I want to know God’s thoughts, - KU Leuvenitf.fys.kuleuven.be › ~christ › pub › ENposters.pdf · 2006-10-26 · I want to know God’s thoughts,... the rest are details. Initiative

I want to knowGod’s thoughts,

... the rest are details.

Initiative of the Department of Physics and Astronomy, K.U.Leuven, for the exhibition “... the rest are details, Einstein 1905 - 2005”

I want to knowGod’s thoughts,

... the rest are details.


The wonder year 1905 seems to be all about details. Many felt that the end of physics was near. The great

theories had been formed, the foundations had been laid and the rest were details, it seemed. Nevertheless,

these details were the subject of the 1905 publications.

The quotation in the title is taken from:

Esther Salaman, "A Talk With Einstein", The Listener, 1955, 54:370-371.

Salaman was a student in physics in Berlin during the twenties, and the text she published after the death of

Einstein reminds us of that period. Einstein said about himself:

"I'm not much with people and I'm not a family man. I want my peace. I want to know how God created this world. I am not interested in this or that phenomenon, in the spectrum of this or that element.

I want to know His thoughts, the rest are details."

And indeed, Einstein had the reputation of thinking to the very heart of the matter and he preferred the

most fundamental problems. He wanted to capture the ultimate reality of nature. The questions of 1905

concerned the building blocks of matter, the nature of light and the relationships between events in space

and time. Although he did care about experimental verification and applications, we are familiar with the

image of Einstein as a deep theoretical thinker.

Paradoxically, many of these “details” in the life and work of Albert Einstein did not remain details for long.

Einstein appeared to consider his personal life a mere detail, but many others clearly considered such a detail

so important that Einstein, apparently against his will, became an icon and authority. From the 1920’s,

Einstein was welcomed as a star, with mass media attention that was not always focused on his scientific

work.

Einstein stayed in Belgium just for a few months, apparently another detail, but this stay took place at a

crucial moment in his life and in world history. In 1933, he visited De Haan and the pacifist Einstein fought

his last battle with the scientific and political authorities in Germany. After 1933, Einstein never again

returned to Europe. Because of his contacts with Belgium, he became involved in the Manhattan Project,

the development of the American atomic bomb. This was a final appalling application of his formula

E=mc2, which in 1905 was a mere detail and addendum to his first publication on the special theory of

relativity.

“... the rest are details”

Initiative of the Department of Physics and Astronomy, K.U.Leuven, for the exhibition “...the rest are details, Einstein 1905-2005”

1879 Birth of Albert Einstein in Ulm (Germany) on March 14

1901 Swiss national Publishes first article (on capillarity)

1902 Appointment in the patent bureau in Bern

1905 “Wonder year” - publishes pioneering articles

1907 Principle of equivalence (gravitational field and accelerated movement)

1911 Closing address at the first Solvay conference Professor in Prague

1912 Professor Eidgenössische Technische Hochschule in Zürich (Switzerland)

1914 Beginning First World War Professor in Berlin, member of the Prussian Academy

1915 General theory of relativity

1916 President German Physical Society

1917 Director new Kaiser Wilhelm Institute First articles on cosmology and on ‘lasers’

1918 End of First World War

1919 Deflection of light confirmed during solar eclipse Marries Elsa Einstein

1920 Demonstration in Berlin against theory of relativity

1921 Nobel Prize in Physics

1923 Compton effect proves the existence of photon

1924 Article on Bose-Einstein condensation

1926 Heisenberg and Schrödinger: quantum mechanics

1927 Fifth Solvay conference, Einstein and Bohr debate quantum mechanics

1933 Adolf Hitler comes to power Einstein stays in Belgium Leaves Europe forever. Becomes a professor in Princeton, New Jersey (Institute for Advanced Study)

1934 Deprived of German citizenship 1939 Letter to President Roosevelt regarding the atomic bomb

1940 Beginning of the Second World War Einstein becomes an American citizen

1945 Atomic bombs on Hiroshima and Nagasaki (Japan) End of the Second World War Einstein protests against nuclear armament

1955 Einstein dies in Princeton (USA) on April 18

Initiative of the Department of Physics and Astronomy, K.U.Leuven, for the exhibition ”... the rest are details, Einstein 1905 - 2005”

"As long as I have the choice, I shall only remain in a country where political freedom and tolerance prevail, and where all citizens are equal by law. Political freedom implies the freedom to express personal political views, both orally and in writing; tolerance implies respect for the opinion of every individual. These conditions do not exist in today’s Germany. (...)"

A. Einstein, Antwerp, March 1933

"The Preussische Akademie der Wissenschaften is mainly alarmed because of Einstein’s activities as a troublemaker. (...) Therefore, it sees no reason to regret his resignation." - Preussische Akademie, April 1, 1933

"I hereby declare that I have never participated in any scandalmongering. (...) The German press has deliberately given a distorted version of my words (...)" - A. Einstein, De Haan, April 5, 1933

"The Akademie has reason to believe that Herr Einstein, who denies participating in scandalmongering, has done nothing to counter insinuations and libel. (...) - Preussische Akademie, April 11, 1933

The members of the Akademie particularly disliked the fact that Einstein

refused to defend the German people. They were convinced that an

intercession by the famous professor could benefit Germany.

Pacifism

Einstein during a peace march

Einstein detested the German militaristic outlook and even as a young man he opposed the aggressive

attitude of his countrymen. At the age of 16, he left his country and in that way escaped military service.

