Let’s face it: to think that the universe has a history that started with a kind of birthday some 13.8 billion years ago is weird. It resonates with many religious narratives that posit that the cosmos was created by divine intervention, although science has nothing to say about that.
What happened before time began?
If everything that happens can be attributed to a cause, what caused the universe? To deal with the very tough question of the First Cause, religious creation myths use what cultural anthropologists sometimes call a “Positive Being,” a supernatural entity. Since time itself had a beginning at some point in the distant past, that First Cause had to be special: it had to be an uncaused cause, a cause that just happened, with nothing preceding it.
Attributing the beginning of everything to the Big Bang begs the question, “What happened before that?” That’s a different question when we are dealing with eternal gods, as for them, timelessness is not an issue. They exist outside of time, but we don’t. For us, there is no “before” time. Thus, if you ask what was going on before the Big Bang, the question is somewhat meaningless, even if we need it to make sense. Stephen Hawking once equated it with asking, “What’s north of the North Pole?” Or, the way I like to phrase it, “Who were you before you were born?”
To ask from science to “explain” the First Cause is to ask science to explain its own structure. It’s to ask for a scientific model that uses no precedents, no previous concepts to operate. And science can’t do this, just as you can’t think without a brain.
Saint Augustine posited that time and space emerged with creation. For him, it was an act of God, of course. But for science?
Scientifically, we try to figure out the way the universe was in its adolescence and infancy by going backward in time, trying to reconstruct what was happening. Somewhat like paleontologists, we identify “fossils” — material remnants of long-ago days — and use them to learn about the different physics that was prevalent then.
The premise is that we are confident that the universe is expanding now and has been for billions of years. “Expansion” here means that the distances between galaxies are increasing; galaxies are receding from one another at a rate that depends on what was inside the universe at different eras, that is, the kinds of stuff that fill up space.
The “Big Bang” was not an explosion
When we mention the Big Bang and expansion, it’s hard not to think about an explosion that started everything. Especially since we call it the “Big Bang.” But that’s the wrong way to think about it. Galaxies move away from one another because they are literally carried by the stretch of space itself. Like an elastic fabric, space stretches out and the galaxies are carried along, like corks floating down a river. So, galaxies are not like pieces of shrapnel flying away from a central explosion. There is no central explosion. The universe expands in all directions and is perfectly democratic: every point is equally important. Someone in a faraway galaxy would see other galaxies moving away just like we do.
(Side note: For galaxies that are close enough to us, there are deviations from this cosmic flow, what’s called “local motion.” This is due to gravity, The Andromeda galaxy is moving toward us, for example.)
Going back in time
Playing the cosmic movie backward, we see matter getting squeezed more and more into a shrinking volume of space. Temperature rises, pressure rises, things break apart. Molecules get broken down into atoms, atoms into nuclei and electrons, atomic nuclei into protons and neutrons, and then protons and neutrons into their constituent quarks. This progressive dismantling of matter into its most basic constituents happens as the clock ticks backward toward the “bang” itself.
For example, hydrogen atoms dissociate at about 400,000 years after the Big Bang, atomic nuclei at about one minute, and protons and neutrons at about one-hundredth of a second. How do we know? We have found the radiation left over from when the first atoms formed (the cosmic microwave background radiation) and discovered how the first light atomic nuclei were made when the universe was merely a few minutes old. These are the cosmic fossils that show us the way backward.
Our experiments can currently recreate conditions that existed when the cosmos was one trillionth of a second old. For us, that seems like an absurdly small number, but for a photon – a particle of light — it’s a long time, allowing it to travel a trillion times the diameter of a proton. When discussing the early universe, we must set aside our human time norms and intuitions.
Of course, we want to keep returning as near to t = 0 as possible. But we finally meet a brick wall of ignorance, and all we can do is extrapolate our current hypotheses, looking for signs of what was going on far earlier, at energy and temperatures we can’t test in the lab. One thing is certain: very near to t = 0, Einstein’s general theory of relativity, our current theory defining the characteristics of space and time, fails.
This is the world of quantum mechanics, where distances are so small that we must rethink space as a granular environment rather than a continuous sheet. Unfortunately, no viable theory exists to characterise this granularity of space or the physics of gravity at the quantum scale (known as quantum gravity). Of course, there are contenders, such as superstring theory and loop quantum gravity. However, there is currently no evidence pointing to either of the two as a credible description of physics.
Quantum cosmology does not provide an answer.
Nonetheless, our curiosity drives us to push the boundaries closer to t = 0. What else can we say? In the 1980s, James Hartle and Stephen Hawking, Alex Vilenkin, and Andrei Linde developed three models of quantum cosmology in which the entire universe is regarded as an atom using an equation similar to that used in quantum mechanics. In this equation, the universe is a wave of probability that connects a quantum realm with no time to a classical realm with time — i.e., the universe we live in, which is now growing. The shift from quantum to classical would represent the true birth of the universe, with the so-called Big Bang being an uncaused quantum fluctuation as random as radioactive decay: from no time to time.
Is one of these simple models valid, and hence the scientific explanation for the First Cause? Could we use quantum physics probability to eliminate the requirement for a cause entirely?
Regrettably, no. Sure, such a model would be an incredible intellectual achievement. It would be a huge step forward in understanding the origin of all things. However, it is insufficient. Science cannot occur in a vacuum. It requires a conceptual framework to function, which includes concepts such as space, time, matter, energy, calculus, and conservation rules for quantities such as energy and momentum. A building cannot be built from ideas, and models cannot be built without concepts and laws. To request that science “explain” the First Cause is to request that science explain its own structure. It is to request a scientific model that operates with no precedents or previous conceptions. And science, like you, cannot do this without a brain.
The First Cause remains a mystery. You can pick religious faith as an answer, or you can trust science will solve everything. But, like the Greek Skeptic Pyrrho, you can embrace the boundaries of our reach into the unknowable with humility, enjoying what we have accomplished and will undoubtedly continue to accomplish, without the need to know and explain all. It’s fine to be left in the dark.
Curiosity is blind without mystery, and mystery is lame without curiosity.