Episode 42: The Lorentz Transformation - The Mechanical Universe

Summary

This script explores the historical and theoretical foundations of the theory of relativity, highlighting the contributions of physicists like Lorentz, Fitzgerald, and Einstein. It discusses the Michelson-Morley experiment, which failed to detect the luminiferous aether, leading to the development of the Lorentz transformation equations. The script delves into the concept of the constancy of the speed of light and how it challenges traditional notions of time and space. It also touches on the personal influences and the significance of Einstein's approach to relativity, which redefined our understanding of the universe.

Takeaways

• 🌌 The conventional history of relativity starts with the Ether theory, which was disproven by the Michelson-Morley experiment, leading to Einstein's theory of relativity.
• 🔍 The real story of relativity involves the Lorentz transformation, which includes the constant speed of light derived from Maxwell's equations.
• 🚂 At the end of the 19th century, the speed of trains was the fastest human experience, with the Earth's rotation around the Sun being faster but unnoticed by inhabitants.
• 🌟 The Michelson-Morley experiment aimed to detect motion through the Ether by measuring the speed of light, but found that the speed of light is constant regardless of the observer's motion.
• 🤔 GF Fitzgerald and Hendrik Lorentz proposed that motion through the Ether causes a contraction in the direction of motion, which was a key insight for the theory of relativity.
• 🕰 Lorentz's work suggested that time, as well as distance, is affected by motion, leading to the idea that time dilation occurs in moving frames of reference.
• 📏 The Lorentz transformation equations express how time slows and distances contract in a moving frame, and they join time and space into a single continuum.
• 🌐 Einstein's special theory of relativity was based on two postulates: the laws of physics are the same in all inertial frames, and the speed of light is constant for all observers.
• 🚀 Einstein's theory provided a deeper understanding of the Lorentz transformation, viewing the constant speed of light as a fundamental principle rather than an appearance.
• 📚 There are two independent histories of the theory of relativity: one through the Ether theory and Lorentz's work, and the other through Einstein's independent development of the same theory with a different perspective.

Q & A

What was the conventional history of relativity mentioned in the script?

The conventional history of relativity mentioned in the script includes the theory of the Ether, the Michelson-Morley experiment which showed the Ether theory was wrong, and then Albert Einstein's formulation of the theory of relativity.

What is the Lorentz transformation and why is it significant?

The Lorentz transformation is a set of equations that describe how space and time coordinates transform from one inertial frame of reference to another moving relative to the first. It is significant because it incorporates the constant speed of light and introduces the concepts of length contraction and time dilation, which are fundamental to the theory of special relativity.

What was the Michelson-Morley experiment aiming to prove?

The Michelson-Morley experiment aimed to detect the motion of the Earth through the luminiferous Ether by measuring the effects of the Ether on the speed of light.

What was the unexpected result of the Michelson-Morley experiment?

The unexpected result of the Michelson-Morley experiment was that the speed of light was found to be the same regardless of the motion of the observer, which contradicted the expectation that the speed of light would vary depending on the observer's motion through the Ether.

Who were Albert A. Michelson and Edward Morley, and what was their contribution to the development of the theory of relativity?

Albert A. Michelson and Edward Morley were American physicists who conducted the Michelson-Morley experiment. Their experiment, which failed to detect the luminiferous Ether, contributed to the development of the theory of relativity by challenging the classical understanding of space and time.

What was Hendrik Lorentz's contribution to the understanding of the Michelson-Morley experiment results?

Hendrik Lorentz contributed to the understanding of the Michelson-Morley experiment results by proposing the concept of length contraction, suggesting that objects contract in the direction of motion relative to the Ether, which could explain why the speed of light appeared constant to all observers.

What is the significance of the speed of light in the theory of relativity?

In the theory of relativity, the significance of the speed of light is that it is constant for all observers, regardless of their relative motion. This constancy leads to the concepts of time dilation and length contraction, which are fundamental to understanding the behavior of objects at speeds close to the speed of light.

What is the principle of relativity as mentioned in the script?

The principle of relativity, as mentioned in the script, states that the laws of physical phenomena should be the same for an observer at rest and for an observer in uniform motion. This principle is a cornerstone of the theory of special relativity.

How did Albert Einstein's approach to the theory of relativity differ from Hendrik Lorentz's?

Albert Einstein's approach to the theory of relativity differed from Hendrik Lorentz's in that Einstein based his theory on two postulates: the principle of relativity and the constancy of the speed of light for all observers. Einstein's approach was more fundamental and universal, while Lorentz was focused on explaining specific experimental results like those from the Michelson-Morley experiment.

