Some Thoughts on Light.
There seems to be an almost mathematical property of light. Where light can be in two states. Either it's a ray or it's being diffused. It's almost always forming rays though even when diffused. However you could say that diffusion is about destroying a ray. A ray carries information about it's origin in the wave-fronts which comprise it. If it passes through glass it's giving incorrect information about it's origin because the rays have been altered by being offset. This itself is the result of diffusion. Light diffuses around the atoms in a glass (because the wavelength is larger than the distance between atoms) There seems to be something about light that makes it hard to diffuse.
Diffusion takes place when light passes through a slit smaller than it's wavelength. This is true of all waves. A ray is a series of wave-fronts stacked up to form a ray. An analogy would be a building. Imagine a tall skyscraper as a ray pointing straight up. Imagine that the floors are the wave-fronts. For every ray there will be many wave-fronts. You can't really form a ray without them. A ray always has to be wider than it's wavelength. The smaller the wavelength the thinner the ray can be. An X ray survives when passing through a human body without diffusing because it's able to form rays that never touch a single electron or proton. The wavelength of visible light is greater than the distance between atoms and so there is a great deal of diffusion that takes place. It's a similar effect that makes the sky blue. Red light passes around the atoms in the sky because it has a higher wavelength. This is because it diffuses but it recombines after passing by the atom. With blue light there is less bending and more blockage. So the blue light recombines less and instead bounces off the blue atoms in the atmosphere. When it bounces off it is the same as forming a shadow. So the blue light survives as a ray or gets blocked completely by atoms while red light bounces off atoms less but recombines more.
Much of the phenomena in our world is the result of this difference between diffusion and rays.
Reflection Absorption and Transmission:
There are 3 basic things that can happen when light hits a surface however there are more than just 3 types of surface.
The basic 3 though are Transmission, Reflection and Absorption.
For each one there is a corresponding surface:
Transission = Transparent Surfaces
Absorption = Opque Surfaces
Reflection = Reflective surfaces
But this really oversimplifies the problem because there are several types of reflection. All reflection is a bit confusing though because it's not clear if there really is a difference between absorption and reflection. When an atom absorbs a color an electron takes the energy of a photon and moves to a higher orbital. Then later it will release that energy and move back to it's original orbital.
One might say that absorption is just a part of reflection and that the complete process is reflection and absorption is only half the process. But reflection in my opionion happens when an electron isn't able to move to a higher orbital and the photon moves away in a random direction. At the level of a single photon it's not taken into account the idea of direction. Reflection is often seen as allowing a ray to move off at a specific angle based on the angle of incidence. But at the atomic level with a single photon you are not dealing with waves and wavefronts. Wavefronts are what get reflected. The question of whether a single photon has a wavefront may not matter. It's a good question though. Because it may be that each photon does have a particular wavefront and can be reflected at some angle which could be predicted. With normal waves though the particles that make up the wave move in random directions but it may not be the case with photons.
However for a single photon hitting an electron reflection takes place when it's not able to move the electron to a higher orbital. It then leaves the atom and moves away. This is reflection by the definition I'm using.
There are several types of reflection lets say three.
1 reflection from a metal surface
2 reflection from a smooth surface
3 reflection from a rough surface.
I want to tackle metal first since it's always neglected. The reason metal is shiny is because when light bounces off it the light remains in phase. You could almost refer to a mirror or metal surface as a type of hologram. The image in the mirror isn't like a photograph. It's actually 3 dimensional and almost indistinguishable from the what its' reflecting. In order for this to take place you all the waves that bounce off it must be intact. They can't be out of phase. So Light that bounces off a mirror is reflected. It's not absorbed is it? If it were absorbed you would think there would be too much time elapsing between absorption and release. If enough time elapsed and that amount of time would have to be incredibly small since light travels so quickly. The light that left the surface would be out of phase and being out of phase would prevent it from recreating the colors of light at the proper angles. Imagine how many wave-front pass a given point on the surface of a mirror or a chrome object. Consider the speed of light. Light travels so fast that a huge number of waves pass a given point per second. I wouldn't think there would be much time for absorption. This happens in metals because the electrons interact with the light. Basically the light is strong enough to interact with the electrons but they release the photon quickly. So perhaps metals do absorb and reflect but very quickly. This is because in metal the electrons are much more easily moved. However they don't move to a higher orbital and stay there but they move from one atom to another and move back. It may not be a matter reflection then but absorption and release. However in the case of metal this absorption and release is so incredibly uniform that though time passes between absorption and release this time is totally uniform as all the atoms in involved are the same. This might be tested by checking if there are two kinds of reflection. This first type and the second type of reflection which is reflection from a smooth surface.
