Tag Archives: Newton

Everything is flux but it’s not always been recognised

Decorative photograph or ruins of Fountains Abbey next to River SkellI am teaching thermodynamics to first year undergraduate students at the moment and in most previous years this experience has stimulated me to blog about thermodynamics [for example: ‘Isolated systems in nature?’ on February 12th, 2020].  However, this year I am more than half-way through the module and this is the first post on the topic.  Perhaps that is an impact of teaching on-line via live broadcasts rather than the performance involved in lecturing to hundreds of students in a lecture theatre.  Last week I introduced the second law of thermodynamics and explained its origins in efforts to improve the efficiency of steam engines by 19th century engineers and physicists, including Rudolf Clausius (1822 – 1888), William Thomson (1827 – 1907) and Ludwig Boltzmann (1844 – 1906).  The second law of thermodynamics states that the entropy of the universe increases during all real processes, where entropy can be described as the degree of disorder. The traditional narrative is that thermodynamics was developed by the Victorians; however, I think that the ancient Greeks had a pretty good understanding of it without calling it thermodynamics.  Heraclitus (c. 535 BCE – c. 475 BCE) understood that everything is in flux and nothing is at rest so that the world is one colossal process.  This concept comes close to the modern interpretation of the second of law of thermodynamics in which the entropy in the universe is constantly increasing leading to continuous change.  Heraclitus just did not state the direction of flux.  Unfortunately, Plato (c. 429 BCE – c. 347 BCE) did not agree with Heraclitus, but thought that some divine intervention had imposed order on pre-existing chaos to create an ordered universe, which precludes a constant flux and probably set back Western thought for a couple of millennia.  However, it seems likely that in the 17th century, Newton (1643 – 1727) and Leibniz (1646 – 1716), when they independently invented calculus, had more than an inkling about everything being in flux.  In the 18th century, the pioneering geologist James Hutton (1726 – 1797), while examining the tilted layers of the cliff at Siccar Point in Berwickshire, realised that the Earth was not simply created but instead is in a state of constant flux.  His ideas were spurned at the time and he was accused of atheism.  Boltzmann also had to vigorously defend his ideas to such an extent that his mental health deteriorated and he committed suicide while on vacation with his wife and daughter.  Today, it is widely accepted that the second law of thermodynamics governs all natural and synthetic processes, and many people have heard of entropy [see ‘Entropy on the brain’ on November 29th, 2017] but far fewer understand it [see ‘Two cultures’ on March 5th, 2013].  It is perhaps still controversial to talk about the theoretical long-term consequence of the second law, which is cosmic heat death corresponding to an equilibrium state of maximum entropy and uniform temperature across the universe such that nothing happens and life cannot exist [see ‘Will it all be over soon?’ on November 2nd, 2016].  This concept caused problems to 19th century thinkers, particular James Clerk Maxwell (1831 – 1979), and even perhaps to Plato who theorised two worlds in his theory of forms, one unchanging and the other in constant change, maybe in an effort to dodge the potential implications of degeneration of the universe into chaos.

Image: decaying ruins of Fountains Abbey beside the River Skell.  Heraclitus is reported to have said ‘no man ever steps twice into the same river; for it’s not the same river and he’s not the same man’.

We inhabit time as fish live in water

A couple of weeks ago (‘Only the name of the airport changes’ on June 12th, 2019) I wrote about the stretching and compression of time while I waited for my much delayed flight to Reno. I mentioned Aristotle’s view of time as the measurement of change; however, Newton believed that time passes even when nothing changes. Einstein resolved the conundrum, represented by these different views, using the concept of a space-time domain forming a gravitational field containing waves. My title is a quote from Carlo Rovelli’s book, ‘The Order of Time‘. And, according to Rovelli, ‘mass slows down time around itself’, which I think will cause waves in the space-time domain .  Conservation of energy implies that the movement of an object will tend towards space where time passes more slowly, i.e. in the vicinity of large masses. Hence, things fall downwards because time runs more slowly close to the Earth. This implies that time passes more slowly at the airport than on the plane in flight; but, of course, the differences are too small for us to measure or perceive.

