History of Science - 11.
Francesco Grimaldi-(1618-1663).
Joseph Lagrange-(1736-1813).
Leonhard Euler-(1707-1783).
Thomas Young-(1773-1829).
Augustine Fresnel-(1778-1827).
William Wollaston-(1766-1828).
Josef von Fraunhofer-(1787-1826).
Michael Faraday-(1791-1867).
Armand Fizeau-(1819-1896).
James Clerk Maxwell-(1831-1879).
Albert Einstein-(1879-).
Albert Michelson-(1852-1931).
Hendrik Lorentz-(1853-1928).
Until the end of the 18th century Newton’s conceptions of light as a stream of particles,
dominated over the wave model of light.
Over the next 100 years a new understanding of light developed.
Even before Newton, there was some evidence that light travels as a wave.
Italian physicist Francesco Grimaldi studied light by letting a beam of sunlight into a darkened room,
through a small hole.
When the beam passed through, a second small hole on to a screen, the image on the screen formed,
by the spot of light had coloured fringes.
This was slightly larger than it should be if light travelled in straight lines.
He concluded correctly that, the light had bent outwards slightly, a phenomena he called diffraction.
His other experiments provided evidence that light travels as a wave.
His findings were published 2 years after he died.
Newton read Grimaldi’s book, when he was 21, but he did not appreciate the wave model.
Leonhard Euler, is usually remembered for his work in pure mathematics.
He developed the idea of the principle of least action.
One manifestation of this is that light travels in straight lines, by the shortest routes.
Joseph Lagrange, carried forward this work, which provided the basis for the,
mathematical description of the quantum world, in the 20th century.
Euler introduced the mathematical notations like pie, e, and i.
In 1733, he made the mistake of directly looking at the sun.
This cost him the sight of his right eye.
Unfortunately in 1760, he went blind on his left eye also due to cataract.
This did not come in the way of his prodigious mathematical output.
Euler published his model of light in 1746.
He made the analogy between light waves and sound waves.
The analogy is imperfect, and shows how the wave model was still not developed at that time.
Thomas Young was born in Somerset in 1773.
He was a child prodigy.
He could read English at the age of 2, and Latin when he was 6.
He rapidly moved to Greek, French, Italian, Hebrew, Syriac, Arabic, Persian, Turkish and Ethiopic,
by the time he was 16.
He came from a wealthy family, and received no formal education.
He did not need it, and studied on his own.
He studied widely including ancient history, archeology, physics, chemistry, and much more.
At the age of 19, he started to train for the medical profession.
He received his MD. in 1796.
He was already well known in the scientific circles.
He had explained the way muscles change the shape of the lens of the eye, to help it focus,
in his first year as a medical student.
He was elected a Fellow of the Royal Society at the age of 21, for this.
In Cambridge he gained the nickname of ‘Phenomenon’ young, for his ability and versatility.
His uncle passed away, and left him with his house, and a fortune.
In 1800, at the age of 27, he setup his medical practice in London.
Though he remained active in medicine, for the rest of his life,
he continued to make wide-ranging and important contribution to science.
He gave lectures at the Royal Institute, which sometimes went over the heads of his audience.
Young correctly explained astigmatism, was caused by uneven curvature of the cornea of the eye.
He also discovered that colour vision is produced by combination of 3 primary colours,
red, green and blue, which affect different receptors in the eye.
He estimated the size of molecules.
He served as the Foreign secretary to the Royal Society.
He played a leading role in deciphering the Rosetta Stone.
Young is best remembered for his experiments in light, which proved that light travels as a wave.
In 1800, he compared and contrasted Newton’s and Huygens’s models of light.
He supported the wave model of Huygens.
He proposed that different colours of light corresponds to different wavelengths.
In 1801, he announced the key idea of interference in light waves.
This is like the way, waves in a pond interfere with each other, when we throw two pebbles into the pond,
at the same time, in different places.
Young explained how Newton’s rings could be explained by interference.
He used Newton’s own experimental data to calculate the wave length of red light,
as 6.5 into 10 to the power of minus 7 meters,
and violet light as 4.4 into 10 to the power of, minus 7 meters.
These numbers agree well with modern measurements.
It shows how good and experimental Newton was, and how good a theorist Young was.
Young devised the double slit experiment, that bears his name.
The experiment makes a pattern of light and shade, called a ‘interference pattern’.
The exact spacing of the pattern, depends on the wavelength of the light.
