- 3132 - LIGHT - speed and power? It is crazy math and a rash of scientific units but it illustrates that light comes from electricity and magnetism. Maxwell made this discovery simply looking at his equations trying to understand how electricity and magnetism works. You can understand it simply by reading this Review:
----------------------- 3132 - LIGHT - speed and power?
- I Had No Idea Light Traveled That Fast!
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- Light travels at 657,633,500 miles per hour.
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- Light travels at 186,237 miles per second.
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- Light travels slower in other medium, or appears to. It really only travels at light speed but in other media it can be absorbed and re-emitted so it appears to be traversing the medium at a slower speed. Light only has 2 speeds. “zero or light speed“.
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- If you see a bolt of lighting and you want to know how far away the lightning struck, you count, 1 second, 2 seconds, 3 seconds, 4 seconds and then the clap of thunder. You waited 4 seconds for the sound to reach you.
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- Sound travels at 750 miles per hour.
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- Sound travels at 0.208 miles per second.
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- Sound travels 1100 feet per second.
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- So the lighting strike is 8/10ths of a mile away.
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- Meanwhile the lightning has traveled 745,000 miles.
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- The Moon is 239,000 miles away so the light would have traveled to the Moon, reflected and traveled back to Earth, re-reflected and traveled back to the Moon while you were waiting to hear the thunder.
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- If you were on the Moon you would see the lightning in 2 seconds, but you would wait 13 days for the thunder to arrive.
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- Ok, I know, sound can not travel through outer space, so, in fact you would never hear the thunder. The Moon has no atmosphere so there is no sound on the Moon. We interpret sound as what our ears can hear.
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- Actually, sound is a density wave that our ears are sensitive to and it needs a medium like air to travel through. However, to destroy a myth, outer space is full of sound waves, called density waves.
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- The density waves in space are very important to the evolution of our Universe. The sound waves detected in the Cosmic Microwave Background radiation allowed astronomers to calculated the age of the Universe, 13.75 billion years old.
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- The harmonics in the sound wave allowed the calculation of the composition of the Universe to be 73% Dark Matter, 23% Dark Energy, 5% Ordinary Matter. All that we know and understand lies in that little 5%.
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- Density waves are responsible for creating the structure of the galaxies throughout the Universe. Sound waves are responsible for the birth of stars.
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- Back to that light that left the lighting bolt. It would take 4 hours of the light to reach Neptune. If we had a spacecraft there we would need to send the radio signal 4 hours early before it told the spacecraft what to do. Then we would have to wait another 4 hours for the spacecraft to tell us that it did it.
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------------- Neptune is 30 Astronomical Units from the Sun.
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------------- We are 1 AU.
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------------ 1 AU is 93 million miles.
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------------ Light travels 11,200,000 mils per minute.
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----------- It takes light 242 minutes to get there 29 AU away.
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- To communicate to the nearest star we would have to send the message 4.3 years in advance.
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- To get to the Andromeda Galaxy we would need to send it 2,500,000 years in advance, and then wait that long for a response.
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-------------- Light travels vast but space has enormous distances. By the way Andromeda Galaxy is the farthest thing you can see with the naked eye. Check it out. It too 2.5 million years to reach your eyes.
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- How powerful is light and how does it come out of electricity and magnetism?
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- We can not learn all about the Universe using only “ light”. There is just too little of it. Even if we expand the meaning of ‘light” beyond visible light to the entire electromagnetic spectrum our vision is limited. 95% of the Universe does not respond to electromagnetic radiation or forces.
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- And, there is a wide range of intensities of light. Obviously the farthest stars and galaxies are very dim as light intensity falls off at the inverse square of the distance. Long time exposures are required to collect enough light to gather an image.
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- And, there is a wide range of frequencies of electromagnetic radiation. Light waves are a very small sliver from 700 to 900 nanometers wavelength. Electromagnetic radiation starts ate radio waves and goes through many octaves of wavelengths before reaching Gamma Rays that have the smallest wavelengths and the highest frequencies. We needed to invent special detectors to “see” everything beyond our little sliver of visible light.