Image: Art work ‘Gaia’ by Luke Jerram in Liverpool Cathedral

Source:

Carlo Rovelli, The Order of Time, Penguin, 2019.

Hands-in-pockets

I often have the opportunity to take a ‘hands-in-pockets’ tour of a laboratory or facility during the course of visits to world-class research institutions.  ‘Hands-in-pockets’ means that you can look must but you must not touch anything or take photographs.  Some of these tours are more exciting than others; one very fast computer looks very much like another and one very expensive microscope looks very much like another.  However, a couple of weeks ago, we visited the library of Christ Church Oxford for five minutes and there, to my amazement and delight, lying almost casually on a table were first editions of two of the books that form the foundation of modern science.  Isaac Newton’s ‘Philosophiae Naturalis Principia Mathematica’ published in 1687 and Darwin’s ‘On the Origin of the Species’ published in 1859.  Now, we understood why the librarian had been reluctant to let us take a peek.  My hands stayed firmly in my pockets but the temptation to turn the page of the Origin of Species, which was open, or to open Newton’s great work was huge.  Instead, we walked slowly around the room, which besides us and a skeleton of a horse was empty, soaking up the atmosphere.  We left quietly, thanking the librarian at the bottom of the stairs for letting us take a peek.  I didn’t discover why they have a skeleton of horse in the library with their great collection of books – I didn’t feel I could ask the librarian as we left!

We are all citizens of the world

A longer post this week because I was invited to write an article for the Citizens of Everywhere project being organised by the Centre for New and International Writing at the University of Liverpool. The article is reproduced below:

Scientists seek to discover and describe knowledge, while engineers seek to apply and deploy the same knowledge by creating technology that supports our global society.  In their quests, both scientists and engineers are dependent on each other and on those that have gone before them.  On each other, because scientists increasingly need technology in order make discoveries, and because engineers need new scientific discoveries to drive innovation; and both groups stand on the shoulders of their predecessors, to mis-quote Isaac Newton who said he was able to see further by standing on the shoulders of his predecessors.  Scientists and engineers have to build on the achievements of their predecessors, otherwise nothing would be achieved in a single lifetime.  This process is enabled by the global dissemination of knowledge and understanding in our society, which does not recognise any boundaries and flows around the world largely unimpeded by the efforts of nation states and private corporations.  As Poincaré is reputed to have said ‘the scientist does not study nature because it is useful; he studies it because he delights in it, and he delights in it because it is beautiful’.  The feeling of delight is a reward for hours of intense study; but, the realization that you are the first to recognise or discover a new scientific fact generates so much excitement that you want to tell everyone.  Scientists have always met to share their findings and discuss the implications.  As a young researcher, I had a postcard above my desk showing a photograph of the attendees at the 5th Solvay Conference in 1927 at which 29 scientists from around the world met to debate the latest discoveries relating to electrons and photons.  Seventeen of the 29 attendees at this conference went on to receive Nobel prizes.  Not all scientific meetings are as famous, or perhaps as significant, as the Solvay conference; but, today they are happening all around the world involving thousands of researchers from scores of countries.  Besides the bureaucratic burden of obtaining visas, national boundaries have little impact on these exchanges of scientific and technological knowledge and understanding.  If you are a researcher working in the subject with sufficient funding then you can attend; and if your work is sufficiently novel, rigorous and significant, as judged by your peers, then you can present it at one of these meetings.  You can also listen to the world’s leading experts in the field, have a discussion over a coffee, or even a meal, with them before going back to your laboratory or office and attempting to add to society’s knowledge and understanding.  Most scientists and engineers work as part of a global community contributing to, and exploiting, a shared knowledge and understanding of natural and manufactured phenomena; and in this process, as global citizens, we are relatively unaware and uninfluenced by the national boundaries drawn and fought over by politicians and leaders.  Of course, I have described a utopian world to which reality does not conform, because in practice corporations attempt to protect their intellectual property for profit and national governments to classify information in the national interests and sometimes restrict the movement of scientists and technologist to and from states considered to be not playing by the right set of rules.  However, on the timescale of scientific discovery, these actions are relatively short-term and rarely totally effective.  Perhaps this is because the delight in the beauty of discovery overcomes these obstacles, or because the benefits of altruistic sharing outweigh the selfish gain from restrictive practices.  (Of course, the scientific community has its charlatans, fraudsters and free-loaders; but, these counterfeiters tend to operate on a global stage so that even their fake science impacts on the world-wide community of scientists and engineers.)  Participation in this global exchange of ideas and information makes many of us feel part of a world-wide community, or citizens of the world, who are enfranchised by our contributions and interactions with other citizens and international organisations.  Of course, along with everyone else, we are also inhabitants of the world; and these two actions, namely enfranchisement and inhabiting, are key characteristics of a citizen, as defined by the Shorter Oxford English Dictionary.  Theresa May in her speech last October, at the Conservative party conference said: ‘If you believe you’re a citizen of the world, you’re a citizen of nowhere.’  If she is right, then she rendered many scientists and engineers as aliens; however, I don’t think she is, because citizenship of the world does not exclude us from also being citizens of other, local communities; even though politicians may want to redraw the boundaries of these communities and larger unions to which they belong.  However, in practice, it is hard to avoid the fact that we are all inhabitants of planet Earth and have a responsibility for ensuring that it remains habitable for our grand-children and great-grandchildren; so, we are all citizens of the world with its associated responsibilities.

