Gravity Chapter
2 continued
Natural Forces
In considering the human visual sense and the perspective
gained by it we have touched on just one of the forces
that act upon us, in fact the only visible one, light,
however there are a number of invisible forces that act upon us and
that stimulate our senses. In our consideration of reality we must
therefore look at the most important of these.
Temperature
The largest sensory organ of the body is the
skin, and it is this organ that is stimulated by variations
in temperature.
Our internal body temperature is about 36°C and our skin
temperature about 24°C. This latter temperature is about
the environmental level that most humans would find comfortable.
The human body protects itself against variations to the
optimum skin temperature in two main ways, firstly by exuding
perspiration (sweating) above this temperature, the evaporation
of which cools the skin, and secondly by raising the body
hair to a more erect position below this temperature, the
effect of which is to maintain an insulating layer of air between
the skin and the cooler atmosphere.
These protective measures are however only effective to
certain levels, and these levels are to a certain extent
dependent on such things as physiological factors, race
and acclimatisation.
Temperatures at the surface of the earth can vary between
the extremes of plus and minus 50°C, and continued exposure
to such extreme levels will result in, on the one hand,
an increase in the rate of perspiration and consequently
loss of fluid into the surrounding air, leading to dehydration,
and on the other, a progressive reduction in body temperature
due to the constant emission of heat energy from the body
into the atmosphere, leading to what is termed ‘exposure’, both of
which could ultimately result in death.
Exposure to wind and rain can also affect our body temperature,
wind will for example enhance the cooling effect of perspiration
by speeding up its evaporation and will also reduce the
insulating effect of the air layer surrounding the skin
by quickly replacing it with cooler air.
The temperature of rain is generally cooler than the atmosphere
at the surface and, as water absorbs heat very rapidly,
when this cooler water comes in contact with the skin it
will extract heat from the body.
Of course the combination of wind and rain, as a result
of the accelerated evaporation of cold water on the skin,
has a doubly negative effect on body temperature.
Today the main focus and expenditure of most people is
directed to sheltering themselves from exposure to the
weather.
Shelter can be dwellings (however modest or elaborate),
offices and industrial buildings, etc., in fact any building
that is designed to admit humans, down to bus shelters
and public toilets.
Additionally however, while of course their primary function
is transportation, ships and boats, trains and buses, aeroplanes,
cars and trucks also come into this category as does clothing,
with perhaps the exception of some ‘fashion’ clothing.
Sun’s Radiation
The sun emits a wide band of frequencies of radiation
reaching the surface of the earth of which only a small
part, light, is visible to us. The frequencies to either side of this
visible radiation are the infrared and the ultraviolet bands, and both
of these affect us directly and these effects are well known. The remaining
invisible frequencies affect our lives to a lesser and
varying extent, directly or indirectly.
The infrared radiation that is emitted by the sun and strikes
the earth, directly or indirectly result in the forces
that daily and seasonally create the local weather patterns
that we experience. These changes in the weather ultimately result
in the fluctuations in local atmospheric conditions that are represented
by what we term as temperature and that are sensed by the skin and
these conditions are continually changing, hourly, daily and seasonally.
Temperature Perspective
Temperature scales, such as the Fahrenheit
and Centigrade scales, used as a yardstick the difference
between the freezing and the boiling points of water, however
the scientific scale is the Kelvin scale, which is based
on the graduations of the centigrade scale, but is extended
down to the minimum possible temperature or the minimum
theoretical temperature of absolute zero or zero degrees
Kelvin, (-273.15°C).
Converting our comfortable human temperature
of about five degrees centigrade either side of the skin
temperature of 24°C to the Kelvin scale would give a range of between
300° and 310°K.
Thus our body temperature is about 300°K above absolute
zero and if we consider that the temperatures in the sun
have been calculated to be in the region of 15 million
degrees Kelvin, then it is clear that our experience and
perspective of temperature is near the very lowest extreme
of the range. Or in other words we are in relative, and
in universal, terms extremely cold.