What is the Lorentz factor (gamma) and how does it relate to time dilation and length contraction?

The Lorentz factor, denoted by gamma (γ), is a mathematical factor that relates the time and space measurements of an object in motion to those in a stationary frame of reference. It is given by the equation γ = 1 / √(1 - v²/c²), where v is the relative velocity and c is the speed of light. The Lorentz factor is used to calculate time dilation (moving clocks run slower) and length contraction (objects in motion contract in the direction of motion).

Outlines

00:00

🌌 Introduction to the History of Relativity

The paragraph introduces the historical context of the theory of relativity, starting with the Ether theory and the Michelson-Morley experiment that disproved its existence. It discusses how Albert Einstein's theory of relativity emerged as a result. The narrator corrects the common misconception about the historical development of the theory, hinting at a more complex and nuanced story that will be explored later. The paragraph also introduces the Lorentz transformation, emphasizing the importance of the speed of light as a constant in modern physics, derived from Maxwell's equations and measured by Michelson with remarkable precision.

05:03

🚂 The Impact of Technology on Perceptions of Speed

This paragraph delves into the concept of speed at the end of the 19th century, where trains represented the epitome of speed. It contrasts the human experience of speed through trains with the speed of the Earth orbiting the Sun, highlighting the relative nature of speed. The paragraph discusses the Ether theory and how it was tested by Michelson and Morley, aiming to detect the Earth's motion through the Ether by measuring the speed of light. The unexpected result of the experiment, showing that the speed of light is constant regardless of the observer's motion, is explained, leading to the initial skepticism and eventual acceptance of this phenomenon through the work of Fitzgerald and Lorentz.

10:07

🔬 The Lorentz Transformation and the Contraction Hypothesis

The paragraph explores the Lorentz transformation and the concept of length contraction. It explains how Lorentz and Fitzgerald proposed that an object moving through the Ether would contract in the direction of motion, a phenomenon later attributed to the properties of electrons. The discussion continues with the implications of this contraction for understanding the Michelson-Morley experiment and the constancy of the speed of light. The narrative also touches on the idea that time, like distance, is affected by motion, setting the stage for a deeper understanding of relativity.

15:08

⏱️ The Relativity of Time and the Principle of Relativity

This paragraph introduces the concept of time dilation and the principle of relativity as proposed by Galileo and later formalized by Henri Poincaré. It discusses how the laws of physics should be the same for all observers in uniform motion, challenging the traditional notions of time and space. The narrative explains how Lorentz developed equations to describe the effects of motion on rulers and clocks, leading to the understanding that a moving clock appears to run slower to a stationary observer. The paragraph also highlights the significance of the Lorentz transformation in unifying time and space.

20:09

🌐 The Development and Implications of the Lorentz Transformation

The paragraph discusses the Lorentz transformation in detail, explaining how it accounts for the observed phenomena of time dilation and length contraction. It describes the historical context in which Lorentz published his electron theory, which included the essential equations of the theory of relativity. The narrative then shifts to Albert Einstein's perspective, who was influenced by Lorentz's work and developed his own theory of relativity based on two fundamental postulates. The paragraph concludes by emphasizing the importance of the Lorentz transformation in understanding the special theory of relativity and its impact on the concepts of space and time.

25:12

🚀 The Space-Time Diagram and the Different Perspectives on Relativity

This paragraph introduces the concept of space-time diagrams as a tool for visualizing the effects of relativity, such as the relativity of simultaneity and the contraction of rulers in motion. It contrasts the perspectives of Lorentz and Einstein on the theory of relativity, highlighting how Lorentz viewed the constant speed of light as an appearance, while Einstein considered it a fundamental principle. The narrative concludes by acknowledging the independent yet converging paths of Lorentz and Einstein in the development of the theory of relativity, and it sets the stage for further discussions on the topic.

Keywords

💡Theory of Relativity

The Theory of Relativity is a fundamental concept in physics that describes the relationship between space and time. In the video, it is discussed as a theory developed by Albert Einstein, which revolutionized our understanding of the universe by introducing the idea that the laws of physics are the same for all observers in inertial frames, and that the speed of light is constant for all observers, regardless of their motion. This theory is central to the video's theme as it explores the historical development and implications of these groundbreaking ideas.

