You've probably heard of electrons and protons,
the building block particles that make up atoms.
But there are all kinds of other particles in the universe,
and we have a pretty good idea of what they are and how they interact.
But even our best theories struggle when it comes to big nasty questions.
Like, where does mass come from?
And what is dark matter made of?
There may be a theory that can answer these questions at a stroke.
It's elegant, mathematically speaking, but is it true?
It's called "Super Symmetry".
If you wanted to explain why all stuff in the universe behaves the way it does,
you could do a lot worse than the so-called "Standard Model".
Developed in the 1960's and 70's,
it categorises all fundemental particles as either "leptons", like electrons,
"quarks", the building blocks of protons and neutrons,
or "force carriers", like photons, which transmit electric and magnetic force.
The Standard Model is a triumph of modern physics,
every particle the theory predicts has been observed in experiments,
except for one.
The Higgs boson, a force carrrier thought to give other particles the property of mass,
has so far eluded direct detection.
And what's worse, experiments suggest that if the Higgs boson exists,
it would likely be way lighter than the simple Standard Model predicts.
But all is not lost.
Physicists can get around this problem with a little mathematical tweaking.
Think of the Standard Model as an old school hi-fi stereo system,
and the variables in the theory are like the knobs on the amplifier.
To get the sound you want you can twiddle the various bass, mid and high levels,
tweaking by tiny amounts until it sounds just right.
That's fine for listening to [Led] Zeppelin records, but instead of just 3 knobs
the Standard Model has almost 20.
How would you know how to set them all?
With no real physical reason for turning one know one way, and another the other way,
it's all very arbitrary, and not how we'd like to think the universe actually works.
It would be nice if there were a more elegant solution.
As it turns out the theory of Super Symmetry allows the mass of the Higgs boson
to be in the right range without fine tuning the math.
It does so by introducing a whole new cast of particles to pair up with the ones
we already know about.
These super partners are like bizarre world versions of the Standard Model particles only more massive.
And not only do they interact to solve the Higgs mass problem,
they also provide a plausible explanation for dark matter.
The mysterious mass that makes up the bulk of the universe.
The problem is none of these super particles have been detected yet.
Even by the Large Hadron Collider, which many thought would have found them by now.
This doesn't mean Super Symmetry isn't true, but it leaves the door open
for all kinds of other theories, from messier versions of the Standard Model
to more exotic theories envoking extra dimensions.
So far, with no Higgs boson and no super partners, the chance of having
a simple theory to explain everything seems to be getting smaller.
But that may be ok.
After all, there's nothing that says the physical world has to follow elegant mathematical rules.
As much as we might hate to admit it, it could be that even at its most fundamental levels,
reality is just messy.