Reflection From a Smooth Surface:
Even in non metals there is some reflection. Whether glass which is mostly allows transmission there will still be some reflection. This is because light slows down in glass and not all the light can pass through. The light slows down inside so there is a traffic jam at the surface forcing light to bounce off. Luckily light doesn't get stuck but photons or light waves simply pass through one another. So why can't they all pass through? Good question. But just notice there is a difference between this type of reflection and that of metals. As we noted earlier reflection from a mirror may not actually be reflection (in the technical sense since it could be both absorption and reflection). Well this type of reflection really isn't reflection either because it's a property of all waves. It's reflection however it may be that reflection is just a property of all waves and not some unique behavior separate from the others but actually a property of Transmission through a transparent medium that slows down the light.
We still haven't properly covered Transmission.
Transmision:
Transmission is when light doesn't have the energy to push electrons to a higher orbital and as a result it moves around them. This has to do with diffusion and it's another property of waves. This greater distance causes it to slow down. It's not really slowing down it's just that the waves have a longer path around the particles in the glass. Because the light is lower wavelength however the light survives. Everything you see around you is actually mostly empty space. So instead of asking why are things transparent the real question should be this: Why are things Opaque? This is due to absorption of light. Light that gets absorbed sort of disappears because it's moved to a higher orbital. Then the light is released but at a particular wavelength. This wavelength may or may not be visible and is equally likely to be released into the object itself and so you wont see it. But any light that doesn't get absorbed gets released or passes through. The light that gets released however gets reflected at various levels. Non metals are almost all somewhat transparent. The light passes into an object and gets reflected but at different angles.
Now I'm wondering why it doesn't pass through. But the thing is that when light is absorbed it ties up the electrons. So the electrons that have absorbed the light are occupied and can't absorb any more and so that light that they don't absorbed gets reflected in a similar way to the light through glass. It's met up with a sort of traffic jam. No more light can be absorbed and yet because the light is reflected at different depths the light isn't reflected out of phase. It doesn't take much to make it out of phase. It just has to penetrate a little but it probably penetrates the surface a lot but just no where near the amount it can with glass or crystal or water. With transparent objects the light exits at the same phase it entered at. Now with white objects almost all the light is reflected. It's like none of the light is absorbed so the excuse of a traffic jam wont work. White objects can be smooth and reflect some light but most of the light isn't reflected in phase. If it's got a smooth surface some light will be reflected but that's because it's smooth on the surface. The rest of the light penetrates enough that it gets a certain distance however it's too weak to move the atoms to a higher orbital. It's also not able to pass through for some reason. I mean the atoms are far apart just like with glass however for some reason all the light gets reflected and yet it's out of phase.
I think white objects just transmit light however somehow that light is broken up. It may be due to light losing phase. it ends up out of phase and doesn't pass through. It's like the light that bounces off the surface. If the white object is composed of many different types of clear particles of different refractive indexes the light will all eventually be reflected. This can be seen by looking at snow. Close up you can see that every snowflake in a snow covered mountain is actually clear. But from a distance the snow appears to be a coat of white paint. It's opaque. Not because the snow isn't clear (it is). But because the light is bouncing off many different surfaces. If the snow melts though and becomes a solid block of Ice it will be clear. That's because it's uniform and there is less reflection. In the case of snow the difference of refractive index is due to there being many pockets of air between the snowflake crystals. In the case of opaque paint there are many different clear particles but they all have different refractive indexes. The result is that the light eventually all reflects back. White objects are like reflectors. But an actual reflector made by man is actually a retro reflector designed to reflect light back in the direction it came from. This can be dome by cutting a hollow cube along it's seams or edges so that you create two identical half cubes and coating the inner surface with a mirror.
