Some answers to the question people have been asking for millennia
For as long as we’ve been a distinct species, humans have stared up at the sky and wondered where it all came from: all those points of light, the blazing sun, the silvery moon that goes from the thinnest of slivers to round fulness and then back to sliver once more, and the Earth we stand on.
Until very recently, our tiny ape-brains fabricated childish stories of gods, goblins, and ghouls. Because we grew up watching adults make things like sharp-edged flints, pointed spears, and later artifacts such as baskets, jars, swords, and jewelry, we assumed someone or something must have “made” the world we inhabit. As our mental universe revolved around our own quotidian concerns, we were simply unable to progress beyond the most simplistic myths.
Even back then, however, the myths were wholly inadequate. The problem was always one of regression. If a small child asks, “where did the world come from?” and is given the answer “our gods made it,” then the child, if it possesses any modicum of intelligence, will naturally proceed to ask, “then where did the gods come from?”
And that’s where all the mummy god and daddy god myths fall apart like a dandelion caught in a warm summer breeze.
Story-tellers tried to solve this glaring problem by inventing ancestors for the gods, and then ancestors for those ancestors, but the whole business quickly became so ridiculous that it risked straining the credulity of even the most simple-minded peasant. So grand depictions of voids and chaos were invented to distract attention from the gaping logic hole in the center of all such tales, much as contemporary entertainments attempt to mask the vacuousness of their story-lines behind grand CGI spectacles.
The problem with all god-myths is that they explain nothing whatsoever. If we introduce gods to account what we see around us, we have to account for where these gods come from otherwise we’ve merely introduced a totally pointless recursion. And if the answer is “the gods were always there” then we could skip the tediously redundant deities altogether by simply saying “the world was always here.”
Fortunately for those who are more interested in reality than in childish tales, the development of technologies since the Renaissance has gradually revealed more and more about the universe we briefly inhabit. Although telescopes were invented to provide commercial advantage by enabling a lucky few to spot ships on the horizon and thus profit from this advanced knowledge by trading in the markets, the very same instruments could be pointed up toward the night sky. By this means Galileo was able to detect moons around the planet Jupiter, discredit contemporary myth-based cosmology, and open the doors for observation-based discovery.
Since then we’ve learned that far from being located in the center of a tiny creation, we inhabit a planet orbiting one sun among billions in an outer spiral arm of one galaxy among trillions. Thanks to Hubble and others, we know this universe is continually expanding, so that the average distance between these trillions of galaxies is perpetually increasing. We are a small speck in an infinite universe.
But: where did it all come from?
It turns out there is no simple answer to this important question. From observational evidence, cosmologists can say with a fair degree of certainty that our universe began around 13.8 billion years ago. When it started, ours was a tiny universe of pure energy about 10-³⁵ meters in diameter. That’s 100,000,000,000,000,000,000 times smaller than a proton. It was smaller than anything we can detect with even the most sophisticated modern equipment.
This tiny universe then expanded very quickly so that in less than 0.001 seconds it increased in volume by 10⁷⁸ and reached the size of a large galaxy.
There’s simply no way for our brains to have any visceral understanding of events occurring at these scales. At this point in time our universe was pure energy a a level we can’t come remotely close to mimicking in today’s largest particle accelerators.
The expansion of our universe continued until the pure energy condensed into particles, most of which was annihilated in a great matter-antimatter extinction, turning back into energy again. But for reasons that aren’t yet understood, there was a slight imbalance in the amount of baryonic matter (the stuff than we now call protons, neutrons, and electrons) produced so that when the great annihilation was over there was some positive stuff left over.
And that’s what we’re all made of, all these billions of years later, in a universe that has been expanding since its first moment and is now so vast we can detect only a fraction of it. Most of the universe is now accelerating away faster than the speed of light so that we’ll never be able to see the majority of what’s beyond a current radius of approximately 46.5 billion light-years.
Most people have heard that our universe began with a “big bang,” which was Fred Hoyle’s dismissive term for the phenomenon. As a firm believer in the steady-state universe, Hoyle hated the idea of a beginning. Unfortunately for Hoyle, all the evidence points to just such a beginning, including the Cosmic Microwave Background, which is the universal bath of photons produced a few hundred thousand years after our universe got started.
