Physics – A Brief History

Mathematical disciplines began in antiquity with the Babylonians and with Hellenistic writers such as Archimedes and Ptolemy. Ancient philosophy, meanwhile, included what was called “Physics”.

The philosopher Thales of Miletus (7th and 6th centuries BCE) proclaimed that every event had a natural cause. Thales also made advancements in 580 BCE by suggesting that water is the basic element. Anaximander, famous for his proto-evolutionary theory, disputed Thales’ ideas.

During the classical period in Greece (6th, 5th and 4th centuries BCE) and in Hellenistic times, natural philosophy slowly developed into an exciting and contentious field of study.

Around 240 BCE, as a result of a seminal experiment, Eratosthenes accurately estimated the circumference of the earth. In contrast to Aristotle’s geocentric views, Aristarchus of Samos said the Earth rotated around its own axis, which, in turn, revolved around the Sun.

Archimedes laid the foundations of hydrostatics, statics and calculated the underlying mathematics of the lever. His screw underpins modern hydroengineering, and his machines of war helped to hold back the armies of Rome in the First Punic War.

Ptolemy was one of the most famous physicists during the time of the Roman Empire. He used sophisticated geometrical techniques to map the motion of the stars and planets. He added calculations of the distance of the Sun and Moon from the Earth, based upon his improvements to the observational instruments used at that time.

Almost nothing of Hipparchus’ direct work survived. Of the 150 reputed Aristotelian works, only 30 exist, and some are “little more than lecture notes”.

Maharishi Kanada was the first to systematically develop a theory of atomism around 200 BCE. It was further elaborated by the Buddhist atomists Dharmakirti and Dignāga during the 1st millennium CE.

Atomism (from Greek, atomon, i.e. “uncuttable, indivisible”) is a natural philosophy proposing that the physical universe is composed of fundamental indivisible components known as atoms.

In the 7th to 15th centuries, scientific progress occurred in the Muslim world. Many classic works in Indian, Assyrian, Sassanian, and Greek were translated into Arabic.

Ibn al-Haytham is considered to be the “father of the modern scientific method” due to his emphasis on experimental data and reproducibility of its results.

Ibn Sīnā was a polymath from Bukhara (in present-day Uzbekistan) responsible for important contributions to physics, optics, philosophy and medicine. He published his theory of motion in Book of Healing (1020), where he argued that an impetus is imparted to a projectile by the thrower.

Hibat Allah Abu’l-Barakat al-Baghdaadi (c. 1080-1165) adopted and modified Ibn Sina’s theory on projectile motion.

Ibn Bajjah proposed that for every force there is always a reaction force. He was a critic of Ptolemy and worked on creating a new theory of velocity to replace the one theorized by Aristotle.

Nasir al-Din al-Tusi was a Persian astronomer and mathematician who died in Baghdad.

Scholastic European scholars sought to reconcile the philosophy of the ancient classical philosophers with Christian theology. Aristotelian physics became the foundation for the physical explanations of the European Churches.

Scholastic physics described things as moving according to their essential nature. The theory of impetus, the ancestor to the concepts of inertia and momentum, was developed along similar lines by medieval philosophers such as John Philoponus and Jean Buridan.

During the 16th and 17th centuries, the Scientific revolution took place in Europe. Dissatisfaction with older philosophical approaches had begun earlier and had produced other changes in society.

Polish astronomer Nicolaus Copernicus (1473–1543) gave strong arguments for the heliocentric model of the Solar System. The Greek-Egyptian astronomer Ptolemy (2nd century CE) had suggested that the Earth revolves around the Sun.

Galileo’s role in the university culture of his era was subordinated to the three major topics of study: law, medicine, and theology. He was famous for his support for Copernicanism, his astronomical discoveries, empirical experiments and his improvement of the telescope.

Galileo’s support for heliocentrism provoked controversy and he was tried by the Inquisition. His discovery of the Jovian moons was published in 1610 and enabled him to obtain the position of mathematician and philosopher to the Medici court.

French philosopher René Descartes (1596–1650) was well-connected to, and influential within, the experimental philosophy networks of the day. He had a more ambitious agenda, which was geared toward replacing the Scholastic philosophical tradition altogether.

The Dutch physicist, mathematician, astronomer and inventor Christiaan Huygens (1629-1695) was the leading scientist in Europe between Galileo and Newton. He came from a family of nobility that had an important position in the Dutch society of the 17th century.

Sir Isaac Newton created a single system for describing the workings of the universe.

Newton’s principles proved controversial with Continental philosophers, who found his lack of metaphysical explanation for movement and gravitation philosophically unacceptable. A bitter rift opened between the Continental and British philosophical traditions.

Swiss mathematician Daniel Bernoulli (1700–1782) made important mathematical studies of the behavior of gases. In 1733, he derived the fundamental frequency and harmonics of a hanging chain by solving a differential equation.

During the 18th century, thermodynamics was developed through the theories of weightless “imponderable fluids” such as heat, electricity, and phlogiston.

In 1821, William Hamilton began his analysis of Hamilton’s characteristic function. In 1835, he stated Hamilton’s canonical equations of motion. In 1847, Hermann von Helmholtz formally stated the law of conservation of energy.

In 1821, Michael Faraday built an electricity-powered motor, while Georg Ohm stated his law of electrical resistance in 1826. In 1831, Faraday and independently Joseph Henry discovered the reverse effect, the production of an electric potential or current through magnetism – known as electromagnetic induction.

In the 19th century, the connection between heat and energy was established quantitatively by Julius von Mayer and James Prescott Joule, who measured the mechanical equivalent of heat in the 1840s. In 1849, Joule published results from his series of experiments which show that heat is a form of energy.

James Maxwell published his papers on a dynamical theory of the electromagnetic field in 1864. In 1859, Maxwell worked out the mathematics of the distribution of velocities of the molecules of a gas. The wave theory of light was widely accepted by the time of Maxwell’s work.

The statistical mechanics of Ludwig Boltzmann and Josiah Willard Gibbs studies the statistics of microstates of a system and uses statistics to determine the state of a physical system. The statistical versus absolute interpretations of the second law of thermodynamics set up a dispute that would last for several decades.

At the end of the 19th century, physics had evolved to the point at which classical mechanics could cope with complex problems involving macroscopic situations. The triumph of Maxwell’s theories, for example, was undermined by inadequacies that had already begun to appear.

In 1896 Henri Becquerel discovered that certain kinds of matter emit radiation on their own accord. In 1897, J. J. Thomson discovered the electron, and new radioactive elements found by Marie and Pierre Curie.

Einstein’s radical theory of relativity revolutionized science. His major contribution was the recognition that the speed of light in a vacuum is constant, i.e. This does not impact a person’s day-to-day life.

Einstein argued that electromagnetic laws should remain valid independent of reference frame. The theory arose out of contradictions between electromagnetism and Newtonian mechanics. Einstein demolished the ether concept in his special theory of relativity.

Einstein’s theory of relativity described the gravitational effect at every point in space. The curvature of space-time completely replaced Newton’s universal law of gravitation. By 1916, Einstein was able to generalize this further, to deal with all states of motion.

Quantum mechanics is the theory of atoms and subatomic systems. The first 30 years of the 20th century represent the time of the conception and evolution of the theory.

Quantized theory of the atom gave way to full-scale quantum mechanics in the 1920s. New principles of a “quantum” rather than a “classical” mechanics were based on probabilistic relationship between discrete “states” and denied possibility of causality.