… is a wholly nonsensical phrase when dealing with the subject of the “beginning” of time as we know it, because time as we know it only began when the Big Bang happened, according to the Big Bang Theory. Time itself, as we know it, began at the beginning, however it’s entirely possible this universe has existed in some form or another infinitely.
This theory (by the scientific definition — a falsifiable framework that has yet to be falsified) is our current, most accurate cosmological model as to the origin of, well, existence, based on all the evidence available to scientists presently. It postulates that between 13.5 and 14 billion years ago, time itself started to be; our universe developed from what was apparently a quantum foam in a singularity (an infinitely dense particle no bigger than a single atom — remember, most atoms are mostly empty space, so you can assume that this quantum foam had no such space in it) in an extremely rapid expansion.
This could have happened suddenly, or it could have taken an infinite amount of subjective “time” outside the scope of this universe in some greater multiverse (should one exist), but we don’t know. It could also have been the result of an oscillating universe wherein the last iteration of the universe ended in a total collapse of everything that resulted in this tiny singularity made of perfect order — every quark and lepton and gluon in its initial state and not bound to anything else, a pure quantum froth without form or function and taking up almost no space at all, with no space between each quark. It could have happened because of fluctuations in some tiny part of the singularity, or it could have happened from outside influence, such as a creator deity that exists outside the scope of the universe (we’ll revisit this later, don’t worry), or several branes of the higher-dimensional “bulk” colliding, restricting the contents of the universe to three-plus-one dimensions. The point is, we’re not sure what caused the universe to start ticking, but it did. I’ll bold this next section for the benefit of certain individuals: The Big Bang theory cannot, and does not, attempt to explain how the universe came to be a singularity, nor what gave that first quark that first sideways flick. This is for other theories to work on. In much the same way that the Theory of Evolution has absolutely zippo to say about the Big Bang, the Big Bang theory has bupkes to say about how the initial state got seeded.
I’m going to link to a graphic from Time Magazine which explains how we understand the universe’s early history to have occurred (with numbers obtained from the The Kingfisher Young People’s Book of Space), as it’s a pretty good visual aid. I’ll also walk us through the process step by step through to what we understand as our universe today.
After the first single unit of Planck time, meaning 10-43rd of a second (that’s a 0, a decimal, and 42 more 0′s followed by a 1), the universe was about the size of a grapefruit, it was incredibly hot, and was still primarily made of quarks. After 10-32 of a second had passed, the universe was roughly 1027°C, much too hot for the electron stew to do anything but continue churning and swirling amongst itself. The universe was starting to cool down rather rapidly though — imagine a balloon during the initial expansion. If you’ve ever stretched an uninflated balloon repeatedly, then felt its surface, it gets quite warm just from this stretching action. It always cools off pretty quickly though, you’ll also notice. The whole contents of the universe probably got hot like this because of that expansion from the Big Bang, but as entropy only increases, and the initial singularity was the instance of pure order and that had already been thrown out the window, the universe started to cool off.
At about 10-6secs, the universe was down to a balmy 1013°C, allowing quarks to start clumping together into protons and neutrons. This is a big step forward from the superhot quark foam we started off with, because now actual stuff could start to form. It would take until about three minutes after the Big Bang, though, for the universe to cool enough for nuclei for hydrogen and helium to form from all the quarks bouncing around looking for stuff to clump to in amongst the superhot fog — and even then, it was still 108°C. This was the perfect temperature for nuclear fusion — and that perfect temperature lasted for 17 more minutes as the universe cooled, allowing for the nuclei to form for the lighter elements up to deuterium but not providing enough time for anything heavier to form. This fog was also both too dense and too hot to allow light to shine through it, if there was any light TO shine outside of the light caused by the initial burst of energy from the Big Bang.
Afterward, the universe was cool enough that not much of anything happened but further expansion, and further cooling, until about 300,000 years after the initial expansion, when the universe was a mere 10,000°C. At this point, electrons and neutrons could start bonding with the existing hydrogen and helium nuclei to form proper atoms. Other atoms formed, but the vast majority of the universe was made up of hydrogen and helium alone. This also allowed for the fog to start to clear up — light could begin to shine through it, not that there was much light around aside from the waning residual light from 300,000 years prior.
