Introducing Models in Science

The structure of the enzyme lysozyme.
(The structure of the enzyme lysozyme.)

We have always needed models to understand the complex world in which we live. Models allow our minds to safely explore reality; and models scale tiny and huge objects to a size that we can comprehend and become familiar with. Models are therefore essential in the scientific quest for a rational understanding of the physical universe. Visualization is, moreover, an immense aid to the scientific imagination, as it seeks new relationships and connections between concepts and phenomena - the process which is at the heart of scientific discovery.

Models have been used since the beginning of scientific thought, and some of the earliest and most detailed scientific models relate to astronomical observations. The earth centric cosmologies of the ancient world were perfected in the Ptolemaic system of the universe. This highly complex and beautiful structure explains a wide range of observations on the motions of planets and stars. The Ptolemaic system was of course swept away by the Copernican revolution in the 16th century, which produced far simpler heliocentric models for the solar system; these explain astronomical data more straightforwardly and could subsequently be rationalized by Newton's gravitational theory.

A snapshot from a simulation of the formation of a spiral galaxy.
(A snapshot from a simulation of the formation of a spiral galaxy..)

In astronomy and cosmology, which are among the most enduring scientific grand challenges, models are therefore crucial. 'Global modeling' is also playing an increasingly important role in new sciences that aim to understand how the earth's atmosphere, oceans and interior work. Their role in engineering and applied sciences is obvious, but contemporary technology is expanding enormously their range and sophistication. For example, the complex model of the distribution of pressure over the wings of a fighter aircraft in flight; and detailed and accurate information of this type is, of course, a valuable design tool in the aerospace industry. Our emphasis here is, however, on the role of models in understanding matter at the microscopic level - the world of atoms and molecules - and in revealing the marvellously varied ways in which atoms combine to give structures of immense complexity and beauty; structures that support life like the enzyme lysozyme above whose atomic architecture was first elucidated at The Royal Institution in 1965. And structures which lead to extraordinary and technologically important properties, such as the high temperature superconducting material whose crystal structure is shown below. While the symmetry and elegance of molecular structures is illustrated by the spherical carbon molecules of 'Buckminster Fullerene' materials.

Note: There is additional information on galaxy formation simulation linked here. The essence of the simulation is illustrated above. A circular region of space is defined as shown on the left and divided into a collection of rings and areas within each of these rings. At each time step in the simulation the regions next to active regions have a finite probability of becoming active. This simulates the initiation of star formation caused by the explosion of a nearby supernova where the shockwave precipitates the condensation of hydrogen clouds into the seeds of star formation through gravity. (You can expand the image by clicking on it).
The crystal structure of carbon C60 Buckminsterfullerene.
(The crystal structure of carbon C<sub>60</sub> Buckminsterfullerene.)
The crystal structure of a high temperature superconductor.
(The crystal structure of a high temperature superconductor.)