Light - The basis of everything

My obsession with light is not accidental it has been a journey. It is axiomatic that we make assumptions in our search to explain, and gloss over specifics. I am guilty of that. We assume, and rarely stop to explain what we assume, and that as they say, is the "devil in the detail". As an example, I guarantee that even the very smartest people assume and accept but do not understand, they share the same willingness to gloss over as every mere mortal. A great example is how the sun creates light. I will be going into great depth later on this, but the true reason we have light from the sun is literally an impossible process. We know that in order for light to be produced there is a threshold on how hot things need to be for specific atoms to interact to create light (we know because we have replicated the process on earth).

I believe that the process of creating "light", ie: the production of the photon, is the most fundamental and important of all processes. Without light from the sun there is no life. Without the Sun, planets can move along the geodesic path that we call an orbit. This article will explain the process of how a photon is created from the Sun to a light bulb and how ethereal light is.

What is an atom ?

The structure of an atom is still a mystery. We know a lot but there are several aspects to the atomic structure that are amazing. The atom is made up of two areas, the Nucleus and the Electron Cloud which surround the nucleus. The basics are as follows;

NUCLEUS

• At the center of an atom is a Nucleus (called a sub atomic particle). Typically we find two types of particles in the Nucleus. You will find (in a variety of combinations and numbers) a sub atomic particle (with mass) called a Neutron. The second sub atomic particle is called a Proton. Consider the nucleus the heart of the atomic structure. Atoms are particles and have a measurable mass(within reason of our ability to measure at the atomic level).
• Neutrons have no "electrical" charge. What this means in the classical sense is that they neither repel of repulse other particles, they are neutral to other "charged" particles.
• Protons have a classical Positive (+) charge. It is easier to consider charge the way we do electrical charge (however, although way beyond this short article, charge is another way we describe things without being completely accurate, it is convenient to use charge when we describe how particles interact). In this instance it would just as easy to consider it a negative charge if we are consistent with how each sub atomic particle interact.
• Neutrons and Protons are actually made up of smaller particles called Quarks. What creates either is the combination quarks (in their case there are three quarks). To be best of our knowledge these constitute the smallest particles, however this is to the best of our knowledge and technological ability to measure at this size. It is the interaction of the quarks within the sub atomic particles that determine how atomic structure changes and interacts. (The value of +1 relates to the three smaller particles called quarks that make up a proton and the volume of electron volts (v) they carry in unison).

• Interestingly, atoms typically have multiple Protons. As a child knows when he/she pushes to magnets together, they will repel if the two + or 2 - ends are pushed together. So lets say there are 3 positively charged Protons, the nucleus is somehow able to defy the force of repulsion between the three Protons and glue them to the Nucleus (called the Strong Nuclear Force).

ELECTRONS

• Around the Nucleus is an "atmosphere" that envelopes the Protons and Neutrons (much like the atmosphere around a planet). The classical view of the atom (which is really not that old) is that electrons wiz around the center like satellites that orbit the planet. Electrons can orbit at different distances from the Nucleus. The higher the orbit the greater the energy associated and the easier it is for the higher orbits to break off and float away. Again, this is a classical view, but while some of the information is correct, it is somewhat wrong in terms of how electrons exist and where they are.

In the image above you can see the simple model that we teach high schoolers. The electrons orbit at specific distances from the nucleus. The further they are away from the center, the higher the amount of energy and thus easier it is for them to interact with external influence (though again, not really the case, it is the electron jumping from lower to higher orbits that determines what is expelled, but let's keep examining).

• Electrons have a negative - charge (the opposite of our Proton). They somehow manage to wiz faster enough around the nucleus that they do not head toward the positively charged Proton (to which they should be attracted, like two magnets would be).
• Electrons appear to orbit in fixed distances from the center mass nucleus. The higher orbits would like a rocket ship require greater energy than lower orbiting electrons.
• Electrons are a sub atomic particle which should have mass. Unlike the Neutrons and Protons, an Electron (as far as we know) is made NOT made up of smaller particles. It is part of a family called "Leptons".
• Electrons have a stationary mass of approx 10 30 Kilograms (10 to the power of 30 - linkedin will not let me correctly note that).

It was Neils Bohr who looked at the atom from a quantum mechanical vantage and developed the following model.

Bohr was clear that atom's (like anything really), like to be in a state of equanimity. They do not like to be jiggled or moved around. An atom with structure will always tend towards stasis. The orbits of specific electrons will be a constant, however, if you subject atoms to external energy (whatever the format, heat, vibration etc), as the law of energy conservation states, the volume of energy introduced must be absorbed (it can not be destroyed in part or whole). This causes electrons to absorb the incoming energy and jump from a lower to a higher orbit, replete with the energy added from outside sources. The distance the electron jumps is very important. It is this distance which determines what kind of light is expelled. As stated, atom's hate disturbance, and want to return to their "natural" ground state, so once the external energy source has moved on, the electron that jumped to a higher energy state jumps back to its normal orbit, and the energy it absorbed is released in the form of energy BUT if you have read my other work, the energy is Light !

