Thought for this day.    11 June. 2015

Because someone believes that the earth is flat does not make the earth flat. Because someone believes that the earth is at the centre of the Universe does not make it the centre of the Universe, although in this case there is strong evidence to suggests that in one sense this is the case. For thousands of years many religious groups have believed that not only is the earth at the centre of the Universe but that everything else revolves around it. To be fair, prior to our modern scientific age it looked like it did from our perspective on the earths surface. However observations by Galileo (15 February 1564 – 8 January 1642) using his newly improved telescope established that the apparent retrograde motion of the planets coupled to the observed motion of the moons of Jupiter could only be explained in terms of a sun centred solar system (as suggested earlier by Nicolaus Copernicus). Galileo spent the rest of his life under house arrest for making this suggestion, and under threat of torture was made to recant his theory. Just one of the many examples where religious dogma held up the progress of science for many years, in some cases centuries.

We now have a well established theory supported by a prodigious amount of evidence that spacetime began with a Big Bang event about 13.798 thousand million years ago. Because space itself, and time also, began from a single point and expanded outward in every direction, then no matter where you are in the Universe everything else always appears to be moving away from you no matter in which direction you look. To understand this concept we sometimes think in terms of a two dimensional analogy in the form of a black rubber sheet being stretched progressively in all directions by being pulled equally along each edge. Imaging that this rubber sheet is covered in a network of white dots. If you imagine that you are sat on one of these dots, it doesn’t matter which one, then every other dot will appear to be moving away from you giving the impression that you are somehow special and at the very centre of this expansion. In this sense the earth could be said to be at the centre of the Universe. It’s a sobering thought that as an observe in the Universe, from your perspective, no matter who you are or where you are, you would be quite justified in saying I am at the centre of my observable Universe. However, don’t let this go to your head because anyone else could justifiably say the same thing.

These thoughts are based on current scientific theories and although they are supported by vast amounts of experimental evidence a good scientist must always keep an open mind in terms of the small probability that the theory may not represent the whole truth. Indeed one day it may be replaced by a completely different theory of which the current one may just be a special case. There’s only one thing worse than religious dogma and that’s scientific dogma. The only thing that I know for certain is that I know nothing for certain.

Brian Kershaw.