💡Lorentz Transformation

The Lorentz Transformation is a set of equations that describe how measurements of space and time differ for observers moving relative to one another. In the video, it is mentioned as a crucial part of the special theory of relativity, which was initially developed by Hendrik Lorentz to explain the null result of the Michelson-Morley experiment. The Lorentz Transformation is integral to the video's narrative as it illustrates how the perception of space and time changes with relative motion.

💡Speed of Light

The speed of light is a universal constant, approximately 299,792 kilometers per second in a vacuum, and is a cornerstone of the theory of relativity. The video emphasizes its importance in modern physics and its role in the Michelson-Morley experiment, which failed to detect the motion of Earth through the 'luminiferous aether' due to the constancy of the speed of light. This constant speed is a key element in the video's exploration of relativity and the universe.

💡Ether

The Ether was a hypothetical medium once believed to be the carrier of light waves, as sound waves are carried by air. In the video, the Ether is discussed in the historical context of the Michelson-Morley experiment, which aimed to detect the Earth's motion through this medium. The failure to detect the Ether led to significant shifts in the understanding of light and space, making the Ether a pivotal concept in the video's historical narrative.

💡Michelson-Morley Experiment

The Michelson-Morley Experiment was a crucial experiment in the late 19th century that attempted to detect the motion of Earth through the Ether by measuring the speed of light. The video describes how this experiment showed no detectable effect, leading to the conclusion that the Ether did not exist as previously thought. This experiment is central to the video's exploration of the historical development of the theory of relativity.

💡Length Contraction

Length Contraction is a phenomenon predicted by the theory of relativity where an object's length appears shorter when it is moving relative to an observer. In the video, it is explained as a consequence of the Lorentz Transformation and is illustrated through the example of an interferometer. Length contraction is a key concept in the video as it demonstrates how motion affects the perception of space.

💡Time Dilation

Time Dilation is a concept in the theory of relativity where time appears to pass more slowly for an object in motion relative to a stationary observer. The video explains how this phenomenon is a consequence of the Lorentz Transformation and is essential for understanding the relativity of simultaneity. Time dilation is a significant concept in the video as it challenges traditional notions of time and space.

💡Galileo's Relativity Principle

Galileo's Relativity Principle states that the laws of physics are the same in all inertial frames. The video discusses how this principle was extended by Einstein to include the constancy of the speed of light, leading to the development of the special theory of relativity. This principle is a foundational concept in the video's explanation of the evolution of scientific thought.

💡Space-Time

Space-Time is a four-dimensional continuum that combines the three dimensions of space with the dimension of time. In the video, it is used to illustrate the relativity of simultaneity and the effects of motion on the perception of space and time. The concept of space-time is central to the video's exploration of the theory of relativity and its implications for our understanding of the universe.

💡Hendrik Lorentz

Hendrik Lorentz was a Dutch physicist whose work on the electromagnetic theory of light and the development of the Lorentz Transformation equations laid the groundwork for the theory of relativity. The video discusses his contributions to the understanding of length contraction and the constancy of the speed of light. Lorentz's work is highlighted in the video as a precursor to Einstein's more comprehensive theory.

Highlights

The conventional history of relativity is logically correct but not historically accurate.

Lorentz transformation is a key part of the theory of relativity, focusing on the speed of light.

The speed of light, derived from Maxwell's equations, is essential for understanding modern physics.

The Michelson-Morley experiment showed that the speed of light is the same for all observers, contradicting the Ether theory.

GF Fitzgerald and Hendrik Lorentz proposed length contraction to explain the Michelson-Morley results.

Lorentz's explanation for the contraction phenomenon was linked to the properties of electrons.

Lorentz believed that the electron was responsible for the constancy of the speed of light for all observers.

The concept of length contraction was used to explain why the Michelson-Morley experiment failed to detect motion through the Ether.

Lorentz's work led to the development of the Lorentz transformation equations.

The Lorentz transformation equations express the mathematical essence of the special theory of relativity.

The theory of relativity implies that time and distance are affected by motion.

Henri Poincaré objected to the limited nature of Lorentz's explanation, proposing the principle of relativity.

Albert Einstein's work on relativity was influenced by Lorentz's equations and the principle of relativity.

Einstein's theory of relativity was based on two postulates: the relativity principle and the constancy of the speed of light.

Einstein's theory deduced the same equations as Lorentz but with a deeper understanding of their implications.

The Lorentz transformation equations join time and space together, changing the traditional meanings of these concepts.

The theory of relativity has two independent historical narratives, one through Lorentz and the other through Einstein.

