If driver-less cars are the future then we had better take account of plate tectonics! You have no doubt heard the stories “driver follows satnav instructions and ends up in a field!” Well what about driver-less cars? Their success is crucially dependent on Global Positioning Systems (GPS). If you have a smart phone you have a GPS; by linking with one or more satellites a GPS can triangulate its position with varying levels of accuracy. In a driver-less car you want to be sure that the car’s GPS is both accurate and linked to the road map, half a metre out and you could be facing the oncoming traffic!
Maps and their datum’s
In the UK the Ordnance Survey has been making maps since 1747. These maps are based on the British National Grid, a system of rectilinear lines (northings and easting) superimposed on the curved surface of the earth. This is typical of what are known as country, or local-co-ordinate, systems.
Australia is no exception. In the summer of 2016 it was reported (BBC, 29 July 2016) that Geoscience Australia was moving Australia so that the gap between its local co-ordinate system and that of global navigation satellite systems (GNSS) were in closer agreement. When we way ‘moving Australia’ what they mean is moving the official longitude and latitude of the origin (zero point) of their local co-ordinate system. The Geocentric Datum of Australia, the origin for the country’s local co-ordinate system, was last updated in 1994 since when Australia has moved about 1.5 m north due to plate tectonics. Driver-less tractors are already a feature of some Australian farms so the problem is very real irrespective of what may or may not happen with respect to driver-less cars.
Plate tectonics is constantly and subtly re-arranging the World’s geography. For example, the distance between London and New York is growing by about 5 cm each year, in a decade that is 50 cm and in a hundred years 5 m. Plate tectonics is a big deal and is also an essential paradigm to understanding the Earth’s geological past.
Paradigms and gladiatorial science
A paradigm is a model or conceptual framework of ideas with which to organise and interpret observations and data. It is bigger than a hypothesis, but less definitive than fact or theory. Scientists make arguments; they advance explanations, models and ideas by reasoned and evidenced argument. They articulate their ideas, garner supporting evidence and/or test them against that evidence. In natural science there are few absolute rights and wrongs; it’s not like a maths problem in which you can look the answer up in the back of the book!
Inductive science involves observing and noting everything around you; in our case observing the natural world. From that body of data you look for patterns, make logical inferences and deductions developing ideas which as they gather support become irrefutable and take on the status of fact or theory. It is a philosophy of investigation that was first formalised by Francis Bacon (1561-1626) in 1620: one observes nature, proposes a modest law to generalize an observed pattern, confirms it by many observations, ventures a modestly broader law, and confirms that, too, by many more observations, while discarding disconfirmed laws. In this way a laws grow ever broader but never exceeds the observations on which it is founded. As a philosophy of science it is not without its problems. Take the case of the hypothesis ‘do black swans exist?’ Any number of observations of white swans will not address the question, but find one black swan and the hypothesis is proven.
This alternative method of science is called ‘falsification’ – rather than gather supporting evidence for an idea how can you formulate a test that will disprove it? In this view of science one is constantly working to disprove the ideas and models you propose. It is a view of science proposed by Karl Popper (1902-1994) amongst others.
Thomas Kuhn (1922-1996) proposed in his famous book The Structure of Scientific Revolutions, influential in both academic and popular communities, that periods of normal science dominated by paradigms are overturned by periods of revolutionary science establishing new paradigms and renewed stasis.
Little did Alfred Wegener (1880-1930), a leading explorer and meteorologist of his time, know that he was laying the foundation for one of the biggest paradigm shifts in earth science when he proposed his idea of continental drift on the 6 January 1912. Amassing palaeontological, lithological and structural evidence he proposed that continents had moved over the Earth’s surface in the past. He famously pointed to the ‘jigsaw’ like fit of Africa and South America, something that Francis Bacon had noted previously. He coined the term Pangea for a giant supercontinent that had once existed.
Science can be brutal, often gladiatorial; propose an idea that is too radical for the scientific establishment and they will turn and savage you. That is what happened to Wegener and his ideas of continental drift were neglected until geophysical exploration of the ocean following the Second World War began to throw up new data. On the basis of this data the paradigm of plate tectonics emerged in the late 1960s and early 1970s revolutionising our understanding of our planet both past and present . One of the greatest scientific paradigm shifts of the twentieth century. A number of popular reviews were published to mark the centennial anniversary the best of these is by Romano and Cifelli (2015) published in Science.
Finally I came across this wonderful song on YouTube the other day which celebrates Wegener’s contribution; I have no idea what he would make of it!
Professor Sandcastle 