6 Special Relativity
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transformations, now known as the Lorentz Transformations. This explanation was, however, totally ad hoc, and as such only acceptable as a working
proposition. In this regard, it was similar to Max Planck’s ad hoc quantum
explanation of black body radiation that we discussed in the last Chapter.
The physics that underlay the Lorentz Transformations was supplied by the
same young genius who had sorted out what lay behind Planck’s mysterious quanta, in between carrying out his duties as a patent clerk in Berne,
Switzerland.
6.5 Here Comes Einstein
In the annus mirabilis of 1905, the 26 year-old Albert Einstein published
six papers, three of which would revolutionise the field of Physics. One of
them [2] reintroduced the Lorentz Transformations as a consequence of a
very daring assumption, i.e. that the speed of light c had to be exactly the same
for all inertial frameworks, thus becoming a universal constant and rendering
the ether superfluous.
So, why does all the credit go to Einstein and not to Lorentz?
Fame is a Fickle Food
Upon a shifting plate [3].
Not all the kudos in science finishes up where it rightly belongs, and a
discussion of the pros and cons of the many examples would fill a lengthy
monograph. However, in this case the reason for Einstein’s fame is because
his conjecture provides a full justification for the Lorentz transformations and
leads us, as we shall see, to some astonishing conclusions.
What does it mean when we say that the speed of light is constant in all
inertial frames of reference? Let us imagine that, in our example from the
previous Sections, Peter, instead of throwing a ball towards Mary, directs a
ray of light past her. He measures the speed of the light as it leaves him
and obtains a value of c kph. Mary then measures the speed of the light
as it passes her, and, because the train is moving at 10 kph, using Galilean
transformations we would expect her to obtain a value of c-10 kph. However,
she doesn’t. She also obtains a value of c kph.
We would surely expect something of this kind if the speed of light were
infinite. Adding or subtracting finite numbers from infinity yields infinity. 4
4 Mathematicians may cringe, but in Chap. 8 we shall learn that physicists have even resorted on
occasions to subtracting infinity from infinity and obtaining a finite number.
109
transformations, now known as the Lorentz Transformations. This explanation was, however, totally ad hoc, and as such only acceptable as a working
proposition. In this regard, it was similar to Max Planck’s ad hoc quantum
explanation of black body radiation that we discussed in the last Chapter.
The physics that underlay the Lorentz Transformations was supplied by the
same young genius who had sorted out what lay behind Planck’s mysterious quanta, in between carrying out his duties as a patent clerk in Berne,
Switzerland.
6.5 Here Comes Einstein
In the annus mirabilis of 1905, the 26 year-old Albert Einstein published
six papers, three of which would revolutionise the field of Physics. One of
them [2] reintroduced the Lorentz Transformations as a consequence of a
very daring assumption, i.e. that the speed of light c had to be exactly the same
for all inertial frameworks, thus becoming a universal constant and rendering
the ether superfluous.
So, why does all the credit go to Einstein and not to Lorentz?
Fame is a Fickle Food
Upon a shifting plate [3].
Not all the kudos in science finishes up where it rightly belongs, and a
discussion of the pros and cons of the many examples would fill a lengthy
monograph. However, in this case the reason for Einstein’s fame is because
his conjecture provides a full justification for the Lorentz transformations and
leads us, as we shall see, to some astonishing conclusions.
What does it mean when we say that the speed of light is constant in all
inertial frames of reference? Let us imagine that, in our example from the
previous Sections, Peter, instead of throwing a ball towards Mary, directs a
ray of light past her. He measures the speed of the light as it leaves him
and obtains a value of c kph. Mary then measures the speed of the light
as it passes her, and, because the train is moving at 10 kph, using Galilean
transformations we would expect her to obtain a value of c-10 kph. However,
she doesn’t. She also obtains a value of c kph.
We would surely expect something of this kind if the speed of light were
infinite. Adding or subtracting finite numbers from infinity yields infinity. 4
4 Mathematicians may cringe, but in Chap. 8 we shall learn that physicists have even resorted on
occasions to subtracting infinity from infinity and obtaining a finite number.