BIG BANG THEORY (part 2)
IN MY last article, I outlined the search to find the physics behind the Big Bang and explained how physics is still being baulked by the puzzle to find the last few trillionths of a second of pre-history.
In a sense, it is like the greatest detective story of all time – no-one knows for sure why the Big Bang happened, and how.
Science can reach within a few trillionths of a second of creation; but beyond that, physics breaks down and it is anyone’s guess; even a theoretical physicist would agree on this. Whether you call that missing knowledge gap ‘God’, or a scientific missing link is all a question of faith and interpretation.
Since the beginning of science, people have puzzled over Nature itself and the major forces within such.
Perhaps the most famous is gravity; it is the most ‘apparent’ to us, but there are three other forces of Nature: these are (1) electro-magnetism (actually two forces joined together); (2) the Strong Nuclear Force and (3) The Weak Nuclear Force. Gravity is the weakest of the four but the most effective over long distance.
The great quest of particle physicists today is the search for a so called Theory of Everything. Part of the quest of the Large Hadron Collider at CERN is not just to find exotic particles such as the Higgs Boson, but also to try to unravel the mystery of the grand unification of all the forces of Nature.
At the moment of the Big Bang (if you accept such) all these forces would have been in a point of perfect unison.
As the universe has cooled and expanded over the years, not only have the particles of matter separated out, but the major forces have divided, though the majority still interact.
Most electricians and high school students are aware of the link between electricity and magnetism; but this wasn’t always the case.
The first force to be realised was gravity by Isaac Newton 1687. He realised that objects in the universe attract every other object with a force proportional to their mass.
This was a profound idea and important as for the first time it seemed that the actions of the universe could be measured to some mathematical accuracy.
Newton was actually a fervent believer in God and thought the movements of the universe were directly due to ‘His’ actions.
The link between electricity and magnetism was realised when a Danish physicist called Orsted noticed that that a compass needle was deflected by a nearby battery he was using.
Michael Faraday later realised that if an electric current could produce a magnetic field, then a magnetic field should produce an electric current. More to the point he realised forces are transmitted by fields.
James Clark Maxwell further developed this idea in the 1860s by realising the intimate relationship between electromagnetism and light.
He realised that electromagnetic waves moved through space in a wave – and to his astonishment that the speed that he calculated equalled that of light.
The electromagnetic spectrum – with which we are familiar today (of which visible light is just one part) is a manifestation of this property.
Electro-magnetism is a very powerful long range force - but only acts on those particles which have an electrical charge.
The other two forces are called the Strong and Weak nuclear forces.
The Strong Nuclear Force is the ‘glue’ which binds protons and neutrons together in the atomic nucleus – and the three quarks within each.
The Weak Nuclear Force is responsible for radioactivity.
All of these forces have force carrying particles called ‘bosons’ and scientists are slowly working towards unifying all the forces.
The weak nuclear force was unified with electro-magnetism in the late 1960 – it was called the electro-weak force.
But attempts at unifying this with the strong nuclear force - to form what is known as a Grand Unified Theory - have since been baulked.
But the greatest challenge remains in unifying a Grand Unified Theory with the final force of gravity – to create what is referred to as a theory of quantum gravity, or in shorthand The Theory of Everything.
The nearest they have such currently is the Standard Model of Particle Physics, which charts all the basic particles and forces in the universe.
To this has recently and triumphantly been added the Higgs Boson.
Bosons are force carrying particles; each of the four main forces are theorised to have particles which carry their force.
Photons and two others carry the ‘electro-weak’ field; gluons the strong nuclear force; and the Higgs boson the so called Higgs field, which is important in the concept of mass in the universe.
All of these cannot be assimilated with gravity in one large unified theory; the concept of a boson called a graviton is the one which should carry the gravitational force but it is not part of the Standard Model.
The problem lies at the so called quantum level (the very small level of physics where chance seemingly plays a key part in the position and measurement of particles).
While quantum versions of some of the four main forces have been found, the quantum theory of gravity remains elusive; it did to Einstein and others.
Nobel Prizes lie in wait for those clever enough to crack such.