Dis-Continuum

English: The Clump looking from the Redhouse
English: The Clump looking from the Redhouse (Photo credit: Wikipedia)

Where ever one looks, things mostly seem to be in lumps or clumps of matter. We live on a lump of matter, one of a number of lumps of matter orbiting an even bigger lump of matter. We look into the sky when the bigger lump of matter is conveniently on the other side of our lump of matter and we see evidence of other lumps of matter similar to the lump of matter that our lump of matter orbits.

We see stars, in short, which poetically speaking float in a void empty of matter. We can see that these stars are not evenly distributed and that they gather together in clumps which we call galaxies. Actually stars seem to clump together in smaller clumps such as the Local Cluster of a dozen or so stars, and most galaxies have arms or other features that show structure at all levels.

Ancient Galaxy Cluster Still Producing Stars
Ancient Galaxy Cluster Still Producing Stars (Photo credit: Wikipedia)

The galaxies, which we can see between the much closer stars of our own galaxy, also appear to be clustered together in clumps, and the clumps seem to be clumped together. Of course, the ultimate clump is the Universe itself, but at all levels the Universe appears to have structure, to be organised, to be formed of lumps and clumps, variously shaped into loops, whorls, sheets, arms, rings, bubbles, and so on.

OK, but in the other direction, towards the smaller rather than the larger, our planet has various systems, weather, orogenic, natural, social and evolutionary. All sorts of systems at all levels, from global scope to the scope of the smallest element.


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In other personal worlds, below the level our interactions with our families, we have all the systems that make up our own bodies. The system that circulates our blood, the system that processes our food, the system that maintains our multiple systems in a state homeostasis.

That is, not a steady state, but a state where all the individual systems self-adjust so that the larger system does not descend into a state of chaos, leading to a disruption of the larger whole. Death.

The main pathways of metabolism in humans, sho...
The main pathways of metabolism in humans, showing all metabolites that account for >1% of an excreted dose. ;Legend PNU-142300, accounts for ~10% of excreted dose at PNU-142586, accounts for ~45% of excreted dose at steady state PNU-173558, accounts for ~3.3% of excreted dose at steady state (Photo credit: Wikipedia)

By and large most systems in our environment are made up of molecules, which are in turn made up of atoms. Atoms are a convenient stopping point on the scale from very large to very small. They are pretty “well defined”, in that they are a very strong concept.

Atoms are rarely found solo. They are sociable critters. They form relationships with other atoms, but some atoms are more sociable than others, forming multiple bonds with other atoms. Some are more promiscuous than others, changing partners frequently.


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These relationships are called molecules, and range from simple to complex, containing from two or three atoms, to millions of atoms. The really large molecules can be broken down to smaller sub-molecules which are linked repeatedly to make up the complex molecules.

To rise higher up the scale for a moment, these molecules, large and small are organised into cells, which are essentially factories for making identical or nearly identical copies of themselves. The differences are necessary to make cells into muscles or organs and other functional features, and cells that make bones and sinews and other structural parts of a body.

A section of DNA; the sequence of the plate-li...
A section of DNA; the sequence of the plate-like units (nucleotides) in the center carries information. (Photo credit: Wikipedia)

As I said, atoms are a convenient stopping point. Every atom of an element is identical at least in its base state. It may lose or gain electrons in a “relationship” or molecule, but basically it is the same as any other element of the same sort.

Each atom consists of a nucleus and surrounding electrons, a model which some people liken to a solar system. There are similarities, but there are also differences (which I won’t go into in this post). The nucleus consists a mix of protons and neutrons. While the number neutrons may vary, they don’t significantly affect the chemical properties of the atom, which makes all atoms of an element effectively the same.

An early, outdated representation of an atom, ...
An early, outdated representation of an atom, with nucleus and electrons described as well-localized particles on well-localized orbits. (Photo credit: Wikipedia)

Each component of an atom is made up of smaller particles called “elementary” particles, although they may not be fundamentally elementary. At this level we reach the blurry level of quantum physics where a particle has an imprecise definition and an imprecise location in macroscopic terms.

Having travelled from the largest to the smallest, I’m now going to talk mathematics. I’ll link back to physics at the end.

Nucleus
Nucleus (Photo credit: Wikipedia)

We are all familiar with counting. One, two, three and so on. These concepts are the atoms of the mathematical world. They can be built up into complex structures, much like atoms can be built into molecules, organelles, cells, tissues and organs. (The analogy is far from perfect. I can think of several ways that it breaks down).

