1905: Annus Mirabilis

Human history can truly be divided into two phases- the one before 1905 and the one after 1905. Why was 1905 so important for human history…

It all started with a 16-year-old’s daydream in 1896…what it would be like to catch up with a light wave?

Things like a gift of a compass from his father when he was 4 years of age, filled him with a sense of wonder- of a ‘secret power behind the movement of the needle.’. Despite flashes of brilliance this teenager as a child was a scholarly misfit. Slow as a child, he received low marks in grammar school. He got him get kicked out of high school because of his bad attitude The various business crises of his father, which affected the fortunes of the family, did not destroy the atmosphere of free thought, experience, and sense of mistry about nature in which he grew up. He failed in his first attempt to get into a polytechnic institute. When he finally got in, he cut classes so frequently that he only passed his exams by borrowing a friend’s notes.

However, the musings on the nature of light as a teenager stuck firmly in his mind over the decade that followed, as he studied physics in Zurich and was finally granted a Diploma in 1900. After graduating, this now 21 year old spends almost two frustrating years searching for a teaching post and while searching gets fired from a position as a private tutor. Finally with the help of some personal influence from his friend’s father, he joins the Swiss Patent Office at Bern in 1902 as a lowly assistant examiner. His daytime clerical job entailed evaluating patent applications for various devices. Like so many other civil servants before and since, he spent hours of his workday goofing off — which, in his case, meant filling scraps of paper with calculations and equations. Working here, he was passed over for promotion until he “fully mastered machine technology”. He is barely able to make ends meet as he gets married in 1903 and further adds to his responsibilities as his first child is born in 2004. His career as a scientist was stagnant after the rejection of his doctoral thesis, and his scientific passion had been relegated to his spare time. On 30th April 1905, this young man finally completes his thesis and is awarded a PhD by the University of Zurich. To the scientific world, he is still a 26-year-old nobody.

 This no-body…Albert Einstein!!

All he had were his own scribbles, a close circle of young friends and colleagues, working in relative isolation from the scientific world. All he had, with which he developed the mathematical tools needed to solve the deep mysteries of the physical world. Apart from competing his PhD dissertation, this young man publishes five papers that essentially shatter the very foundations of science and the world would never be the same again.

The year, 1905- Einstein’s annus mirabilis—his miraculous year!


In chronological order these were as follows:

Light quantum paper:

Einstein, Albert. Über einen die Erzeugung und Verwandlung des Lichtes betreffenden heuristischen Gesichtspunkt. Annalen der Physik 17 (6): 132–148 (1905). “On a heuristic point of view concerning the production and transformation of light” was received by Annalen der Physik on March 18, 1905. This was published in Annalen der Physik 17, 132-148 (1905). 

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Einstein’s solution of the photoelectric effect was one of the foundational works of quantum theory. It opened our eyes to the dual nature of matter, and paved the way to our modern understanding of the cosmos, the atomic and subatomic world.

Thesis on Molecular Sizes:

The Ph.D. dissertation “On a new determination of the Molecular Dimensions” was completed on April 30, 1905. It was printed at Bern and submitted to University of Zu ̈rich on July 20, 1905. He also sent a paper based on the thesis to Annalen der Physik soon after the thesis was accepted on August 19, 1905 by the University which appeared in Annalen der Physik 19, 289-305 (1906) next year. 

Brownian Motion paper:

 Einstein, Albert. Über die von der molekularkinetischen Theorie der Wärme geforderte Bewegung von in ruhenden Flüssigkeiten suspendierten Teilchen. Annalen der Physik 17 (8): 549–560 (1905) The paper “On the motion of small particles suspended in liquids at rest required the Molecular Kinetic theory of heat” was received on May 11, 1905 for publication and appeared in Annalen der Physik, 17, 549-560 (1905).

The jerky fluttering movement of dust-motes dancing in a sunbeam in air was known since the ancient Greeks was given the name Brownian motion by Robert Brown in 1827. It was controversial throughout the 1800s on whether colliding atoms caused this. At the heart of the debate was the fact that atoms couldn’t be measured. You could speculate about their existence all you wanted, but the atomic hypothesis was untestable.

Einstein in this paper used this simple observation to provide an irrefutable evidence for the existence of atoms. What Einstein showed was that the diffusion of an object undergoing Brownian motion will diffuse at a particular rate (known as the mean squared displacement), and that this rate depended upon the number of atoms or molecules in a mole of the fluid in which the object is suspended (Avogadro’s number). From this one could determine the size of molecules or atoms. For the first time, a measurable quantity allowed us to probe the atomic realm. It wasn’t just the idea, but rather the precision of Einstein’s results that many scientists found so convincing. Einstein’s work settled a dispute that had raged for nearly a century, and it placed kinetic theory on an experimental foundation. From this work, Newtonian physics, chemistry, and thermodynamics were connected.