In 1914, shortly before the oubreak of the First World War, Einstein returned to Germany. He was deeply

shocked by the violence in his homeland. After the German defeat in 1918, Einstein continued to devote

himself to peace. Thanks to his Swiss nationality and his pacifist attitude during the past war, he was able

to travel freely in Europe, in contrast to other German scientists. However, his success and speeches against

German nationalism stirred up many jealous and hostile reactions in his own country. All the more, Einstein

worked all the harder for a peaceful world. In 1932, he began to think that he would never see Germany

again. Time would prove Einstein right. He resigned from the Preussische Akademie der Wissenschaften

and the Kaiser Wilhelm Institut für Physik. He then went to the German embassy in Brussels, where he

renounced his German nationality (keeping his Swiss nationality). Finally, he made an official declaration:

Because of his opinions, Einstein’s houses were plundered, members of his family were harassed and his

bank account was blocked. His books and articles were burnt. A sharp exchange of letters with his former

colleagues then followed.

Initiative of the Department of Physics and Astronomy, K.U.Leuven, for the exhibition ‘ ... the rest are details, Einstein 1905 - 2005’

Arrival in AntwerpWhen Adolf Hitler came to power in Germany in March 1933, Albert Einstein and his

wife Elsa were on their journey home from the United States, where he had given a number

of guest lectures in Pasadena. During his absence, the nazis had launched a witch hunt

against the Jews and a smearing campaign against the scientist. His house in Caputh was

searched for arms, allegedly hidden there by communists. Only a bread knife was found...

Einstein’s bank account was blocked, all his possessions and even his cherised yacht were

seized. Einstein heard this news when on the ship ‘Belgenland’ of the ‘Red Star Line’.

On the 28th of March, the 'Belgenland' docked in Antwerp, where Mr. and Mrs. Einstein

were given a warm welcome by the mayor, Camille Huysmans, a number of professors and

Flemish friends. Shortly thereafter, Einstein said to numerous journalists during a press

conference in the hotel ‘Century’ that instead of continuing his journey to Hamburg, he had

decided to stay away from Germany, as long as no guarantee was given regarding freedom

of speech and protection of all citizens. For six months, Einstein stayed in Belgium, a

country not at all unknown to him: he had repeatedly participated in the meetings of the

Board of the ‘Solvay Institute’ in Brussels and his uncle, Caesar Koch, had lived in Antwerp.

Moreover, he had friends in Belgium, among whom the Belgian pro-

fessors Theophile de Donder and Arthur De Groodt from Antwerp.

Furthermore, he already maintained a frequent correspondence

with king Albert and queen Elisabeth. Mr. and Mrs. Einstein spent

a couple of days in the château Cantecroy (Oude-God) in Mortsel,

with professor De Groodt, and finally continued their stay in the villa

‘Savoyarde’ in De Haan, rented on their behalf by Mrs. De Groodt.

Copyright pictures: Centre for study and documentation Oorlog en Hedendaagse Maatschappij (War and Modern Society) Brussels


Stay in De HaanIn De Haan, Einstein was able to resume his scientific activities; in Brussels and Ostend, he

gave a few lectures to the Rotary Club. In the evenings, he occasionally played the piano in

‘Hotel des Dunes’, run by the mayor of De Haan. Einstein was also an excellent violinist and

even gave a violin concert in the Ostend Assembly Hall in the presence of Queen Elisabeth.

Fearing an attack on his life, the Belgian government provided permanent surveillance at

the Villa Savoyarde, where Einstein was staying at that time. Even during his daily walks in

the dunes, Einstein was closely guarded by plain-clothes policemen. The threat of an attack

didn’t seem to worry him, and, on more than one occasion, he tried to shake off his guardians.

Einstein was not a solitary person, and ,during his short stay in De Haan, made many friends. His accidental

meeting with Alfons Blomme developed into a solid friendship. One day in 1933, Blomme, a well-known

painter from Roeselare, was walking through the farmlands of the Vlissegem polders and saw in the

distance a girl enthusiastically trying to paint a goat. To avoid disturbing her, he made a detour. After a

while, he returned to the same place and saw that the canvas was still blank. Blomme then offered to

help, and the girl was so enthusiastic that she asked him for painting lessons. Blomme refused at first, but

when the girl said she was Einstein’s daughter, he gave in and saw this as a good opportunity to get to

know Einstein better. So, Blomme and Einstein became friends through the latter’s step-daughter Margot.

Because Einstein’s Villa Savoyarde in De Haan was often the focus of attention from curious visitors,

Blomme lent him two rooms in the Villa Memlinc. In that way, Einstein could study and play music in

peace in Blomme’s rooms. Einstein played the violin while Blomme accompanied him on the piano.

Through Blomme, Einstein quickly found a circle of friends, including James Ensor and Aldous Huxley.

On May 8th, 1933, Blomme asked Einstein

whether he could paint his portrait. The scientist

answered laughingly: “Why not now, I’m standing

right in front of you?”. Because this was outside,

high up on the dunes near Blomme’s villa, many

photographers came to watch. Photos appeared in

many newspapers: “Einstein posing for Blomme”.

This spontaneous session resulted in a unique portrait,

Blomme being the only painter in the world to have

painted a portrait of Einstein from the live model.

Albert Einstein and Alfons Blomme (1933) CollectionAMVC-Letterenhuis Antwerp


Einstein in De Haan

Pictures by Eduard Le Bret and Maurice Antony. By courtesy of the municipal board of De Haan and of Georges Le Bret.


