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2152 - What It Means To Be Visible. -
Things are visible because electromagnetic energy reaches our eyes. But, what causes electromagnetic energy? In a word, “atoms“. For
the energy of light that our eyes can see we are limited to a spectrum of
wavelengths from 400 nanometers blue light to 750 nanometers red light. Above and below these wavelengths lies
ultraviolet and infrared that our eyes can not quite visualize.
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-
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---------------------------------- 2152 -
What it means to be visible
-
- What does it
mean to be visible? If something is
visible it usually means that your eyes are sensitive to the electromagnetic
radiation they are receiving. Of course,
other detectors besides eyes can be used to detect a much wider range of
electromagnetic radiation.
-
- Electromagnetic radiation and gravity are the
only two ways we know of to communicate “information“. Both are carried by massless particles, or
waves, known as photons and gravitons.
Because they are massless they must always travel at the constant speed
of light. The maximum speed that
information can travel is the speed of light.
You cannot learn anything any faster than that. Sorry, even I have my limitations.
-
-
Electromagnetic radiation and information come to us, and to our eyes,
in very small bundles of energy. The
energy of each photon of light is E = h*f.
The photon energy, “E“, is directly proportional to the frequency of
oscillation ,”f”, of the electric wave and the magnetic wave that are
oscillating together.
-
- “h” is a constant for the units we use to
measure the action of the energy. In our
case “h” = the constant 6.7 * 10^-11. This constant is known as Planck's Constant
of Action.
-
--------------------
E = h
* f
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--------------------
Photon Energy = 0.000,000,000,067 * frequency
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--------------------
Photon Energy = kilograms * meters^2 / seconds^2
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--------------------- Photon Energy
= joules, which is the name given to kg*m^2/sec^2
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---------------------
Photon Energy = electron volts
-
- 1 electron-volt
equals 1.6*10^-19 joules. The electron-volt is a much smaller unit of measure
so, for these small energies it is much easier to work in "eV" units.
-
- These units
for energy should look familiar to you.
Remember, E=m*c^2. Energy is
directly proportional to mass. In this
case the constant of proportionality is the speed of light squared. “c^2”
= 9*10^16.
-
--------------------
E = c^2
* m
-
-------------------- Mass Energy = 90,000,000,000,000,000 * mass
-
-------------------- Mass Energy =
kilograms * meters^2 / seconds^2, or joules
-
The “h” Constant of Action is a very small number for
a single photon. The “c^2” number is a very large number for a kilogram
of mass converted into energy.
-
- However, the
electromagnetic energy of the photon is directly proportional to the frequency
of oscillation. And, electromagnetic
energy spectrum of oscillations covers a wide range of frequencies from radio
waves, to light waves, to X-rays and to Gamma Rays.
- The low
energy radio frequency waves have oscillations in the order of 1000 cycles per
second. (kilohertz).
-
---------------------
Energy of radio wave = 6.7*10^-11 * 1000
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---------------------
Energy of radio wave = 6.7*10^-8
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---------------------
Energy of radio wave = 0.000000067 joules.
-
- At the other
end of the spectrum, the high energy Gamma Ray frequency waves have
oscillations in the order of 10^24 cycles per second. (femtohertz).
-
---------------------
Energy of Gamma Ray =
6.7*10^-11 * 10^24
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---------------------
Energy of Gamma Ray = 6.7*10^13
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---------------------
Energy of Gamma Ray = 6,700,000,000,000 joules.
-
- As you can
see the electromagnetic spectrum covers a wide range of energies.
-
- For the
energy of light that our eyes can see we are limited to a spectrum of
wavelengths from 400 nanometers blue light to 750 nanometers red light. Above and below these wavelengths lies
ultraviolet and infrared that our eyes can not quite visualize.
-
- 400 and
750 nanometers wavelengths correspond to frequency of oscillations of 750*10^16
cycles per second for blue light and
0.04 * 10^16 cycles per second for red light. Frequency * wavelength = speed
of light. f * w = c
-
---------------------
Energy of blue light =
6.7*10^-11 * 750*10^16
-
---------------------
Energy of blue light = 5 * 10^8 joules
-
---------------------
Energy of blue light = 500,000,000 joules.
-
---------------------
Energy of red light = 6.7*10^-11
* 0.04*10^16
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---------------------
Energy of red light = 0.26 * 10^8 joules
-
---------------------
Energy of red light = 25,600 joules
-
- So, you can
see that blue light has a lot more energy than red light. That is the reason infrared makes you feel
warm, but violet and ultraviolet light give you a sunburn.