Human Concept of Temperature
Here we need to clarify the human concept
of temperature, as temperature is not a force in itself.
If it is not a force in itself then the variations in it that we experience
must be the result of some force and it is important to differentiate
between temperature and these forces.
Here the first point that must be considered is that matter
(and we are matter) in any of its states, i.e. solid, liquid
or gas, when heated or cooled attempts to regain equilibrium with
its local environment by emitting or absorbing energy to or from
its surroundings.
As stated the temperature of the surface of the skin is
about 24°C and the greater the variation from this temperature
upwards or downwards the greater are the sensations of
hot and cold that we experience.
So if there are two rooms, one at 0°C and one at 40°C,
if we place ourselves in one room we will feel cold, and
if we place ourselves in the other we will feel hot.
What is happening here is that the matter in these rooms,
i.e. the atmospheric gases, are on the one hand extracting
energy from the relatively warmer surface of our skin and
on the other hand are imparting energy into our relatively
cooler bodies. In these circumstances our body is trying
to maintain its overall energy level as represented by the optimum
internal body temperature of about 36°C. Of course, if the temperature
of these rooms were maintained and we were left in one without protection
or sustenance we would die from either exposure or dehydration and
our body would ultimately absorb or emit energy and convert to a
state of energy equilibrium with the rest of the matter in the room.
If we place a mercury thermometer, that shows an initial
temperature of 24°C, in each room it will on the one hand,
emit energy from the body and the liquid of the thermometer
into the atmosphere of the room and, on the other hand
will absorb energy from these gases.
In both cases it will attain thermal equilibrium with the
matter in the room and the resultant contraction or expansion
of the indicant liquid (e.g. mercury) will show the appropriate
temperature.
Thus ‘temperature’ is an indication of the relative energy
content of matter and when we experience the sensations
of ‘hot’ and ‘cold’ we are in a situation where the energy
content of the matter surrounding us is greater or lesser,
which results in an energy flow to and from this matter.
This, our everyday experience, is an example of the fact
that nature in any circumstance does not tolerate an energy
imbalance and continually, throughout the universe, attempts
to right such imbalances.
Thus our sensations of hot and cold are generated by the
transmission of energy out from and into our bodies.
However, while these flows of energy can be given labels,
such as (infra-red) ‘radiation’ or ‘conduction’, as to
how the atoms of the gases surrounding us absorb, emit
and transfer this energy, there is currently no sensible,
comprehensible and rational explanation.
Pressure
Pressure is also a force exerted on our bodies
that directly stimulates our largest organ, the skin, and
we experience this from two sources. The first, resulting from the
pressures that are exerted on the soles of the feet when standing,
the pressure on our backsides when sitting and the pressure
on a large part of the surface of the body when lying down
and on any part of the body which is supporting its weight
or part of it, is caused by the pull of the earth’s gravity.
Of the total energy that a human being expends in its lifetime,
a large part of this is expended in overcoming the force
of gravity. For example, we expend considerable energy
in opposing, or working against, this force by simply sitting,
standing, walking, and moving our bodies or parts of it,
in addition to lifting, moving other objects and it can
be said that we spend our lives opposing the force of gravity only
at the last to succumb to it in death and return to the earth from
which we came.
This pressure is the ultimate cause of the wear or deterioration
of parts of our bodies that is often experienced later
in life, typically at the hip, the knee joints and the
spine.
So while the effects of the sun’s radiation are the most
apparent, the main force acting upon us, that has the greatest
physical effect, is the force of gravity, but this, because
it is consistent and almost invariable, is generally not
consciously recognised or considered.
The other source is the consistent pressure exerted by
the atmosphere, which is also not generally noticed due
to the fact that any fluctuations are so small they are
not clearly felt.
These small changes in this pressure are again due to the
sun’s radiated energy. The process of the infra-red radiation
being absorbed by the earth’s surface and then being transferred
to the air that is in contact with it and the consequent
expansion and reduction in density of this air causes it
to rise convectively and eventually form the weather systems
that we call high pressure or anticyclones. These together
with the obverse, the low pressure systems called depressions or
cyclones result in the minor changes in atmospheric pressure that
generally most people are not consciously aware of, but are measured
by a barometer.
