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How do you explain a lot of complicated science to a group of people consisting mainly of non-scientists?
That’s easy if you are Dr Claire Lee, a particle physicist working on the Large Hadron Collider (LHC) in Switzerland. She used her sharp intelligence, wry humour and some of the clearest slides yet seen at Scifest Africa 2017, to explain The Building Blocks of the Universe – from Quarks to the Cosmos.
Lee delivered the Christina Scott Memorial Lecture at Scifest Africa on Saturday evening.
She was born and raised in South Africa but currently works in Switzerland. Her mother, who was present at the lecture, lives in Grahamstown.
Her lecture was an engaging blend of talking about how she left South Africa to work on Atlas, one of the four main projects of the LHC, and how a particle physicist goes about solving the mysteries of the universe.
Lee said that particle physicists search for the building blocks of the universe. They care about things that are really small and how these pieces fit together. She summed it up neatly, “We want to know why the universe looks like it does.”
To gain some perspective on the kind of particles Lee was talking about, she explained that our bodies are made of atoms and that atoms contain a nucleus and electrons. Zooming further into the nucleus, we find that the protons are made up of three quarks: two up-quarks and one down-quark.
It was not within the scope of the lecture to explain the difference between the up- and the down-quarks, nor was there time to account for the peculiar names for the six quark flavours: up, down, top, bottom, strange and charm.
Instead of fixating on the distinctions between various types of quarks, Lee chose to describe how physicists at the world’s most powerful particle collider work with protons: “We smash these particles together, and it’s a lot of fun.”
Lee said while the work of a particle physicist at a massive, cutting-edge installation such as the LHC might seem impressive, she spends most of her time in the daily grind of computer coding. She has never had a programming lesson in her life which made it necessary to develop her own coding system which is “changing stuff and seeing what happens”.
She said one of the best ways of describing what they do on the Atlas experiment is that, “we hunt for things we expect, but haven’t discovered yet”, and one of the main tasks of the LHC was to either find the Higgs boson, or prove that it doesn’t exist.
The LHC slipped in and out of international headlines in 2012 as evidence mounted in both the CMS and Atlas experiments that they were independently on the verge of discovering the elusive Higgs boson.
In March the following year the LHC was able to announce they had found a particle that coupled with its measured interactions with other particles “strongly indicates that it is a Higgs boson”.
As confirming the existence of the Higgs boson was the main goal of the collider, scientists working on the project were understandably elated, but found they were confronted with an even bigger problem.
Adding together the mass of all known particles, including the Higgs boson, accounts for what appears to be only five percent of the mass of the universe. Astrophysicists have calculated that there must be much more mass in the universe than they can explain.
They know there must be more because only considerably more mass or energy can explain the rapidly expanding universe and the gravitational effects on galaxies. Lee said that currently scientists believe the universe is made of 27% dark matter and 68% dark energy, but so far no one is able to give an explanation of what these phenomena are.
Dr Lee left the audience with the tantalising prospect of wondering about the other 95%.