Gravity Chapter
3 continued
Van der Waals Equations of State
Later in the century technological
advances provided the means to subject gases to much higher
pressures, and these developments posed a further question for kinetic-atomic
theory in that, for example, when compressing a gas to
its liquid state, this did not proceed at all as expected or predicted
by the theory.
In the case of carbon dioxide gas, it was observed that
when the pressure reached a force of 60 atmospheres, no
further increase in pressure was necessary and the gas
spontaneously condensed and reduced in volume to the liquid state.
According to the kinetic-atomic theory as outlined above
the volume of the gas should decrease in direct proportion
to the increase of pressure applied to it and the pressure
should progressively increase all the way until the volume
of the liquid state is reached.
Figure 5
The graph above shows both the theoretical or ‘ideal’ gas
progression and the actual, observed progression to the
liquid state of carbon dioxide.
The solution to this paradox was to suggest that the carbon
dioxide molecules behaved as the theory predicted and do
not exert any appreciable attraction on each other, up
to the point where the pressure of 60 atmospheres was applied. At
this point it was suggested that, at this proximity, the molecules
become strongly attracted to one another, and further when in the
closer proximity of the liquid state the complete reverse occurs
and the molecules acquire a state of strong repulsion to one another,
as depicted below.
Figure 6
However this solution to the problem not only contradicts the basic
assumption of the theory in that molecules exert no appreciable
attraction on one another, it is of course also illogical as there
is no explanation given as to why and how these changes in attraction,
repulsion and neutrality occur at these particular separations and
no justification can be supplied for these assumptions. 4
But these new assumptions enabled a set of mathematical
formulae to be established, e.g. Van der Waals ‘Equations
of State’ 5,
which could be put to practical use in predicting the approximate
behaviour of gases in a greater range of conditions. In other words
the theory was adjusted to suit the observed reactions in practice.
Here again it must be emphasised that, as in the beginning
of the century, in the latter part of the 1800s there was
widespread disagreement in scientific circles, and not
only kinetic atomic theory but also other, conflicting, ideas about
the ultimate basis of matter were promoted.
The Ultra-Violet Catastrophe
In the late 1800’s and at the turn of
the century the spectrum of electromagnetic radiation was
being examined.
A piece of metal, for example, when heated absorbs the
energy applied to it and, if its environment is at a lower
temperature, it then begins to emit heat itself. This emission
is not initially visible, but at some point in the continuous
application of energy the metal starts to glow red and it is then
beginning to emit energy at the top end of the infrared spectrum
together with some from the lower visible spectrum, light. Further
heating results in a progressive change in colour, whereupon the
metal is emitting visible radiation, or ‘white’ light.
Experiments were set up using apparatus such as ‘black
boxes’; these were essentially ovens, having the interior
surfaces coloured black, heated to high temperatures.
In one wall of such an oven, a small hole allowed radiation
emitted by the interior walls to escape and the spectrum
of radiation from a range of temperatures was observed
and analysed.
Kinetic atomic theory states that atoms in a solid are
vibrating or oscillating within set parameters and that
the amplitude of these oscillations are directly related
to the temperature, and that all frequencies of vibrations
should be possible and the heat emissions continuously
converted into electromagnetic radiation (as long as
energy is being supplied to it).
On these assumptions and on the basis of Newtonian, or
‘classical’ mechanics a formula was devised by Rayleigh
and Jeans, the Rayleigh-Jeans radiation law and this predicted
that a solid could, at a finite temperature, radiate an
infinite amount of energy, which would extend through the
ultra-violet spectrum to the higher frequencies of x-rays and so
on and lead to the emission of all its energy.
Observations showed however that while the Rayleigh-Jeans
law applied to low frequencies, at higher frequencies the
intensity peaked and then progressively decreased, this
failure of classical mechanics was described at the time
as the ‘Ultra-violet catastrophe’.
Quantum Theory and Mechanics
This problem was addressed
by Max Planck, who examined the data from black body experiments
mathematically, and by a process of trial and error eventually
came up with a formula that fitted the observed curve of the ratios
of frequency to intensity.