As of 1927, Einstein was a regular guest of the royal family. Both the king and the queen were fond

of Einstein, and, especially between Elisabeth and the scientist, a solid friendship arose that was

expressed in their regular and familiar correspondence. In his turn, Einstein found them ‘people of

a rare simplicity and friendliness’ and he told his wife Elsa that he ‘had been received with a moving

cordiality’ and that he ‘had rarely found such purity and gentleness in two people’. Whenever he visited

the royal couple, Einstein brought his violin so that he and Elisabeth could play and enjoy music

together. The letters they wrote each other after Einstein had moved to the United States, prove both

sides a desire to play the violin together, and a certain nostalgia for the hours they had spent together.

Einstein and Elisabeth also shared the same political convictions, both sympathised with the Soviet

system. Furthermore, Einstein was completely indifferent as regards rank, something that enormously

appealed to Elisabeth.

One fine example of Einstein’s modesty and negligence of social differences is the story of his

train voyage to Brussels for his visit to the palace in Laken. The palace chauffeur was sent to fetch

him at the station. However, as the man did not find Einstein in the first class, a lady-in-waiting

was dispatched to be on the watch in the palace park. ‘Finally, she saw someone coming down

the lane, in the scorching summer heat and completely covered in dust. His hairs swayed to the

rhythm of his steps. He juggled a violin case that he held straight in front of him while whistling

a happy tune.’ Einstein said to the queen that he had no idea someone was to pick him up, and the

chauffeur in his turn said he could not imagine that Her Majesty’s guests would be traveling third

class. At another occasion, Einstein decided to go to the palace unexpectedly. In a cheap Brussels

hotel, he requested a telephone call with the palace of Laken. Because he looked fairly dishevelled,

the hotel owner thought Einstein was an anarchist or a madman, and promptly called the police.

When the nazis seized power in Germany, Albert and Elisabeth helped to arrange the

stay of Einstein and his wife in Villa Savoyarde in De Haan, where his safety could be

guaranteed. After Einstein told president Roosevelt that the supply of uranium in the former

Czechoslovakia was within easy reach of nazi Germany, he was asked to write a letter to

queen Elisabeth to convince her to put the uranium of the Belgian Congo at the disposal

of the United States in order to prevent it from falling into the hands of the Germans.

Einstein, Albert & Elisabeth


Contemporaries

Max Planck

Henri Poincaré

The Dutch physicist Hendrik Antoon Lorentz was the first to give an explanation for the paradoxes in the theory of the electromagnetic field of Maxwell. Einstein called him “the most important person I have ever met in my life”.

Einstein was not the only one who started modern physics. Other important scientists, such as Max Planck, Henri Poincaré and Hendrik Antoon Lorentz were dealing with very similar questions... and answers.

The Russian-German scientist Hermann Minkowski developed the mathematical principles of the theory of relativity.

During the first Solvay Congress in 1911, the prominent physicists met to debate the state of physics.


The new Copernicus?

Einstein and Eddington

The solar eclipse as observed in Sobral

Based on his general theory of relativity, Einstein predicted in 1911 that light does not always travel on a straight path through space, as was generally accepted at that time. The path of light beams would deflect from a straight line under the influence of gravity.

The British astronomer, Arthur Eddington, saw the solar eclipse of May 1919 as the perfect opportunity to study the deflection of light. He organized expeditions to Sobral (Brazil) and the island Principe (West-Africa). His observations were revealed on the 6th of November 1919 during a joint meeting of the Royal Society and the Royal Astronomical Society in London. They confirmed Einstein’s theory!

Paul Ehrenfest, who succeeded Lorentz, was a good friend of Einstein, and wanted to offer him an appointment in Leiden. Einstein however did not want to leave Berlin, but he accepted an appointment as “guest professor”, for which he had to stay a couple of weeks in Leiden each year. His opening address took place on the 27th of October 1920. The “comet-like life in Leiden” greatly appealed to him.

In 1921, Albert Einstein received the Nobel Prize in Physics 'for his services to Theoretical Physics, and especially his discovery of the law of the photoelectric effect’. The theory of relativity was regarded as insufficiently proven for the award of the prize.

The following day, on the 7th of November, the spectacular news was published in the London Times, shortly followed by other international papers such as the New York Times and De Nieuwe Rotterdamse Courant, with an (anonymous) text of Lorentz. At one stroke Einstein became famous with the public at large. Several German papers, such as the Berliner Illustrirte Zeitung, cheered Einstein as the new Copernicus.


Einstein and Lemaître

Niels Bohr Einstein and Bohr

In 1917, Einstein published his theory of the universe. According to him, the universe was a stable space and he tried to discover its conditions of equilibrium. However, he was contradicted by several scientists, among whom professor Lemaître from Leuven, who presented a model of a universe that is constantly expanding. His findings were confirmed by the observations of the American Edwin Hubble. Their hypothesis would later be called the Big Bang theory.

Cosmology and Quantum

At the fifth Solvay Conference in 1927, Einstein debated the quantum theory (the theory studying the smallest possible particles of matter) with Niels Bohr. Bohr stated that the physical characteristics of particles, and hence the physical phenomena, can in general not be known with absolute certainty, but Einstein refused to admit this. For many it seemed that Einstein was outrun by a younger generation.


Fame, Pro and Contra

Einstein in Japan, 1923 Einstein in the Collège deFrance, Paris, 1922

- Quel concert de louanges ! Ces dames parlent encore de leurs couturiers.- Mais non, il s'agit d'Einstein ! (Dessin de P.Portelette)

Everyone wanted to get a glimpse of the new celebrity. In the early 1920’s, Einstein was invited all over the world to explain his theory. He visited the United States, England, France, China, Japan, Palestine, Spain and South-America. The scenario repeated itself wherever he came: masses of curious admirers and a great deal of media attention.