Special theory of relativity paper:

Einstein, Albert (1905-06-30). “Zur Elektrodynamik bewegter Körper”. Annalen der Physik. 17 (10): 891–921. The paper “On the electrodynamics of moving bodies” was received for publication on June 30, 1905 and appeared in Annalen der Physik 17, 891-921 (1905). 

We live in a universe of space and time. Events occur at a particular time, and in some location in space. In this way, space and time can be seen as a background against which things happen. Throughout most of human history from Galileo to Newton to Maxwell, this background was seen as absolute. Each event occurs at a unique point in space and time, and in principle everyone can agree what that point is. Intuitively, it makes a lot of sense. In our everyday lives the Earth seems to be an unmoving rock, and acts as a point of reference for everything we do. Sure, we now know the Earth moves around the Sun, but it doesn’t feel that way.

Einstein extended this principle so that it accounted for the constant speed of light and that there was no absolute state of rest.A defining feature of special relativity is the replacement of the Galilean transformation of Newtonian mechanics. Time and space cannot be defined separately from each other. Rather space and time are interwoven into a single continuum known as spacetime. Events that occur at the same time for one observer can occur at different times for another. The theory is “special” in that it only applies in the special case where the curvature of spacetime due to gravity is negligible. He postulated that it holds for all the laws of physics, including the laws of mechanics and electrodynamics.

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E = mc2 paper:

Einstein, Albert. Ist die Trägheit eines Körpers von seinem Energieinhalt abhängig? Annalen der Physik 18 (13): 639–641 (1905). The paper “Does the inertia of a body depend on its energy context” was received for publication on September 27, 1905 and appeared as Annalen der Physics 18, 639-641 (1905).

This was the basis of the atomic bomb, new discovery of new particles, nuclear power plant, the birth of the universe and our own existence as star dust (Twinkle, Twinkle, Little Stars…We are Stardust

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Longer version:


Soon after publishing the special theory of relativity in 1905, Einstein started thinking about how to incorporate gravity into his new relativistic framework. In 1907, beginning with a simple thought experiment involving an observer in free fall, he embarked on what would be an eight-year search for a relativistic theory of gravity. After numerous detours and false starts, his work culminated in the presentation in November 1915 of what are now known as the Einstein field equations. These equations specify how the geometry of space and time is influenced by whatever matter and radiation are present, and form the core of Einstein’s general theory of relativity.

The current description of gravitation in modern physics, comes out of this work. It generalizes the special relativity and Newton’s law of universal gravitation, providing a unified description of gravity as a geometric property of space and time, or spacetime. The conceptual framework provided by Einstein has been confirmed in numerous observations and experiment to date.

The amount of bending of light with gravity known as gravitational lensing is one of the predictions of Albert Einstein’s general theory of relativity. The first observation of light deflection was performed by noting the change in position of stars as they passed near the Sun on the celestial sphere. The observations were performed in May 1919 during a total solar eclipse. The solar eclipse allowed the stars near the Sun to be observed. Observations were made simultaneously in the cities of Sobral, Brazil and in Sao Tome and Principe in West Africa. The observations demonstrated that the light from stars passing close to the Sun was slightly bent, so that so that stars appeared slightly out of position. The result was considered spectacular news and made the front page of most major newspapers. It made Einstein and his theory of general relativity world-famous.

When asked by his assistant what his reaction would have been if general relativity had not been confirmed by Eddington and Dyson in 1919, Einstein famously made the quip:

“Then I would feel sorry for the dear Lord. The theory is correct anyway.”

The Global Positioning System (GPS) is a confirmation of Einstein’s general theory of relativity. Einstein’s theory has important astrophysical implications. For example, it implies the existence of black holes—regions of space in which space and time are distorted in such a way that nothing, not even light, can escape—as an end-state for massive stars. There is ample evidence that the intense radiation emitted by certain kinds of astronomical objects is due to black holes. Predicted in 1916 by Albert Einstein, there are gravitational waves: ripples in the metric of spacetime that propagate at the speed of light. On February 11, 2016, the Advanced LIGO team announced that they had directly detected gravitational waves from a pair of black holes merging. In addition, general relativity is the basis of current cosmological models of a consistently expanding universe.

Einstein’s day dreaming and thought experiments remind me of what he said about his year at the Cantonal School in Aarau after he failed to join the polytechnic institute in Zurich.

“On account of its liberal spirit and genuine sincerity, and teachers who did not lean on external authority of any kind, this school has left on me an unforgettable impression. Compared to the six years of schooling in an authoritatively run German gymnasium, I became intensely aware of how much education leading to independent activity and individual responsibility is to be preferred to the education which relies on drill, external authority, and ambition. Real democracy is not an empty illusion.”

Are the teachers and parents of children listening!!


Copiously borrowed from Wikipedia and Youtube

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