Another influence on atmospheric pressure is that due to
the separate or the combined gravitational attraction of
the sun and the moon. Again such minor fluctuations in
pressure are not immediately apparent but the tidal effect
of these gravitational forces on the oceans is of course
an observed phenomenon.
That this force of pressure acts upon fluid matter is quite
apparent to us, for example by submerging ourselves underwater
a metre or two we will experience a significant increase
in pressure that is directly due to the force of gravitation
acting on the liquid (and the gases) above us.
The effects on solid matter are not so apparent, but the
example of the compression of organic matter laid down
over millions of years and resulting in for example, the
carbon based solid fuel we call coal, is an indication
that gravitational pressure also has an effect on solid
matter.
Pressure Perspective
As with temperature, the pressures
we experience on the surface of the earth are also very
near the lowest extremes. The atmospheric pressure at the
surface of the earth is conveniently described as being one atmosphere
and it has been calculated that the pressure at the centre of the
earth is in the region of 3.5 million atmospheres and,
as the mass of the sun is many millions of times greater
than the earth, the pressure at its centre is proportionately
larger, in other words, in human terms, a totally unimaginable
pressure, and this is just a small star. The other extreme
of pressure is in ‘outer space’ where the pressure is closer to zero.
In this film of gas on our small planet we are therefore much closer
to this ‘outer space’ extreme of very low pressure than we are to the
huge pressures at the centre of planets and stars. To put
this into percentage terms we exist in pressures that are a tiny fraction
of one percent from zero.
Gravity
We have considered the reality presented by our senses,
looked at the limitations of the senses and discussed
the natural forces that affect or influence these. These
essential forces that dominate our lives as organic matter are, the
radiant energy from the sun, in particular the light spectrum and the
infrared and ultraviolet spectra, gravity and the atmospheric pressure
acting upon us as a result of gravitational attraction and the relative
energy levels (or temperature) of the matter that surrounds us.
We are matter, we consist solely of matter put together
in an organic construction, and the whole of the environment
that we live in consists of matter, as does the earth,
the solar system, our galaxy and the universe as a whole.
The universe consists of matter and energy and every particle
of matter in the universe is attracted to every other particle
of matter in the universe. This is the law of universal
gravitation that was established brilliantly over 300 years
ago by Newton and enabling us to calculate the effects of this force,
and since then we have discovered nothing to doubt the veracity of
his statements.
For example it is possible to measure the slight difference
in gravitational attraction at the equator and the North
Pole, which is due to the fact that the earth is not a
perfect sphere.
This means that a body of equal weight will fall through
an equal distance at a slightly different rate in these
places, but what causes the weight to fall can only be
ascertained by knowing the intrinsic nature of the matter
of the body and of the earth and of the intervening matter,
the atmospheric gases.
It is burnt into our consciousness that all matter is ultimately
‘atomic’, and the basis of the current atomic theory of
matter was established over a hundred years ago, however
it has not led to any understanding of how gravity is transmitted
through the intervening gas to both the body and the earth.
Gravity is the predominant and ultimate force in the universe.
We can ‘see’ the effects of this force in the solar system,
where the huge planets of Jupiter and Saturn are held in
orbit by the sun’s gravitational forces at, for us unimaginable,
distances and this force extends to even further from the
sun, such as to the distant planets Pluto and Neptune and further
to the comets and other bodies and matter, that are difficult to
view even with the most powerful telescopes.
Thus gravity is the key to understanding the universe and
understanding how it is transmitted is of immense importance
and yet physicists not only have no idea of this, they
are theorising about the universe in ignorance of the ultimate
cause of this force, and this effectively makes any assumptions
made, and hypotheses formed, on the basis of current knowledge of
questionable validity.
It is therefore necessary to have a brief look at the history
of atomic theory to attempt to see why has there been no
progress to this goal.
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