This can be calculated by measuring the spacings of the stripes in the pattern.
10 years later, Young refined his model, suggesting that light waves are produced,
by a transverse undulation, rather than being longitudinal waves, like those of sound.
His physicists friends were angered by the suggestion, that anything Newton said could be wrong.
They ridiculed Young’s idea, that darkness could be made by adding two beams of light,
which are out of phase.
Augustine Fresnel was born in 1788 in Normandy.
He was a son of an architect, who retreated to his country estate,
to escape the turmoil of the French Revolution.
Fresnel was educated at home, till the age of 12.
In 1809, he qualified as a civil engineer, and worked for government road projects in France.
Alongside his job, Fresnel took an interest in optics.
Fresnel was unaware of the work of Young, Huygens and Euler.
He developed his own model of light, completely from scratch.
Fresnel approach to a wave model of light, was also based on diffraction.
The French academy offered a prize for whoever could provide the best experimental study,
of diffraction, and back it up with a theoretical model.
Fresnel submitted his theory of the wave form of light.
The judges were confirmed Newtonians, who favoured the corpuscular model.
However, they arranged for a physicist to test the theory.
The test proved that light travels as a wave.
The wave model of light, was upgraded from a hypothesis, to a theory.
Fresnel was elected to the French academy in 1823.
He was made a Fellow of the Royal Society in 1825.
In 1827, he received the Rumford medal, 100 years after the death of Newton.
Fresnel died a few days later from TB.
Fresnel had developed a lens made of concentric annular rings of glass,
each with a slightly different curvature.
It is now called as the Fresnel lens.
Light now was becoming possibly the most valuable tool in science,
through the Young discipline of spectroscopy.
Spectroscopy requires a combination of a prism, for spreading out light into its spectrum of colours,
and a microscope to scan the spectrum.
When light is studied this way, it can be seen that there are many distinct sharp lines in the spectrum,
some bright and some dark.
The English physicist and chemist William Wollaston noticed this first, in 1802.
Wollaston was a supporter of Dalton’s atomic theory, and had discovered rhodium and palladium.
The German physicist Josef von Fraunhofer independently discovered this spectrum lines in 1814.
He followed the discovery with a proper investigation of the phenomenon.
The lines are now called Fraunhofer lines.
He also invented another technique for spreading the light out into the spectrum,
called the diffraction grating.
He worked for an optical laboratory, where he tried to improve the quality of glass in lenses and prisms,
for scientific work.
His skills made the fortunes of the company, Munich Philosophical Instrument Company.
It laid the foundation for Germany to become pre-eminent in the manufacture,
of optical systems for a century.
Fraunhofer studied the effect on sunlight on glass, and saw many more dark lines in the solar spectrum,
then Wollaston, thanks to the superior quality of his instruments.
He counted a total of 576 lines between the red and violet ends of the spectrum,
and measured their wave lengths.
He also noticed similar lines in the spectra of Venus and the stars.
He proved that they were a property of light itself, and not of the glass in the prisms.
He never found out what made the lines, but he perfected the use of spectroscopy in science.
Robert Bunsen and Gustav Kirchhoff further investigated spectroscopy.
The Bunsen burner is named after Robert Bunsen.
When a substance is heated in the clear flame of a Bunsen burner,
it provides a characteristic colour to the flame.
Substances containing sodium, colour the flame yellow.
Even without spectroscopy this provides a simple way to test,
whether particular elements are present in a compound.
With spectroscopy we can go one step further.
Each element, when hot, produces a characteristic pattern of bright lines in the spectrum.
Anywhere that we see those lines in a spectrum, we know the element associated with those lines.
Each pattern is as distinctive as a finger print, on a bar code.
When a substance is hot, it produces bright lines, as it radiates light.
When the same substance is cold, it produces dark lines in the spectrum, as it absorbs background light,
at precisely the same wave length, it radiates light when hot.
In 1859, Kirchhoff identified the characteristic sodium lines, in light from the sun,
proving that sodium is present in the atmosphere of the sun.
In a striking example of the power of spectroscopy, it enabled astronomers to find out,
what the stars are made of.
In 1868, Pierre Jansen and Norman Lockyer, found a pattern of lines in the solar spectrum,
which did not match the fingerprint of any known element on Earth.
Lockyer inferred that they must belong to a unknown element, which he named as Helium,
from ‘Helios’, the Greek word for the sun.
