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The Illusion Of Light
What makes your brain tick?
According to researchers, the parts of your body, if you don't use it you lose
it, particularly your brain. The more you use it, the more logic & brainier you
are. Could that be true?
What is light ?
Light is the electromagnetic spectrum made up of an array of electromagnetic
waves which behave like tiny particles known as the
electromagnetic phenomenon.
In order for us to see, light must first reflect, transmit,
or scatter from the object our vision associated with light that has
interact the object.
Light will follow the same path if it goes in the opposite direction, thus if
you can see somebody else in your mirror, that person can also see you.
If you stand in front of a mirror, you will see a virtual image of yourself behind the mirror,
how far behind is actually equal in distance, both images (you and
virtual) are equal in size and distance -- virtual
size, virtual colour, virtual distance, as long as the mirror is flat, and if
the mirror is curved (concave or convex), the size and distance of you are not equal but the law of
least time still holds.
A curved mirror behaves slightly differently in angular orientation, in other
word -- the points on the surface are not parallel to one
another, focal points made focal planes.
For example:
A concave (curving inward) mirror causes light to reflect on the surface
curving inward and made things look further away, like the inside of a spoon.
Thus to correct near-sightedness, lens has thicker edge than at the centre to
diverge the incident rays, thus appear coming from a single point in front of
the lens -- a diverging lens.
A convex (curving outward) mirror causes light to converge (focus) on
the surface curving outward and made things look smaller, like the back of a
spoon. Thus to magnify an image, lens has thicker centre then at the edge -- a
converging lens.
So if you want to take a picture of yourself with a camera a meter away from
the mirror, you should set the camera a two-meter distance due to frequency of
light doesn't change upon reflection.
Principle of least time
The speed of light enters the mirror
due to our eye-brain system cannot tell the time difference
(if any), thus an object exists in front or behind (convex or concave) a mirror is
an illusion, even surface materials only reflect as little as 4% (such as
clear glass) or 90% (such as shiny aluminium or silver surface) of incident
lights back.
And if you set the speed of these tiny electric particles vibrating at a
frequency of (4.3 x 1014 to 7 x 1014) per
second, this electromagnetic wave will activate your electrical antennae in the
retina of your eyes -- light is simply electromagnet waves in
these range of frequencies.
The angle of incidence equals the angle (degree) of reflection
can be measured by an imaginary perpendicular line on a reflecting
surface is called the normal line -- the incident ray, normal line
and reflected ray all lie on the same plane.
The lower frequency @
4.3 x 1014
appears red and the higher frequency @ 7 x 1014 appears violet.
If you wave a dim light in the dark, you will notice a fading dimension of
particle-like moving charges -- that's the electric current moving at speed and is called the magnetic fields.
The fact that we see a wavy or shimmering effect, say over a hot stove is
due to the various least-time paths of light as it passes through varying
temperatures and densities of air.
Story has it that during the American revolution, heroes of towns tell their
folks to hang lanterns aloft in the belfry arch...
One -- if the Brits invade by land.
Two -- if the Brits invade by sea.
And as night fell the heroes look on the belfry height...
A glimmer then a gleam of light !!!
They spring to their saddles, the bridle they turn
But linger and gaze till height on their sight
A second lantern in the belfry height
A spontaneous electric field is the changing magnetic field -- this vibrating
electric and magnetic field regenerate each other to make up the electromagnetic
waves, which radiate from the vibrating source.
The speed of light
The strength of this spontaneous field depends on the speed of the vibrating
motion of radiation. The greater the radiation the higher the spontaneous
fields, the higher the radiating energy, and at a critical point of no return,
mutual induction would continue indefinitely with neither a loss nor a gain in
energy -- that's the speed of light which was realized by James Clerk Maxwell at
about 300,000 kilometres per second.
The spectrum of light wave moves at the same speed but in arbitrary marked
frequencies -- the classification of this phenomenon range from 0.01 hertz
(Hz) to the order of 1000's hertz (kHz) such as radio waves,
and higher still VHF and MHz for TV (from 50 MHz) band waves, follow by microwaves
(billion hertz) and heat waves (infrared waves @ trillion hertz).
Smooth vs. rough surfaces
A rough surface reflect light in many directions turn out to be a
blessing for short wavelength communications and is called a diffuse reflection,
and a smooth surface diffuse only about 1/8 (one-eighth)
of the wavelength of light, this little diffuse reflection is called polished
wavelength, and is ideal for long wavelength broadcasting signals.
Thus a rough surface for short wavelength communications and a smooth
(polished) surface for long wavelength radio waves, a parabolic mesh (dish) for
short wavelength diffuse reflection and a polished antenna (aerial) for a long
wavelength broadcast.
Most of our environment is seen by diffuse reflection, and enables us to see
objects from any direction or position; except diffuse reflection signals do
bounce off obstructions -- the ghost image on our TV for example is the result of
reflected signal time delays.