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- AM radio at 1230 Hertz on your dial has photons of energy of 7.42*10^-31 Joules.
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- If you get a suntan with ultraviolet photos at 2.5*10^15 Hertz, or cycles per second, each photon is 17*10^-19 Joules of energy. Ultraviolet rays are 2.3 trillion times more powerful than the radio waves.
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- An X-ray photon would be 1.6*10^-15 Joules of energy.
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- Here is a quick summary of the wavelengths of “ light”:
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-------------------- Gamma Rays -------------------- 0.01 nanometers
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-------------------- X-rays ---------------------------- 1 nanometers
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-------------------- Ultraviolet --------------------- 100 nanometers
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-------------------- Visible ------------------------- 500 nanometers
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-------------------- Infrared --------------------- 100,000 nanometers
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-------------------- Microwaves -------------------- 1 centimeter
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-------------------- Radio -------------------------- 1 meter
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- A 100 watt light bulb has a photon energy of 2.05 *10^-19 Joules. Its temperature is 3,000 Kelvin. How many photons are coming off the light bulb?
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- There are 480,000,000,000,000,000,000 photons coming off the light bulb every second. The human eye can detect as little as one photon. Unless you are old like me and you need at least 10 photons to detect the light.
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- Light has power, amazing power. It is the light radiation coming from the core of a star that prevents the star from being collapsed by gravity.
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- The radiation from the Sun that reaches the Earth ahs 1,000 watts of power per square meter. The sunshine hitting you is 45,000 times more powerful that the TV station’s electromagnetic signal that is also hitting you.
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- Light gets its power from electricity and magnetism. The 1,000 watts of power coming from the Sun is a 900 volts per meter electric wave traveling perpendicular to a 0.3*10^-5 Tesla magnetic wave. The wave oscillation is side to side , not back and forth like a sound wave or a density wave.
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- To convince you that the light power comes from electricity and magnetism we can go back to when this was discovered. It was discovered in Maxwell’s equations for an electric field and a magnetic field.
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- His equations included the permeability of free space and the permittivity of free space. The product of these two parameters was the speed of light squared, 9 * 10^16. When Maxwell saw this he recognized it as the speed of light and concluded that light was an electromagnetic wave.
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----------------- Permeability is the ratio of magnetic flux density to the magnetic field strength in free space.
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------------------Permeability = 4 * pi* 10^-7 Tesla* meters / amperes
---------------- Tesla is a unit of magnetic induction equal one Weber of magnetic strength per square meter.
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--------------- Permittivity is the ratio of electric displacement is a dielectric medium to the electric field strength.
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--------------- Permittivity = 8.8 * 10^-12 Coulombs^2 / Newton * meters^2
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---------------- Coulomb is a unit for the quantity of electricity equal to the charge transferred in one second across a conductor in which there is a constant current of one ampere.
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------------- Newton is a unit of force that produces an acceleration of one meter per second on a mass of one kilogram.
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- In Maxwell’s equation ------------- 1 / permeability * permittivity
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-------------------------------------------- 1 / (4 * pi * 10^-7) * ( 8.8*10^-12)
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-------------------------- 1 / 111 * 10^-19
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-------------------------- 9 * 10^16 meters^2 / seconds^2
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- That is the square of the velocity of light, ( 3 * 10^8 meters / second)
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- It is crazy math and a rash of scientific units but it illustrates that light comes from electricity and magnetism. Maxwell made this discovery simply looking at his equations trying to understand how electricity and magnetism works.
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- Who would have thought that placing a phone call for a dime would lead to a cell phone for $200 a month? Other Reviews available abut light:
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- 3124 - LIGHT - standing on a light beam? The electromagnetic force carried by photons is basically light. It is these light photons that travel between the electrons and the protons in the nucleus of atoms. So, you could say that light beams are holding you at the surface of the Earth. It is the light between the atomic particles that is holding you up.
