Where does the first ray of light from the universe come from? What is the working principle of light?
Where does the first ray of light from the universe come from? What is the working principle of light?
Light is both common and mysterious. We bathe in the warmth of the golden sun every day, using incandescent lights and fluorescent lights to remove darkness. But what exactly is it? When the sun passed through the dusty room, when the rainbow appeared after the storm, or when the straw in a glass of water looked bent, we glanced at its essence. However, these glances will only cause more problems. Just spread in the form of waves, rays or particle flow? Is it monochrome or a variety of colors mixed together? What are the common characteristics of light, such as absorption, reflection, refraction and diffraction? Where does the first light in the universe come from (that is, the origin of light)?
Figure: As a citizen living on the sun on the sun, it is difficult to ignore the existence of the sun. In this article, we pay tribute to the light, because a worldless world will be a gloomy place.
You may think that scientists know all the answers, but light still surprised them. For example: We always want to take it for granted that the spread of light is faster than anything in the universe. Then, in 1999, the researchers at Harvard University were a matter of material state called Bolute-Einstein condensed to reduce the speed of the beam to 61 kilometers per hour per hour. Normal light speed is 18 million times the speed! Just a few years ago, no one would think of such feats. However, when you think you have understood the principle of light, it ignores your efforts and seems to change its nature.
However, we have made great progress in understanding of light. In the history of science, some wise men in the world use their intelligence and wisdom to devote themselves to the study of light. Albert Einstein tried to imagine what it would look like “riding” on the beam. “If someone chases a bright run?” He asked himself, “If a person runs fast enough, will time be as fast as time as light?”
However, Einstein’s research on light has gone at the forefront. For the working principle of Xieguang, we must put it in the appropriate historical background. Our first stop is the ancient world. There, some earliest scientists and philosophers thought about the true nature of this mysterious material. This material can stimulate vision and make things visible.
What is alone?
Over the past few centuries, our views on light have undergone tremendous changes. The first real theory about light comes from the ancient Greek. Many of these theories are trying to describe light as light -one moves from one point to another. Pythagoras is known for its right triangle theorem. He proposed that vision was caused by the light emitted by human eyes.
The view of Ishichiru is exactly the opposite: the object produces light, and then the light spreads to the eyes. Other Greek philosophers -the most famous is Oujide and Ptolemy, which is very successful to use ray charts to display light from one smooth surface, or occur from one transparent medium to another transparent medium. Reflection.
Arab scholars have further refined these ideas and developed the geometric optics now -apply geometric methods to the optics of lens, mirrors and prism. The most famous geometric optical practitioner is Ibn Al-Haytham, who lived in Iraq from 965 to 1039. Ibn Al-Haytham recognizes the optical component of the human eye, and correctly describes the process of vision that the light reflection from objects to human eyes. The Arab scientist also invented the pinhole camera, discovered the law of refraction, and studied some light -based phenomena, such as rainbow and solar eclipse.
In the 17th century, some famous European scientists began to have different views on light. A key figure is the Dutch mathematician-astronomer Christiamian Huyattos. In 1690, Huygers published his “Light theory”, which described the understanding of light. In this theory, he speculated that the existence of some intangible medium -Ether -Ether -fills all the blank spaces between objects. He further speculated that when the luminous body caused a series of waves or vibrations in Ether, the light was formed. These waves then advanced until they encountered objects. If that object is eye, waves will stimulate vision.
This is one of the earliest theory of light waves. Not everyone accepts it, Isaac Newton is one of them. In 1704, Newton proposed a different solution -one describing light as material or particles. After all, light spreads in line, rebounding from the mirror, just like the ball bounced off the wall. No one has really seen light particles, but even now, it is not so easy to explain why this is. These particles are too small or moved too fast to see these single particles with their eyes.
It turns out that all these theories are both correct and wrong, and these theories are useful for certain behaviors to describe light.
