THE CHALLENGE TO NEW IDEAS
The fifth Solvay Conference, named after the Belgian industrialist Ernest Solvay, began in Brussels in September 1927. Present were the leading physicists of the day, including Albert Einstein, Paul Dirac, Niels Bohr, Erwin Schrodinger, Werner Heisenberg and Wolfgang Pauli. The main talking point of the conference was to be the relatively new subject of quantum mechanics and, as such, signalled the continuation of a discussion between Niels Bohr and Albert Einstein regarding the former’s theory of complementarity. The Theory of Complementarity states that particles, such as electrons, have pairs of properties that are unable to be measured or observed at the same time. Essentially, this means that if we are able to measure a property such as momentum accurately, then we cannot accurately measure the same particle’s position. Einstein did not agree; and as it turned out this would be by no means the last theory of quantum mechanics that he would have problems with despite the fact that Bohr would even use Einstein’s own theory of relativity to prove a point related to complementarity. Einstein’s problem was one of classical physics, visualisation and causality against the strange, at times weird, theories governing the quantum world. Saying, “there is a good chance this may be the case”, was not good enough for Einstein.
In order to prove his point that two quantum measurements could be made accurately at the same time, Einstein came up with a series of ‘thought experiments’ that he put to Bohr as proof that his theory of complementarity, or Copenhagen interpretation, was flawed. In one experiment, Einstein asked Bohr to consider a box which had inside it a clock connected to a small shutter. The box is then filled with photons and weighted. At a known time, a single photon is allowed to escape through the clock activated shutter. The box is then re-weighed and by Einstein’s famous equation E = mc2 , the exact energy of the photon can be calculated. Thus, the time of release and the energy of the photon have been measured accurately at the same time; in violation of Bohr’s complementarity theory and energy-time complimentary pair uncertainty relationship. Bohr’s response the following day, made reference to a box, with clock and shutter inside the box as Einstein had described, but suspended by a spring. On the stand supporting the box, was a pointer and scale to indicate the box’s rest or starting position. Finally, a changeable small weight, used to return the box to its starting position when the weight inside the box changed, was suspended from the bottom of the box. Any change in weight could easily, once more, be converted into lost (or gained) energy by Einstein’s equation. Bohr’s argument was that in trying to adjust the size of the weight the box would be subject to moving up and down before eventually settling, once the correct weight was in place and the pointer was pointing at the rest position. According to Einstein’s own Theory of General Relativity, the movement of the box in this way, and therefore the clock, both within a gravitational field, meant that the time measured by the clock in the box was now uncertain in that the clock in the box would measure time more slowly than a clock at rest and within the observer’s own reference frame. The longer it takes to get the right weight in position, the worse things get. This meant that to get an accurate measurement for energy, which meant spending a lot of time getting the weight just right, the time of release was now uncertain due to time dilation. Bohr had won another round!
So was this a case of an older scientist, with long established views on how the world, and beyond, works at odds with a new way of thinking? Certainly, it is the case that many scientific discoveries and breakthroughs are made by scientists in the earlier part of their careers; Einstein was only 26 years old when he published his Theory of Relativity. And is there a case in science of two steps forward and one step backwards due to opposition for new ideas from the scientific establishment? Whatever the case, it is clear that one of the goals of successive generations is to shoot at whatever went before, whether this be the fastest, the most, the highest or even our long perceived understanding of how something works, only to one day be told that everything we thought to be true was in fact all lies. And is it not also the case that in order to make progress, that our starting point is always what is there already. Many will play about with what is there but a few, such as Einstein and Bohr, will be brave enough to change it entirely.
SO FAR SO GOOD......BUT WHAT NEXT?
Our latest estimate for the age of the universe, based on examining the distance away from us of the oldest stars and then extrapolating back based on the known expansion rate of the universe, is around 13.7 billion years. What we know as The Big Bang happened at this time; not so much an explosion in the conventional sense, where matter spreads out evenly from a central source, but instead an explosion everywhere at the same time. There then went on a long period of cooling during which, to begin with, electrons, positrons, neutrinos and photons (light particles) dominated along with smaller numbers of protons and neutrons. As the temperature dropped to around thirty thousand million degrees centigrade, the electrons and positrons began to annihilate each other at a faster rate than they could be created. As the universe cooled further atom nuclei of heavy hydrogen and helium formed and then later, after another period of cooling, hydrogen and helium atoms began to form by combining with the small number of electrons which had survived the earlier positron-electron annihilation. The resulting gas then began to clump together due to gravity, finally forming our stars and galaxies we see today. Our own solar system was formed in this way around 4.5 billion years ago with Jupiter being the first planet to form. Not long after the earth’s own formation, around 100 million years later, water appeared (most likely following a strike by a water laden meteorite) and the oceans began to take shape, leading to, in another one to five hundred million years, the first signs of life. It was to be almost another 4 billion years later (five to seven million years ago) that our own first primitive ancestors began to appear in Africa.
So, what have we been doing since? Not surprisingly, all we need to do is to look at the world around us today to see the answer to this question. By simply looking, we in fact see the evolution of our world in that we only see the continued existence of our ‘good ideas’ much in the same way that only the fittest species have survived. Much of what we see then, such as agriculture and our ability to make and use tools, has simply got better. Technology is now the main driver of where we go next, developing small digital devices with the power of a super computer from only a few years ago to developing an effective virus for a world pandemic in a matter of months. It is certainly the case that places such as CERN have helped to drive our technological advances as well as trying to uncover the mysteries of the universe and the quantum world. The discovery of the Higgs particle in July 2012 was the confirmation of theory put forward almost half a century before and helped confirm the validity of the Standard Model; the theory describing all elementary particles and three of the four known forces. The fact is that we still know very little of how our world, and indeed universe, works. The quantum world is still baffling (beyond baffling to most of us!) and we only have an understanding of a small fraction (5%) of what makes up the universe. The rest is in the form of dark matter – around 27% - which holds our galaxies together and prevents them flying apart and dark energy – around 68% - whose effects can be seen in the way that the expansion of the universe is accelerating rather than, as previously, thought, slowing down. So never stop being totally amazed at how we got here and what we have achieved in such a short time. And what next? A theory of everything that combines the four forces of electromagnetism, gravity, the weak and strong nuclear forces? The creation of dark matter? A cure for every known disease? Certainly the technology to help us achieve all of this, and lots more that we cannot perceive because its existence is still too far off, is coming closer every day due to advances in new technologies such as quantum computers alongside larger colliders capable of generating larger, more energetic, collisions and therefore revealing yet more understanding of the world in which we live.
