Lead
"Light" is emitted by stars such as the sun, and it is also the greatest source of energy on the earth, the natural light source is releasing huge energy every second in the stellar nuclear fusion reaction, forming light and spreading to the earth, and providing energy for the growth of all things on the earth.
But artificial light is different from natural light in terms of spectrum and propagation, so why can light fly at a speed of 300,000 kilometers?
Why does light travel so fast, and where does it come from?
1. The existence and propagation mechanism of light.
There are two kinds of matter in the world, one is made up of particles and the other is made up of fluctuating energy, which is the existence of light.
According to the composition of the atoms that make up the matter, it can be divided into "plasma", which is made up of ions and electrons, and "regular matter", which is made up of atoms and molecules, and light is made up of these two substances.
Light is a "particle wave", particles and waves have the characteristics of both substances, light energy flies at the speed of light with the speed of motion, and can also travel like water waves, the wavelength of light is very short, and light has a specific frequency, so the speed of light propagation is at the speed of light.
The wavelength and frequency of light directly determine the color and brightness of light, the longer the wavelength and the lower the frequency, the darker the color and brightness of the light, and vice versa.
Light can be emitted but also absorbed, and light travels at the speed of light, and in the form of waves.
Obstacles are encountered during propagation, and refraction, reflection, and diffraction phenomena occur after encountering obstacles, which is why light produces holograms and images.
The color of light is also determined by wavelength, there are seven colors in the solar spectrum, which are red, orange, yellow, green, cyan, blue, and violet, and there are more than 400 types of light contained in the solar spectrum.
The light emitted in the solar spectrum will pass through the ionosphere of the earth, most of it will be absorbed, and only two kinds of light can penetrate, one is harmful ultraviolet rays, and the other is ultraviolet rays that are beneficial to human health.
There are also two kinds of light, one is natural light, the other is artificial light, natural light is the light emitted by the sun, artificial light source is used in lamps, such as the light produced by electric lights, there is only a spectrum, no ultraviolet rays.
Although both natural light and artificial light have spectrums, there are differences in the mode of propagation, natural light propagation mode is like water flow, while artificial light propagation mode is like a large waterfall, whether it is natural light or artificial light, it is transmitted at the speed of light.
Light is able to travel at a speed of 300,000 kilometers and does not need to accelerate yet, which is related to the stationary mass of the photon, an object with mass needs to apply power if it wants to fly in the universe, and the photon has zero rest mass and is therefore able to travel at the speed of light.
2. The speed of flight of light.
Light energy flies at a speed of 300,000 kilometers, whether it is in a vacuum or in the air, the speed of light is constant, and the speed of other substances in a vacuum is generally the same as the speed of air flight, even if it is flying in a vacuum, it is also the speed of flight in air.
Light travels at a speed of about 300,000 kilometers per second, so light energy travels 7 times around the Earth's equator.
The speed of light is about 3.00*10^5 kilometers per second, 24 hours a day, 3600 seconds per hour, so light can travel about 25.92 billion kilometers per day.
How fast does light fly?
In order to understand the speed of light more intuitively, we can compare it with the moon.
The distance between the moon and the earth is about 384,000 kilometers, the circumference of the earth is about 4.4*10^4 kilometers, the spectrum of the sun travels from the earth to the moon, it takes 1.28 seconds, and the distance from the earth to the moon is about 384,000 kilometers, so it only takes 1.28 seconds for light to fly from the earth to the moon.
Thus, the spectrum of the Sun can reach the Moon at a speed per hour, and light travels through space at the speed of conventional matter and does not need to be accelerated.
Does light fly fast?
Or starting from the spectrum of the sun, if the sun's energy is fully exerted and all its energy is turned into explosive energy, then the energy of this explosion can destroy all objects outside the solar system.
However, light travels at a speed of 300,000 kilometers per second, and the distance from the sun to the earth is 1.5*10^8 kilometers, at which light is able to fly to the earth in 500 seconds.
Although there is still a long way to go from the energy in the universe, the sun also transmits a huge amount of energy, allowing life on Earth to be abundant.
3. The phenomenon of bending light in the universe.
Light can travel in the universe at a speed of 300,000 kilometers, but light is not massless, the rest mass of the photon is zero, so light can travel in the universe at a speed of 300,000 kilometers.
In the universe, light will be affected by gravity, and light, after being affected by gravity, will bend, and light, after being affected by gravity, will gather various substances and energies in the universe together, therefore, objects with gravitational attraction will have a gravitational pull on light, resulting in the phenomenon of bending of light.
When light flies in the universe, it passes through various stars, whether it is a supermassive star or a black hole in the universe, after the light passes, it will exert a gravitational pull on the light and bend the light.
When light flies near the black hole, it will suck light into the interior of the black hole due to the gravitational pull of the black hole, and when the light flies inside the black hole, the speed will slow down, and finally it will be absorbed by the black hole when it cannot escape.
Therefore, the attraction of black holes is so powerful that it can even swallow light, so why are black holes so violent?
A black hole is a super-strong gravitational field, its radius is too small to be seen, but its gravitational pull is incomparably strong.
The mass of the black hole is very large, so the gravitational pull generated will be very strong, and there is no speed of light to escape, and it can only be sucked in by the black hole, so the black hole is also called the "end place".
epilogue
Light can fly not only at a speed of 300,000 kilometers, but also around the Earth's equator at a speed of 300,000 kilometers seven times.
The speed of light is constant, but the direction of light can be changed, and light is affected by gravity during its flight, so it also bends.
The existence and propagation mechanism of light reveals the complexity and mystery of the material world, and the characteristics of light-speed propagation are of great significance to the development of science and technology and the progress of human society, such as optical communication, optical devices and other fields.
The in-depth study of light will help us better understand the laws of nature and improve the ability of human beings to use and control light.