Searching for secrets beneath the symmetries of Lyme
Science feature by Professor Glenn Patrick
A WALK around Lyme Regis reveals some beautiful buildings forming the unique character of the town. One of the common features is the use of symmetry to make the design pleasing on the eye.
Take the Dinsosaurland Fossil Museum in Coombe Street. This is a building which has matching, arched windows to the left and right of the door.
The central circular window on the upper floor is split into ten sectors displaying an additional touch of rotational symmetry. The net effect is something which is rather attractive and appealing.
The Royal Lion Hotel in Broad Street is another attractive building featuring symmetric bay windows. The Prince of Wales motto – Ich Dien – and his emblem of three ostrich feathers is even repeated three times to emphasise the design.
Many other beautiful buildings make good use of symmetry. Next time you are in town, look at the precise placing of the elegant arched, sash windows of the Post Office.
The stonework, columns and carvings on the Jubilee Pavilion in Marine Parade are also reflected on both sides of the entrance.
The pink symmetrical façade of Belmont is another prime example with its well-spaced urns and repeated Coade stone carvings. Symmetry is not confined to buildings.
Aristotle long ago argued that symmetry was one of the chief forms of beauty and it has been suggested that the reason we find certain people attractive is because their faces are symmetric. Think of your favourite film star – Brad Pitt or Catherine Zeta Jones say – and it becomes clear that there is a certain Hollywood look that succeeds in the movie world.
As can be seen in buildings like the Parthenon and the paintings of Leonardo da Vinci, symmetry has a long history. In fact, it was the Ancient Greeks who first came up with the idea of a “golden ratio” used to proportion a design to give an aesthetically pleasing result …. or even an attractive face.
Yet, there are also counterexamples which break this convention. Sometimes, quirky features interrupt the symmetry and introduce extra character. The Guildhall, with its turret, pretty cottages with thatched features on the roof, a crooked chimney and fake windows are good examples.
My boss once said that he was short, fat but interesting, making the point that good proportions are not everything in humans and our idiosyncrasies help define us!
What about symmetry in the natural world? The distinctive lamp posts of Lyme Regis incorporate ammonites into their design with one ammonite spiralling clockwise (like a left-handed screw) and the other ammonite curling anticlockwise (like a right-handed screw).
This appears symmetric, but if we stand on the other side of the post, the left-handed ammonite becomes right-handed and vice-versa. The ammonite is not identical to its mirror image – there is an asymmetry.
Gastropods – or snails – are more obviously asymmetric. When viewed from above, their spiralling shells can wind clockwise or anti-clockwise.
Oddly though, each species of snail is usually entirely composed of only one type. In fact, 90 per cent of gastropods have right-handed (or dextral) shells.
From the outside, the human body is also an example of left-right symmetry. Our eyes, ears, arms, legs, etc. are duplicated on either side of our mid-line giving a well-balanced image. But there are again hidden asymmetries.
I am left-handed which puts me very much in the minority along with 10 per cent of the population. Hidden inside the body, the major organs have a specific location with the heart and stomach normally on the left and the liver, gall bladder and appendix on the right. In just 0.01 per cent of people these positions are reversed – a condition called situs invertus.
Deep inside our molecules, the DNA double helix always has a right-handed spiral and the twenty amino acids – the building blocks of proteins – found in our living cells are all left-handed. The surface symmetry of the body is again broken by these hidden asymmetries.
Symmetry breaking may well explain why we are even here!
We all know from sci-fi movies, that antimatter has the opposite properties of matter and when the two meet they wipe each other out producing a burst of energy. When we collide particles in laboratories like CERN, we create equal amounts of matter and anti-matter – there is a sort of democracy between the two.
Puzzlingly though, when we look for antimatter in the Universe, we find very little of it. The International Space Station – regularly seen in the skies over Lyme Regis – hosts an experiment which has detected over 166 billion cosmic rays from deep space and found no evidence for primordial antimatter.
We would have expected equal amounts of matter and anti-matter to have been produced in the Big Bang – just like at CERN – so where has it all gone? The answer seems to be that there are very small differences – or asymmetries – in the properties of matter and antimatter, which mean that matter has a slight advantage.
Some of these asymmetries have been measured in experiments since the 1960s and I was recently part of a project detecting more at the Large Hadron Collider. Amazingly, this seems to be part of the reason that we exist.
If matter and anti-matter were created in equal amounts in the Big Bang with exactly opposite and symmetric properties, then it would all have annihilated within a microsecond. We would not exist – the Universe would just be filled with radiation.
In fact, this is almost the case – for each proton in the Universe there are 10 billion particles of radiation (photons). We owe our very existence to a lack of perfect symmetry.
The only fly in the ointment is that the asymmetries found so far are not strong enough to explain where all the anti-matter has gone.
The splendid buildings in Lyme surely hold many fascinating secrets behind their beautiful symmetric facades – just like the Universe.
Glenn Patrick is a particle physicist and science communicator who explores the quantum world of sub-atomic particles (including at the Large Hadron Collider) and now lives in Lyme Regis