Interesting question, isn’t it? If the thing you’re investigating is invisible, or so small or fleeting that you can’t even put it under a microscope, it’s hard enough to even determine if it exists and where.
Figuring out what shape it has is even more tricky.
Now, you could argue that if you can’t see something, its shape or form doesn’t really matter either.
After all, it’s not like you’re choosing a sidetable, and you and your partner keep arguing whether you want the vintage kidney-shaped or the slick rectangle one.
But just like size sometimes matters, form sometimes matters, too – even if you can’t see it.
In today’s text, I’ll show you how form can be important even for very small particles – and what trick physicists use to make the invisible visible.
Oh, and as always on The Hidden Things, we’ll also talk about how this matters to you, and how you can apply the same trick to your own hidden issues.
On we go!
(Sidenote: You might remember my recent short read about black holes. That’s another great example of making something visible which, by nature, is invisible. In the case of the black hole, though, it wasn’t its form, but it’s meer existence.)
But before we dive into why form matters for some small particles, and how to determine it, let’s start with a bit of background knowledge. Just in case you’re not a particle physicist…
Atoms are the smallest unit of matter. They are grouped into elements: aluminium, calcium, or oxygen are all elements, and they consist of single atoms.
But atoms themselves consist of even smaller particles: protons, neutrons and electrons. Protons have a positive charge, electrons a negative charge, and neutrons are, well, neutral – they have no charge.
So two protons repel each other, as do two electrons. But a proton and an electron gravitate towards one another.
Each atom consists of a nucleus of protons and neutrons, and electrons which are swirling around that nucleus. (Nucleus just means core in Latin, but it sounds a lot cooler.)
In the periodic table that you might remember from school, atoms/elements are grouped by the number of protons they have in their nucleus: Hydrogen, for example, has just one proton, while aluminium has 13.
(The element with 42 protons is called molybdenum, btw. Just in case you were wondering.)
If the charge of an atom is neutral, there are exactly as many electrons swirling around the core as there are protons in the core. If there are more electrons, it has a negative charge. If there are less electrons, its charge is positive, since there are more positive particles in the atom than negative ones.
What’s interesting is what happens in the core, aka the nucleus, though…
Besides the protons, there can also be neutrons in the nucleus. And while the protons somehow determine a lot of the characteristics of the atom, the neutrons seem to have some important effect on its form (among other things).
The nucleus form of a lot of atoms we come across is pretty boring: They look like a ball.
(Although “look” is probably the wrong word here…)
But there are other forms of atomic nuclei. For example, some of them resemble a football. Or put in more fanciful terms, they’re ellipsoidal.
To understand why form matters in this case, we need to take a closer look at some of the current research in particle physics.
You see, experimental particle physicists are a bit crazy. (Sorry, guys, it needs to be said!)
They spend a lot of their life planning and conducting experiments which take place in huge, obscenely expensive, windowless bunkers. In these experiments, they try to do things like “creating” new elements.
Now, if you imagine a happy particle physicist, holding up a rock-size piece of a new element and smiling proudly into the camera: Forget about it.
The particles we’re talking about are few and far between – sometimes it takes days to create one atom.
And a lot of them aren’t that keen to stick around either: Especially the heavier atoms (i.e. the ones with more protons) tend to come apart pretty quickly. Like, really quickly – having one of them hang around in the experimental tube for a few seconds is a big thing.
But of course, particle physicists are also just humans like you and me. And like all humans, they dream of creating something new. It’s the old alchemists dream, I guess, only now we’re using some much more fancy equipment.
So particle physicists all over the world dream of creating some of the heavier atoms, but with a longer shelf life. Long enough to actually be useful.
With these stable atoms, we could assemble enough material to actually build something useful – like we can build stuff from aluminium or other elements.
I told you above that the same element may have a different number of neutrons in its nucleus. These different atoms are called isotopes.
You might know this term from discussions of radioactivity, but isotopes don’t necessarily have to be radioactive, and they don’t have to decay either. Different isotopes of the same element simply contain a different number of neutrons in their nucleus.
For example, carbon always has six protons. The stable isotope Carbon-12 has an additional six neutrons in its nucleus. But there is also an isotope Carbon-14 which has an additional 8 neutrons (6 protons + 8 neutrons = 14). And Carbon-14 is radioactive and decays over time.
So the number of neutrons in an atoms core matters a lot. In fact, the right number of neutrons makes an isotope stable – or not.