• The distance jumped and the energy released created a specific frequency / wavelength of light, whether it is visible, IR etc, which we can calculate with some basic equations.

Electron Jump

Let's examine this a little deeper (without the brain itch).

• According to the Bohr approach, atom's are structured in terms of the distance the electron band's are from the Nucleus. This distance is directly related to a specific amount of "energy" this electron contains (contains is a poor choice of words, as we shall later see when we examine the Probabilistic nature of the Electron in terms of its location and it's energy).
• Electrons are quantized; they exhibit a distinct, measurable amount of energy at a specific orbit/ distance from the nucleus. This energy can not be decimalized, diminished, reduced. It is binary. It exists as it is, and it jumps to different level of energy (again which is quantized), BUT when it returns to the original band, it exhibits the same eV as before.
• Quantized also means that electrons cannot exist in between each band. As I have said many times, Nature does not understand decimals. Electrons can ONLY exist as specific distances from the nucleus.
• This distance / Energy level is a function of the atom. Electrons and the Energy associated with each band can ONLY interact with a specific amount of incoming energy.
• Electrons can and do jump between these bands / orbits instantaneously (no lag/ delay) but can only jump if the energy incoming is equal to the distance between bands. A jump lower can only emit a specific amount of energy which is equal to a very specific kind of Photon (light). We can actually calculate the frequency and wavelength of the light emitted.
• The higher the distance from the nucleus the great the "energy" associated.
• Electrons will happily orbit forever at the distance from the nucleus until an external force (this could be energy in terms of light or heat). This orbit is perpetual (why, we do not really know).

How Light Is created by an Electron Jump

So, as we hopefully explained above, it the "jump" that the electron makes from a higher state of "orbit" to a lower state of "orbit" is the event that cause light to be created (from the expelled energy that electron loses).

• Everything loves calm. An atom, left to its own devices will happily do nothing.
• When an external force disturbs this calm, it transfers energy to the atom (whether its heat, light, magnetism etc), and it is electron in the outer area that soaks up this energy.
• The atom, will allways tend towards the calm, so at some point this extra energy from the external force is ejected out in the form of measurable light.

We can calculate what kind of light is expelled as follows;

In 1885, Jahann Balmer derived an equation to calculate the visible wavelengths that can come from the hydrogen atom (or rather its electrons). The Bohr lines (electron orbits) appear at 410 nm, 434?nm, 486?nm, and 656?nm (being the physical, measurable distances they can jump to/from). These electrons are falling to the 2nd energy level from higher ones. This transition to the 2nd energy level is now referred to as the "Balmer Series" of electron transitions.

Johan Rydberg used Balmers work to create an equation to calculate what kind of light is created (rather the wavelength/ frequency which you can cross reference with the electromagnetic spectrum).

So, I promised not to bore you, but below is the calculation I used (I reference many other videos/ examples that are NOT my work, many smarter people than me have already done the hard work).

• Our electrons can jump from a Ground state or n=1 (0 electron volts eV), to various levels. This ONLY happens in finite states. It can only jump to a higher energy state equal to the incoming energy that would facilitate that jump.
• If the electron in ground state go from n=1 to n=3, it absorbed 7eV (electron volts). This can only happen if incoming light etc has 7eV.
• Our electron is jiggling and moving, and decides to jump down to n=2, it emits energy in the form of light (of whatever wavelength) equal to 2eV. The electron is now 5eV.
• The electron, eager to return to its ground state must now jump back to 0=eV, emitting the 5ev.
• According to the math a 5eV photon is equal to 250nm wavelength which is close to visible light.

Probability and the Electron - Reality

The reality of the atom however is stranger than fiction. Quantum mechanics ruined the classical view. There are no electrons wizzing at specific altitudes. The Heisenberg uncertainty principal states that it is a complicated thing to know the location and the speed (momentum) of a particle at the same time. Indeed, establishing one or the other means you have collapsed a thing called the Wave Function. As an example if you see a spec moving through the sky, you can break out your telescope and zoom in close and you can see its a satellite. However when you are looking up close you have its location, but at this point have no idea what it's speed it. Take away the telescope and you can see the spec moving through the sky but would struggle to pinpoint where it is other than a generalized view.

As quantum mechanics evolved, we developed a view of the atom that is mind blowing. Quantum uncertainty and QED (from the utterly brilliant Richard Feynman), very clearly predict that specific quantum particles exist more as a function or probability than reality. They exist , but until we try and measure them, they exist only as a function of probability.

Light bouncing off a mirror can reflect of every inch of a mirror (see my other articles), but what we see is the more probable route it can take.

In terms of a the electron, it can be everywhere above the nucleus. It's location is best described as being a somewhere within a "cloud" of probability.

• Around the nucleus there is a probability of where the electron can be. It is NOT a satellite whizzing around in a specific location. It is a possibility of where it is.

Below is an iron atom, with a very unclear area around the nucleus where the electron could be.