Helium was identified in Earth only in 1895.
By then the nature of light had been completely resolved,
thanks to the understanding of electricity and magnetism, from the work of Michael Faraday,
and James Clerk Maxwell.
This is regarded as the most profound piece of new physics, since the time of Newton.
Michael Faraday was born in 1791, to a blacksmith in England.
His father James Faraday suffered from ill health, and was often not able to work.
The children were raised to poverty.
Their education did not extend beyond the basics of reading, writing and arithmetic.
When Faraday was 13, he started to run errands for a bookseller and a bookbinder.
Later he was apprenticed to learn bookbinding, and moved to a room above his shop.
Faraday read voraciously from the piles of book available to him.
He became fascinated with electricity.
In 1810, he became a member of the city philosophical society, which was a group of young men,
who met to discuss exciting new discoveries in science.
He carried out experiments in chemistry and electricity, and discussed them with other members.
Faraday took detailed notes at these meetings, and he had four bound volumes of these notes,
by the time he was 21.
His employer showed off his notes to a customer, which resulted in an invitation,
to attend a series of lectures by Humphry Davy at the Royal Institute, in 1812.
He attended the lectures and took detailed notes as usual.
Though he dreamed of becoming a scientist, there seem to be little chance of becoming a reality.
He was employed as a bookbinder, but kept applying for any menial job.
Then he had a stroke of luck, which would change his life.
Humphry Davy was temporarily blinded by an explosion in his lab.
He needed somebody with a little knowledge of chemistry, to act as his secretary for a few days.
Faraday presented Davy, the notes he had taken of his lectures,
and pleaded for any modest job at the Royal Institute.
Davy offered him the post of a laboratory assistant,
but warned him that there is not much money in science.
Faraday did not care, and took the job for a guinea a week, in 1813.
He was given free accommodation in a room on top of the Royal Institute building.
He was also given candles, and fuel for his fire.
Later Davy asked him to accompany him and his wife, as his assistant and a valet,
on a scientific trip to Europe.
Davy’s wife treated him like a servant, and made life very difficult for Faraday.
In spite of this Faraday stuck on to his job.
He met many leading scientists in Europe.
He went on to become from Davy’s assistant to Davy’s collaborator.
He also learnt French and Italian.
In 1821, he married Sarah, but they did not have any children.
In 1820, the Dane Hans Christian Oersted, in his experiments, had discovered that,
there is a magnetic effect associated with electric current.
This magnetic field seemed to operate in a circular fashion,
compared to a conventional straight forward push-pull forces of bar magnets,
which was known at that time.
The sensational news spread across Europe, and many people repeated the experiments,
and tried to come up with an explanation.
William Wollaston was one of them, who suggested that electricity travels in a helix, down a wire,
which gives rise to the circular magnetic field.
Wollaston visited the Royal Institute, and conducted some experiments with Davy,
to test his hypothesis, but it failed.
Faraday repeated Wollaston’s experiments to validate it.
In the process he discovered that a magnet moves around a fixed wire carrying electric current.
He published this in 1821.
But some people, including Davy, thought he was trying to steal the credit for Wollaston’s work.
Davy in fact tried to prevent Faraday from becoming a member of the Royal society.
But other scientists appreciated the significance of his work,
and he was elected a Fellow of the Royal Society in 1824.
Faraday’s discovery forms the basis of the electric motor.
He became famous across Europe for this discovery.
60 years after Faraday’s discovery, electric trains started running, in Germany, Britain, and the USA.
Faraday went on to work in chemistry.
He was the first person to liquify chlorine in 1823.
He discovered benzene in 1825.
Benzene had the archetypal ring structure, which in the 20th century was discovered,
to be a key importance, in the molecules of life.
In 1825, he became the director of the Royal Institute.
He introduced a new series of popular lectures, many of which he gave himself.
In 1833, he became a Fullerian professor of chemistry, at the Royal Institute.
In his 40’s at that time, he returned successfully to the work on electricity and magnetism,
which was his greatest achievement.
In the 1820’s there was a question on the minds of many scientists, including Faraday.
If an electric current can induce a magnetic force, can an magnet induce electric current?
By 1831, it became clear through the work of some scientists,
that an electric current passing through a wire wound in a helix, would act like a bar magnet,
with the north and south pole.
If the wire was wound around the iron rod, it would become a magnet, when the current is switched on.