However, not everyone welcomed Einstein’s theory of relativity with open arms. Scientists and physicists tried to find paradoxes or contradictions. Many physicists found it hard to come to terms with the theoretical, counterintuitive bases of the theory of relativity. In addition, there was the growing anti-Semitism in Germany. The movement of the Deutsche Physik, led by the Nobel Prize winners Lenard and Stark, was opposed to Einstein’s ‘Jewish’ physics and promoted a more experimental ‘Aryan’ physics. Shortly after Hitler had come to power, all Jewish scientists at universities were dismissed.

Cartoon of Jozef Plank (pseudonym: Seppla), one of the most important nazi cartoonists of Germany. Einstein is swept off the Einsteinturm in Berlin.


Publications on the theory of relativity

Num

ber o

f pub

licat

ions

The wise old man

Right up to his last years, Einstein continued from Princeton his struggle against the use of nuclear weapons. His death in 1955 caused great shock throughout the world. Many newspapers and magazines reported on the death of the scientist, who already during his life had become the public face of science.

After the atomic bombs on Hiroshima and Nagasaki, Einstein, like many other scientists, participated in protests against the atomic bomb. They tried to alert the population to the dangers of a nuclear war with publications such as One World or None in March 1946. Einstein’s last public appearance was his contribution to the so-called Russell-Einstein manifesto, the starting point for the later Pugwash conferences.

After his stay in Belgium, Einstein moved to the United States where he carried out research at the Institute for Advanced Studies (Princeton). Although he was not directly involved in the making of the American atomic bomb, he wrote a letter to President Roosevelt in 1939 pointing out that the recent discoveries in nuclear physics could be used to make bombs. He warned Roosevelt that the nazis might already be working on such an atomic bomb.


''I am able to love the human race, but when it comes to solid relations I am a horse for a single harness. I failed twice. [Marriage] is an unsuccessful attempt to make an incident ever lasting.

All marriages are dangerous.''

Albert... privately''My life is a simple thing that would interest none; it is a known fact that I was born and that is all that is necessary. ''

“If my theory of relativity is proven successful, Germany will claim me as a German and France will declare that I am a citizen of the world. Should my theory prove untrue, France will say that I am a German and Germany will declare that I am a Jew.”

“There is no other way of educating but to be an example - if it can’t be helped, a deterring one.”

Left: Einstein with his second

wife Elsa and step daughter

Margot.

Right: Travel photos (ca. 1922)

Left: Einstein with his first

wife Mileva, and their son

Hans Albert.

Right: Mileva with their sons

Hans Albert and Eduard.

“I sometimes wonder why it was me who invented the theory of relativity. The reason why, I think, is that normal adults no longer think about the problems of space and time. That is only for children. However, my intellectual development was retarded and I could only think about space and time when I had already grown up. ”

Einstein fell in love with Mileva

Marić, a Serbian co-student

at the Eidgenössische Technische Hochschule, Zürich. They married

in 1903.


“Teaching should be such that what is offered is perceived as a valuable gift and not as a hard duty.”

Einstein first went to school in

Germany and later in Switzer-

land. He very much disliked a

schoolsystem based on force,

fear and military discipline. In Switzerland, he enjoyed the develop-

ment of personal liberty and responsibility. Einstein was a very good

student. In the certificate of qualification for university matriculation

of the Aarau Kantonsschule, the grade 6 means excellent, 5 is good.

Galileo Galilei (1564-1642)Galileo Galilei experimented with rolling and falling objects, and is one of the founders of mechanics.

He discovered among others that force is the cause of acceleration, not of speed.

Enclose yourself with some friend in the main cabin below decks on some large ship, and take along some flies, butterflies , and other small flying animals; also take a large bowl of water with some fish in it; hang up a small bucket

that empties drop by drop into a vessel with a narrow opening beneath it. With the ship lying still, observe carefully how the little animals fly with equal speed to all sides of the cabin. The fish swim indifferently in all directions and the falling drops end all up in the vessel beneath: in throwing something to your friend, you need to throw it no more strongly in one direction than in another, the distances being equal (...) When you have observed all these things carefully, have the ship proceed with any speed you like; as long as the motion is uniform and not fluctuating, you will discover not the least change in all the effects named; nor could you tell from any of them whether the ship was moving or lying still. Galileo, 1632

Isaac Newton (1642-1727)

Galileo’s principle of relativity

Mechanics describes the effects of forces on the movement of bodies, enabling us to calculate the path of bodies that for example fall or collide.

The laws of Newton provide the equation of motion: if the initial positions and initial velocities are known, the forces affecting the masses can be used to calculate how the particles will move.

What is mechanics?

MechanicsHow positions get

changed...

Newton’s law of gravitation

This law connects the sublunary mechanics with the supralunary mechanics, just as in the tale of the falling apple: when Isaac ob-serves the apple falling, he suddenly understands that the force causing the apple to fall to the ground is the same force that keeps the moon in its orbit around the earth and the earth in its orbit around the sun.

Two masses attract each other along their con-necting line with a force equal to

Just like Einstein, Isaac Newton stood on the shoulders of giants. His ‘Philosophiæ Naturalis Principia Mathematica’ from

1686 contains the mathematical principles of classical mechanics. The principles of Newton:

• Space and time are absolute. They form the never changing décor against which all motions are measured.

• Initial positions and initial velocities unambiguously determine the path of masses by the specified force

• The mechanics of an observer at rest cannot be distinguished from the mechanics of an observer at a constant velocity (Galileo’s principle of relativity).

● is the gravitational constant;● and are the masses of the bodies;● is the distance between the bodies.

