are so foreign to our intuition that everyday concepts like position and speed don’t apply. Instead of saying an electron is here at point x, we instead say that there is some probability of finding an electron in some range of positions. We don’t know exactly where it is as words like “exactly” don’t mean anything in the quantum world!
So what does this have to do with the emptiness of space? Everything!
If we look at the most absolute nothingness that we can find and we zoom in to the smallest scales, we can infer that the emptiness is a hotbed of quantum activity! Particles are popping in and out of existence so quickly that you or I wouldn’t even say they existed. There is energy in the vacuum and we can see it (check out the Casimir effect for more information).
Something from nothing
Now let’s roll back the clock to “before” the Big Bang, as people who pose this question would call it. We know that our proto-Universe must have been very small, and was thus in the quantum regime. If, by some mechanism, these quantum fluctuations were amplified so that they became very large, then they exit the quantum mechanical regime and can become physical particles (as we would think of them). We call this mechanism Inflation (which my group believes we may have detected).
So it’s not that there was nothing and then suddenly there was something, but that the Universe was in a state that was governed purely by quantum mechanics. Inflation then amplified quantum fluctuations in our proto-Universe onto large scales that then became our Universe as we know it.
Because of quantum mechanics, there is no such thing as nothing.
Image of the Flame Nebula courtesy of NASA