Faraday conducted experiments to see if this would work the other way round.
Faraday found that moving a bar magnet, in and out of a coil of wire, causes current to flow in the wire.
He thus discovered a moving magnet induces an electric influence, in its vicinity.
Faraday had now invented the electric generator of dynamo.
The discovery was presented to the Royal Society in 1831.
This made Faraday one of the top scientists of this time.
Faraday continued his work, in electrochemistry, with important industrial applications.
The terms electrolyte, electrode, anode, cathode and ion were introduced by him.
He introduced the term ‘Lines of force’ in 1831.
The school experiment in which iron filings are sprinkled on a piece of paper,
above a bar magnet, which forms curve lines linking the two poles, illustrates this concept.
As early as 1832, Faraday was suggesting that magnetic forces take time to travel across space.
This rejected Newton’s concept of instantaneous action at a distance.
He proposed that a wave motion was involved.
He thought the same concept may apply to sound and light.
He lacked the mathematical skills to carry forward these ideas, and hesitated to publish it.
He however wrote a paper with these ideas, and placed it with a seal in a vault, in the Royal Society,
to be opened after his death.
Faraday introduced the concept of force fields.
He proposed that magnetic, electric and gravitational lines of force filled the universe.
The material world from atoms to the Earth, Sun and beyond, he said, was simply a result of the knots,
in the various fields.
These ideas were far ahead for their time, and they had no impact in 1844.
Modern theoretical physicists view the world in a similar way.
In one of his lectures, he suggested that light could be explained,
in terms of vibrations of electric lines of force.
At that time it was thought that light requires a fluid medium, the aether, to carry waves of light.
He pointed out that the vibrations, he was referring to was latitudinal,
and not push pull waves, like sound waves.
He said that propagation of the wave would take time.
He speculated that gravity might operate in a similar way.
Faraday remained active in his late 50’s.
He was advisor to the government, on science education, and other areas.
He turned out the offer of a knighthood.
He twice declined the invitation to become the president of the Royal Society.
When his mental abilities started failing when he was 70, he offered to resign from the Royal Institute,
but was asked to stay on.
He gave his last lecture at the Royal Institute in 1865.
He died in 1867.
At the end of 1840’s, the French physicist Armand Fizeau made the first accurate,
ground based measurement of the speed of light.
He was able to estimate the speed of light with in 5%, of the modern value.
In 1850, Fizeau also showed that light travels more slowly in water than in air.
Leon Foucault worked with Fizeau on scientific photography.
They obtained the first detailed photographs of the surface of the Sun.
He also measured the speed of light, using more refined equipment.
His estimate was within 1% of the modern value, of 299, 792.5 km per second.
Later this turned out to be invaluable for Maxwell’s theory.
James Clerk Maxwell descended from affluent Scottish families.
He was born in 1831.
Maxwell’s mother, died of cancer when he was just 8, which removed possible restraining influence,
on the development of his uncouth ways.
He had a happy and close relationship with his father, who encouraged his intellectual development.
At the age of 10, he went to Edinburgh academy for a proper education.
He was nicknamed ‘Daffy’, for his country manners, and presumed lack of intellect.
He had a unusual mathematical ability, and at the age of 14, he invented a way of drawing an oval,
using a piece of string.
Though not a big achievement, it was published using his father’s influence.
In 1847, he went to the university of Edinburgh, where he studied for 3 years.
He then moved to Cambridge, where he graduated in 1854.
As an outstanding student, he became a fellow of Trinity College.
He developed on Young’s theory of colour vision.
He wrote a paper on Faraday’s Lines of Force.
This laid the foundation for his later studies.
Maxwell’s work on colour vision, was the foundation for the method of making colour photographs.
His work is also the basis of the system used in colour TV, colour inkjet printers, and computer monitors.
Maxwell became a professor of natural philosophy at Marischal college, in Aberdeen.
In 1858, he married Katherine, the daughter of the principle of his college.
She was 7 years older, and they never had any children.
Katherine acted as an assistant to Maxwell in much of his work.
Maxwell later became professor of Natural philosophy and astronomy at King’s college in London.
It was there he completed his great work on electromagnetic theory.
William Thomson had found a mathematical analogy, between the way heat flows through a solid,
and the patterns made by electric forces.
Maxwell believed that physical images of theoretical models, are less important than the,
mathematical equations that described what is going on.
This was an important concept that Maxwell introduced.
