Tuesday, 4 March 2014

Laws of Nature, Common Sense and Religion (Part 2)


In Part 1 we had discussed why common sense is fundamentally incapable of explaining and making sense of the world we live in.  Simply, it is a matter of scale.  The world operates at the atomic/molecular level (~0.000001 mm or a nano meter) where particles move near the speed of light (300,000 km/sec) while common sense is built up over centuries from observations made by our senses operating at distances typically greater than 0.1 mm and speeds less than 0.1 km/sec.  Additionally, time scales for understanding fundamental chemical and biological processes are less than a billionth of a second, more than a million times faster than our reaction time.

To understand the working of the natural world using common sense is like trying to understand the geography of the UK by standing at a corner in George Square in Glasgow! An impossible task.

We had built up a whole series of laws by extrapolating what we could observe with our senses - that is until about 500 years ago when technological advances started to extend the limits of our observations. The rest is history; now in the 21st Century, we are truly appreciating the intricacies of the natural world and I believe, correctly formulating the laws governing it - the laws of nature. Theories of Relativity and Quantum Mechanics have made possible the development of new technologies - digital, nano-, bio-, medicine and many others.  Life without these is unimaginable. To somebody living in the 19th Century, the technology today will be science fiction.

Humans like to make sense of things.  With extremely limited empirical information, acquired through our senses, for our ancestors it would have been impossible to explain much of what was happening around us. Natural phenomena like rain, thunder, lightening, tides, storms, earthquakes, motion of heavenly bodies, infectious/mental and other diseases etc. are mediated by causes well outside the range of human perception.  Theories and explanations would be put forward – of course different in different societies – to make sense of such events.  This can give rise to beliefs, customs, rituals, superstitions etc.
Who controls the clockwork-like motion of heavenly bodies; what causes earthquakes and storms? There has to be some almighty, omniscient being looking over the working of nature, controlling everything happening on the Earth.   
Reproduction and death were mysteries.  What happens after death would be a great puzzle.  Losing a loved one for ever is difficult and it would be natural to assume that he/she comes back to life again at some other place and time. Alternately, after death the person would go to some other unknown world where he/she will have access to all the comforts and good life, may be not available when alive.  
A mind full of a large number of unanswerable questions is very receptive to any suggestion that can even partially reduce the bewilderment.  

In distant past humans, with nomadic lifestyle, did not have a great deal of interaction with others.  They were preoccupied with the problems of survival - finding food and shelter was more important than worrying about the philosophical questions of how and why of things.  As humans started to settle in communities - particularly after discovering agriculture - they started to face a whole set of new problems.  In a community, one has to live in close proximity with the neighbours, there is more time to reflect on the natural phenomena around you and people would be living longer so there would be more continuity between generations.  Some sort of tradition will begun to be defined.  


Having evolved from the apes and with the history of struggle to survive, human nature would have the tendency to be selfish - hoarding of food and providing comfort to the family must have been of utmost importance. Physical strength would help to grab more land for growing food and to ensure security.  How does a community survive when everybody is fighting for a bigger share of whatever is available?  There is no point if the mightiest kills all the neighbours; then we are back to nomadic lifestyle. One needs a system of government and rules of conduct and, of course, punishment.      


If I am an intelligent person then I could exploit the situation by solving all the problems in one stroke.  I would attribute all the natural phenomena to an almighty who is benevolent by giving us rain for growing food, wood for making our huts, cows for milk etc. but will punish our collective bad behaviour by bringing storms, earthquakes, diseases and other natural calamities.  Someone who will nourish us but also punish us. He will also tell us how to behave in the community.  This code of conduct will be given to the community through a medium - somebody who can communicate with the almighty being.  Humans are too ignorant and too frail to question what the almighty decides - they must accept without question what is being decided for them.  They must have faith - blind faith is better as this makes the implementation of rules easier ensuring stability of the society. 

We have religion with an almighty God who we must try our best to please.  We have to have a prophet who can bring the message and the priests who can interpret the word of God for the common man.

Let us face it, most of the humans are not that clever.  They are already confused with what is happening around them in nature and about their safety and well-being.  A good lazy way for them will be to follow the code of conduct - it comes with the additional promise of good life after death. To keep reminding the community about the rules of conduct, we have to have beliefs, rituals and superstitions  - if faith is strong then all these make good sense - the main thing is not to question, just follow.


Of course, different regions will have their own unique way of describing God and the rules of conduct, rituals etc.  It does not really matter as nobody is there to question?  If one falls out of line - faith is shaken - then the community can take care of that by removing the unfaithful altogether. The good of the community is paramount and the chief priest can always decide what God wants - he has a direct line to Him.

One can have one God or several Gods looking after different issues. You can have unwritten code of conduct, everything is verbal (easier to modify) or you can have one book or several describing the will of God.  One does not even have to have a God - it could be just an energy field or an abstract being - who is somehow passionately concerned about the earthlings and their welfare.  As long there is unquestioning faith, the system can and has worked.  And it has worked for several millenia.

The question is how do the laws of nature (derived from the empirical evidence) and religion (needed historically to make sense of things) live side by side.  Things will be straightforward but for the idiosyncrasies of the human mind.  We shall leave this for the next installment (Part 3).