At this point, I can hear the wheels in your head turning.
Yes, you’re right!
What the particle physicists are trying to find are stable isotopes of the heavy elements. And that means they have to get the number of neutrons right.
There’s a model where atom nuclei consist of orbital shells which are stacked inside each other. Each shell can only contain a certain number of protons and neutrons. Once a shell is closed (i.e. full), additional particles have to be stored in another shell.
Due to the forces between the protons and neutrons, an atom is more stable if its shells are fully stacked. And also due to these forces, when the nucleus shells are all closed, the nucleus takes the form of a ball.
Now, as an unsuspecting non-particle physicist, it looks pretty simple:
Why don’t we produce isotopes of an element which contain just the right number of neutrons to fill all relevant shells (together with the fixed number of protons)?
Turns out that it’s not quite as simple – but I reckon you guessed that already. 😉
Proton-neutron combinations which form particularly stable nuclei are even called “magic numbers”. That’s how elusive they are.
Because, unfortunately, it’s not easy to know for sure how many particles fit into each shell. There are different models which in turn make different predictions.
And since producing such heavy elements is a fairly tedious, expensive and time-consuming process, it’s not like we can just assemble a few hundred instances of each isotope and see how long they last.
This is the part where form matters. Finally! 😉
(There’s also something we can learn from all this, but we’ll get to that later.)
Now, in their search for stable heavy elements, smart particle physicists have come up with a cunning plan:
Why don’t we determine the form of the nuclei of different isotopes – and when we find something ball-like, we know where to look for stable isotopes.
In order to do that, they irradiate the electrons (remember, they are still swirling around in the nucleus’ orbit, even though we’ve completely ignored them so far!) with laser light.
Depending on which light these electrons absorb, it’s possible to determine their trajectory around the nucleus – and this reveals the form or shape of the nucleus itself.
Well. This is all cool and nice, and it might have gone deeper into particle physics than you ever wanted to go.
But hey – we’re not here for fun, remember? We are here to look into the structures behind things!
(Or maybe we’re here for fun, too. After all, discovering structures and patterns and relationships IS fun.
Also, from today’s investigation, you’ve already learned the fun party fact that the core of some atoms is football-shaped. As far as conversation starters go, that’s a lot more interesting than the weather!)
But back to the really interesting stuff:
We started out with the question: How do you determine the form of something invisible?
And if you should ever start a career in particle physics, you now know that one valid answer to this question is:
Ping whatever is surrounding the invisible thingy with laser light to determine the trajectories that surrounding stuff is moving on, and from these trajectories, deduce the shape of the invisible stuff in the middle.
But for all the rest of us, one question might be even more important:
How is all this relevant to me and my life? And have I really just spent seven minutes of my life reading an article about people who shoot laser light on particles?
I’m sure you’ve got stuff in your life that you can’t see, but you know it’s there. Things which are invisible, or hard to grasp, or you just can’t put your finger on them.
Your big project isn’t as successful as it should be, and nobody really knows why.
Your relationship is turning in circles around the same arguments, over and over, and you can’t see a way out of it.
Your business feels stuck, but from the inside, it’s hard to see what the pointless routines are.
In all these cases, there are “invisible” things at the core of something bigger:
Things you might not be able to see or put into words, but you know they’re there – and knowing their form would be a big help in overcoming whatever issues you have.
It’s like standing at the shore of a lake big without being able to see it in full. But what you can do is hike around it with your trusted GPS device. And from your “trajectory” around the lake, you now know its form.
(That’s more or less the same thing the particle physicists are doing, only that their equipment is a lot cooler and way more expensive than the GPS app on your mobile.)
So the next time you’ve got one of those invisible issues at the core of something, and you just can’t determine what the real form of the problem is…
… take a hike around it. Look at it from different angles. Get a feel for where the issue starts, and where it ends.
What’s included in it – and what’s clearly not part of the core issue?
What or who is moving around it, and in which ways?
If the issue had a different shape, would the paths around it be more effective? More fun? Easier to bear or more profitable?
Is the issue itself even the main problem, or is the main problem whatever is going on around it?
The next time you’ve got an issue at the core of something, and you just can’t put your finger on it – pretend to be a particle physicist. Heck, you could even build your own particle accelerator!Next time you can't get to the core of a problem, think like a particle physicist! (you could even build your own particle accelerator) Click To Tweet
Image: Braedon McLeod on Unsplash