It all began with steam engines, developed and made practical in the 18^th century, which were quite inefficient. Very little of the fuel (coal) consumed in heating water and making steam was converted into useful work (i.e. useful motion).

Engineers grew interested in studying the way in which heat flowed from one point to another in a closed-system and the manner in which it was converted into work. They hoped to learn to make the steam engine more efficient and, perhaps thereby, to understand the Universe better. In this way a new science, thermodynamics (meaning ‘heat movement’ or ‘heat in motion’ in Greek) came into being.

The First Law: The Conservation of Energy (E)

Anything that could be converted into work was, and still is, called energy. Heat, therefore, as well as certain other phenomenon – such as light, sound, motion (kinetics), etc. – came under the general heading energy.

The idea of energy is older than its name. Even in the time of Galileo Galilei (1564-1642), scientists recognised the existence of some constant quantity involved in certain physical problems. In the late 17^th century Leibniz (1646-1716) gave the quantity mv² the name of vis viva (‘living force’). In 1807 Thomas Young (1773-1829) proposed the term ‘energy’. Finally, in 1856 the modern term ‘kinetic energy’, was introduced by Lord Kelvin (1824-1907).

By the 1840s, James Joule (1818-1889), Julius von Mayer (1814-1878), and Hermann von Helmholtz (1821-1894) were convinced that if all the forms of energy were lumped together the total remained constant in any ‘closed-system’ (including the Universe). [Obviously there is no practical method to test this hypothesis on a cosmic scale.]

According to the laws of thermodynamics, energy might be changed from one form into another, but it could neither be created out of nothing, nor totally destroyed. This is called the law of conservation of energy – the first law of thermodynamics.

Conservation of energy is said to be the most basic natural law that scientists have yet discovered, and scientists maintain that no case has ever been found in which it doesn’t hold. [Well, there is no possible way to find out if and how energy is created, or destroyed, on a cosmic scale – it is all pure conjecture!]

On one occasion there was serious doubt among scientists though. Radioactivity was first discovered in 1896 by Henri Becquerel (1852-1908) while working on phosphorescent materials, and large quantities of energy seemed to be appearing out of nowhere within atoms.

But then in 1905 came a ‘hero on a white horse’ – a Don Quixote. Albert Einstein (1879-1955) alleged that mass could be converted into ‘pure’ energy, and that the huge energies produced by radioactivity were compensated by the disappearance of tiny amounts of mass in the relationship, E = mc². [However, this notion of reality is totally misleading.]

According to Einstein, (pure) energy is presumably far more ethereal than matter, being composed neither of atoms nor even of subatomic particles.

Nonetheless, energy is not something with substance (ethereal or otherwise), but like mass, energy is a quality of matter – energy is matter in motion, energy is movement. Where there is no matter there is no energy! Where there is no moving matter, there is no energy! Energy = Mass in (relative) motion, i.e. E = mc². [Besides, is the speed of light (c = 2.99 x 10⁸ m/s) really a constant, or the upper limit of speed in the Universe?]

This equation is not a unique (or mystical) energy-matter conversion equation that describes the energy ‘released’ when matter is rather mysteriously converted into ‘pure’ energy. In addition, mass (m) and energy (E) are not in anyway equivalent as many scientists like to claim.

The classical equation from physics for the ‘kinetic’ energy of a moving object, E_k = 1/2mv², which states that the moving object’s ‘kinetic’ energy (E_k) is equal to one-half of its mass (m) times its velocity (‘v’, or ‘c’ in the case of light) squared. In fact, this is more accurately stated as the full, and proper, ‘kinetic’ energy equation:

Full Reflection ==>  1/2mc²  ≤  E_k  ≤  mc²  <== No Reflection. [For light]

A number of different derivations can be found for Einstein’s equation, but the following classical approach in the case of light will suffice, namely:

1. p = E/c, or the momentum of light (p) equals its energy content (E) divided by its velocity (c)
2. p = mc, or the momentum of light (p) equals its mass (m) multiplied by its velocity (c)
3. Therefore, E/c = mc (= p), equating lines 1 and 2
4. Now, E = mc², by rearranging line 3

In general, we can say that the kinetic energy of any ‘perfectly’, elastic, material body, with a mass equals to ‘m’ kilogramme, and a velocity of ‘v’ metres per second is:

E_k = 1/2mv² (or E_k = mv² for a lump of clay.)

