It’s a little over a hundred years ago.
The nineteenth century was at its fag end. The Spanish, French, Holy Roman and the Mughal empires had by then collapsed. The British empire was at its height.
Significant advances in medical knowledge contributed to the wellness of the people and increase in population. Remarkable progress was made in all fields of science – mathematics, physics, biology, chemistry, metallurgy and so on. Aspirin was invented and ambitious technology to fly in the sky for mass transport was taking shape.
Physicists of the day became smug. Everything worth knowing about nature and its laws were considered to have already been known.
Lord Kelvin, himself a respected Physicist, declared: “There is nothing new to be discovered in physics now, all that remains is more and more precise measurement.”
With the dawn of the twentieth century, the times, however, turned very tumultuous. Rather innocuously but suddenly.
Twenty-something Physicists from different parts of Europe began to demolish all the carefully constructed concepts that ruled the roost for centuries before them.
There was excitement all around.
The supposedly all pervading aether in the entirety of the universe, almost like a divine-entity, was established to be non-existent.
The words of the doubting Toms who said that the presence of ‘atoms’ could never be proved were disproved.
Hot bodies were found to cool down, not gradually but, by losing their heat in discrete amounts radiated out as packets of energy. Light too was found to move as streams of little packets when it was transmitted. These packets of energy were given the name – “Quanta” (quantum – singular).
Soon, the most revolutionizing Quantum Physics took shape.
The cozy assumption that ‘space’ where we all exist was absolute and unchanging was shaken up. The snug belief in the irrevocable one-way arrow of time along which all things get pushed was punctured. The confidence of the Physicists who boasted that they could predict the location of any object in the universe if they were given all the information about its current position was tattered beyond redemption. An element of probability replaced the definitive determinism about the laws of nature or even our own existence.
Quantum Physics comprehensively described how small particles of the size of an atom or smaller would behave. It is unlike anything we are familiar with or can know intuitively. For example:
- An atomic or subatomic size particle can exist here, there or anywhere all at the same time, as if it is smeared allover the universe. Probably, there is a denser smear where you think you find it.
- If two particles come once in touch with each other, they never lose again their bond, even if they are separated to the either end of the universe. If a change is brought out on one of them, the other reacts instantaneously.
- These particles can pass through thick walls and appear on the other side in no time at all as if they penetrated through the obstructions by tunneling.
- These particles can exist simultaneously in more than one state – equivalent to saying that a cat, say, can be dead and alive at the same time. What exact state it is in (dead or alive) depends on the observer also and not merely on the cat.
- The particles can travel from the past to the present and on to the future and equally comfortably from the present or future to the past. The arrow of time is not a one-way street for them.
- Vacuum is a place of ‘nohingness’ for us. But it actually sizzless with the constant birth and death of these particles. Vacuum derives enormous energy from the appearance and disappearance of these particles.
- When these small particles propagate, they move sometimes as bullets, and sometimes like waves on the surface of a lake. What exactly is their form is incomprehensible (we shall discuss this matter in more detail in the next part of this article).
And imagine that all of us and everything we operate with are made up of such strangely behaving particles! Do you think you are still there if what constitutes you is partly here, partly maybe on moon, and God knows where else!
Most of this revolution in Physics had happened not in expensive laboratories; nor did it result from the joint effort of a host of specialists. It came about from the intense contemplative ‘gedankenexperiment’ (thought experiment) of sage-like scientists working individually at their own desks.
There were undoubtedly many stalwart scientists who knit the earth-shaking paradigm-shifting new Physics of those times. But one name that tops them all is, indisputably, that of Dr. Albert Einstein. With a series of ground-breaking papers in one year, he changed irrevocably the face of Physics in 1905. By another decade, he came up with his Theory of Relativity to explain the gravitational attraction by massive bodies.
The thus-far inexplicable change in the orientation in the orbit of the planet Mercury as it orbited around the Sun (precession of the perihelion) was not any more a heavenly mystery. Einstein’s theory could explain it very accurately. His theory explained why large bodies like the earth have gravity. He said that such massive entities bend the fabric of space like you create a depression with your body weight when you sit on a trampoline.
Even the distant stars in the sky began to yield their secrets to the inquisitive minds of the astronomers. Based on the equations that Dr. Einstein established, one of the Physicists (he was actually a clergyman too) proposed that at one time in the past the entire universe should have been no bigger than the size of the period at the end of this sentence. The theory said that the universe evolved from that point size to what it is now over billions of years – much like what our ancients said from the anDa (egg) to the brahmAnDa (cosmos).
Yes, The Modern Physics had arrived.
The most accurate estimate of the age of the universe based on data from space satellites (WMAP, 2010 and PLANCK, 2013) today is 13,800,000,000 (i.e. 13.8 billion) years. Our Solar system and the earth formed about 4.5 billion years ago and are expected to have a further life of about 4.5 billion years.
(Compare the above periods to a Kalpa or one day time in the life of Brahma – 4.32 billion years. Brahma has equally long night time. The Kaliyuga is supposed to have started in 3100 B.C. E. as per the astronomical calculations using modern computer software. It lasts for 432,000 human years. A Mahayuga, comprising Kali, Dwapara, Treta and Krita yugas, has a length of 4,320,000 years).
Thus in less than three decades after the heralding of the twentieth century, two broad theories emerged – the Quantum theories explaining the physics of the small particles and Relativity theory of Dr. Einstein dealing with large bodies, though nobody knew at what size of the matter the physics changes from one theory to the other.
Dr. Einstein also proved the identity of matter and energy through his famous equation
E = m c2
where ‘m’ represents the mass of the matter and c is the constant speed at which light travels. Thus all matter could be converted into energy as per the above equation.
As per the present understanding of the Physicists, energy manifests in the form of four forces in the universe – the electromagnetic force, the weak nuclear force, the strong nuclear force and the gravitational force. It is common sense that these four forms of forces must have had existed as a single force in the beginning of the universe. But unfortunately, Physicists are still unable to deduce the nature of that single Grand United force.
The principles of Quantum Physics applicable for small particles could not be used when all the forces are merged into a singularity at the beginning of the universe because of the enormous mass of the dot (into which the matter of the entire universe gets compressed). The Relativity theory which is useful for understanding heavy masses becomes inapplicable because of the minute size of the particle. As a result, Physicists to this date do not know what sort of laws will be valid for application at the beginning of the universe. Everyone is eagerly awaiting the arrival of another Einstein to throw light on the problem.