Imagine the light as light, which can accurately describe three well -known phenomena: reflection, refraction and scattering. Let’s spend some time to discuss.
In the reflection, light is shot to a smooth surface (such as a mirror) and rebound. The reflection light is always reflected from the surface of the material from the angle of the surface of the incident light. In physics, it is called the law of reflection, which is: “incident angle is equal to reflex angle.”
Definition of light
Of course, we live in an imperfect world, not all surfaces are smooth. When the light is shot to the rough surface, because the surface is uneven, the incident light will reflect at various angles. This scattering occurs on many objects we encounter every day. The surface of the paper is a good example. If you observe it under a microscope, you will find it particularly rough. When the light is on the paper, the light waves reflect on all directions. This is why the paper is so useful -no matter what angle you look at the surface, you can read the text on the printing page.
The refraction occurs when the light is transparent (for example, the air) through another transparent medium (water). When this happens, the light will change the speed, and the light will reflected, reflecting it in the direction of us as the “law line”. This is a straight line that is perpendicular to the surface of the object. The bending amount or refraction angle of the light wave depends on the degree of the material to slow down the light. After entering the diamond, it greatly slows down, so it can shine. The refractive index of diamonds is higher than water, that is, those glittering light traps will slow down the light to a greater extent.
The refraction and reflection of light
Lee -lens, like a lens in a telescope or glasses, uses the refraction of light. The lens is a piece of glass or other transparent substances, and its curved side is used to concentrate or disperse light. The lens is used to reflect the light at each boundary. When light enters transparent materials, it is refracted. When the same light leaves, it reflects it again. The net effect refracted at these two boundaries is that the light changes the direction. We use this effect to correct a person’s vision, or to enhance vision by making the distant objects closer or small objects look bigger.
Unfortunately, the theory of rays cannot explain all the behaviors shown by the light. We also need some other explanations, such as what we have to discuss next.
Unlike water waves, light waves follow more complicated paths, and they do not need media to spread.
At the beginning of the 19th century, there was no real evidence to prove the fluctuation theory of light. This situation changed in 1801. At that time, Thomas Yang, a British doctor and physicist, designed and running one of the most famous experiments in the history of science. It is called a double seam experiment today, and it requires a simple device -a thin card with a light source, one side by side with two holes and a screen.
Thomas Yang’s double seam experiment
In order to perform this experiment, Thomas Yang allowed a bunch of light to pass through the pinhole and hit the card. He infer that if the light contains particles or simple linear light, the light that is not blocked by the opaque card will pass through the slit and spread to the screen in a straight line, and two highlights will be formed on the screen. Thomas Yang did not observe the two highlights, and replaced him that he saw the barcode pattern of light and dark alternating on the screen. In order to explain this unexpected model, he imagined that he was spreading in space like water waves, with peaks and valleys. He thought about it and concluded that the light wave passed through each slit to form two independent waves. When these waves reach the screen, they interfere with each other. A bright tape is formed in the place where the two peaks overlap and superimposed, and the bands are formed in a column of a row and a valley that completely offset each other.
Thomas Yang’s work has inspired people to reintegrate the work principle of light. Scientists began to mention the light waves and changed the description of reflection and refracting accordingly accordingly, pointing out that the light waves still follow the laws of reflection and refraction. By the way, the refraction of the light wave explains some of the visual phenomena we often encounter, such as the mirage. The mirage is a kind of illusion that the light waves that move from the sky to the ground are refracted by heated air.
In the 1860s, the Scottish physicist James Clark Maxwell (James Clerk Maxwell) described light as a very special wave -a wave composed of electric fields and magnetic fields. The movement direction of these fields and waves vibrates right -angle, and it becomes right -angle vibration. Because it has electric field and magnetic field, it is also called electromagnetic radiation. Electromagnetic radiation does not require medium to spread. When it spreads in vacuum, it moves at a speed of about 300,000 kilometers per second. Scientists call the speed of light and one of the most important numbers in physics.