Saturday, 1 March 2014

The Curie Family - A remarkable Story (Part 2: Irene and Frederic Joliot-Curie)

Marie and Pierre Curie started the new discipline of radioactivity. Attempts to understand this strange and puzzling phenomenon and the source of energy in radioactive decays engendered the field of Nuclear Physics. Marie Curie and other pioneers like Ernest Rutherford worked and studied naturally occurring radioactivity but nobody was thinking about producing new radioactive nuclides not found in nature - producing artificial radioactive elements.  This would really be a "Holy Grail".  Already natural radioisotopes had shown their effectiveness in medicine, chemistry and research.  Artificially produced radioisotopes would be a game changer.

This is exactly what Irene and Frederic Joliot-Curies achieved and were immediately recognized by the award of the 1935 Nobel Prize in chemistry. Their journey to stardom was not without setbacks and they missed two certain opportunities of being the first to make groundbreaking discoveries which earned Chadwick (discovery of the neutron) and Anderson (discovery of the positron) the 1935 and 1936 Nobel awards respectively.

Irene and Frederic were two very different personalities.  Irene grew in the shadow of her mother Marie Curie.  She developed an intuitive feeling about radioactivity, went to Stockholm in 1911 for the Nobel award ceremony, accompanied Marie Curie during her American trip  where they received a charmed welcome.  Irene had helped Marie during the first world war with X-ray work saving lives of thousands of soldiers and joining the Radium Institute to work on her doctorate to study the radiation from polonium-210. Irene was cut-out for achieving great things - she was intelligent, head strong and very hard working.
Frederic, three years younger than Irene, came from an engineering background and in December 1924 when he was hired by Marie Curie, Fred was doing national service, had no serious physics qualifications. Frederic was a gregarious and outgoing young man who found Irene somewhat enigmatic.
They soon started to like each other and despite Marie Curie's serious reservations, got married in October 1926 and adopted the name Joliot-Curie.
Irene and Frederic made a great team.  They were immensely helped by having strong alpha particle fluxes from the polonium source that Marie curie had collected at the Radium Institute. Frederic also turned out to be very good with instruments and had sensitive detectors like ionisation chambers and cloud chambers for detecting particles.

Discovery of the neutron:


Chadwick concluded that Bothe-Becker radiation consisted not of gamma rays but of neutral particles of the same mass as the proton, i.e., neutrons.  Joliot-Curies had done the right experiment but their interpretation robbed them of being the first to discover the neutron.

Discovery of the Positron:
Joliot Curies had a very sensitive cloud chamber.  During their studies of cosmic rays, they observed positron tracks in their films.  They interpreted the positron tracks as due to negative electrons which had been scatterd in the backward direction.
This is a picture of one of the first positron tracks observed by Anderson in 1933. It was taken in a cloud chamber in the presence of a magnetic field of 2.4 Tesla pointing into the paper (so the particle paths are curved to the left). The cloud chamber (17x17x3 cm) contained a gas supersaturated with water vapour. In the presence of a charged particle (such as a positron), the water vapour condenses into droplets - these droplets mark out the path of the particle. 
The band across the middle is a lead plate, 6 mm thick, which slows down the particles. The radius of curvature of the track above the plate is smaller than that below. This means that the particle is travelling more slowly (23 MeV) above the plate than below it (63 MeV), and hence it must be travelling upwards. From the direction in which the path curves one can deduce that the particle is positively charged. That it is a positron and not a proton can be deduced from the long range of the upper track - a proton would have come to rest in a much shorter distance (~5 mm) 
Carl Anderson won the 1936 Nobel Prize for Physics for this discovery.  
Picture taken from C.D. Anderson, Physical Review 43, 491 (1933).

Production of Artificial Radioactive Elements:
"With the neutron, we were too late; with the positron, we were too late; now we are in time"  ... Frederic Joliot Curie, Jan 1934




Discovery of Nuclear Fission  
Yet again Irene and Frederic missed the opportunity to get credit for their pioneering experiments in the observation of the fission of uranium.




Irene and Frederic had strong views about atomic weapons, peace, women's rights and had overt communist leanings.  Their views lost them favour with the politicians and to some extent with the scientific establishment, particularly in France.
Frederic was a true patriot. Pretending to be busy with his research in nuclear physics, he risked his life by using his lab to manufacture explosives and radio equipment for the Resistance. After the liberation of France, he was appointed director of the National Center for Scientific esearch. He was elected to the French Academy of Sciences.  Soon thereafter he became head
of the French Atomic Energy Commission. His task was to make France a world leader in the nuclear industry. Irène became not only a commissioner but also the director of the Radium Institute. 
 But the Joliot-Curies' political activities led to their downfall. In spring 1942 Fred had secretly joined the French Communist party, at that time a leading anti-Nazi force. Although Irène never became a member, she sympathized with many movements in which French Communists took a lead, including support of equal rights for French women.
At the height of the Cold War, Fred was dismissed from his position at the French Atomic Energy Commission. A few months later Irène also lost her post as commissioner.