As science, in particular quantum theory developed in the 20th century,
it became clear that images and physical models that we use to try to picture what is going on,
is far beyond the reach of our senses.
They are no more than crutches to our imagination.
We can only say, a particular phenomenon behaves like say, a vibrating string,
not that it is a vibrating string.
It is quite right to say that light behaves like a wave in many circumstances,
under other circumstances it behaves like a stream of tiny particles, just like Newton thought.
We cannot say that light is a wave or is corpuscular.
We can only say under certain circumstances, it is a wave or a particle.
Another analogy is the idea that the universe started with a big bang, some thirteen billion years ago.
The big bang model is the best way of picturing the universe long ago.
It is a model that matches the available observations and mathematical calculations.
The concept is important, when we move on from the classic science of Newton,
to the ideas of the 20th century, where we cannot touch and see the model.
Models are important and helpful, but they are not the truth.
Scientific truth resides in the equations.
It was equations that Maxwell came up with.
In 1861 and 1862, Maxwell published a set of papers ’On physical lines of force’.
He presented how waves are propagated.
By putting together what was already known about electricity and magnetism,
Maxwell found that the waves should propagate at the speed of light.
In 1864, he published the important paper, which summed up everything that is possible to say,
about electricity and magnetism, in a set of four equations, now known as Maxwell’s equations.
Except for certain quantum phenomena, every problem involving electricity and magnetism,
can be solved using those four equations.
Carrying forward, what Faraday hinted at, he unified the two forces of electricity and magnetism,
into just one field, the electromagnetic field.
This is why Maxwell is viewed along with Newton, in the pantheon of great scientists.
Newton’s theory of gravity, and Maxwell’s equations explained everything,
known to physics at the end of the 1860’s.
Maxwell’s equations had a constant ‘c’, representing the speed of electromagnetic waves.
In his experiments he determined that ‘c’ was the same as the speed of light.
Maxwell predicted that there could be other forms of electromagnetic waves,
with wavelengths much longer than visible light.
We now call them radio waves.
In late 1880’s Heinrich Hertz carried out experiments, that confirmed the existence of radio waves.
He showed that they travel at the speed of light, and like light, can be reflected, refracted and diffracted.
It is further proof of Maxwell’s theory of light.
Maxwell’s equations also tell us that the electrical and magnetic ripples,
in a electromagnetic wave are at right angles to one another.
Maxwell published a great book on electricity and magnetism in 1873.
He was asked to setup and head the Cavendish laboratory in Cambridge, which opened in 1874.
This became the important centre for new discoveries in physics, for many decades.
In 1879, at the age of 48, he died of cancer.
Albert Einstein was born in 1879.
His father and uncle setup a electrical engineering business, which installed electric lights in small towns.
The company eventually lost out to the giants of German electrical industry,
including Siemens and the German Edison company, and had to close down in 1894.
Einstein did his schooling in Germany.
He was intelligent and independent minded, and did not fit into the rigidly disciplined schools of Germany.
At that time there was compulsory army service for all young men.
Einstein renounced his German citizenship, to avoid military service.
He moved to Italy, where his family, including his only sister Maja, were located at that time, in 1895.
He took the entrance test to the Swiss Federal Institute of Technology, and to his surprise, he failed.
He had to spend 1 year in a Swiss secondary school.
However, in 1896 he gained the entrance to the institute.
He logged with the principle of the school, Jost Winteler, and became lifelong friends,
with the Winteler family.
Later Einstein’s sister Maja married Winteler’s son.
In Zurich, Einstein enjoyed life to the full.
He got his girlfriend Mileva Marie pregnant.
The illegitimate baby was adopted.
He did the minimum work required to satisfy his teachers.
He read and studied widely outside the official curriculum.
He expected to do brilliantly in the final examination, and get a job, at the institute.
He did graduate in 1900, but not brilliantly.
His professors did not employ him, since they thought he was not suited for hard work.
In 1903, he married Mileva, and had a son Hans Albert, in 1904.
He had a second legitimate son Eduard in 1910.
In 1905, he worked as a patent officer in Bern.
In 1905, he published Einstein’s special theory of relativity.
It was about the constancy of the speed of light.
There was already experimental evidence that the speed of light is always the same,
irrespective of how the person measuring is moving.
Einstein approached the subject of light, from Maxwell’s equations.
The equation contains a constant ‘c’, which is the speed of light.