Below the “atomic” level of the integers is the “elementary” level of the rational numbers, what most people would recognise as fractions. Interestingly between any two rational numbers, you can find other rational numbers. These are very roughly equivalent to the elementary particles. Very roughly.

Half of the Hadron Calorimeter
Half of the Hadron Calorimeter (Photo credit: Wikipedia)

One might think that these would exhaust the list of types of numbers, but below (in a sense) the rational numbers is the level of the real numbers. While many of the real numbers are also rational numbers, the majority of the real numbers ate not rational numbers.

The level of the real numbers is also known as the level of the continuum. A continuum implies a line has no gaps, as in a line drawn with a pencil. If the line is made up of dots, no matter how small, it doesn’t represent a continuum.

Qunatum dots delivered by ccp
Qunatum dots delivered by ccp (Photo credit: Wikipedia)

A line made up of atoms is not a continuum, nor is a line of elementary particles. While scientists have found ever more fundamental particles, the line has apparently ended with quarks. Quantum physics seems to indicate that nature, at the lowest level, is discrete, or, to loop back to the start of this post, lumpy. There doesn’t seem to be a level of the continuum in nature.

That leaves us with two options. Either there is no level of the continuum in nature and nature is fundamentally lumpy, or the apparent indication of quantum physics that nature is lumpy is wrong.

Pineapple Lumps (240g size)
Pineapple Lumps (240g size) (Photo credit: Wikipedia)

It’s hard to believe that a lumpy universe would permit the concept of the continuum. If the nature of things is discrete, it’s hard to see how one could consider a smooth continuous thing. It’s like considering chess, which fundamentally defines a discontinuous world, where a playing piece is in a particular square and a square contains a playing piece or not.

It’s a weak argument, but the fact that we can conceive the concept of a continuum hints that the universe may be fundamentally continuous, in spite of quantum physics’ indications that it is not continuous.


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A equals B

Weather icon: temperature equal
Weather icon: temperature equal (Photo credit: Wikipedia)

The whole universe is full of inequality. No two galaxies are exactly alike, no two planets are exactly alike, no two grains of sand are exactly alike, no two atoms of silicon are exactly alike. Wait a minute, is that last one correct?

Well, in one sense each atom of silicon is alike. Every silicon atom has 14 protons in its nucleus, and, usually, 14 neutrons. However it could have one or two neutrons extra if it is a stable atom, or even more if it is a radioactive atom. Alternatively it could have less neutrons and again it would be radioactive.

Monocrystalline silicon ingot grown by the Czo...
Monocrystalline silicon ingot grown by the Czochralski process (Photo credit: Wikipedia)

So two silicon atoms with the same number of neutrons in the nucleus are “equal” right? Well, of course a single atom by itself is seldom if ever found in nature, and two isolated similar atoms are very unlikely. But suppose.

An atom of silicon is said to have electron shells with 14 electrons in them. Without going into unnecessary details these electrons can be in a base (lowest) state or in an excited state. With multiple excitation levels and multiple electrons the probability of two isolated atoms of silicon with all electrons in the same excitation state is extremely low.

Atom Structure
Atom Structure (Photo credit: Wikipedia)

In practise of course, you would not find isolated atoms of silicon at all. You would find masses of silicon atoms, perhaps in a random conformation, or maybe in organised rows and columns. One of the tricks of semi-conductors is that the silicon atoms are organised into an array, with an occasional atom of another element interspersed.

Atoms according cubical atom model
Atoms according cubical atom model (Photo credit: Wikipedia)

This has the effect of either providing an extra electron or one fewer in parts of the array. Under certain conditions this allows the silicon atoms and the doping element to pass the extra electron, or the lack of an electron (known as a hole) along the array in an organised manner, a phenomenon known in the macroscopic world as an electric current.

English: Drawing of a 4 He + -ion, with labell...
English: Drawing of a 4 He + -ion, with labelled electron hole. (Photo credit: Wikipedia)

So, while two atoms of silicon may in some theoretical physical and chemical sense be equal, in practice, they will be in different states, in different situations. What can be said about two silicon atoms is that fit an ideal pattern of a silicon atom, in that the nucleus of the atom has 14 protons. Some of the properties and states of the two atoms will be different.