Once Maxwell introduced the concept of electromagnetic waves, everything was orderly. Scientists can now develop a complete light work model based on the structure and functions of the wavelength and the frequency of wavelength and frequency. According to this model, there are many sizes of light waves. The size of the waves is measured by the wavelength. The wavelength is the distance between the two corresponding points of any continuous wave, usually the distance from peaks to peaks or valleys to valleys. The wavelength range of light we can see from 400 nanometers to 700 nanometers (or one billion -dollar). However, all the wavelengths contained in the definition of electromagnetic radiation extend from 0.1 nanometer in gamma rays to the centimeter and meters in radio waves.
Light waves also have many frequencies. Frequency refers to the number of waves at a wave of space within any time interval (usually one second). We measure it in a cycle (wave) or Hz per second. The frequency of visible light is called color, with a range from 43.0 trillion Hertz (red) to 75.5 trillion Hz (purple). Similarly, the entire frequency range exceeds the visible part, from the small small radio waves in the small ray of 3 billion Hertz, to the Gamma rays greater than 3 billion Hertz (3 × 10^19).
The energy in the light wave is proportional to its frequency: high -frequency light has high energy; low frequency light has low energy. Therefore, gamma rays are the largest (partly because it is so dangerous to humans), and the energy of radio waves is the smallest. In the visible light, purple energy is the largest and red. As shown in the figure, the entire frequency and energy range are called electromagnetic spectrum. Note that this number is not drawn proportionally, and the visible light only accounts for one thousandth of the spectrum.
This does not mean that the discussion of the light is over. Einstein’s work in the early 20th century re -evoke an ancient concept.
Light as a particle
Maxwell’s theoretical treatment of electromagnetic radiation (including description of light waves) was so elegant and foreseeable, so that many physicists in the 1990s believed that there was nothing to say about light and its working principles. Then, on December 14, 1900, Max Planck put forward a simple but disturbing idea: light must carry the energy of discrete amounts. He proposed that these quantities must be a unit with basic energy increase HF, of which H is a cosmic constant. It is now called Planck constant, F is the frequency of radiation.
Lighting releases the energy package on the solar board, and can be generated by using these energy to use these energy
In 1905, Albert Einstein proposed Planck’s theory when he studied the photoelectric effect. First, he began to illuminate UV on the metal surface. When he did this, he was able to detect electrons emitted from the surface. This is Einstein’s explanation: If the energy in the light is bundled, then people can think that light contains tiny blocks or photons. When these photons hit the metal surface, they are like a billiards, transferring energy to electrons, and electronics are separated from their “father” atoms. Once released, electrons move along the metal or pop up from the surface.
The theory of light came back to “revenge”. Next, Niels Bol used Planck’s idea to improve the atomic model. Earlier scientists have proved that the atoms are composed of positive charge nucleus. The nucleus is surrounded by orbit by electrons like planets, but they cannot explain why electrons cannot simply spiral into the atomic nucleus. In 1913, Boer proposed that electrons existed on discrete orbit based on its energy. When an electron jumps from a orbit to a lower track, it emits energy in the form of photons.
The theory of quantum theory of light — the idea of the existence of light as a tiny bag or particle (known as a photon) — slowly starts to appear. Our understanding of the material world will no longer be the same.
Wave particle duality
At first, physicists were unwilling to accept the dual properties of light. After all, many of us like to have a correct answer. But in 1905, Einstein paved the way for the two phenomena of the waves of light. We have discussed the photoelectric effect, which allows Einstein to describe the light as a photon. However, later in the same year, he added a turning point to this story in a paper that introduces the theory of narrow sense. In this article, Einstein regards light as a continuous wave field, which is obviously contradictory to describe light as a particle flow. But that was part of his genius. He willingly accepted the strange nature of light, and chose the attributes that he could best solve the problem that he tried to solve.