According to Maxwell, all observers will measure the same light speed, ’c’,
regardless of whether they are moving towards the source of light, or away from it.
It was clear that Newton’s laws of motion, and Maxwell’s equations cannot both be right.
Other scientists thought that, something is not quite right in Maxwell’s theory.
Einstein, always iconoclastic, considered the alternative, that Maxwell was right,
and in this case, Newton was wrong.
This was the basis of his great insight.
It would be interesting to see the experimental evidence which confirms, how right Maxwell was.
Though Faraday attempted to dismiss the concept of ether, if refused to die.
Maxwell himself had suggested an experiment to measure the velocity of Earth, relative to the ether.
The challenge of carrying out this experiment was taken up by American physicist, Albert Michelson,
and Edward Morley, in 1887.
They found no evidence, that the Earth moves relative to the ether.
The speed of light they found was the same in all directions from Earth, though Earth was moving.
Michelson was obsessed with light, and devised better and better experiments to measure,
the speed of light.
He received the Nobel prize in 1907 for this.
In 1926, at the age of 76, he determined the speed to be 299,796 plus or minus 4 km per second.
This was close to the modern value of 299,792.458 km per second.
The Irish physicist George Fitzgerald took Maxwell’s equations seriously,
and suggested an explanation for it.
He set out the concept of what we now call radio waves, before Hertz confirmed it.
He suggested that the failure of the Michelson-Morley experiment to measure,
any changes in the speed of light, regardless of the direction with respect to the Earth’s motion,
could be explained if the Earth shrank by tiny amount, in the direction of the motion.
The same idea was independently put forward in the 1890’s by the Dutch physicist, Hendrik Lorentz.
He produced what are known as the Lorentz transformation equations, in 1905.
The shrinking effect is now known as the Lorentz - Fitzgerald contraction.
Einstein worked from 1st principles, based on the fact that Maxwell’s equations,
specify a unique speed of light.
Einstein came up with equations that were mathematically identical,
to the Lorentz transformation equations.
Einstein envisaged the space occupied by an object itself shrinking, in line with the motion of the object,
relative to an observer.
The equation also described time dilation.
Moving clocks run slow, relative to time measured by the stationary observer.
Also, there is an increase in mass of moving objects.
The special theory reveals that no object can be accelerated to above the speed of light.
If accelerated to the speed of light, its mass would become infinite,
so infinite energy would be needed to make it go faster.
The theory reveals the equivalence of mass and energy, in the most famous equation in science,
E=mc squared.
The other key feature of the special theory, is that there is no preferred state of rest in space.
All motion is relative.
Any observer who is not being accelerated can consider himself to be at rest.
A spaceship travelling close to the speed of light to a star 10 light years away,
will seem to a stationary observer, to complete the journey in less than 10 years,
according to the clocks in the spaceship, because the moving clocks run slow.
For anything that is travelling at the speed of light, time stands still.
From the point of view of a photon, it takes no time at all, to cross the 150 million kilometers,
from the sun to the Earth.
A clock riding with a photon, would stand still.
From the photon’s point of view, it is because it is travelling at the speed of light,
the space between the sun and the Earth shrinks to nothing, so it takes no time at all to cross it.
Though all this sounds bizarre, the predictions of the special theory of relativity, has been confirmed,
many times in experiments.
It is only because these effects show up, if things are moving close to the speed of light,
that we are not aware of them in every day life.
They are not common sense, but yet it is a proven theory.
Many physicists understood the importance of both the,
Lorentz transformation equations and Einstein’s work.
The significance difference between Einstein’s work and that of Lorentz and Fitzgerald began to be
fully appreciated, only after 1908.
In 1908, Einstein’s teacher, who called him a lazy dog, presented the idea, not just in terms of.
mathematical equations, but in terms of 4 dimensional geometry.
This is the geometry of space and time, or spacetime.
He gave a lecture, where he said space and time will fade away, and only a kind of union of the two,
will preserve an independent reality.
Einstein at first was not happy with the geometrization of his ideas.
However, it was precisely this geometrical union of space and time,
that would lead to his greatest achievement, the general theory of relativity.
After 1905, physics would never be the same again.
We will later discuss Einstein’s most important achievement, in his annus mirabilis,
for which he received the Nobel prize.
It laid the foundations of quantum theory.
Fundamental physics in the 20th century would develop in ways, that could not have been imagined,
by the classical pioneers, such as Newton and Maxwell.