Example: If is the mass of the earth, and is the radius of the earth, then = 9,81 m/s is the acceleration of free fall.



core

1. There are positive and negative electric charges.

2. Magnets have a south pole and a north pole; there are nofree magnetic charges.

3. Electric currents or changing electric fields cause magnetic forces.

Changing magnetic fields cause electric forces.4.

Let there be light...

J.C. Maxwell

Concept of fieldM. Faraday

magnet

core

coil

Electromagnetism

Z

N

Pickups

Guitar string(magnetizable)

coil

Permanentmagnet

toamplifier

First law“The energy of the world is conserved”

NEVER ANY ENERGY CRISIS

The change of the internal energy of a system = heat entered into the system - work done by the system.

Within a closed system, the energy during a transformation equals the amount of energy the system receives from the surroundings, either via heat or via work. It is not possible to make an engine that only produces energy.

ThermodynamicsThe control over

fire!

What is thermodynamics ?

• Thermodynamics appears with everything that has to do with heat conversions. The industrial revolution in the 19th century was mainly made possible by thermodynamics, and the steam engine played an important role in the development thereof. Each time you describe a situation or a development in terms of temperature, pressure or density, you practice thermodynamics.

• You want to know how efficiently an engine works. You want to know the relations between temperature, pressure and density. You want to know which conversions of matter are possible, how much energy is needed and what might get lost? You want to control fire...

• In doing so, you will need some principles and equations which summarize the many thermodynamic phenomena, without worrying too much about their microscopic derivation.

Second law“Entropy tends to a maximum”

It is impossible to produce a cyclic heat engine that only absorbs a certain amount of heat from a reservoir and completely converts this into an equal amount of work.

ENTROPY = measure for energetic chaos or spreading

Heat always flows from a warm to a cold body, never the other way. When you mix warm and cold water, you will get lukewarm water and that will never again divide itself in warm and cold water.

Equilibrium is the state of maximum chaos or entropy at a certain energy of temperature.

S. Carnot(1796-1832)

The ideal gas lawpV = RT

One litre of air at ambient temperature has a specific pressure.

• Heat is a spontaneous energy flow between bodies that have different temperatures.

• You will notice something getting warmer when temperature rises.

• You can also heat something by friction.

• If you increase the amount of material, you will need more heat for the same temperature increase.

• Some materials are better heat conductors than others.

• Latent heat: add 1 litre of water at 78° C to 1 litre of ice at 0° C, and you will get 2 litres of water at 0° C.

J.W. Gibbs(1839-1903)

R. Clausius(1822-1888)


asymmetries [which

It is known that theelectrodynamics of

Maxwell leads to

cannot be observed].

If the Brownianmotion together with its regularities can really be observed, then thermodynamics is no longer exact [under the microscope].

rPHYSICS 1905

MECHANICS

THERMO-DYNAMICS

ELECTRO-MAGNETISM

fluctuation theoryatomic hypothesis

Brownian motion

special theory of relativity

time and space

quantum mechanics photon hypothesis

black body

It seems that most unifying principles are firmly established and that any future progress should mainly be sought in the rigorous application of these principles on all phenomena that we are yet to study.

A. Michelson, 1894

Some dark clouds hanging over the dynamic theory of light and heat...

Lord Kelvin, 1900

There is a deep formal difference between the theoretical

image that physical scientists have formed of the ponderable bodies and on the other hand the electromagnetic processes.

A. Einstein, 1905

BETWEEN THE END AND THE BEGINNING

ether?atoms?

photons?


A. Einstein: On the movement of small particles suspended in stationary liquids, as required by the molecular-kinetic theory of heat.Annalen der Physik 17, 549-560 (1905)

ATOMIC HYPOTHESIS AND BROWNIAN MOTION

What is Brownian motion?

Brownian motion is the completely erratic, seemingly accidental, movement of granules in a liquid that can be seen under a microscope. The atomic or molecular hypothesis gives an explanation for this arbitrary movement: the disordered movement of these granules is the result of many collisions with the molecules of the liquid. Even if the impact is very small and zero on average, fluctuations in the direction and the size of the collisions lead to the displacement of the particle, once in this direction, then in an other.

Application of the Brownian motion

The study of the Brownian motion fits in with the more general fluctuation theory, that is not limited to physics. In 1900, Bachelier already used similar models in his study of financial markets. Nowadays, Brownian models are being used to model the exchange rate of shares and options in financial mathematics.

Robert Brown was a Scottish botanist. He observed the erratic movement of granules in a liquid.

Robert Brown(1773-1858)

Einstein gathers information on the microscopic world from the Brownian movement:

The spreading in the concentration is proportional to the temperature and inversely proportional to the diameter of the granules ; is the stickiness of the liquid.

By determining Boltzmann’s constant , the number of molecules in one drop of water can be counted...

Is it possible and useful to maintain the atomic or molecular image of matter?

“It was my first intention to find facts that would confirm in the most reliable way the existence of atoms with a certain finite size...”

In order to support the atomic hypothesis and to show how one can go beyond thermodynamics, Einstein uses the phenomenon of Brownian motion.

The erratic movement of a granule in water

The average displacement in 1 minute is about 0,006 millimetre.


Diffusion =

-

Annalen der Physik 17, 549-560 (1905)

Both thermodynamics and mechanics arrive here at an intersection. At first sight, both roads seem very different...

MechanicsMechanics

Thermodynamics

Thermodynamics

What is your answer to the following question?

Imagine that in a catastrophe all scientific knowledge would be destroyed and only one sentence could be passed on to the next generation of beings; which statement would contain the most information in as little words as possible?

The answer of Richard Feynman (physicist, 1918-1988):

“All things are made of atoms, little particles that move around in perpetual motion...

.... attracting each other when they are a little dis-tance apart, but repelling upon being squeezed

into one another”.

