Give me a pearly white smile! There you go. Now consider this: the calcium in your teeth was cooked up inside a giant red star, billions of years ago. So were the iron in your blood and the carbon in your genes.
In fact much of the stuff that makes up you and me was made in those cosmic laboratories a long, long time ago. That’s how astronomer Carl Sagan put it. We’re made of “star stuff”.
This is the story about matter and why a €6-billion giant underground super-cooled magnetic tunnel which straddles the Franco-Swiss border, the Large Hadron Collider (LHC), matters. It will allow physicists to see what the fabric of the cosmos was like in the moment after it was born, just as the infant universe began bawling out across the heavens.
Stuff — everything — is made of atoms. The ancient Greeks figured that out. More recently, though, we’ve worked out that each atom is made up of a nucleus, with electrons spinning around it. Inside the nucleus are protons and neutrons, inside those are quarks and other particles — smaller and smaller, like a Russian doll unfolding. But that’s about as close as we’ve zoomed in.
Now physicists want to shoot protons around the 27km-long circular tunnel almost at the speed of light and smash them into one another to see what happens because they reckon there’s more to the heart of the Russian doll than we’ve seen so far.
It all started with a giant bang, the Big Bang. All matter — the stuff that became the fabric of life — blasted out from a single point and has been expanding outwards ever since. In the sliver of time after the bang, things cooled, allowing the first particles to form — the first threads that would become the woven cloth of complex matter: electrons, protons, neutrons. It cooled further, allowing those particles to come together to form the first atoms of mostly hydrogen and helium. The universe is just a few minutes old.
Space looked like a foggy night, thick with clouds of atoms for the first few hundred thousand years. These slowly spun together, forming the first stars — seething nuclear reactions whose temperatures were hot enough to cook those particles up into some of the heavier elements that later became the building blocks of you and me. These suns exploded, dusting the sky with rubble which went on to become the next generation of stars.
Matter recycled through a few generations of suns before some of it came together to form this planet, Earth. And nearly 14-billion years after the Big Bang, one species emerges that has the consciousness to understand time and space and can look back along the vast timeline of the cosmos and understand what we are: a delicate fabric woven together from the kinds of materials that were cooked up in cosmic explosions.
Particle physicists now hope that by smashing protons together, they’ll recreate that sliver of time, less than a billionth of a second after the Big Bang, to see what shape and form matter took in that fraction of time, before matter shapeshifted into the particles that we know today. It’s as if we’ve unwoven the fabric and untwisted the individual threads of yarn, but now we want to look into the fibres that make up the thread.
Specifically, physicists are looking for something called the Higgs particle — a fairly large and unstable particle which they think existed just after the Big Bang, but then quickly came apart (or “decayed”) to form the more permanent particles that have recycled through time until today.
The instrument — the largest scientific experiment in history — was switched on last week and sent the first batches of protons looping through the collider’s underground tunnel. The first collisions are expected to happen only within the next two months. It might be a few years before they have enough information to know whether or not the Higgs particle exists.
If the Higgs doesn’t exist, that’s fine too. A door will close on one theory, but open on others. It’s a complex series of ideas that are being tested in the collider: how do the building blocks of our universe have mass; what’s the relationship between matter and antimatter; what about dark matter?
The smashing together of protons in the LHC is a reminder that we’re all made up of the same stuff, “star stuff”. We’re clusters of common particles first, even before we’re Earthlings, mammals, human beings. Suddenly political affiliations, religious persuasions, ethnic references and skin pigments seem strangely inconsequential. We have so much more in common than we have separating us, starting with our teeth, built from the calcium cooked up in the heart of giant hot stars long ago.