The visible frequency of light is only a millionth of 1% from the overall
electromagnetic phenomenon. Much higher frequencies beyond ultraviolet
(beyond visible light) extend into the X-ray and gamma-ray (million trillion)
regions, and seem to overlap with no clear boundaries,
recent discovery of terahertz (THz) was based on
this arbitrary regions of classification.
Different frequencies result in different wavelengths -- low frequencies
produce a long wavelength and high frequencies produce a short wavelength, thus
in theory:
A 1 Hertz wavelength vibrate once in 1 second is 300,000 kilometres long
(that's the speed of light), thus a 10 Hertz wavelength vibrates 10 times in
1 second is 30,000 kilometres long, and...
@ 1 Hertz vibrates 1 times/s = 300,000 kilometres long
@ 10 Hertz vibrates 10 times/s = 30,000 kilometres long
@ 100 Hertz vibrates 100 times/s = 3,000 kilometres long
@ 1000 Hertz vibrates 1000 times/s = 300 kilometres long
@ 10,000 Hertz vibrates 10,000 times/s = 30 kilometres long
@ 100,000 Hertz vibrates 100,000 times/s = 3 kilometres long
@ 1 million Hertz vibrates 1 million times/s = 0.3 kilometres long
@ 10 million Hertz vibrates 10 million times/s = 0.03 kilometres long
@ 100 million Hertz vibrates 100 million times/s = 0.003 kilometres long
Thus it's easy to see that very short wavelengths overlap with no clear boundary and
interact with our vision -- there's radiation everywhere in our universe.
TV or radio receivers are simply devices that sorts and amplifies these
tiny currents. Visible light vibrates at a very high rate, some 100 trillion
times per second (1014 Hertz).
When a light wave is incident upon a transparent material (such as glass)
which has a natural vibration frequency in the ultraviolet range, activates
the electrons in the atomic nucleus of the material.
Atoms in glass hold the energy of ultraviolet light for a while (about 100
millionths of a second) and this energy of vibrating electron is re-emitted
as light @ speed of C again.
It is this delay that results in a lower then average speed of light
through a material, in water light travels at about 75% of its speed, with the
exception of metal, light excite the free electrons in them thus they conduct
heat and electricity well.
Clouds are semi-transparent to ultraviolet thus you still get sunburn on a
cloudy day though much had been filtered out by clouds.
A larger light source over a small object produce a blurry shadow and a smaller
light source over the same object produce a sharp shadow called umbra.
And a penumbra appears at solar eclipse when the sun, moon
and earth in a straight line path to each other, and at lunar eclipse
an umbra occur when the sun, earth and moon in a straight line path to each
other -- the moon disappear, the earth totally block off sun light to the
moon.
How do we see?
Light is the only thing that we see with our optical instruments -- our
eyes.
Light hit our eyes cornea which bends about 70% of the light before
passes to the pupil (which acts as aperture in the iris) and then
passes through the lens which further bends light into focus on the
object to the back layer of our eyes.
This layer is the extremely sensitive retina wall and the fovea
(centre on the wall) examine details of objects. Along the wall near the
fovea is the blind spot connecting to our communication systems.
The retina is composed of tiny antennae that resonate to the incoming
light frequencies. There are two basic shapes of antennae, the rods
and the cones.
There are 3 types of cones for the 3 base range of visible spectrum
frequency detections: low-frequency light, intermediate frequencies and
higher-frequency (as the frequencies of red, green and blue made the visible
spectrum).
The rods predominate towards the periphery of the retina, while the 3
types of cones are denser toward the fovea. Rods are sensitive only to
lightness or darkness (not colour), thus we can sense motion or object from
the corner of our eyes.
Rods are more sensitive to the blue end of the colour spectrum where the
cones are more sensitive to the red end, thus blue appear brighter than red
in dim light. And female can see a bit more colour than male, all
artists knew that as female made better artist.
The rod and cone cells are interconnected for visual receptors to combine
the information in the retina -- our eyes do much of the decision making
process
before passing on to our brain, and the iris do much of the thinking, the
intensity reveals in the size of our pupils -- card players knew from the
pupil of opponent.
Author
10/02/2010
Notes:
(1) James Clerk Maxwell (1831–1879)
(2) Terahertz (THz) is in the region of 300 gigahertz (3x1011) and 3 terahertz
or (3x1012) of the electromagnetic spectrum.
(3) In glass light travels @ 0.67 of C subject to type of glass, and in
diamond @ 0.41 of C.
(4) The phenomenon of rods sensitive to blue is called the Purkinje effect
named after the Czech physiologist Johannes Purkinje who discovered it.
(5) A convex mirror makes things look smaller.
(6) The retina ganglion neurons are categorized into three functional: X-,
Y-, and W- cell types.
The X-cells are for high-resolution vision and consists of about 40% of the
cell types, but only 5-10% of the Y-cells (also the largest of the three) for
peripheral fields and respond to fast movement, and about 50%-55% W-cells
(the smallest of the three) for the directional movement vision.
Or read my
thought ?
What's the moral in these stories?
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