Einstein's contribution to the theory of relativity was not just minor, but represented a profound shift in understanding.

Transcripts

foreign media

[Music]

[Music]

thank you

thank you

last time I told you the conventional

history of relativity

there was the theory of The Ether

and then the Michaelson Molly experiment

showed that it was wrong

and then Albert Einstein produced the

theory of relativity

as I told you then that story is

logically correct but not historically

correct

well what is the real story

I'll get back to that in a little while

first of all I would like to tell you

about a part of the theory which is

still called the lorentz transformation

[Music]

in the lorentz transformation there is

above all

the speed of light

the speed that sprang from Maxwell's

equations

the three hundred thousand kilometers

per second that Michelson measured with

Landmark accuracy

the speed which is essential in modern

physics

and vital to understanding the universe

as it really is

and at the end of the 19th century when

Lawrence derived his transformation

equations

when it came to speed the most moving

Human Experience

was provided by trains

the automobile

which would eventually outpace the train

wasn't quite in gear

and air travel was barely off the ground

big or small

sophisticated or Child's Play

trains were the very image of speed

and in fact the only thing on Earth that

moved people faster

was the Earth itself

orbiting the Sun at 108 000 kilometers

per hour

the inhabitants of the planet may not be

aware of the speed but speed it is

and to physicists at the turn of the

century it was speed relative to

The Ether

since the time of Aristotle The Ether

was believed to be the very stuff of

which the heavens themselves were made

that concept remained mere speculation

until two Americans set out to prove

once and for all

that what was then called The

luminiferous Ether

did in fact exist they were Albert a

Michelson

and Edward Morley

and their goal was to detect motion

Through The Ether by measuring its

effects on the speed of light

[Music]

in one attempt after another

with the most sensitive experimental

device ever constructed

they found exactly what they weren't

looking for

the interferometer showed that

regardless of the motion of the Observer

the speed of light is the same

for Michelson and Morley this was bad

news

and it traveled fast

as fast as a boat could carry it to

Ireland

there physicist GF Fitzgerald an early

champion of Maxwell's electromagnetic

theory of light examine michelson's

otherwise disappointing results

Fitzgerald's explanation was that in its

motion Through The Ether one arm of the

interferometer was contracted by a

fraction of its length which was just

the right amount to allow the two light

beams to arrive simultaneously

immediately most scientists scoffed at

the idea

however when Henrik Lorenz arrived at

the same idea no one was laughing

Not only was he the world's expert on

Maxwell's electromagnetic Theory

but lorentz gave a tangible explanation

for the contraction phenomenon

he thought it had to be a property of

the electron

whose existence had just been confirmed

by J.J Thompson and his colleagues in

England

it seemed that in electrons they'd found

the inner parts of atoms

the ultimate constituents of matter

but they hadn't discovered all the

things that electrons actually do

one possibility Lawrence believed is

that an electron will contract in the

direction of motion

if that were true and since everything

is composed of electrons then an

interferometer would contract in the

direction of motion

so would a ruler

and so with a locomotive

while length contraction took care of

the Michelson Morley experiment

lorentz knew more was needed to explain

all the experiments that had failed to

detect motion Through The Ether

since he still believed in The Ether and

the fact that the Earth moved through it

he felt that somehow the electron must

be responsible for this amazing fact

about life

regardless of the speed with which they

themselves are moving all observers

measure the same speed of light

certainly other speeds say the speed of

a moving train

aren't the same to all Observers

to an observer on a platform for example

this Train's passing had a good clip

but to someone on the train

the train speed seems to be zero and the

ground outside seems to be moving

instead

therefore as Galileo was well aware in

the Renaissance

and as the Stella knows today

the speed of an object depends on the

observer's speed

but Lorenz said that perceptions of

light waves would be radically different

he suggested that even someone traveling

at nearly the speed of light

would still observe light moving at

three hundred thousand kilometers per

second

how could that be

consider two observers in relative

motion

in this case

Albert

and Henry

just for the sake of argument

at the exact place and time they pass

each other

they observe a flash of light

a sphere of light expands outward from

that point

since each measure the speed of light

relative to himself

each believes correctly that he is

always at the center of that expanding

sphere

even though they themselves move farther

and farther apart

how can two people

in different places

both be at the center of the same sphere

to confirm his perception

each sets up light detectors and equal

distance apart

however while Albert's detectors

register the light arriving

simultaneously he believes the light

strikes Henry's detectors at two

different times

[Music]