Do atoms really exist?

Together with many of his contemporaries, Einstein is convinced of the granular structure of matter. Of course, the idea “matter made of atoms” was not new. Atomists such as

Democritus of Abdera (circ. 460-370 B.C.) stated that, essentially, there exist only atoms contained in empty space. Atoms are the smallest substances and cannot come into being, nor can they disappear.

ATOMIC HYPOTHESIS AND BROWNIAN MOTION

Mechanics versus thermodynamics

Mechanics and thermodynamics: two disciplines of physics with a different language. Do you know how to link the following concepts?

Counting molecules

Einstein translates the mechanism of Brownian motion in testable formulas. The displacement of the granules can be linked to the diffusion process. In diffusion, an initial concentration (e.g., a drop of ink) is spread out in the course of time over the solvent (e.g., in water). Einstein links the diffusion (depending on the temperature and stickiness of the solvent and the size of the dissolved granules) with the observed displacement of the granules. The apparent accidental and very erratic movements in the liquid are now being described in rigorous, although statistical laws. One important result: atoms/molecules can be counted!

The Avogadro number: there are about

6.000.000.000.000.000.000 molecules in one drop of water...

DensityTime reversible

TemperatureEnergy

HeatWork

Power

PressureSpeed

Position

ThermodynamicsMechanics

T

Energ

Irreversibility

Entropy

О

О

О

О

О

О

О

О

О

О

О

О

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О

О

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О

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ThermodynamicMechanic

A. Einstein: On the movement of small particles suspended in stationary liquids, as required by the molecular-kinetic theory of heat.

Initiative of the department of Physics and Astronomy, K.U.Leuven, for the exhibition “... the rest are details, Einstein 1905 - 2005”

PHOTON HYPOTHESISA. Einstein: A heuristic point of view concerning the production and transformation of light.


M. Planck(1858-1947)

Black body

A black body is a material that absorbs incident radiation for 100% and reflects nothing. A black body is also able to emit electromagnetic radiation by heating the material. The wavelength (colour) of the emitted light depends on the temperature.

Let us take the example of a piece of iron; as it is heated, the iron will first glow red, then yellow and finally it will emit a blue and even white light. Which wavelength (or colour) is the most intense, depends on the tem-perature. Max Planck succeeded in describing the experimentally found curve mathematically.

He thereby introduced the constant of nature , later referred to as Planck’s constant.

What is light ?

Light is electromagnetic radiation. This radiation is generated when electric charges move back and forth (in antennas) and transmits itself at the speed of light. Depending on the wavelength, there is a difference between various forms of electromagnetic radiation: radio waves, micro waves, infrared radiation, visible light, ultraviolet light, X-rays and gamma rays.


1016 1018 1020

Wavelength (meter)

Approximately the size of...

Frequency (Hertz)

Radio Micro Infrared Visual Ultraviolet X Gamma

1012 1015108104

Applications...

T (°C)- 35°

- 30°

- 25°

- 20°

103 10-2 10-5 550 • 10-9 10-8 10-10 10-12

building insect needle cell molecule atom nucleushuman

p

p

pn

nn

n

np

pp

Ene

rgy

Wavelength

800°C

1300°C

1800°C

700 nm500 nm400 nm 600 nm

the position of the maximum determines the colour of the heated object.

The photon hypothesis

Einstein makes a revolutionary suggestion: light also consists of particles, the so-called light quanta or photons. Einstein discovers that light behaves exactly

the same way as a gas when he assumes that light with a frequency is made of indepen-dent particles with energy:

is a constant of nature.

Ludwig Boltzmann is the founder of statistical mechanics. He succeeded in connecting thermodynamics with Newton’s mechanics.

His statistical interpretation of the basic principles of thermodynamics allowed Einstein to discover an analogy between gas particles and black body radiation. These radiation particles or light quanta are now called photons.

PHOTON HYPOTHESISA. Einstein: A heuristic point of view concerning the production and transformation of light.


Einstein, the Mediator

Albert Einstein is a mediator… Einstein is connecting statistical thermodynamics with electromagnetism.

Near the end of the 19th century, it was already understood that matter consisted of particles. In a gas these particles move according to the laws of mechanics. Heat can be understood as motion. Einstein learnt that from the works of Ludwig Boltzmann.

Einstein draws attention to the difference with the electromagnetism of Maxwell, where everything happens continuously and not via particle components. Light is a wave that stretches in space and that carries energy with all possible values.

L. Boltzmann(1844-1906)

The photoelectric effect

Einstein gave the law of the photoelectric effect, that describes how electrons can escape from a metal surface irradiated by light with a certain frequency. Only when the photon energy is larger than the energy needed to free the electron from the metal, electrons will be liberated. The law of the photoelectric effect was completely confirmed by experiment and earned Einstein the 1921 Nobel Prize in Physics.

Revolutionary?

Newton published “Opticks” in 1704, in which he described light as particles.

The principle of the photoelectric effect

The photoelectric effect can be explained using the analogy of a beverage machine. With the photoelectric effect, electrons can only be freed when the incident light has a sufficiently high frequency, hence sufficiently high energy. Any energy higher than the energy needed to free the electron, is used to give the electron a higher speed.

Compare this with the following situation: a beverage machine only accepts coins of €1 or €2. One bottle costs €1. It doesn’t matter how many coins of less than €1 you put in the machine... you will never get a drink. However, with coins of €1 or more, you get a drink from the machine, and maybe even some change.


Potassium metal

2 eV is the energy needed to free one electron

- -

s

SPECIAL THEORY OF RELATIVITY

A. Einstein: On the electrodynamics of moving bodies.Annalen der Physik 17, 891-921 (1905)

Speed of light =

distance / time=

INVARIANT

space and time are intertwined!

