Science, Religion, and the Big Bang


Physicists used to think that the universe
had existed forever, unchangingly, because that’s what their observations of the night
sky suggested. Needless to say, this view clashed with the “origin” or “creation” stories
of most major religions, which hold that the universe had a beginning. So it’s not surprising that it was a Catholic
priest, Georges Lemaître, who was one of the first major proponents of a new scientific
viewpoint – that the universe DID have a beginning. Lemaître, of course, was also an excellent
mathematician and scientist and based this conviction not (just) on his religious beliefs
but upon new experimental evidence from Edwin Hubble that showed the universe was expanding.
This evidence, combined with the mathematics of general relativity allowed Lemaître to
“rewind” cosmic history and calculate that the farther back in time you go, the smaller
the universe had to be. The natural conclusion is that everything we can currently see in
the universe was at one point in time more or less at one point in space. Lemaître called
this idea the “primeval atom”, but of course today we know it as “the big bang theory”. Except “big bang” is a horrible name – it
would be much more accurate to call it “the everywhere stretch”. Because one of the most
common misconceptions about the big bang is that it implies that the entire universe was
compressed into a single point from which it then somehow expanded into the surrounding…
nothingness? It is true that the observable universe, that is, the part of the whole universe
we can see from earth, WAS indeed shrunk down to a very very small bit of space, but that
bit of space was NOT a single point, nor was the rest of the Universe also in that same
bit of space. The explanation for this is the magical power
of infinity. The whole universe is really big – current data show it’s at least 20 times
bigger than the observable universe, but that’s just a lower bound – it might be infinite.
And if you have an infinite amount of space, you can scale space down, shrink everything
to minuscule proportions, and still have an infinite amount of space. Kind of like how
you can zoom out as much as you want from a number line, but it’ll still be an infinite
number line. Essentially, space doesn’t need anywhere to
expand “into” because it can expand into itself and still have plenty of room. In fact, this
is possible even if space turns out not to be infinite in size, though the reasons are
complicated and have to do with the infinite differentiability of the metric of spacetime… But anyway, the event unfortunately known
as the big bang was basically a time, long ago, when space was much more squeezed together,
and the observable universe, that is, everything that we see from earth, was crammed into a
very very small piece of space. Because the ENTIRE early universe was dense and hot everywhere,
spacetime was curved everywhere and this curvature manifested itself as a rapid expansion of
space throughout the universe. And although people call this “the big bang”, it wasn’t
just big, it was everywhere. And it wasn’t really an explosion – it was space stretching
out. It’s really quite unfortunate that “the Everywhere Stretch” isn’t nearly as catchy
as “the Big Bang”. Which brings us to the “big bang singularity”,
which is an even horribler name because every single word is misleading. I mean, “singularity”
seems to imply something that happened at a single point. Which isn’t at all what it’s
referring to – it SHOULD be called “the part of the Everywhere Stretch where we don’t know
what we’re talking about.” Basically, our current physical models for the universe are
unable to properly explain and predict what was happening at the very very beginning when
the universe was super SUPER scaled down. But rather than call it the “time when we
don’t have a clue what was happening, ANYWHERE”, for some reason we call it a “singularity”. This ignorance, however, does conveniently
answer the question What happened BEFORE the big bang? Because it tells us the question
isn’t well defined – back when space was so incredibly compressed and everything was ridiculously
hot and dense, our mathematical models of the universe break down SO MUCH that “time”
doesn’t even make sense. It’s kind of like how at the north pole, the concept of “north”
breaks down – I mean, what’s north of the north pole? The only thing you can say is
that everywhere on earth is south of the north pole, or similarly everywhen in the universe
is after… the beginning. But once time began, whenever that was, space
expanded incredibly quickly all throughout the universe – for a little while. Then expansion
slowed, the universe cooled, stuff happened, and after a few billion years, here we are. One thing we still DON’T know is why this
Everywhere Stretching happened – that is, why did the universe start off in such a funny,
compressed state, and why did it follow the seemingly arbitrary laws of physics that have
governed its expansion and development ever since? For Georges Lemaître, this might be where
God finally comes into the picture to explain the things science can’t. Except that experimental
evidence doesn’t actually rule out the possibility that there may indeed be a time “before” the
beginning, a previous age of the universe that ended when space collapsed in on itself,
getting quite compressed and dense and hot, but not enough to mangle up our ideas of what
time is. It would have then bounced back out, stretching in a fashion similar to what we
call the big bang, but without the “we don’t know what we’re talking about” singularity
part. So, physics may actually be nudging us back to the view that the Universe is eternal
and didn’t begin after all. In which case Professor Lemaître might have to rethink
his interpretation of the words “in the beginning.”