The Big Bang is still the most widely supported hypothesis for the origin of the universe,
but it isn’t completely watertight. There are still some holes in the theory, problems with it,
and mysteries that it doesn’t quite solve. The true nature of the earliest particles,
for example, those present right at the beginning of everything, is one such mystery… but science
may well have finally found some answers. This is Unveiled, and today we’re answering
the extraordinary question; Did one particle really save the universe?
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Thanks to modern science, we know that if you zoom far enough into anything you’ll eventually
get to a base level of fundamental particles. A microscopic plain of existence beyond which it’s
literally impossible to travel. It’s a unique, shapeshifting, head-trip of a physical realm
that now inspires many a sci-fi story or zany YouTube video. But it wasn’t always this way,
and we haven’t always known quite so much about the subatomic world.
Before the 1920s, the concept of the universe being constructed of fundamental particles at
all was almost entirely unknown. Instead, most theories followed traditional thinking first
set out by the Ancient Greeks. The idea broadly went that the universe was built of continuously
smaller chunks and that, if you were to cut into them, they would endlessly break down
into infinitely smaller pieces. However, thanks to modern technology in the early
decades of the twentieth century, physicists such as Einstein, Planck, and Rutherford
were finally able to go against this concept and provide an alternative. For the first time,
it was shown that the universe does have a final, fundamental level - made up of tiny pieces called
Quanta - and also that the standard laws of physics didn’t apply there. Instead,
science established a new set of rules for dealing with this world of the very small, quantum
mechanics. And this would later (in the 1970s) inspire the Standard Model of Particle Physics.
The Standard Model says that everything in the universe is composed of only a few fundamental
particles and four fundamental forces. It posits that by analysing how these interact with each
other, we can begin to understand how the universe really works. But the Standard Model is also a
work in progress and it, too, remains incomplete. Which means that there are still some crucial,
existential questions that it struggles to provide answers for. The issue of matter, for instance -
the stuff that makes up everything we can see - still isn’t entirely explained. Specifically,
we don’t yet know how it came to be here. How it came to dominate the universe. And now, we’re back
to the beginning of everything… the Big Bang! When it comes to the Big Bang, what’s known as
the matter-antimatter asymmetry problem is a major issue. Most versions of the Big Bang
Theory say that the early universe should’ve had equal amounts of matter and antimatter.
An equal number of particles and antiparticles (which are particles with opposite charge).
Then, when the two opposites met, they should’ve annihilated each other… cancelled each other out…
leaving behind just energy. The earliest moments after the Big Bang should, then, theoretically,
have seen particles and antiparticles popping in and out of existence…
until all that was left was an empty void. That’s what should’ve happened, but we know that
it didn’t. As is proven by the reality that’s all around us, we know that ordinary matter somehow
prevailed over antimatter. We know that a tiny percentage of ordinary matter didn’t go through
this annihilation process… that about one in one billion parts of it was able to survive.
And that that tiny amount eventually formed the building blocks of existence. Of everything. The
universe was born, and it quickly surged to become the amazing expanse that it is today.
But scientists are still left scratching their heads over how and why it all happened.
Thankfully, that head-scratching could soon be coming to an end, thanks in part to a 2021 study
focussing on one of the fundamental building blocks of the universe, the charm meson - an
extremely light, subatomic particle. Also known as the D-zero meson, the charm meson is one of
just four particles cited within the Standard Model that can exist as though both particle and
antiparticle at the same time. It does this via a phenomenon called quantum superposition…
and as it moves between the two states, we say that it oscillates between the two.
It’s heavy science… but what does it all have to do with saving the universe? Well, in June 2021,
analysis of data from the Large Hadron Collider was published by a team of scientists from Oxford,
Edinburgh and Warwick Universities. It specifically focussed on the charm meson particle,
recording millions of meson interactions triggered by the world’s largest particle accelerator.
Although we knew that charm mesons existed as both particle and antiparticle before this study,
evidence of the oscillating transition backward and forward between the two had never been
observed. This was largely because, as the study ultimately showed, charm mesons tend to decay
too quickly, compared to the time it takes for them to move between particle and antiparticle.
One of the scientists leading the study, Professor Guy Wilkinson of Oxford University, explained
as part of an official statement that, “the oscillation is very slow and therefore extremely
difficult to measure within the time that it takes the meson to decay”… before reiterating that,
“the vast majority of particles will decay before they have a chance to oscillate”.
Nevertheless, this study managed to record charm mesons oscillating enough times to begin drawing
some subatomic conclusions… and inspiring some further lines of thought. Most significantly,
the measurements taken seem to suggest that regardless of the speed at which charm mesons
move between particle and antiparticle, they don’t quite do so evenly. It could be, then,
that there’s a very slight alteration from the 50/50 split that science would usually expect…
which, when we reverse all the way back to the moment of the Big Bang, could have been vital.
It could be that charm mesons atypically produce more ordinary particles than antiparticles. That,
therefore, a tiny, tiny fraction of those ordinary particles were able to outlast their antiparticle
partners, which then started to tip the cosmological balance in favour of ordinary matter.
Because, from the initial moments of the Big Bang, we know that gradually more and more ordinary
particles were allowed to come into being… leading all the way up to the matter-rich universe we see
all around us today. The stars, and planets, and creatures, and comets. We know that they’re all
made of ordinary matter (and not antimatter)… but this observation of oscillating charm mesons
could finally show us why that is. Importantly, the findings so far don’t
yet confirm that charm mesons really do settle as ordinary particles more frequently than they
do as antiparticles. Proving or disproving that will be the next step for researchers.
But, still, we’ve arguably never been closer to understanding how the Big Bang played out.
What the conditions were really like. Of course, science has grappled with the world’s
biggest questions for centuries… and history shows us how a steady stream of innovations,
inventions and genius theories have propelled us to where we are now. But it’s only relatively
recently that we’ve started looking for answers in the world of the very small. Traditionally we’ve
looked out at the stars and the sky, trying to make sense of it all… but now we’re looking in.
More than ever before, humankind is dialling down its existence to the most fundamental nuts and
bolts possible… with particle physics ranking amongst the fastest growing sectors in all of
science. It’s a difficult place of research, played out across a microscopic realm where almost
all the conventional rules of physics break down and refuse to work. And yet, we are beginning to
get to grips with it. We are making progress. And this latest revelation - born out of the ongoing
research at the Large Hadron Collider - is another tiny but mighty step toward a new enlightenment.
Really, it doesn’t get much larger or more all-encompassing than the actual universe itself…
and we’re still so far away from fully understanding it. But we now know that it’s
secrets are tied up in subatomic packets. That it’s guided by forces and particles we cannot see.
And that it’s shaped, and was maybe even started, by them, as well.
And that’s why this one particle, the charm meson, really might have saved the universe.
What do you think? Is there anything we missed? Let us know in the comments, check out these other
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