So, Einstein’s very famous equation doesn’t refer to a mysterious ‘matter-energy conversion’ process, but is merely the classical ‘kinetic’ energy (i.e. the motion of material bodies) equation of physics in another form. There is no reference to the creation of ‘pure’ energy from matter anywhere in the derivation above. In addition, it does not state that mass (m) and energy (E) are equivalent in anyway either.

Energy can be converted into work (one type of physical motion into another), and the law of conservation of energy states that the quantity of energy (motion) in the Universe, or any other ‘closed-system’, must stay the same forever.

Well, three questions:

1. Is the Universe a closed-system? Some scientists say yes, and I can but only wonder! It is not possible to proof that the universe in an open or closed-system!
2. Does the total energy in the Universe stay constant over time?
3. And what about the so-called ‘heat death of the Universe’. More about this later.

Now, if the quantity of energy in any ‘closed-system’ stays the same forever; can one then convert energy into work endlessly. Since energy (the ‘movement of matter’) is never destroyed, can it be converted into work (useful motion) over and over again?

The Second Law: Entropy, Energy, and Temperature (E & t)

In 1824, Nicolas Léonard Sadi Carnot (1796-1832) held that in order to produce work, heat energy had to be unevenly distributed through a closed-system. There had to be a greater than average concentration (i.e. a higher temperature) in one part and a smaller than average concentration (i.e. a lower temperature) in another part of a closed-system. [Particles of matter must move faster in certain areas of the allocated space than in other areas.]

The amount of work that could be obtained depended on the difference in these concentrations of energy (temperature). While work was produced the difference in these concentrations evened out. When the energy was spread uniformly no more work could be obtained, even though all the energy was still there! [All particles of matter in the allocated space move at a uniform speed. Think about what happens if you mix hot and cold water, for example.]

In 1850, Rudolf Clausius (1822-1888) made this general and applied it to all forms of energy – not just to heat. In the Universe as a whole, he pointed out; there are differences in energy concentration – and that certainly seems true as far as we know. [There is more energy in the Sun than there is out in the cold regions of ‘empty’ space.]

Gradually, over the aeons, the differences are evening out, so that the amount of work it will be possible to obtain will grow less and less forever, until all the energy is evened out and no more work is possible. This is the second law of thermodynamics, the conservation of energy being the first law of thermodynamics.

Clausius worked out a particular relationship of heat and temperature [H/t, measured in joule/kilogramme/kelvin] which, he believed, always increases in value as the difference in heat, energy concentration (H) evened out [because energy (measured in joule) is constant, but temperature (t, measured in kelvin, or Centigrade) drops]. He called this relationship entropy.

The second law of thermodynamics states that the entropy (E/t) of the Universe, as in any ‘closed-system’, is said to be always increasing. In this context, entropy is also referred to as ‘the arrow of time from cosmos to chaos’ – the ‘heat death of the Universe’ and as ‘a measure of the disorder in any closed system’ – a ‘winding-down’ of everything in the Universe.

However, a closer look shows that this ‘winding-down’ generalisation is not evidence of an external ‘arrow of time’ that always flows in a forward direction defined by disorder and decay, but is a sizeable over-generalisation resulting from a very narrow, selective view of the Universe. The Universe is not a steam engine!

The increase of entropy in physical systems, which marks the direction of ‘time’, could not be explained by the laws of Newtonian mechanics and remained mysterious until Ludwig Eduard Boltzmann (1844-1906) clarified the situation by introducing an additional idea, the concept of probability.

Boltzmann held that with the help of probability theory, the behaviour of complex mechanical systems could be described in terms of statistical laws, and thermodynamics could be put on a solid Newtonian basis, known as Statistical Mechanics. [Keep Benjamin Disraeli’s (1804-1881) admonition lies, damned lies, and statistics in mind!]