Planck then asked himself what physical process could fit
this mathematical solution and came up with the suggestion
that matter emitted electromagnetic radiation in discrete
bundles, later called ‘quanta’.
This was a significant development that dramatically and
emphatically changed the nature and the direction of the
physical sciences, as this subsequently led to the development
of quantum mechanics and later quantum electrodynamics
(QED), the latter being the theory, developed by Paul Dirac
in 1928, that combines quantum mechanics, electromagnetism and special
relativity.
These developments made quantum mechanics a very useful
tool for use in a wide range of technologies where a high
degree of accuracy is required.
However each of these developments produced contradictions
that were essentially ignored by physicists, for example
QED predicts that an electron must have infinite mass,
and a mathematical trick is used to overcome this problem
by using an assumed mass in equations.
This was and is, if viewed objectively, a not only a serious
but a fatal result for the theory, but unlike the ‘ultra-violet
catastrophe’ this catastrophe has conveniently been ignored,
brushed under the table in the interests of expediency.
But the most significant problem with quantum theory is
the currently accepted paradox of wave/particle duality
theory.
Wave/Particle Duality
In 1801 Thomas Young carried out his now famous
‘double slit’ experiments on light and analysed the resulting
interference patterns produced to propose that light was propagated
in waveform in contradiction to the earlier Newtonian assumption
that light was corpuscular, or another words consisted of minute particles.
The top part of Figure 7 shows the patterns of alternate
light and dark bands produced in this experiment by the two series
of waves of light from the two slits reinforcing and cancelling out
each other.
Later in the 19th century Clerk Maxwell established that
light was the visible part of the whole electromagnetic
spectrum of radiation emitted by the sun.
Figure 7
In a 1905 paper Einstein explained the photoelectric effect,
where certain metals that have a beam of light directed
at them emit energy, by suggesting that this was due to
the atoms of the target metal absorbing light particles,
which he named ‘photons’, and as a result emitting energy in the
form of electrons, and this later won him a Nobel Prize.
Later Crompton in 1922 carried out experiments with cathode
ray tubes, the results of which were analysed by him to
show that ‘radiation behaves like a corpuscle of well-defined
energy and momentum’.
Thus the situation was arrived at where, the visible spectrum
of radiated energy, i.e. light, was apparently ‘proven’
by different experiments to be to be both a wave and a
particle - subsequently described as a ‘photon’.
However a serious contradiction of this concept of wave/particle
duality arose when Young’s ‘double slit’ experiments were
carried out with particles directed at the slits. The particles,
electrons or photons, each collide with the screen or target
at a single spot, but their overall distribution acts like
a wave on emerging from the other side of the slits and
ultimately interference patterns that are an indication
of wave formations were produced on the detector on the far side.
This experiment, as depicted in Figure 8 ultimately produces
precisely the same pattern as if an ordinary light source
is used.
Figure 8
Scientists were flummoxed by this result and asking; how
can a particle ‘decide’ exactly where to go?
This clearly was a serious problem for quantum theory and
eminent scientists over the next few decades devoted a
huge amount of work to resolving this paradox and the quite
bizarre suggestion was developed by Nils Bohr and Werner
Heisenberg that only when the particle is observed does
it materialise at a certain point. In other words that
human consciousness has a direct impact on the particle.
This led to the mathematical device known as Heisenberg’s
‘Uncertainty Principle’ and to the famous and satirical
proposition of Erwin Schrödingers hypothetical cat experiment.
Again therefore scientists came to the conclusion that
there is nothing wrong with the theory, in this case quantum
mechanics, but instead there is something intrinsically
strange, illogical and incomprehensible about nature itself.
A number of eminent theoreticians strongly condemned this
conclusion, including Plank, Einstein, Schrödinger and
Louis De Broglie, but this opposition did not result in
any change in the bizarre direction that quantum theory
was taking theoretical physics and wave/particle duality
has continued to be accepted by theoretical physicists
to the present day.