The wave particles of light
Today, physicists accept the dual properties of light. In this modern point of view, they define light as a collection of one or more photons, which spread in the space in the form of electromagnetic waves in the form of electromagnetic waves. This definition combines the nature of light waves and particles, making it possible to reintegrate Thomas Yang’s double slit experiment: light spreads from a light source in the form of electromagnetic waves. When it encounters a slit, it passes through and divides into two waves. These waves overlap and approach the screen. However, at the moment of impact, the entire wave field disappeared and a photon appeared. Quantum physicists often describe this: The diffusion wave “collapse” into a small point.
Similarly, photons enable us to see the world around. In a completely dark environment, our eyes can actually perceive a single photon, but usually what we see in daily life appears in the form of countless photons reflected by light sources and objects. If you look around now, there may be a light source in the room to produce photons, and the objects in the room reflect these photons. Your eyes have absorbed some photons flowing through the room, so you look at objects.
But wait, what makes the light source produce photons? This is the next one we will solve the problem.
There are many ways to produce photons, but all methods use the same mechanism inside an atom to complete. This mechanism involves the inspiration of electrons around each atomic nuclear. The working principle of nuclear radiation describes the proton, neutron and electrons in detail. For example, hydrogen atoms have an electron to turn around the atomic nucleus. Two electrons have two electrons around the atomic nucleus. There are 13 electrons around the atomic rotation around the atom. Each atom has a preferred electronic number of the atomic nuclear rotation.
After the electronic transition, the photon is generated when returning to the low -energy orbit
The electrons rotate around the atom nuclear in a fixed orbit -a simple way of thinking is to imagine how satellites rotate around the earth. There are many theories around the electronic orbit, but to understand the light, there is only one key fact that it needs to be understood: electrons have a steady -state natural track, but if you bombard the atoms, you can transition its electrons to a higher orbit. When the electrons in the normal track return to the normal track, photons are generated. In the process of falling from high energy to normal energy, an electron emits a photon -a pack of energy -has very special characteristics. The frequency or color of photons is completely matched with the distance between electrons.
You can clearly see this phenomenon in the gas discharge lamp. Fluorescent lamps, neon lights, and sodium steam lamps are common examples of this electric lamp, which glow with gas through current. The color of the gas discharge lamp is very different according to the type of gas and the structure of the lamp.
For example, you often see sodium steam lamps in highways and parking lots. You can easily distinguish the sodium vapor light, because the sodium vapor light is yellow, which is formed after the sodium atom is excited. Sodium atoms have 11 electrons. Due to their accumulation on the track, one of the electrons is most likely to accept and release energy. The energy packet that is most likely to be launched in the electron is just around 590 nanometer wavelength, which corresponds to yellow light. If you use sodium light to pass through the prism, you can’t see the rainbow -you see a pair of yellow lines.
Biological light: How to light up the organism
Another method of generating photons is called chemical glowing, involving chemical reactions. When these reactions occur in creatures such as bacteria, fireflies, squid and deep -sea fish, the process is called biological glow. At least two types of chemicals are needed to shine. Chemists use universal terms “fluorescentin” to describe a substance that generates light. Scientists use fluorescent enzymes to describe enzymes driving or catalytic reactions.
In summer, fireflies in the woods
Basic reactions follow a simple order. First, fluoresceanase catalyzes fluorescein oxidation. In other words, fluorescein and oxygen combine chemicals to generate oxide fluorescein. This reaction also generates light, usually in the blue or green area of the spectrum. Sometimes, fluorescein is combined with a catalytic protein and oxygen in a large structure called optocoprotein. When ions (usually calcium) are added to the optocromin, it oxidize fluorescence, leading to light activity and unconventional oxidation fluorescein.
Among the marine life, the blue light produced by the glowing of creatures is the most helpful because the wavelength of about 470 nanometers spread further in the water. Moreover, there is no pigment in the visual organs of most organisms, so that they can see the wavelength of longer (yellow, red) or shorter (blue, ultraviolet).