Diffusion takes place when light passes through a slit smaller than it's wavelength. This is true of all waves. A ray is a series of wave-fronts stacked up to form a ray. An analogy would be a building. Imagine a tall skyscraper as a ray pointing straight up. Imagine that the floors are the wave-fronts. For every ray there will be many wave-fronts. You can't really form a ray without them. A ray always has to be wider than it's wavelength. The smaller the wavelength the thinner the ray can be. An X ray survives when passing through a human body without diffusing because it's able to form rays that never touch a single electron or proton. The wavelength of visible light is greater than the distance between atoms and so there is a great deal of diffusion that takes place. It's a similar effect that makes the sky blue. Red light passes around the atoms in the sky because it has a higher wavelength. This is because it diffuses but it recombines after passing by the atom. With blue light there is less bending and more blockage. So the blue light recombines less and instead bounces off the blue atoms in the atmosphere. When it bounces off it is the same as forming a shadow. So the blue light survives as a ray or gets blocked completely by atoms while red light bounces off atoms less but recombines more.
Much of the phenomena in our world is the result of this difference between diffusion and rays.
Reflection Absorption and Transmission:
There are 3 basic things that can happen when light hits a surface however there are more than just 3 types of surface.
The basic 3 though are Transmission, Reflection and Absorption.
For each one there is a corresponding surface:
Transission = Transparent Surfaces
Absorption = Opque Surfaces
Reflection = Reflective surfaces
But this really oversimplifies the problem because there are several types of reflection. All reflection is a bit confusing though because it's not clear if there really is a difference between absorption and reflection. When an atom absorbs a color an electron takes the energy of a photon and moves to a higher orbital. Then later it will release that energy and move back to it's original orbital.
One might say that absorption is just a part of reflection and that the complete process is reflection and absorption is only half the process. But reflection in my opionion happens when an electron isn't able to move to a higher orbital and the photon moves away in a random direction. At the level of a single photon it's not taken into account the idea of direction. Reflection is often seen as allowing a ray to move off at a specific angle based on the angle of incidence. But at the atomic level with a single photon you are not dealing with waves and wavefronts. Wavefronts are what get reflected. The question of whether a single photon has a wavefront may not matter. It's a good question though. Because it may be that each photon does have a particular wavefront and can be reflected at some angle which could be predicted. With normal waves though the particles that make up the wave move in random directions but it may not be the case with photons.
However for a single photon hitting an electron reflection takes place when it's not able to move the electron to a higher orbital. It then leaves the atom and moves away. This is reflection by the definition I'm using.
There are several types of reflection lets say three.
1 reflection from a metal surface
2 reflection from a smooth surface
3 reflection from a rough surface.
I want to tackle metal first since it's always neglected. The reason metal is shiny is because when light bounces off it the light remains in phase. You could almost refer to a mirror or metal surface as a type of hologram. The image in the mirror isn't like a photograph. It's actually 3 dimensional and almost indistinguishable from the what its' reflecting. In order for this to take place you all the waves that bounce off it must be intact. They can't be out of phase. So Light that bounces off a mirror is reflected. It's not absorbed is it? If it were absorbed you would think there would be too much time elapsing between absorption and release. If enough time elapsed and that amount of time would have to be incredibly small since light travels so quickly. The light that left the surface would be out of phase and being out of phase would prevent it from recreating the colors of light at the proper angles. Imagine how many wave-front pass a given point on the surface of a mirror or a chrome object. Consider the speed of light. Light travels so fast that a huge number of waves pass a given point per second. I wouldn't think there would be much time for absorption. This happens in metals because the electrons interact with the light. Basically the light is strong enough to interact with the electrons but they release the photon quickly. So perhaps metals do absorb and reflect but very quickly. This is because in metal the electrons are much more easily moved. However they don't move to a higher orbital and stay there but they move from one atom to another and move back. It may not be a matter reflection then but absorption and release. However in the case of metal this absorption and release is so incredibly uniform that though time passes between absorption and release this time is totally uniform as all the atoms in involved are the same. This might be tested by checking if there are two kinds of reflection. This first type and the second type of reflection which is reflection from a smooth surface.
