[lamchopz]

The term “physics” is associated with all things mechanical, energetic and tangible to the mind. Its alternate name is natural philosophy (for a good reason) which may still have some influence today.

Magnetism was already familiar to the earliest human civilisation but its true nature was not fully appreciated until the nineteenth century as we shall see later.

Perhaps the most notable discovery was gravity by Sir Isaac Newton in the seventeenth century. It is one of the four fundamental forces of Nature as we now believe. Newton’s genius did not rest solely on his ability to conceive ‘gravity’ but also his formulation of the gravitational force itself. Summarily speaking, he made use of the now well-known calculus which was entirely absent in his era. Newton was truly a man ahead of his time.

The discovery of the electric force and its intimate connection to magnetism soon surfaced, following the works of Coulomb, Faraday, Ampere, Lenz and many others. In the nineteenth century, Maxwell successfully summarised the electric and magnetic concepts in his celebrated equations that escalated physics to its acme of glory. Together with Newton’s gravity and Maxwell’s equations of electromagnetism, the scientific community were confident that Nature was entirely within the grasp of our feeble human minds - the fact that we fully comprehended the scope of the now named classical mechanics.

Entered Einstein and his groundbreaking theory of relativity.

But let’s step back (conceptually) a bit. Electromagnetism is the necessary unification of two inseparable forces: electricity and magnetism (more accurately, the propagation of electric and magnetic fields which are orthogonal to each other), which were successfully described by the concept of waves and their interactions. However, a problem arose: the ubiquitous Black Body Radiation that appears in any quantum mechanics introductory class. Using the wave theory, one arrived at Rayleigh’s ultraviolet catastrophe where energy diverged to infinity at small wavelengths while experimental data suggested a completely different outcome. The problem was ingeniously solved by Planck: an ad hoc equation coming from the necessitated discretisation of wavelengths (that is, only an integer number of wavelengths were allowed). This was called quantisation. It does not take a strenuous exercise of the mind to figure what would be the logical consequence of Planck’s revolutionary assumption. Yes, it is the modern day’s quantum mechanics.

Now back to our good old Einstein who shed an immensely luminous beam on our understanding of light (pardon the pun) through his explanation of the photoelectric effect which earned him the Nobel prize. Light, which had always been believed to be of wave nature, was indisputably demonstrated to behave like particles. The wave-particle duality of light eventually became the standard framework in mainstream physics (It is worthwhile to add that light particles are called photons which are the quanta, or “discrete packets”, of the electromagnetic field). Afterwards, it was clear that Einstein was born to turn the world of physics upside down and around: his popular equation E = mc^2 and his ultimate formulation of the theory of relativity which existed in two flavours, Special Relativity and General Relativity. Initial scepticism and ridicules of Einstein’s theory as something that defied commonsense quickly lapsed into silence and as we now see, vocal exaltation of his pure genius. There is a reason why “it doesn’t take Einstein to understand this” these days, right?

However, Einstein was not the whole of modern physics even though his brilliance continued to permeate our current experimental and theoretical device. Even the man himself was not always correct – one of his mistakes was criticising quantum mechanics which granted us remarkable insights into the world of little particles and achieved striking experimental accuracy. It is this co-existence of two equally successful but often irreconcilable disciplines – quantum mechanics and relativity – that put us in many a time great dilemma. The fact that gravity in Einstein’s formulation is an intrinsic property of the spacetime continuum, suggesting that it is a fundamental identity of Nature, has haunted us for decades in our (constantly thwarted) attempts at unifying it with the other three forces: the strong and weak interactions and electromagnetism. Moving on from Einstein’s work, we have continued to innovate and the many great names of modern physics, such as Schrodinger, Heisenberg, Dirac, Yukawa, Cabibbo and an interminable list of others, embellished the now highly regarded branch of science called physics.

Not too long ago, another unification of two of the fundamental forces was achieved: the electroweak theory which fully described both the electromagnetic and weak interactions. It was another step forward since the induction of electromagnetism. But, allow me to take you back (again) a bit and examine the progress of the now particle physics which is growing at a scale previously unseen.