This article was written for the July 2011 edition of Prime Focus, and was one of a series related to 'energy'. It appears here in a slightly adapted form for interested Face Book followers on Macarthur Astronomical Society page...
The
less one knows about the universe, the easier it is to explain – Leon Brunschvicg 1869-1944
Before
moving into the scientific complexities of the 20th century, it is worth
consolidating the synoptic view created over the past few articles. I began this series by asking: ‘What is Energy’;
and continued with an examination of the early growth of human scientific
thought. It became apparent that certain
human traits and conditions stymied human logic and the development of scientific
reflection.
Identified amongst these traits
and conditions were religion and spiritual fantasy, economics, politics, cultural
needs or desires, and fluctuating levels of human curiosity; not to mention
professional envy. Each of the above-mentioned traits or conditions provide a rich area for debate in their own right. The human race has only itself to blame for its incredibly slow scientific development. Even in today's world, there are powerful elements who would, for purely selfish reasons, plunge the world back hundreds of years simply to enhance their own megalomaniacal appetites.
Our
primary interest is astronomy and cosmology, so I don’t intend to stray too far
down a philosophical, political, religious or psychological path. However, to achieve the objective of understanding scientific
development, we should perhaps first be cognizant of the most basic human needs.
‘Maslow’s
Hierarchy of Needs’ plays a large part in human intellectual
development. Without going too deeply
into this phenomenon, suffice to say, Abraham Maslow maintained that without a full
belly, and the most basic needs of life, humans tend not to be too concerned with deeply intellectual or academic matters. One can imagine many periods of human history
where the sole concern was basic survival – not scientific advancement.
http://www.businessballs.com/maslow.htm
Another
aspect worth considering is the difference between ‘scientific development’ and
‘technological development’ – these are two distinctly differing fields of human
enterprise.
http://www.diffen.com/difference/Science_vs_Technology
The Egyptians, for example,
were without doubt technologically advanced.
However, they weren’t necessarily scientifically astute! Quite simply; they made many items that
made life easier and more comfortable, without necessarily understanding the scientific principles
that underpinned them. Much the same could be said today – many of us
drive technologically advanced vehicles – however few understand what makes them work!
One
final point worth consideration; in earlier times, it had been possible, if one
were among a privileged few, to ‘know all
there was to know’. The sum of human
knowledge was such that, without modern day distractions, a person could study
to ‘understand everything’.
The last statement must be taken cautiously;
but reflects how little was understood scientifically. As the Enlightenment progressed into the
Industrial Revolution, science and physics started to get serious. Pandora’s Box inched to open. Scientists began to specialise in their own
focussed areas of interest. The world was still a
large place at the end of the 19th century, with poor infrastructures and communication. Nevertheless, progress was made and information
started to be collated; and more importantly, shared.
By
the end of the 19th century and moving into the 20th century, the three classical states of matter, liquid, solids and gas had been
seriously investigated. Study then progressed into
the non-classical states – glass and crystal etc. http://en.wikipedia.org/wiki/State_of_matter
With the coming of quantum physics, the field would widen again into low
temperature states, high-energy states, very-high energy states and ever onward
into other proposed states.
Hypothesis
built upon hypothesis as theories were proven or disproved; perfect unadulterated
science thrived in this environment.
The First and Second
World Wars would drive further
discoveries – some more welcome than others.
Year by year, scientists presented the human race with a growing array
of deepening mysteries; mysteries that would stretch ordinary mortal mental capacities
beyond everyday limits. Some of these
discoveries have led us to rethink the concept of 'reality' itself. Take the following examples; I take the
liberty of assuming most readers are aware of the properties of an atom in
general terms:
If
one accepts the world human population now to be 6,000,000,000 (6x109)
– and the number of atoms in the human body on average to be 7,000,000,000,000,000,000,000,000,000
(7x1027) then the whole human race comprises: 6x109 x 7x1027
= 4.2×1037 atoms. Stripping away the outer layers of those
atoms, leaving only their nuclei - matter - the space required to ‘store’ the whole human
race can now be reduced to something akin to the volume of a sugar lump.
Or
conversely: the density of a neutron
star – let's say about 20 km in diameter - is such that one teaspoon of its substance has
a mass of about 100 million tons, which is about as much weight as a good-sized
mountain.
The consequential force of
gravity for such a star, is so powerful, that if an object were to fall from just one metre high it
would hit the surface of the star at around 2,000 kms per second, or 4.3
million mph.
These
statements are tricky for people to comprehend, because they lay outside the confines
of ‘common sense’ or logic; but remember, the same ‘common sense’ or logic, was once a valid reason for accepting
the geocentric model of the universe!
http://www.universetoday.com/32607/geocentric-model/
Today,
there are still those who support the notion of a flat earth. Religion and superstition still retain an iron
grip on the human psyche throughout the world. Economics
undoubtedly restricts funding for long term scientific research, and professional jealousy
still gets in the way of scientific progress.