Reflection From a Smooth Surface:
Even in non metals there is some reflection. Whether glass which is mostly allows transmission there will still be some reflection. This is because light slows down in glass and not all the light can pass through. The light slows down inside so there is a traffic jam at the surface forcing light to bounce off. Luckily light doesn't get stuck but photons or light waves simply pass through one another. So why can't they all pass through? Good question. But just notice there is a difference between this type of reflection and that of metals. As we noted earlier reflection from a mirror may not actually be reflection (in the technical sense since it could be both absorption and reflection). Well this type of reflection really isn't reflection either because it's a property of all waves. It's reflection however it may be that reflection is just a property of all waves and not some unique behavior separate from the others but actually a property of Transmission through a transparent medium that slows down the light.
We still haven't properly covered Transmission.
Transmision:
Transmission is when light doesn't have the energy to push electrons to a higher orbital and as a result it moves around them. This has to do with diffusion and it's another property of waves. This greater distance causes it to slow down. It's not really slowing down it's just that the waves have a longer path around the particles in the glass. Because the light is lower wavelength however the light survives. Everything you see around you is actually mostly empty space. So instead of asking why are things transparent the real question should be this: Why are things Opaque? This is due to absorption of light. Light that gets absorbed sort of disappears because it's moved to a higher orbital. Then the light is released but at a particular wavelength. This wavelength may or may not be visible and is equally likely to be released into the object itself and so you wont see it. But any light that doesn't get absorbed gets released or passes through. The light that gets released however gets reflected at various levels. Non metals are almost all somewhat transparent. The light passes into an object and gets reflected but at different angles.
Now I'm wondering why it doesn't pass through. But the thing is that when light is absorbed it ties up the electrons. So the electrons that have absorbed the light are occupied and can't absorb any more and so that light that they don't absorbed gets reflected in a similar way to the light through glass. It's met up with a sort of traffic jam. No more light can be absorbed and yet because the light is reflected at different depths the light isn't reflected out of phase. It doesn't take much to make it out of phase. It just has to penetrate a little but it probably penetrates the surface a lot but just no where near the amount it can with glass or crystal or water. With transparent objects the light exits at the same phase it entered at. Now with white objects almost all the light is reflected. It's like none of the light is absorbed so the excuse of a traffic jam wont work. White objects can be smooth and reflect some light but most of the light isn't reflected in phase. If it's got a smooth surface some light will be reflected but that's because it's smooth on the surface. The rest of the light penetrates enough that it gets a certain distance however it's too weak to move the atoms to a higher orbital. It's also not able to pass through for some reason. I mean the atoms are far apart just like with glass however for some reason all the light gets reflected and yet it's out of phase.
I think white objects just transmit light however somehow that light is broken up. It may be due to light losing phase. it ends up out of phase and doesn't pass through. It's like the light that bounces off the surface. If the white object is composed of many different types of clear particles of different refractive indexes the light will all eventually be reflected. This can be seen by looking at snow. Close up you can see that every snowflake in a snow covered mountain is actually clear. But from a distance the snow appears to be a coat of white paint. It's opaque. Not because the snow isn't clear (it is). But because the light is bouncing off many different surfaces. If the snow melts though and becomes a solid block of Ice it will be clear. That's because it's uniform and there is less reflection. In the case of snow the difference of refractive index is due to there being many pockets of air between the snowflake crystals. In the case of opaque paint there are many different clear particles but they all have different refractive indexes. The result is that the light eventually all reflects back. White objects are like reflectors. But an actual reflector made by man is actually a retro reflector designed to reflect light back in the direction it came from. This can be dome by cutting a hollow cube along it's seams or edges so that you create two identical half cubes and coating the inner surface with a mirror.
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