Most people in the West today think our universe began as a kind of super-explosion that started everything including spacetime. Talking about “before the big bang” was believed to have no meaning, because anything existing before time existed would be a paradox.
Over the last couple of decades, however, it’s been recognized that the problem with the big bang concept is that it begins with a singularity.
We know singularities exist (they’re called black holes) so that isn’t the problem. The problem is that in a singularity, everything we know about classical physics ceases to apply. And as the big bang idea is essentially a product of General Relativity, which is a classical physics concept, it turns out we can’t really talk about those very earliest moments with great confidence. Quantum uncertainty precludes us from doing so.
Instead, quantum physics suggests a different beginning for our universe.
We know that even apparently empty space has things going on. Vacuum energy is the term for the appearance and disappearance of virtual particles that pop in and out of existence due to quantum fluctuations in the fabric of spacetime. If we had instruments capable of peering down into astonishingly tiny areas then spacetime would look a bit like agitated foam, the result of tiny virtual particles appearing and disappearing incredibly fast.
Quantum mechanics also tells us that a phenomenon called tunneling occurs. This is when a particle moves from one position to another despite being theoretically inhibited from doing so. It happens because the particle gains a tiny extra bit of energy from these quantum fluctuations that “boost” it temporarily. It’s not a theoretical issue: now that computer chip fabrication technologies are able to create circuits a few nanometers across, quantum tunneling has become a persistent challenge that chip designers struggle to defeat.
What has quantum tunneling got to do with our universe?
Well, if we consider all that vacuum energy buzzing around throughout empty space, there’s a statistical probability that at some point a tiny piece of this vacuum energy will be able to tunnel from our spacetime universe into a lower energy state. This little escapee from our universe would then dramatically expand and create an entirely new universe of its own, most likely with different physical properties to our own.
If we step back and reflect, we see that this phenomenon could well have been the way in which our own universe began: as a quantum event that tunneled from a previous universe.
Although most universes will either rapidly collapse or stop inflating or expand so fast that matter can never aggregate, a small percentage will be like our own universe and continue to inflate in a manner suitable for complex structures eventually to emerge. As the expanding universes inflate and the average density of matter drops, more such quantum tunneling events can occur.
Given that the average mass-energy density of matter in our own universe is currently around six protons per cubic meter, it may well be the case that our universe has already spawned other bubble universes. As our universe appears to be topologically flat and will therefore continue to expand forever, it seems inescapable that our universe will indeed “birth” many new bubble universes throughout its endless life.
This general idea is called Eternal Inflation. It doesn’t refer to our universe eternally growing larger; instead it means that inflation will persist eternally even if most bubble universes collapse or remain static. It only takes a few bubble universes to keep the ball rolling forever, budding off new bubble universes in their turn, a few of which will bud off new universes, and so on ad infinitum.
It has to be said, however, that while this idea solves a great many problems inherent in the big bang concept, it is presently untestable. And if something can’t be tested it can’t be proven or disproven.
Given the astonishing discoveries we’ve made over the last century and the way in which these discoveries have totally changed the way we think about the universe, it wouldn’t be surprising if new discoveries in the next couple of hundred years should lead to new ideas that will make eternal inflation seem as quaint as Copernican cosmology.
For now, however, eternal inflation is the favored child of most cosmologists.
But does it answer the question of “where did all this come from?”
Yes, and No.
Yes, insofar as it would explain very precisely the origins of our own universe and explain also why we happen to live in a universe in which the fundamental forces are such that complex organizations of matter can arise: it’s a statistical probability.
No, insofar as it can say nothing about how the very first universe got started. It may well be that our concept of time is presently insufficient to address this fundamental problem.
But one thing we can be absolutely certain about: there’s no room in any universe for invisible magical creatures that conjure up worlds much as a magician at a child’s birthday party might pull a rabbit out of a hat. Reality is far too complex and far too interesting to be reducible to tales of gods, goblins, and ghouls.
If you’re interested in delving deeper into modern cosmology I can highly recommend Alan Guth’s MIT lectures and likewise Leonard Susskind’s Stanford Continuing Education lectures, all freely available on YouTube.