When I was a student, thirty years ago, James Lovelock published his famous book, ‘Gaia’ in which he postulated that the world was a unified living system with feedback control that preserved its own stability but not necessarily the conditions for the survival of the human race.  More recently, Max Tegmark, in his book ‘Our Mathematical Universe’, has used the analogy of spaceship Earth stocked with large but limited supplies of water, food and fuel, and equipped with both an atmospheric shield and a magnetic field to protect us from life-threatening ultra-violet and cosmic rays, respectively.  Our spaceship has no captain; and we spend next to nothing on maintenance such as avoiding onboard explosions, overheating, ultra-violet shield deterioration or premature depletion of supplies.  Lovelock and Tegmark are part of a movement away from a reductionist approach to science that has dominated since Descartes and Newton, and towards systems thinking, in which it is recognised that the whole is more than the sum of the parts.  It’s hard for most of us to adopt this new thinking, because our education was configured around dividing everything into its smallest constituent parts in order to analyse and understand their function; but, this approach often misses, or even destroys, the emergent behaviour of the complex system – it’s like trying to understand the functioning of the brain by physically dissecting it.  Recently reported statements about citizens of the world and about climate change, suggest that some world leaders and politicians find it easier, or more convenient, to use reductionism to ignore or deny the potential for complex systems, such as our global society and planet Earth, to exhibit emergent behaviour.

Thomas L. Friedmann in his book, ‘The World is Flat’ warned that ‘every young American would be wise to think of themselves competing against every young Chinese, Indian or Brazilian’.  He was right; we cannot turn back the globalisation of knowledge.  The hunger for knowledge and understanding is shared by all and courses provided over the internet are democratizing knowledge to an unprecedented level.  For instance, I recently taught a course on undergraduate thermodynamics – not normally a popular subject; but, it was made available globally as a massive open on-line course (MOOC) and taken by thousands of learners in more than 130 countries.  The citizens of the world are becoming empowered by knowledge and simultaneously more networked.  Large complex networks are systems that exhibit emergent behaviour, which tends to be unexpected and surprising, especially if you only consider their constituents.