Simultaneity becomes relative

In a moving spaceship, a light beam must travel a longer dis-tance while the speed remains constant, therefore it takes longer before the light beam is reflected and hence moving clocks run slower...

The light clock

You can make a clock by having a light signal reflect vertically via a mirror. At rest, time equals

d is the height and c is the speed of light.

When this clock moves with speed v, light will have to travel a longer distance and because c remains unchanged, this will take longer:

In a spaceship at rest, a light beam travels a distance d in t’ seconds.

In 1905, Einstein invented a revolutionary frame in which both mechanics and electromagnetism can be united. To do this, he starts from two fundamental assumptions:

“All observers who are in uniform motion with respect to each other, observe the same physical laws.”

He takes this principle from Newtonian mechanics. The physical interpretation of the principle will however be radically different because of the second assumption:

“The speed of light does not depend on the speed of the emitter or the receiver.”

The asymmetry of Maxwell

A

Even when a magnet and a coil carry out the same relative movement, you do not obtain an electrical field in both cases. What you get, is the same electrical current.

A-


SPECIAL THEORY OF RELATIVITY

A. Einstein: On the electrodynamics of moving bodies.Annalen der Physik 17, 891-921 (1905)

A. Einstein: Does the inertia of a body depend on its energy content?Annalen der Physik 18, 639-641 (1905)

Ladder paradox

The ladder and the barn are moving towards each other. If we look at the situation from the point of view of the barn, the ladder moves very fast and shrinks in the direction of move-ment. In this way, the ladder fits into the barn. But we can also state that the barn is moving in relation to the ladder and hence is shrinking.

Now the ladder doesn’t fit in the barn... ?!

barn

ladder

movingladder

the moving ladder fitsperfectly in the barn.

barn

barn

barn

ladder

ladder movingbarn

The ladder does not fit in the moving barn

Twin paradox

Emma undertakes a journey and after a fast trip through space, she arrives home biologically younger than her twin brother who stayed on earth: indeed, she kept moving all the way and hence her (biological) clock went slower. Why is it not possible to reverse the situation? After all, you can say that the earth and her brother were moving away from the spaceship and hence that her brother should have been younger.

Are the twins no longer the same ?!

Moving clocks run slower

The earth (and we) are constantly exposed to cosmic radiation. In that way, muons, elementary particles of a certain type, reach us. However, they have a limited lifetime before they decay into other products. Even at the speed of light, they would not have the time to penetrate our atmosphere. Nevertheless... you can detect them and they reach us on the surface of the earth!

If you move away from me at a constant speed, your clock will run more slowly. In the same way, when I move away from you at a constant speed, my clock ticks more slowly:

Who is right, whose clock runs slower ?!Why can we detect muons ?!

Mass is energy

Energy and mass are equivalent. A hot iron is heavier and matter or particles can change into energy. The resistance (or slowness) of an object against a change in movement depends on the energy-content. The faster you move, the heavier you are. In order to move a person in a small spaceship of about 200 kg at half the speed of light, you will need as much energy as the annual energy consumption in Belgium!

But what about light particles that move with a speed of 300.000 km/s ?!

Every physical theory is based on a notion of time and space. But:

how do you measure time ? how do you determine distance ?

Some thought experiments, puzzles and paradoxes...

space

time

AA

B

C

(Illustratie van www.natuurkunde.nl )

20 years10 years 30 years 40 years

1 year

2 years

3 years

4 years

5 years

6 years

10 light-years

20 light-yearslight

distance


QUQUANTUM MECHANICS

THEORY OFTHEORY OFRELATIVITYRELATIVITY

STATISTICAL CAL THERMODYNAMICS

THE LEGACY

Quantum space - time

Quantum gravitation

Cosmology

Macroscopic quantum effects

Quantum fluctuations

Nanophysics

... the rest are details

Big-bang theory

Plasma physics

Astrophysics

Nonequilibriumstatistical mechanics

Biophysics

Blackholes

initial conditionsof the universe

Turbulence

Nuclear physics

Astrobiology

Theory of quantuminformation

Matter laser

Quantum optics

String theory

Solid state physics

Theory of quantum fields

Softcondensed

matter

Dark energy/matter

The largest

The fastest

The most complex

Unification

The smallest

The coldest

The hottest

nonlocal

Chance

PHYSICS-1905 2005


Einstein... philosopher ?Einstein was not a philosopher, although he regularly debated philosophical themes and wrote about them.

These were mostly induced by ethical, religious or political issues. Because of his interest for the

foundations of physics, he regularly wrote about natural philosophy and epistemology (how do we know

something?). He thought he was mostly influenced by philosophers such as Baruch Spinoza and David

Hume, especially by Spinoza, who was his absolute favourite.

As for philosophy of science, he was very impressed by the thoughts of Immanuel Kant and Ernst Mach.

The sceptic empiricism of Hume and Mach, stating that one can only gather knowledge by experience and

experiment - “and even then!” - initially had a very strong influence on his work about relativity.

“It is well possible that without these philosophical studies [Hume and Mach] I would never have come to the special theory of relativity”

Einstein’s basic assumptions in his approach of quantum mechanics often seem of a philosophical

nature and were sometimes contemptuously laughed off by his contemporaries as “merely metaphysics”.

Indeed, Einstein later often conflicted with the more positivist approach of his colleague physicists. It

sounds paradoxical, but nowadays “experimental metaphysics” is often used to indicate the most modern

implementations of Einstein’s ideas and experiments regarding quantum mechanics.