Increasingly,
politics in this modern age has an unfortunate habit of creating misleading
‘scientific facts’ for purely political ends.
In spite of these negatives, whilst it may have slowed, genuine
scientific knowledge continues to develop apace, even in the face of often vitriolic opposition from those with negative vested interests.
Having
indulged in a little consolidation, we can now examine some of the specific
areas of scientific development concerning the nature of the universe. As we have seen scientific arguments and
debates have raged throughout history.
That is the essential strength of science – one must always question the results.
Darwin’s Theory – may be termed ‘only a theory’ – but since first
proposed, all subsequent evidence has only supported and strengthened that ‘theory’. Nothing has cast
serious doubt upon Darwin’s empirical evidence and ensuing conclusions.
Conversely,
the scientific debate that raged for years over the existence of cosmic ether
as the medium by which light moved through the universe, was eventually lost;
in spite of assertions - there ‘must be
something’ in which light could travel.
Common sense again!
http://en.wikipedia.org/wiki/Luminiferous_aether
Since
the Ancient Greeks, it was speculated that light had a finite speed. Our old champion, Galileo, actually carried
out some crude research attempting to establish the speed of light. Some seventy years later, the Danish
astronomer, Ole Roemer estimated the speed of light at about 220,000 km/s – nearly
26% lower than its correct value. It wasn’t
until 1849, that Armand-Hippolyte-Louis Fizeau (1819-1896) made a reasonably successful
attempt to establish the actual speed of light.
In coming years, eminent scientists from Leon Foucault to Mittelstaedt
through to Bergstrand, in 1951, struggled to achieve a correct result.
The
American, Albert Abraham Michelson (1852-1931), typified the calibre of those whose
efforts would lead to an accurate assessment of the speed of light. Michelson is particularly interesting because
his greatest claim to fame was a failed experiment, which lasted an agonising
seven years.
Michelson initially set out
to prove the existence of the enigmatic substance - ‘ether’. Finally – he succeeded in proving
beyond doubt that ether didn’t exist.
http://en.wikipedia.org/wiki/Michelson-Morley_experiment
Incidentally, in 1880 – Michelson estimated
the speed of light to be: 2990,910 km/s.
Although incorrect, it was however a respectably accurate estimate. In 1921-22, Michelson, in association with
Francis Pease, became the first to measure the diameter of a star, other than
the Sun. Using an ‘astronomical interferometer’ at the Mt Wilson Observatory, the pair
successfully measured the super-giant star – Betelgeuse.
In
1905, Albert Einstein demonstrated that the velocity of light was an essential
constant – and in fact the definitive speed for any object.
In 1951, using a Kerr Cell shutter, an
instrument previously used as early as 1875, Erik Bergstrand put the speed of
light at 299,793.1 km/s – an error of just 0.3.
Accumulated knowledge and advances in technology were finally closing
the gap on the elusive ancient speculation.
In the second half of the 20th century, methods such as
cavity resonance techniques, and
later laser interferometer techniques ensured increasingly accurate
measurements of the speed of light. In 1983,
the metre was redefined to increase
the accuracy of various methods of measurement – the current definition now
reads: “the metre is the length of the
path travelled by light in a vacuum during a time interval of 1/299 792 458 of
a second.’
As a consequence of this
reclassification the value of the speed of light in a vacuum is now given as
299,792,458 m/s by the International System of Units (SI).
http://physics.nist.gov/cuu/Units/meter.html
Finally – it is worth remembering, when we
speak about the ‘speed of light’ - we are
in fact referring to the ‘speed of
electromagnetic radiation’. What we
call, visible light is only a small
part of that greater electromagnetic spectrum.
Refs:
BIBLIOGRAPHY Encyclopedi, W. t. (2010). State of Matter.
Retrieved June 1, 2011, from Wikipedia:
http://en.wikipedia.org/wiki/State_of_matter
Fowler,
M. (2009). Galileo and Einstein. Retrieved June 2, 2011, from Uva Dept
of Physics: http://galileoandeinstein.physics.virginia.edu/
Fowles,
G. (1989). Introduction to Modern Physics. Retrieved June 2, 2011, from
Physlink.com: http://www.physlink.com/education/askexperts/ae22.cfm
Gibbs,
K. (2010). Speed of Light. Retrieved June 10, 2011, from School Physics:
http://www.schoolphysics.co.uk/age16-19/Wave%20properties/Wave%20properties/text/Speed_of%20light/index.html?PHPSESSID=325fe609a38643798b41aced112cbcd0
Singh,
S. (2005). Big Bang. London: Harper Perennial.
WikiAnswers.
(2011). How much would a spoonful of neutron star weigh. Retrieved June
1, 2011, from Answers.com:
http://wiki.answers.com/Q/How_much_would_a_spoonful_of_a_neutron_star_weigh
Wikipedia
the Free Encyclopedia. (2011). Speed of Light. Retrieved June 10, 2011,
from Wikipedia: http://en.wikipedia.org/wiki/Speed_of_light
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