Our world through the looking glass

What significance does chirality play in our symmetrical world? Watch Charles Stirling in our 1992 CHRISTMAS LECTURES.

About this series

From the 1992 lecture brochure:

We are set apart from other animals both by the use of language whose control is normally  located in the left side of the brain, and by the fact that unlike most other animals, which have mixed handedness, we are predominantly right handed. Recent speculations have focused on the possibility that these two attributes are interconnected genetically, a link that could lead to an understanding of the neurobiology of language and its molecular biological basis.

In these lectures we shall look at first our own symmetry, overall in terms of handedness and our superficial appearance, and also below the surface at our brains and other organs. Then we shall look at ourselves in the world at large, focusing on the symmetry of our fellow creatures and the artefacts that we have created. The connection of both of these to left-right relationships will be explored.

The most significant handed (chiral) objects we encounter, usually unconsciously, are the molecules that we and all of our surroundings are made of. We will look at the nature of these molecules and trace the understanding of the significance of handedness at the molecular level in the 19th century, for which it was the most far-reaching chemical realisation.

Our contact with handed molecules has profound significance in terms of, for example, sensory perceptions such as taste and smell. We can distinguish between handed molecules and this tells us that our sensory apparatus is itself handed.

Our existence depends upon the handedness of molecules both large and small and without such molecules we would not be able to digest our food, build our bodies, or transmit our characteristics to the next generation.

We return to the opening speculation. The genes - themselves composed of handed molecules - control the development of handedness and cerebral dominance, a link which has the potential to give us an understanding of the biology of language. We leave our consideration of chirality - handedness -with an unsolved mystery. Where do chiral molecules come from?