Niels Bohr: “It is wrong to think that physics has to find out what nature is about. Physics is only occupied with what we can say about nature.”

Albert Einstein: “Physics is an attempt to understand reality, regardless of whether this is observed or not.”

Together with his friends in Bern,

Einstein had studied the Ethics of

Spinoza, which would guide him for

the rest of his life. In 1920, Einstein

wrote a poem “Zu Spinozas Ethik”

starting with the following words:

“How much do I love that noble man

More than I could say with words

Although I fear that he will remain alone

With his radiant holiness.”

In 1932 Einstein emphasises:

“Spinoza was the first man to apply strictly an all penetrating determinism to human ideas, feelings and action.... That requires an unusual integrity, generosity and modesty.” ... “Spinoza is the first philosopher who approached body and soul as one unit, and not as two separate things.”

Einstein called himself a “deeply religious nonbeliever”:

“I believe in Spinoza’s God who reveals himself in the orderly harmony of what exists.”

Einstein’s religious feeling is often indicated as a cosmic religiosity, thus making the programme of sciences

workable.

“Religion without science is blind, science without religion is lame.”


“Within reason : A life of Spinoza” by Margaret Gullan-Whur (2000), St Martins Press

Einstein and artDo art and science form two separate worlds, constantly growing further apart? Many people are convinced

that human and positive sciences have little to say to each other and in any case they do not speak each

other’s “language”.

However, art itself shows an influence of scientific or at least popular scientific ideas. In this context,

Einstein is a more than interesting case. Besides the influence of his ideas on art, Einstein appears several

times as the subject of art.

Les Demoiselles d’Avignon - Pablo Picasso (1907)

Einstein and CubismIn many publications, it is

claimed that cubism had

directly been influenced by

Einstein’s ideas on space and

time. Nevertheless, neither

Einstein’s name nor references

to his work are ever mentioned

in cubist literature. But there

are many references to the

4th dimension, the concept

referring to a closed and

unbounded space where time

no longer exists.

The American philosopher

Sanford Kwinter states

that Einstein’s ideas are not

expressed in cubism, but in

Futurism.

In his book Architectures of

Time (MIT, 2002) he analyses time and space in the theory of relativity and he tries to prove how these

new ideas were rendered. According to Kwinter, the “new modernity” that

surpassed the boundaries of classical physics, formed the basis of futurism. He

states that the scheme of the futuristic architect Antonio Sant’ Elia formed the

first real aesthetic expression of the new notions of time and space.

La Città Nuova - Antonio Sant’ Elia (1914)

“Imagination is more important than knowledge.”


Einstein in artEinstein and WarholWhen Andy Warhol was asked in 1973 to portray the most

important man of the 20th century, Albert Einstein came

immediately to mind. Ultimately, Warhol chose Mao, whom

he thought to be the most popular man of the previous

century. However, Warhol also portrayed Einstein, be it in

another context, namely as one of the most important Jews

of the 20th century. Other persons that were portrayed in

this series include Franz Kafka, Sigmund Freud, George

Gershwin,…

Portrait of Einstein from

‘Ten portraits of Jews of the 20th century’ Andy Warhol (1980)

Einstein and Gerhard RichterThese small black and white portraits are painted

after pictures of great scholars, among them

Oscar Wilde, Franz Kafka and also Albert

Einstein: 48 Western, white, male, European

and American intellectuals in tailor-made suits

according to the mainstream ideas of their time.

Richter does not portray the scholars separately,

but in a long row, thus not giving them an aura

of exclusive scholarship, rather the portrayed

scholars fall into anonymity.

(Van Gelder, February 10, 2005)

48 portraitsGerhard Richter (1971-72)


Icon of the intellectDuring the 20th century, scholars were no longer portrayed in a traditional manner, and more attention was

paid to the social and political implication of this presentation.

That Einstein is regarded as the icon of science, is

perhaps not only due to his brilliant mind. With his

striking white hair and his bushy moustache, he had the

perfect head for the archetypical scientist. At least, he

was portrayed like this and that is how popular culture

and the mass media like to see him. As a well-known

marketing and advertising product, Albert Einstein

appears in advertisements in magazines, on T-shirts,

mugs, cartoons, calendars and postcards and he

regularly appears as a character in a film or television

series. In this way, the eccentric genius with a heart has become a real popular hero, the

widely accepted symbol of intelligence.

Scientists are not always portrayed as wise and good. Einstein too met

with hostility, but after 1920’s he was regarded almost everywhere as

an intellectual hero. After the Second World War, this image was slowly

changed when he was linked with the development of the atomic bomb.

In the 1950’s, Einstein was regularly presented as the father of the nuclear

age, whose geniality had been used for tragic purposes. Later, this negative

image will give way again to a more positive but more stereotypical image.

Einstein has been seen on numerous magazine covers such as Trends and Time. In

2000, the latter even elected him as “Person of the Century”.

The little green Yoda from “Star Wars” is said to owe his appearance to Einstein. The 900 year old Jedi Master was given Einstein’s characteristics in order to look wise and intelligent !?

Einstein’s famous hairstyle, forming a halo around his head as a cerebral aura, had

already been worn by the 19th century astronomer Sir John Herschel. It gave him

an aura of deep wisdom.

“Instinct says beer, reason says Carlsberg”. A commercial from the 70’s for beer.

The icon Einstein in a cartoon of Calvin and Hobbes

(by Bill Watterson).


Documents

I want to know God’s thoughts, - KU Leuvenitf.fys.kuleuven.be › ~christ › pub › ENposters.pdf · 2006-10-26 · I want to know God’s thoughts,... the rest are details. Initiative