Next we discuss common incandescent lamps.
Cantileness: Use heat to create lights
The most common method of exciting atoms is heating, which is the basis of incandescent lamps. If you use a lamp to heat the horseshoe iron, it will eventually become red and hot. If you continue to heat it, it will become fierce. Red is the minimum energy visible light, so in a hot object, the atom has just gained enough energy to start launching the light we can see. Once you apply enough heat to generate white light, you will stimulate many different electrons in a variety of different ways, and all colors will produce -they are mixed together and look like white.
The heat is the most common way we see light -an ordinary 75 -watt -incandescent light bulb uses electricity to generate heat to generate light. The electricity passes through the tungsten wire in the glass ball. Because the filament is too thin, it provides a good resistance to electricity, and the resistance transforms electric energy into calories. The calories are enough to make the filaments white. Unfortunately, this is not very effective. Most of the energy entering the incandescent bulbs lost in the form of heat. In fact, compared with the fluorescent lamp, the typical light bulb input power per tile may generate 15 lumens, while the fluorescent lamp generates 50 to 100 lumens per tile.
Burning provides another way to produce photons. When a material -fuel -quickly combined with oxygen, it will cause burning when it produces heat and light. If you carefully study the bonfire and even the candle flame, you will notice that there is a colorless gap between the wood or the core and the flame. In this gap, the gas rises and heated. When they eventually become hot enough, these gases are combined with oxygen to glow. So what is the flame? It is actually a mixture of visible light, infrared, and some ultraviolet reaction gases.
In the next step, we will discuss laser.
An interesting application of the quantum nature of light is laser. You can understand the working principle of laser, but we will introduce some key concepts here. Laser is an abbreviation of “radiation radiation”, and is a language that describes the same light of photon wavelengths, peaks and valleys. In 1960, the study physicist Theodore H. Maiman developed the world’s first working laser: ruby laser. Ruby laser includes ruby crystals, quartz flash tubes, reflectors and power.
Let’s start with the characteristics of ruby, and review how Miman uses these components to generate laser. Ruby is an alumina crystal, and some of the aluminum atoms have been replaced by chromium atoms. Chromium gives ruby its characteristic red by absorbing green and blue light and reflecting red light. Of course, Mamman cannot use a natural crystalline ruby. First, he must make the ruby crystal system into a cylindrical body. Next, he wrapped the high -strength quartz lamp around the ruby cylinder to provide white light flashing. The green and blue wavelengths in the flash stimulate the electrons in chromium atoms to reach higher energy levels. When these electrons return their normal state, they emit their characteristic ruby red light.
This is where it is interesting. Mindan put one -side reflex mirror on one end of the crystal and a semi -reflector on the other end. The reflective mirror reflects some red wavelength photons back and forth in the ruby crystal. This in turn stimulates other torrential chromium atoms to produce more photons, until a large number of accurate arranged photons rebound back and forth in the laser. Every time a rebound, some photons escape, which enables the observer to perceive the beam itself.
Today, scientists use many different materials to make laser. Some, like ruby laser, emit short pulse light. Others, such as 氦氖 gas laser or liquid dye laser, emit continuous beams.
Let’s study the colorful rainbow next.
It can be seen that light is the light that human eyes can perceive. When you see the visible light of the sun, it looks colorless and we call it white. Although we can see this light, white is not considered part of the visible spectrum. That’s because white light is not a single color light, but a variety of light.
When the sun fell to the wall through a glass of water, we saw a rainbow on the wall. Unless the white light is a mixture of all colors in the spectrum, this situation will not happen. Newton was the first person to prove this. Newton divided the sun into a rainbow spectrum through a glass prism. Then, through the second glass prism, he combined two rainbow sunlight, which produced white light. His simple experiments have confirmed that white light is a mixture of multiple colors.
