13 February 1633 On this day in 1633 Galileo Galilei arrives in Rome to face charges of heresy for advocating Copernican theory

This was a crucial day for the History of Experimental Physics, this is to be distinguished from Theoretical Physics first propagated by the Giant Aristotle (384-322BCE) who was not opposed to experiments, but it was Galileo that spawned the dawning of experimental Physics. There are so many great experiments in Physics/Science that one could discuss, in fact, a great course to teach must perhaps include Galileo’s cannon-ball experiment, Rutherford’s (1871-1937) gold leaf experiment, the Michelson-Morley experiment, Mendel’s (1822-1844) experiment with peas (that I was fortunate to discuss this week at UCL when introducing Statistics to our researchers and considering the “goodness of fit” of his results and the claim that Mendel doctored his results), Penzias(1933-) and Wilson’s (1936-) experiment on background radiation, and Eddington’s (1882-1944) eclipse experiment along with many others, but this is for another post.

Galileo the great Italian Mathematician/Physicist left his hometown without a degree, just a reference but rose to the dizzy height of Professor of Mathematics at Padua University. Of course, he is also well known today for the Galilean transformations that are the limiting case of the Lorentz-Fitzgerald transformations which were instrumental in the development of Special theory of Relativity under the directorship of Albert Einstein (1879-1855).

Returning to Galileo, during his hearing with the church he was forced to recant his views supporting the Copernican (1473-1543) theory that the sun is at the centre of the solar system and not the earth as was proposed by Aristotle and Ptolemy (100AD). One may ask, how did he know this? Well, Galileo was one of the first to use the telescope (which by the way he greatly improved on the design of Hans Lippershey (c1570)) for non-military purposes (recall it was invented so that the location of an invading army could be determined from afar), thus he pointed the telescope at Jupiter and observed the orbits of its moons and determined that they orbited Jupiter and not the earth. Galileo thus had scientific/numerical evidence to verify this. However, when he (Galileo) recanted his views to the church and was then subsequently put under house arrest he uttered the now immortal words:

“E pur si muove” or “Eppur si muove”

Which can be translated as “And yet it moves”, referring to the earth orbiting our nearest star.

Galileo was certainly a man that changed the way that Physics/Science is advanced and ushered into the world the so-called Scientific Method that one suspects all “good” experimenters are instinctively familiar with.

But I recall the words of Karl Popper (1902-1994) and my “old friend” Richard Feynman (1918-1988), during one of his interviews saying that

“One can never verify a theory but one can only falsify it” which I think encapsulates it.