Below is the hydrogen atom. The same possible electron location.

This fundamentally changes our view of atomic structure. The space around the nucleus is filled with possible locations for the electron. It defies our view of classical physics and yet this is the dna of everything.

What is a Photon ?

I have written extensively about light and that if we were to take the most powerful magnifying glass in the world and look at a light source, we would ultimately see that all light is broken up into individual elementary particles called Photons. Photons have a specific amount of energy (quanta) which is an absolute value (for each photon). It can not be dimmed or sliced. It has a particle like value, as defined by Max Planck in his very famous equation;

E = h * c / λ = h * f

E = photon’s energy
H = Planck constant
C = light’s speed
λ = photon’s wavelength
F = photon’s frequency         

• Light exhibits both wave like and particle like behavior (Photoelectric effect).
• Light is simply light. Without light, we would have no planet on which to live.

The story of how light from the sun is derived is amazing.

The light from the sun - Quantum tunneling and Atomic structure

The sun is not hot enough to create light. Photon's are expelled during Nuclear Fusion, where 4 Hydrogen atoms (4 single positively charged Protons) are fused into a Helium nucleus. Protons have the same charge (positive), and should repel. The force of repulsion is approximately 230n at a nuclear distance, so getting 4 to stick together would require a ridiculous temperature. The hotter the temperature the faster atoms move (a more chaotic environment), and the Strong Nuclear Force can overcome the natural repulsion. Now a more chaotic hotter environment does not mean that Hydrogen bumping into each other more often can cause this fusion. The core of the sun is around 27-28 million degrees F, but when we create fusion on earth we need hundreds of millions of degrees ! How is it possible than the Sun can cause 4 Hydrogen atoms (Proton's) to merge and overcome the 230n of repulsive force, when its temperature is too cool to allow this ? The answer lies in the quantum world and can not be explained by classical Newtonian style physics. The detail is way beyond this short article, however the answer lies in probability and density.

When the so called big bang happened, prior to the singular event, temperatures were so hot that atoms could not be formed. There was a sea of plasma so hot that not even light could be formed. When the temperature dropped to the correct level, atom's were formed and the nuclear fusion that could now occur to expel the first light (photons) began. However, this is not the correct explanation.

Classical physics and diagrams would denote a single proton as a spherical particle at the center of an atom. However the proton is a wavelength, a probabilistic outcome. Everything about the atom is probabilistic, in terms location, movement and interactions. There are not 4 protons that glued together, but a probability of interaction.

• Uncertainty means we can not at any time know the location of where an individual proton may be. We can "guess" with accuracy the most likely location. However we are describing a potential energy state, NOT a physical location. This is a difficult thing to comprehend. Again, we are describing the protons energy state, NOT where it is.
• There is non zero probability that a proton can exist in an energy state that seems to defy logic. What this means is that the most likely outcome when protons attempt to collide or get close is that they repel each other. However there is a non zero probability that 4 protons may defy the force of repulsion and bond to create Helium (nuclear fusion).
• This non zero probability is based on a crazy illogical phenomena called Quantum Tunneling and sheer density of hydrogen atoms in a single location.

The best way to describe Quantum Tunneling is to imagine throwing a ball at a wall over and over again. The most likely outcome is the ball bouncing off, but do it enough times and there is a chance that a ball will pass through the solid wall to the other side ! This is quantum tunneling. Albeit unlikely, it can and does happen. Atom's are not a solid entity, they seem to be packed with a lot of empty space, and yet we can stand on a wooden platform or a rock, yet the atomic structure appears to be filled with nothing but the probability of the likely location of nucleus and electron ! Again, the space around the nucleus is not a solid mass, but an area where electrons might be.

The sun, is not hot enough for nuclear fusion, but because of the absolute mass and density there are so many hydrogen atoms (single protons), that the highly unlikely possibility of 4 protons sticking together despite the same charge does occur, and often enough for us to feel the sun's warmth day after day.

My description is an oversimplification of the process, with a high enough temperature it is possible for 4 hydrogen atoms (protons) to overcome the Coulomb barrier (the energy barrier that prevents protons from gluing together) and allow the Strong nuclear force (much stronger than the coulomb barrier but only at very close distances) to glue 4 protons together and create our Helium atom and therefore light (the photon), but the sun is not hot enough. The key is probability. Quantum Tunneling defies classical logic, and yet it happens. Somehow there is a non zero probability that 4 protons can get so close that the strong nuclear force glues them together starting the process of expelling energy in the form of a photon.

The light from a light bulb

So, how does a lightbulb create light ? Following what I wrote previously, as electricity floods the bulb, the atoms in the metal gets excited and the excess energy is released in the form of photons as I described above (at great length).

Not as sexy as the photons that come from the sun, but fundamentally the same energy as an LED, Incandescent bulb, laser.

So in conclusion, the purpose of this piece was the highlight how incredible light is. It is the essence of existence. Without light there would be no life,

Questions, comments, please let me know.

Nigel Heywood