Timeline of Physics’ Theories

For a great insight in science and science related topics, the Timeline of Physics’ Theories is the best way to start off.

Newton’s laws of gravitation

Newton in the late 1600s at the age of 23 years observed the motions of objects that fall towards the earth. He asked himself revolutionary questions like “Does the moon also fall  ?”

He extended his observations on the law of gravitation into the heaven itself.

After rigorously studying the phenomenon of falling objects he derived a conclusion that the moon was a satellite of the earth which was held in the sky not by the motion of celestial spheres but by the laws of gravitation.

He said that the moon continuously falls towards the earth governed by the same laws which describe the falling motion of a rock on earth, but the curvature of the earth cancels the falling of the moon.

Newton drew a simple picture to explain this idea of his.

Imagine you are standing at the top of a mountain and throwing a rock, which eventually falls back into the earth.

Now if the same stone is thrown with greater force it would travel farther before falling to the ground.

Now if the rock is thrown with sufficient velocity, he predicted it would complete a circle and hit at the back of your head.

On these lines he concluded that the moon was a satellite of the earth continually falling towards it.

This is considered as the first step towards unifying laws of physics. It united the laws of heaven and earth.

Maxwell’s Electromagnetic Theory

In the mid-1800s Maxwell made an astonishing discovery that magnetic and electric fields are interconvertible.

He stated that a vibrating magnetic field could create an electric field and vice versa.

Challenging the prevailing notions of magnetic and electric domains he said the two were nothing but two faces of the same coin.

Upon studying the laws which united the two domain he arrived at the most impressive conclusion that light is an electromagnetic wave which travel in the direction perpendicular to the directions of both the vibrating electric and magnetic field.

He also argued that the two fields vibrate in perfect sync.

The idea of light being an electromagnetic wave traveling through vacuum seemed preposterous as it opposed the earlier notions of presence of an ether medium for its propagation.

By the end on 19^th century Maxwell had successfully united the magnetic and electric domains.

Albert Einstein’s theory of special relativity

Einstein was the first of all the physicists of his generation to understand the profound distortion of space and time which was intricately entangled with Maxwell’s theory of EMW.

This understanding of Einstein led to the advent of special theory of relativity and in due course of time he proposed many ideas which can be broadly classified into three main categories namely special relativity, general relativity and the unified field theory.

Special relativity theory -1905

Einstein tried to answer a question which had always bothered him as a child.

“What would a beam of light look like if he would race next to it at a speed of light?”.

On the surface level we may say that light would be frozen in time and one could view the stationary electric and magnetic field.

But a closer study into the Maxwell equations suggest that it does not admit stationary waves as a solution, in contrast they predict that regardless of how hard one tries to catch up with light it continues to travel at the same speed.

Einstein quickly grasped that we should change our notion on space and time.

He also said that at greater speeds the bodies underwent distortions.

This theory not only united the space and time but also matter and energy.

Birth of Atomic and nuclear physics

Einstein’s contemporaries like Neil Bohr, Werner Heisenberg and others indulged themselves in the mathematics related to atomic and nuclear phenomenon.

Quantum mechanics deals with the realm of subatomic particles. This idea was triggered from the then challenging study of black body radiations.

Based on the wavelike behavior of light they failed to predict the red-hot and white-hot colors.

Predictions said these radiations would have infinite energies at very high frequencies which is impossible.

This mysterious conclusion was named the ultraviolet catastrophe.

Max plank found a solution using mathematics to find an equation which would agree with all the experimental data collected.

Those equations led to the realization that energy does exist as granule/particles under certain circumstances and the size is extremely small which reasoned why it was neglected.

This idea faced a lot of skepticism but later in 1905 was undoubtedly explained by Einstein in his papers on the photoelectric effect.

In 1923, De Broglie introduced the concept of matter waves.

He stated that electrons should also possess definite frequency and wavelength just like the light waves.

He supported his theory stating nature loves symmetry.

Based on the relations given by De Broglie, Erwin Schrödinger wrote a complete equation.

Heisenberg’s Uncertainty Principle -1927

States that “It is impossible to simultaneously determine the accurate values of velocity and position of a particle.”

This uncertainty arises due to the fact that in the sub atomic realm the object changes either its velocity or position or both at the instance of measurement of the parameters i.e., just the act of measuring velocity or position causes disturbances so great that it forces the system it to have a different value before and after the measurement.

Failures of Quantum physics

Quantum physics worked perfect for only velocities much lower than the speed of light.

When attempt was made to unify quantum physics with special relativity it failed miserably.

The first merge of the two theory called the quantum field theory was a disaster.

Each time the physicists tried to calculate any value the theory predicted infinite values.

Also the force fields obey inverse square law , which implies its value at the surface is 1/0 i.e., undefined.

Thus is enough to prove a theory useless, a theory ridden with infinities and undefined values and assumption cannot be trusted upon.

Superstring theory

The problems faced by the previous theories can be solved by replacing point particles with strings.

This is the basis of the superstring theory which is the matter of concern in the recent past  

Which is said to close on the unified filed theory – a precise, compact, mathematical skeleton uniting all the forces of nature.

The discoverers of this theory call it the “Theory of the universe “John Schwarz and Michael Green have boldly called this theory as the “Theory of Everything”.

An excitement prevails among all the physicists as this can be a theory which answers all the questions ranging from motion of galaxies to the dynamic nature of the atomic nucleus.

This theory assumes that the smallest building block of matter consists of the tiny vibrating particles.

Which means our understanding of what matter is would now be “Matter consists of particles that are different modes of vibration of a string”.

Which explains the existence of the trillions of different atoms.

If this theory turns out to be true all the information contained in the Handbuch der Physik, the volumes of which occupy an entire library can be derived from a single mathematical equation.