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- 3118 - LIGHT - bending around the Sun? This review is about Gamma, the factor by which light speed increases mass, contracts length in space, and slows down time. Nothing could be stranger
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- 3073 - LIGHT - Light Spectrum discovered? Light is radiation that is emitted and absorbed by matter. Light is electromagnetic radiation because it is a combination of electric waves and magnetic waves that travel at high speeds oriented perpendicular to each other.
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- 2775 - LIGHT - why the constant speed? The speed of light is 299,792,458 meters per second. But why does it have the value that it does? Why isn't it some other number? And why do we care so much about some random speed of electromagnetic waves? Why did it become such a cornerstone of physics?
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- 2751 - LIGHT - Interferometers? The light wave interferometer is one of the most accurate instruments known. The new comb generators will make them more accurate then today’s atomic clocks. Light interferometers and atom interferometers are ultra-precise measurements that will be used to discover many new things.
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- 2684 - LIGHT - keeps getting stranger? We have wave- particle duality, photon entanglement and anti-matter, matter asymmetry as three courses in our college of future study. Entanglement bothers me the most. My imagination can wade through the other two, but not that one. It is just too weird for me to comprehend. Entanglement in the brain? Here is a Review for you to try it.
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- 2683 - LIGHT - the wave-particle duality? - At the time of Isaac Newton in 1687 science considered light to be a beam of particles. In the 1900’s some experiments measuring interference and diffraction concluded that light was indeed waves. Interference is when two waves come together and the beams amplify or cancel each other out depending on how the phases of the waves are intersecting. So, when did light become particles again?
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- 2661 - LIGHT - What It Means 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.
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- 2609 - LIGHT - how to measure its speed ? One of the most common questions asked is whether gravity is instantaneous, or whether there’s a speed limit to how fast the force of gravity can travel. This is not as simple a question as it seems on the surface. Most would say at the speed of light. However the problem with the speed of light, is it gets here too early in the morning.
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- 2537 - LIGHT - stranger than you can imagine? - Is “light” energy what is warping space and time? What about Dark Energy that is the repulsive force expanding space in the Universe? Is “light” responsible for this as well? “Light” has a much bigger role to play in the Universe than what we can “see”. All that we do not see is stranger still.
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- 2402 - LIGHT - There is not enough light. We can never understand the Universe by studying starlight. There is just not enough of it. Starlight comes from the energy, or radiation, from ordinary matter and ordinary matter comprises less than 5% of the Universe. 30% more is Dark Matter and 65% more is Dark Energy. We need a telescope that can see in the ”Dark”.
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- 2387 - LIGHT - how light moves particles. Einstein had developed the theory of special relativity that revolutionized the way we understand light. To this day, it provides guidance on understanding how particles move through space.
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- 2310 - Getting Light from Electricity and Magnetism. Light, electricity, and magnetism seem to me to be three separate things. How can they be connected into electromagnetic waves? We had to discover each one at a time before Einstein even connected them with mass and space.
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- 2306 - How far away is the Sun? When at sea how can we use the Sun to determine our position, longitude and latitude? How can the moons of Jupiter be used as a clock? How can that clock be used to determine the speed of light? Learn from Ole the Danish astronomer:
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- 2210 - There is a star that is looping around the blackhole at the center of our galaxy. Theory of Relativity tells us that light would loose energy leaving a gravity well and it would gain energy entering the gravity well. This energy difference shows up in the change in wavelength of the light. Einstein’s math is tested again.
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- 2260 - Getting light from electricity and magnetism? How do the electric and the magnetic forces, or, waves create light. Or, is it the opposite? Is light that creates the electric and magnetic forces? See here, to learn the answer.
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- April 23, 2021 LIGHT - speed and power? 1386 1389 3132
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--- Some reviews are at: -------------- http://jdetrick.blogspot.com -----
-- email feedback, corrections, request for copies or Index of all reviews
--- to: ------ jamesdetrick@comcast.net ------ “Jim Detrick” -----------
--------------------- --- Friday, April 23, 2021 ---------------------------
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