meanwhile Henry sees the same thing in

reverse

ah

[Music]

they agree on the speed of light

but they disagree on whether events

happen simultaneously or at different

times

this is not semantics nor a petty debate

it means that time as well as distance

has to be affected by motion

however as profound as this was

the French mathematician Ali parque

objected to the limited nature of

Lorenzo's explanation what was needed he

said was a new fundamental law of

physics

the principle of Relativity According to

which the laws of physical phenomena

should be the same

whether for an observer fixed or for an

observer carried along in a uniform

movement of translation

in other words as Galileo had suggested

one state of uniform motion is as good

as any other

after all this idea was the basis of

Galileo's reasoning and the law of

inertia almost 300 years earlier

[Music]

was suggesting that the idea of Galilean

relativity should be generalized to

include all physical phenomena including

light

for example an observer could not

determine whether he was in motion by

measuring the speed of light

since that speed is the same for all

Observers

and that meant age-old Notions about

time and space had to change

himself shied away from examining the

consequences

Lawrence developed the equations needed

to show precisely how much

rulers would have to contract

and clocks would have to slow down

when they were in motion

the essence of his reasoning can be seen

with the aid of the simplest possible

clock

two mirrors a fixed distance apart

with a light beam bouncing back and

forth between them

each bounce of the beam is a tick or a

talk of the timepiece

to Henry

his clock is stationary

and altogether ordinary but for Albert

that clock is moving

and between tick and talk

he sees the light beam trace a diagonal

path

which means it's traveling a longer

distance

but the speed of light is the same for

all Observers

so the light must take a longer time to

travel the longer distance therefore

Albert believes the moving clock runs

slow

but how slow

[Music]

the relativity of time is derived from

the right triangle formed by the

distances traveled

the Pythagorean theorem shows that the

path of the moving light is longer than

the distance between mirrors

by the factor one over the square root

of 1 minus V squared over c squared

this Factor occurs so often in

relativity that it has given its own

symbol

the Greek letter gamma

[Music]

so to an observer at rest

a moving like clock seems to be running

too slowly

by the factor gamma

a ruler or anything else in motion

also seems contracted by that same

factor

and it's called the Fitzgerald

contraction

for speeds much less than the speed of

light

gamma isn't very large

for example the Earth

in its headlong Dash around the Sun is

shortened by no more than the length of

one blade of grass

as for Speed on the Earth while Lawrence

was busy developing his theory

the steam locomotive barrier of 100

miles per hour was broken

at that speed the entire train is

shortened by less than the width of one

atom of the paint on its engine

and Lawrence himself didn't move slowly

he was the international physicist young

physicists from around the world

attended his lectures at the University

of Leiden in the Netherlands where he'd

been a professor for a quarter of a

century

among those who came to Leiden was

Albert Einstein

over the years the rents would have an

enormous professional and personal

influence on Einstein

[Music]

just before his death Einstein said

I have admired and loved Lawrence

perhaps more than anyone else I have

ever known

but it was Lawrence's work as a

theoretical physicist that went beyond

his privileged Circle of Friends

and traveled freely through time and

space

[Music]

knowing he was on the right track

the rents pursued the consequences as

far as he could

if moving things appear shorter

and moving clocks run slower

then how can two people moving in

relation to each other

agree on a consistent description of

where and when some event happened

to answer that what's needed is a set of

equations to replace the old Galilean

transformations

these equations weren't hard to find but

some of their implications

were hard to believe

in Galilean relativity the position of a

point x Prime in a moving frame is

related to its coordinate in a fixed

frame by x minus VT

lorentz found that for the new

relativity this must be multiplied by

the factor gamma

that's the equation along the direction

of motion

in directions perpendicular to the

motion distances are the same in both

frames

and as for time

although clocks can be synchronized in

any one frame

their readings in another frame may

depend on where they are

the time in the moving frame is gamma

times the quantity T minus v x over c

squared

[Music]

together these equations are the lorentz

transformation

they express the mathematical essence of

the special theory of relativity

the lorentz transformation slows time

and contracts distances in a moving

frame

no matter which frame is taken to be

moving

the observer in the moving frame thinks

he's at rest and that the other frame is

really moving

but these equations do more than that

they actually join time and space

together

when an event occurred has no meaning

without saying where it occurred

[Music]

1904 the Netherlands

lorentz publishes the definitive version

of his electron Theory

it contains the essential equations of

the theory of relativity

but Albert Einstein has not yet been

heard from which has caused some to say

that history has given him more credit

than he deserved 1905.