The Achievements of 20th Century Science
This situation could perhaps
be accepted, if it had been just an interim stage in the
progression to a better understanding of nature and in particular the
basic forces that directly affect us, but what has theoretical physics
produced since these developments in quantum theory?
Some will point to nuclear weapons and nuclear energy and
while theoretical physics undoubtedly had an input, the
real work of developing the nuclear bomb was largely a technological
achievement. Of course there would be few who would count this achievement
of science as a benefit to humankind, perhaps a greater proportion
would suggest that the by-product of this military investment, nuclear
power generation is beneficial.
The main focus of physics in the last half century has
been an examination of the components of the nucleus of
the atom, sub-atomic particles. In general this work has
been carried out by means of particle accelerators and many of the
governments of industrialised countries have invested in such facilities.
Since Rutherford’s
primitive apparatus split the atom, these machines have
become more and more sophisticated, larger and larger and more and
more powerful and accordingly of course more and more expensive.
In 1993 a previously hypothetical particle was apparently
identified, the large or the top ‘quark’, and this was
hailed by physicists as a great success.
However the question must be asked as to how this can be
described as a success, what did this knowledge produce,
did any new material that could be used for practical purposes
result? Was there any better understanding of the basic forces of
nature, any progress to understanding the transmission of gravity?
At about this time a huge accelerator facility, planned
for construction in Texas, USA at a cost of $50 billion,
involving the construction of a tunnel 50 km in circumference
was cancelled by the United States.
In this context Werner Heisenberg had earlier suggested
that if the nucleus could be divided into smaller and smaller
particles, ultimately the question must be asked; what
is the point?
Clearly there is no point in the sense that all this effort
has not, and will not, lead to a better understanding of
our human environment. I suggest that the cancellation
of the Texas project is an example of the greater realisation by
governments of this truth.
Many commentators now acknowledge the lack of progress
and the current impasse in science, the following is one
example: -
‘The result of this divorce of theory and reality
has been — a growing sterility and stagnation of fundamental science.
There have been tremendous advances in most areas of physics,
such as materials science and hydrodynamics, which remain
tied to experiment; but since the development of QED in 1928 to 1930,
there have been no major gains in our understanding of the underlying
structure of matter’.6
The Phenomena of Einstein
Einstein published papers on Special Relativity in 1905,
and later, in 1912, on General Relativity, and these
theories were later considered to be validitated, firstly
by their success in predicting an observed aberration in the elliptical
orbit of Mercury, and then by a confirmation of a prediction that light
could be bent by gravitational force. This latter a result of data
obtained from observations of a lunar eclipse in the year 1919. The
results of these experiments considerably raised his standing in scientific
circles.
These successes coincided with the end of the world war
of 1914 to 1918 and as a biographer of Einstein, Milton
Dank commented: -
‘sickened by the useless slaughter, the people
of the warring nations turned from incompetent generals
to a new hero. That he was a shy, absent-minded professor whose work
was far beyond them did not matter. They had been told that
he had drawn a new picture of nature and the structure
of the universe. Tired of the old, bloody world, they were
ready to worship the new one and its creator. For Albert Einstein,
it was sudden, overwhelming fame.’
We need not discuss here the enormous prestige of Einstein
and the adulation that he received from the general public
and in particular in scientific circles throughout the
1900’s but need to understand the long term effects on
the public and on scientists in general.
This prestige was similar if not greater than that afforded
Newton from the late 1700’s onward and resulted in a similar
phenomenon, one of people in general and scientists in
particular being very reluctant to criticise or contradict
their theories and accepting virtually anything written
or said by them as being true. No book that has been published
since the 1920’s that has anything remotely to do with science that
does not mention him, including this one
.
This enormous prestige was a significant factor in finally
eliminating the previously vigorous opposition to some
aspects of kinetic atomic theory, which included the concept
of kinetic motion and the existence of the state of a perfect
vacuum.
Chapter 4 >
Back to Gravity Contents >
|