You can use three flashlights and three different colors of glass paper to do a similar experiment -red, green, and blue (usually called RGB). Cover a flashlight with one or two layers of red glass paper, and fix the glass paper with rubber bands (do not use too many layers, otherwise the light of the flashlight will be blocked). Cover another flashlight with blue glass paper and cover the third flashlight with green glass paper. Enter a dark room, turn on the flashlight, and shine them on the wall to overlap the light, as shown in the figure.
In the place where red and blue light overlap, you will see foreign red. In the place where the traffic lights overlap, you will see yellow. In the place where green and blue are overlapping, you will see cyan. You will notice that white light can be emitted through a variety of combinations, such as yellow and blue, foreign red and green, blue and red, and mix all colors.
By adding various combinations of these so -called additional colors (red, green, and blue light), all colors of visible spectrum can be visible. This is how the computer monitor (RGB monitor) generates color.
Pigment and absorption
Another method of making colors is to absorb the frequency of light to remove them from the white light combination. The color that is absorbed is the color you can’t see -you can only see the color of the rebound back to your eyes, which is called the color reduction method. This is the occurrence of pigments and dyes. The pigment or dye molecules absorb a specific frequency and rebound or reflect other frequencies to your eyes. Percidity frequency is the color of the object you see. For example, the leaves of green plants contain a pigment called chlorophyll. It absorbs blue and red in the spectrum and reflects green.
Reduction method: We see that light is the light of material reflection, and the rest is absorbed
You can use the atomic structure to explain this phenomenon. The frequency of incident light waves is equal to or close to the vibration frequency of the electrons in the material, the energy of the electron absorption of the light waves and starts to vibrate. What will happen in the next step depends on how close the atomic and electrons are. When the electrons are caught tightly, the absorption occurs, and they pass the vibration to the nucleus. This accelerates atoms, collides with other atoms in the material, and then abandons the energy obtained from vibration in the form of heat.
The absorption of light makes the object dark or the frequency of the incoming wave is opaque. Wood is opaque to visible light. Some materials are opaque to some frequencies, but they are transparent to other materials. Glass is opaque to ultraviolet rays, but is transparent to visible light.
The origin of light
Today’s scientists accept the presence of photons and their strange wave particles. They are still arguing about the existence of things, such as where light comes from. In order to answer this question, physicists turned their attention to the Big Bang and the explosion in the subsequent minutes.
The universe explodes from the strange point
You may still remember that the Big Bang is an incident of the birth of the universe. You can read more about how the Big Bang theory works, but here to remind you that some basic knowledge will be useful. About 15 billion years ago, all material and energy were closed in a small area called a strange point. For a moment, this single -point ultra -dense substance began to swell at an alarming speed. As the freshman universe expands, it begins to cool and becomes less dense. This enables more stable particles and photons to form.
The following is a possible thing:
Immediately after the Big Bang, electromagnetic no longer exists as an independent force. Instead, it adds weak nuclear power.
At this time, particles called B and W bosom also exist.
When the universe is only 0.0000000000001 seconds, it has been cooled to enough to let the electromagnetic force break free from the weak nuclear force, and combine B and W bosom into photons. Photon and Quark are freely mixed. Quark is the minimum part of material.
At 0.00001 seconds of the universe, quarks combined with protons and neutrons.
When the universe forms 0.01 seconds, protons and neutrons begin to form atoms.
In the end, when the universe was still at a young age, the photon was released, and the light passed through the dark space cracks.
This light eventually darkened and red, until the nuclear furnace in the star started and started to generate new light. Our sun opened about 4.6 billion years ago and sprayed out of the solar system. Since then, these photons have been flowing to our blue planet. Some photons fall in the eyes of great thinkers -Newton, Huygers, Einstein, which allows them to stop, think and imagine.
The above is the introduction and description of SL3001 White Sparkling Quartz, I hope it can be helpful to you.