Boltzmann maintained that the second law of thermodynamics is a statistical law. Its affirmation that certain processes do not occur – for example, the spontaneous conversion of heat energy into mechanical energy – does not mean that they are impossible, but merely that they are ‘extremely unlikely’. [Nevertheless, the second law is transgressed all around us on numerous occasions each and every day.]

With the discovery of quasars and other mysterious energy sources in the Universe, though, even astronomers are now wondering if the second law really holds everywhere, and under all conditions!

As far as I know the second law of thermodynamics says nothing about energy generated through the influence of gravity and/or electromagnetism. If there is no atomic, or subatomic, movement (zero, or nearly zero Kelvin) in a closed-system theoretically there would be no electromagnetism, but gravity might still be present [?]. [Maybe gravity increases under these conditions to compensate for the loss of other energy types – who knows.]

The Third Law: Zero-Point Energy and Absolute Temperature (t)

In some cases, a zero from which to start counting can be set anywhere. Zero longitude is set arbitrarily. The same is true of the zero in temperature. In the Centigrade (Celsius) scale of temperature, zero degrees is set at the point where pure ice melts or pure water freezes; while in the Fahrenheit scale, it is set at a point were salt water freezes. In either of these cases temperatures below zero may be experienced (negative readings).

Toward the end of the 1700s it began to seem that there might be a limit to cold. Jacques Alexandre César Charles (1746-1823) discovered in about 1787 that gases contracted 1/273 of their volume at zero degrees Celsius for each degree that they are cooled. [This is called Charles’ Law.]

If this were to continue, then, at about minus 273.15 degrees Centigrade (-273°C) the gas should disappear entirely. Of course, this does not happen. The gas invariably turns first into a liquid, then solid, as it is cooled.

William Thomson (1824-1907) extended the idea in the 1860s. He treated temperature as an expression of the velocity of movement of molecules in a substance. The colder the substance, the slower the motion, until the temperature reach minus 273.15 degrees Centigrade where there will theoretically be no motion at all – i.e. no energy. [But no energy means no conservation of energy!]

Because ‘no motion’ is a lower limit, therefore, this will then be the lowest temperature possible. The temperature minus 273.15 degrees Centigrade then is a real zero! In fact, this is an ‘absolute zero’ – zilch oomph. [Well, at least theoretically.]

Thomson’s temperature scale, starting at absolute zero, is called the absolute temperature scale, or the Kelvin scale. A temperature on the Kelvin scale is abbreviated ‘K’, and not ‘°K’.

This brings us to the zero-point energy of a system and the third law of thermodynamics. It is sometimes called the Nernst heat theorem after Walther Hermann Nernst (1864-1941).

According to the third law of thermodynamics it is impossible to reduce a system to its zero-point energy (zilch oomph) by a finite number of processes, no matter how idealised. This then means that (theoretically at least) there will always be some energy left in any closed-system, but less, and less, and less [?]. But then, what about the first law of thermodynamics – the conservation of energy in a closed-system? [This is a real conundrum for me! Keep in mind that there is no such thing as a magical matter-energy conversion process at work!]

The Theories and Laws of Science

The theory of thermodynamics served us well in everyday science, engineering, and in industry. However, did it serve us so well on a cosmic scale? Can we in anyway possible compare the Universe to a steam engine? How can we have the conservation of all energy on the one side and the heat death of the universe on the other? Are ‘black holes’ energy generators in ‘cold’ storage? [‘Black holes’ are a completely different fairy-tale though.]

Everything in science, as in life in general, is based on idealisations, assumptions, and generalisations. So, whenever we look at any theory (or law for that matter) the first questions that we need to ask is what are these idealisations, assumptions, and generalisations that underlie the theory or law. All theories and laws are models of reality and should not be confused with reality.

So then, can we idealise a steam engine as being analogous to the Universe by making certain awfully, broad assumptions and some very, vast generalisations? I don’t think so!

Be static (in equilibrium), and you won’t ‘create’ or use energy. Save your energy to shoot ‘holy cows’! ;-)

Willie Maartens