-
- Our eyes are
amazing instruments in their ability to detect over a range of 20,000
magnitudes of energy levels. Some human
eyes can detect a single photon of light.
Most can detect a level of energy of 4 to 5 photons of light.
-
- Things are
visible because electromagnetic energy reaches our eyes. But, what causes electromagnetic energy? In a word, “atoms“. Light is the oscillation of electric waves
and magnetic waves traveling together at the speed of light. A magnetic wave, or a magnetic field, is
created when an electric charge is in motion.
An electric field is created when a magnetic field is in motion. Each one creates the other when they are
moving through space. And, they only can
move at one constant speed.
-
- The simplest
atom is hydrogen, that is made up of a single positive charge proton at the
nucleus and a single negative charge electron orbiting around it. All atoms are little magnets because the
electric charge of the electron is in motion around the nucleus. Motion is not only linear, it is circular as
well. And, circular motion requires
acceleration.
-
- A force is
not needed to keep an object in motion at a constant velocity in a straight
line. However, if an object’s velocity
is going in a circle its velocity is constantly changing, because the direction
is changing. A force is required to
accelerate a mass. And, acceleration is
the same as a changing velocity, so a force is required according to Force = mass
* acceleration, F = ma.
-
- The mass
times velocity is called angular momentum.
Electrons are always spinning in an atom as well as orbiting. Therefore, electrons always have angular
momentum. A spinning electron always
maintains its own magnetic field resulting from their negative charge being in
motion..
-
- Electrons can
only spin in one of two ways, clockwise,
or flip them over and they can spin counter-clockwise. So, the magnetic field’s poles north and
south can only point in the direction of the spin axis of the electrons up spin
or down spin. If we line up a lot of
electrons in a metal all pointing in the same spin axis direction we create a
permanent magnetic.
-
- As long as
the atom is experiencing constant acceleration, in other words, it's changing velocity remains the same, then
the atom does not emit any photons.
However, if there is a force causing the atom to accelerate its motion,
or the electrons to jump to lower levels of orbit, than photons can be emitted.
-
- Thermal energy is the most common way the
motion of atoms can speed up. Faster
jittering under increasing heat causes acceleration increases causing photon
energy to be radiated out of the atoms.
-
- A force is
needed to cause an atom to accelerate. F
= m*a. Energy is defined as a force
acting over a distance. E = F*d. Therefore, Energy = m*a*d. Electromagnetic Energy is radiated whenever a
charged particle, like the electron, increases its acceleration of motion,
“a“.
-
- Electromagnetic
Energy is also radiated when the electron jumps some distance, “d”, between
orbits, which are at specific energy levels inside each specific atom. Each atomic element in the Periodic Table has
its own unique structure of electrons and energy levels orbiting the
nucleus.
-
- When photons
are emitted, or absorbed, by each atomic element a different frequency
arrangement is created, depending on these unique energy levels. Again, this is according to Energy =
6.7*10^-11 * frequency. So, if
astronomers measure the frequencies in the light spectrums coming from the
stars they can identify what elements are there or in the interstellar gas in
between. This study is called spectroscopy.
-
- Everything
that is visible is either creating electromagnetic energy in its atomic
structure or it is reflecting some of this electromagnetic that is coming from
another atomic structure source.
-
- Our biggest
source for photons is the Sun. But,
anytime atoms gain energy through increased acceleration or loose energy when
electrons drop to lower energy levels, photons are created. Atoms absorbing photons gain energy by moving
electrons to higher energy levels. Atoms
can absorb and emit photons only at the energy levels, and frequencies, permitted
by their own unique atomic structure.
-
- All other photons are reflected. That is why everything has a different
color. What is not absorbed is
reflected. What is reflected is the color you see. Color is just another name for
frequency. Frequency is just another
name for electromagnetic energy.
-
- All electric
fields and magnetic fields are defined from an electric charge being in
motion. All motion is a change of space
per change in time. What makes things
visible is a combination of all of these creations the natural world has given
us.
-
- Just because
something is clearly visible doesn’t mean it is understood. I hope my review helped your understanding a
little.
-
- November 2, 2018. 951
----------------------------------------------------------------------------------------
----- Comments appreciated and Pass it on to
whomever is interested. ----
--- Some reviews are at: -------------- http://jdetrick.blogspot.com -----
-- email feedback, corrections, request for
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--- to:
------ jamesdetrick@comcast.net ------
“Jim Detrick” -----------
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--------------------- Friday, November 02, 2018 -------------------------
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