At the very least the two atoms will be in different locations, moving with different velocities and with different amounts of energy. They can never be “equal as such. The best that you could probably say is that two atoms of the same isotope of silicon have the same number of neutrons and protons in their nuclei.

Periodic table with elements colored according...
Periodic table with elements colored according to the half-life of their most stable isotope. Stable elements. Radioactive elements with half-lives of over four million years. Half-lives between 800 and 34,000 years. Half-lives between 1 day and 103 years. Half-lives ranging between a minute and 1 day. Half-lives less than a minute. (Photo credit: Wikipedia)

When we talk about numbers we stray into the field of mathematics, and in maths “equal” has several shades of meaning. When we say that one integer equals another integer we are essentially saying that they are the same thing. So 2 + 1 = 3 is a bit more than a simple equality and in fact that expression can be referred to as an identity.

Algebraic proofs are all about changing the left hand side of an expression or the right hand side of the expression or both and still retaining that identity between the two sides.

Mnemosyne with a mathematical formula.
Mnemosyne with a mathematical formula. (Photo credit: Wikipedia)

In the real world we use mathematics to calculate things, such a velocities, masses, energy levels, in fact anything that can be calculated. Issues arise because we cannot measure real distances and times with absolute accuracy. We measure the length of something and we know that the length that we measure is not the same as the actual length of the object that we are measuring.

Lengths are conceptually not represented by integers but by ‘real numbers’. Real numbers are represented by two strings of digits separated by a period or full stop. Both strings can be infinite in length though the both strings are usually represented as being finite in length.

1 Infinite Loop, Cupertino, California. Home o...
1 Infinite Loop, Cupertino, California. Home of Apple Inc. and one of Silicon Valley’s best known streets. (Photo credit: Wikipedia)

If we measure a distance with a ruler or tape measure, the real distance will usually fall between two marks on the ruler or measure. So we can say that the length is, say, between 1.13 and 1.14 units of measurement. If use a micrometer we might squeeze and extra couple of decimal places, and say that the length is between 1.1324 and 1.1325. With a laser measuring tool we can estimate the length more accurately still.

You can see what is happening, I hope. The more accurately we measure a distance, the more decimal places we need. To measure something with absolute accuracy we would need an infinite number of decimal places. So when we say that the distance from A to B equals 1.345 miles, we are not being exact, but are approximating to the level of accuracy that we need. Hence A is not really equal to B.

Aurora during a geomagnetic storm that was mos...
Aurora during a geomagnetic storm that was most likely caused by a coronal mass ejection from the Sun on 24 May 2010. Taken from the ISS. (Photo credit: Wikipedia)

A particularly interesting case of A not being equal to B is in the mathematical case where one is trying to determine the roots of an equation. There are various method of doing this and there is a class of methods which can be designated as iterative.

One first makes a guess as to the correct value, puts that into the equation which generates a new value which is, if the iterative method chosen is appropriate, closer to the correct value. This process is repeated getting ever closer to the correct answer.

Plot of x^3 - 2x + 2, including tangent lines ...
Plot of x^3 – 2x + 2, including tangent lines at x = 0 and x = 1. Illustrates why Newton’s method doesn’t always converge for this function. (Photo credit: Wikipedia)

Of course this process never finishes, so we specify some rule to terminate the process, possibly some number of decimal places, at which to stop. More technically this is called a limit.

To prove convergence, in other words to prove that the process will generate the root if the process is taken to infinity, has proved mathematically difficult. I’m not going to attempt the proof here, but after several attempts from the time of Isaac Newton, this was achieved last century, with the introduction of the concept of limits.

English: A comparison of gradient descent (gre...
English: A comparison of gradient descent (green) and Newton’s method (red) for minimizing a function (with small step sizes). Newton’s method uses curvature information to take a more direct route. Polski: Porównanie metody najszybszego spadku(linia zielona) z metodą Newtona (linia czerwona). Na rysunku widać linie poszukiwań minimum dla zadanej funkcji celu. Metoda Newtona używa informacji o krzywiźnie w celu zoptymalizowania ścieżki poszukiwań. (Photo credit: Wikipedia)

One can then say, roughly, that the end result of an infinite sequence of steps in a process (A) is equal to a required value (B), even though the result no particular step is actually equal to B. You have to creep up on it, as it were.

I’ll briefly mention equality in computer programs and social equality/inequality, if only to say that I might come back to those topics some time.

English: Income inequality in the United State...
English: Income inequality in the United States, 1979-2007 (Photo credit: Wikipedia)