Baron Switzerland

Einstein a young physics student

supporting himself as a patent Clerk

finds himself disturbed by seeming

inconsistencies at the very core of

physics Ken inertia and the laws of

mechanics be made consistent

[Music]

Maxwell's theory of Optics and

electromagnetism

[Music]

Einstein decides that they must

even if that means giving up not only

The Ether but the traditional meanings

of time and space

he sets forth two fundamental postulates

the first is

relativity principle the laws of physics

are the same for all inertial frames

his second postulate states that the

speed of light is the same for all

Observers

he simply assumes the phenomenon that

lorentz has been struggling to explain

from these two postulates alone Einstein

deduces exactly the same equations

lorentz discovered earlier

but now they have a very different

meaning

the fundamental concepts of space and

time

have become intertwined

the essence of the idea can be

understood by visualizing time as if it

were another dimension

Albert standing still in space flows

through time

so that a vertical line represents a

fixed point x equals zero in his

reference frame at different times

[Music]

while a horizontal cross-section

represents simultaneous times in

different places

on the other hand someone in motion

Galileo for example

traces an oblique path

foreign

so while what Albert thinks of as a

fixed Point makes a vertical line

Galileo's idea of nothing happening

appears as a tilted line at X Prime

equals zero or anywhere else in his

frame

but of course if Galileo had drawn the

picture his line for standing still

would be vertical

and Alberts would be tilted backward

the same idea can be used to show the

relativity of time

when Henry and Albert observed the same

expanding light sphere

it reaches their detectors at definite

points in time and space

[Music]

these are called events

[Music]

meanwhile the light itself traces out a

cone

to Albert events on the horizontal

cross-section are simultaneous

for him one of Henry's detectors flashes

first

then both of his own flash

simultaneously

and finally Henry's other detector

flashes

[Music]

so he thinks these two events are

simultaneous

but Henry thinks these two events are

simultaneous

so not only are Henry's lines of

constant position tilted

but so are his lines of simultaneous

time

for Henry simultaneous events take place

everywhere on a tilted cross-section

so he thinks one of Albert's signals

goes first

then both of his then Albert's other

signal

of course if Henry were drawing the

picture

he would draw his lines of constant

place and constant time perpendicular to

each other

amazingly that wouldn't change the light

cone at all

this way of looking at things is called

a space-time diagram

and many of the strange effects of

Relativity can be visualized this way

for example

Albert thinks that Henry's ruler isn't

quite a meter long

while Henry seeing Albert speed by

thinks Albert's ruler is shorter

[Music]

on the space-time diagram

Albert measures lengths on his space

axis where Henry's ruler is shorter

[Music]

but on Henry's axes the situation is

reversed

and Albert's ruler is shorter

and what about the mystery of the clocks

how can each think the other's clock is

slow

on the space-time diagram

just follow the bouncing light beams

foreign

[Music]

on Albert's time access Henry's ticks

are farther apart than his own

[Music]

but on Henry's time axis Albert's ticks

are farther apart no matter how he looks

at it

actually there's more than one way to

look at the lorentz transformation

itself

while it was first derived by lorentz

Einstein arrived at the same equations

but from a completely different

direction

lorentz used the equations to explain

the Michelson Morley experiment while

Einstein's goal was to establish

relativity as a fundamental and

Universal principle for all of physics

for Lawrence the constant speed of light

for all observers was a mere appearance

for Einstein this constant speed was a

principle from which all else should be

derived

Lawrence was perhaps the last great

classical physicist but the equations

that bear his name

are at the heart of relativity

and the future it created

in any case there are two completely

independent histories of the theory of

relativity

one of them goes this way there was The

Ether Theory and in the Michelson Morley

experiment and other experiments fail to

detect its existence and then cuancare

and Lorenz with great difficulty produce

the formulas that were necessary to

explain the results of those experiments

and then

completely separately and independently

young Albert Einstein was worried about

a deep problem having to do with the

nature of light and electricity and he

decided that this was the way the world

had to work

and he came up with exactly the same

Theory

but with a far far deeper understanding

of what it meant

so

it's possible to say that Einstein made

only minor contributions to the theory

of relativity just as it's possible to

say that Copernicus did nothing but a

trivial mathematical transformation of

coordinates

but to say that ignores in the most

profound possible way

the real history of both of those

subjects

we'll go on without discussion of the

theory of relativity next time

thank you

[Applause]

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