After the first billion years, the universe is now down to about -200°C, which is still pretty warm for empty space, but pretty close to how cold space is today. It’s also expanded slightly unevenly, as opposed to uniformly, causing some of the hydrogen and helium to be influenced by gravity, coalescing into the first galaxies. Within these galaxies the clumps started to fall together into the first stars. And within those stars, fusion kicked in again due to the pressure and heat generated by all the gravity-based angular momentum that built up, allowing the building of hydrogen into helium. Then, once those first stars died, in the runaway nuclear fusion reaction prior to their going kersplodey, helium was built into all sorts of the heavier elements until the star couldn’t hold itself together any more. When those first stars went supernova, they seeded their environs with the heavier elements like that which we see on Earth today, many of which being prerequisites for life.
Our sun was formed about 4.6 billion years ago (about 9 or so billion years after the Big Bang), from a giant cloud of hydrogen. In all likelihood, as we are certain that the heavier elements are present in our solar system, its collapse in on itself was sparked by the shockwave from a nearby supernova. (It could also have been sparked by gravity from a passing star, we’re not totally clear on what started our little corner of this cosmic ballet.)
As the swirling mass of gas spun and spun, it flattened into a disc shape. Like a figure skater pulling in its arms, the more it flattened and coalesced, the faster it all spun. The sun, a main-sequence yellow dwarf star, took 99.85% of the mass of the solar system, the greedy beggar. The four giant planets make up the bulk of the remainder. That’s right, all the planets combined make up 0.135% of the mass of the solar system. And the sun itself, being in the center, has 2% of the angular momentum of the solar system, where the planets, all being outside that center point, have the remainder. Everything that wasn’t fast enough to settle into a proper orbit fell into the sun or into its nearest planetary mass. The early solar system was a demolition derby, and what remains is what survived after all that time.
And yet, even now, there’s a cloud of frozen ice particles surrounding our solar system like a shell. We call this the Oort Cloud. It’s the source of pretty well all the comets that fly by us, and it could very well be where most of the water on Earth came from. We can hypothesize quite a few things about its existence, though we don’t have a lot of hard evidence about it yet. It’s thought to be the remnant of the proto-planetary disc form of our solar system. Meaning, there’s still lots of evidence of the solar system’s earlier forms that we can look at to extrapolate the actual chain of events leading up to us, here, on this pale blue dot in this vast ocean of space.
So that catches us pretty well up to today. It’s at this point that I have to point out that, as in the second paragraph of this post, up until today every single explanation of the origin of the universe has been grossly inaccurate as compared to what the evidence itself says happened. There’s a reason that I leave the door open for a creator deity to have started this universe — because we just don’t know much about its origins outside of where the evidence points and where our theories make accurate predictions, and right now, we don’t have a lot of proof that the universe is a wholly closed system (even though “universe” by definition means “everything that is”) — there could be higher-dimensional cause and effects that made the universe start up, or there could be ways that other “universes” bleed into our universe — there could be all sorts of stuff we haven’t yet figured out.
The point is, up until today, saying “the gods made that” has been a premature and incorrect proposition for every other thing we’ve ever explained away, from lightning to the sun to the order of colors in the rainbow. This universe is comprehensible. It stands to reason that the origin of the universe is comprehensible too. We might have to scour this universe for the evidence that proves ultimately that our theories are correct, but for me, as long as they go on making correct predictions and build on established science, they are the only options worth considering for the origins of this universe.
One does not need to “know everything” to realize that a deist god is extraordinarily unlikely, and that specific gods (like Thor or Wotan or Yahweh) are specifically constructs of a human mind looking for the truth and needing an anchor to hold onto when the truth wasn’t readily apparent to society’s level of scientific capability. Not only are they crutches, but they are vulnerabilities — they encourage people to use one another and kill one another in the name of a non-existent entity for whom they owe alleigance; and whom malevolent and cynical entities (e.g. The Pope, any religious figurehead of any sort) take advantage of, in order to manipulate and control others.
If you want the truth, start with the evidence, and work your way to the conclusions. If you don’t trust the conclusions others have drawn, start with the evidence they drew them from yourself. If you need to start all the way from first principles, do that. And if everyone did this, all religions would fall and all dogmas would fail, and melt away in the light of reason. We would then enter a golden age of scientific discovery where all false conclusions would be thrown out and what’s left is universally accepted — even by those who otherwise would believe in the dogmatic faiths that lead humans astray from the path of discovery.
A guy can dream.