-
8/6/2019 Mechanical Picture of the Universe_2
1/3
Mechanical picture of the Universe
Kevin Tang
Department of Physics, Loughborough University
4th
of May 2010
There is a branch of science known as cosmology that concerns
itself with the past, present and
future of the universe as a whole. How did that universe begin?
How has it evolved? And where is it
going? There is another branch of science called mechanics, it
is a profound and philosophical
branch. From the smallest particle to the largest cluster of
galaxies, what keeps it all going? Whether
it is speeding up, slowing down, changing direction or cruising
straight ahead. Why does it all behave
the way it does? All these questions have been around as long as
there have been people around
asking them. Even the earliest human inhabitants of this planet
must have looked up at the sky and
asked, how does it all work? And they have taken the first steps
in discovering and understanding
the mechanical universe.
Around the 4th
century BC a number of Greeks developed a model of the universe
in which the Earth
was stationary and everything else moved in giant perfect
circles around the Earth. This view of the
cosmos is one the most enduring beliefs in human history. But
then in the 17th
century all these
ideas have changed to a new vision of the cosmos. At that time,
Prague had a powerful alignment of
forces. Star data gathered by Tycho Brahe and a man with a
mathematical ability to use it, Johannes
Kepler. Not too long after that, a new model of the universe has
been rediscovered by a Polish man
called Nicholas Copernicus, a model where the sun is at the
centre of everything. He did this while
dropping the belief of perfect circles and tried other shapes,
until finally he found one, an ellipse.
In July 1609 Galileo Galilei, who was professor of mathematics,
designed and built a telescope from
scratch. Using this telescope he could turn distant objects to
appear a lot closer, therefore he
uncovered new evidence about the cosmos by pointing his
telescope to the heavens. He was the
first one to see Jupiter and its moons which also suggested that
the planet Earth is not at the centre
where everything spins around it.
A couple of years later a great thinker of all times Isaac
Newton explained what keeps the planets
moving in elliptical orbits. He worked out a comprehensive
theory of gravity as he saw an apple
falling from a tree. He asked himself whether the force pulling
the apple down is the same force that
keeps the moon spinning around. And in that moment the theory of
gravitation is born. Isaac
Newton used a thought experiment to describe the path of the
moon. If the ball leaves the cannon
slowly, gravity would pull the ball back to Earth and if the
ball leaves it too quick it would fly off into
space, but if the ball has got just the right speed it would
orbit the Earth just like the moon. Isaac
Newton outlined the universal laws of motion to explain how the
planets move. He is not only a
great scientist, but he also inspired other intellectuals to
look for universal laws that could explainhuman behaviour, history
and even politics.
There was now a new stable model of the universe, a clockwork
universe governed by a few simple
laws. But again this idea has changed in the early 20th
century when Edwin Hubble discovered that
our planet is insignificant in the vast universe. He found that
very far away there are a lot more
galaxies present which are similar to our Milky Way and most of
them are receding at an astonishing
speed. This lead to a new thinking, that our universe is
expanding and therefore there must have
been a starting point 13 billion years ago, the Big Bang.
-
8/6/2019 Mechanical Picture of the Universe_2
2/3
Mechanics, the oldest and yet modern science plays a huge role
in the formation of the modern
picture of the universe, which is an important component of the
scientific outlook. Mechanics is also
the first fundamental theoretical system in history of the
development of science. It is not only a
model for the creation of new scientific fields in physics,
cosmology, chemistry, biology and other
branches of natural science. Its concepts and mathematical
apparatus are also being used
successfully at the present time as the starting point for new
ideas and new fundamental theories.
On the other hand, mechanics as a theoretical system appears
also to be the foundation for the
creation of new theory that reveals the fundamental
relationships and properties of nature. For
example, the special and general theories were created using the
methods of mechanical theory,
such as thermodynamics and electrodynamics. The establishment of
quantum mechanics which has
been applied in chemistry as well as biology is simply
impossible without classical mechanics.
Mechanics therefore is also of great value in the development of
modern science.
The mechanical picture of the universe is a systemized
representation of nature surrounding us
which is based on Newtonian mechanics and which is realized by a
set of fundamental scientific
concepts, philosophic categories, visual objects and models.
According to this picture, the universe
consists of three mutually independent entities: matter,
absolute space and absolute time. The
fundamental relations in nature are the law of inertia, the law
of motion and the law of universal
attraction. The most important characteristics of the behaviour
of material objects are mass, energy,
force, momentum, angular momentum, length, time interval,
velocity and acceleration.
The first scientific picture of the universe, the mechanical
picture, appears as a successor to natural
philosophy. As a matter of fact, the core of this picture of the
universe represents the earlier ideas of
philosophers about nature and the speculative constructions of
natural philosophersabout the
origin and structure of the terrestrial and cosmic bodies. More
than that, although the picture of the
universe is based on mechanics, it gradually came to be enriched
because of concepts from other
fields of science like biology, physiology and astronomy.
The next important step forward had its origin in the Maxwellian
electrodynamics of moving bodies
and later led to the creation of the special and general
theories of relativity. According to the
principle of the unity of physics, after the special theory of
relativity was created it became
necessary to transform the Newtonian theory of gravitation in
accordance with the bases of this new
theory. This was the basic content of the new scientific picture
of the universe, the relativistic
picture of the universe.
In it, the physical universe is considerably different from the
Newtonian universe, where the
mechanical picture of the universe characterised the universe as
consisting three independent
entities. The physical universe is a single material structure
according to this relativistic picture of
the universe. One of its attributes is four-dimensional symmetry
of space-time.
-
8/6/2019 Mechanical Picture of the Universe_2
3/3
In the construction of any scientific theory, there is the
problem of explaining comprehensively a
given set of natural processes. Therefore mathematics is used
for searching for new physical laws
and for predicting the existence of previously unknown effects.
A new theory is introduced,
quantum mechanics which is also the basis for the quantum
picture of the universe. The most
important ideas of quantum mechanics, quantum nature of energy
emission and absorption, has
been advanced by Max Planck and further developed by Albert
Einstein. The quantum picture of theuniverse considers jointly the
particle and wave properties of matter.
The relativistic and quantum picture of the universe is the core
of the modern scientific picture of
the universe. This picture of the universe is being essentially
supplemented by very important
achievements in those sciences and scientific fields which
either were created or which are passing
through a period of revolutionary change.
Therefore the mechanical theory of Newton and the mechanical
picture of the universe, as
demonstrated by great investigators, played an exceptionally
important role in the establishment of
the modern scientific picture of the universe, which was the key
concept of the entire picture of the
universe. That also strengthened the materialistic position of
science as a whole.
