What we see is because of light. Light is a kind of radiation and a form of energy, and we’ll talk about its properties below.
Converting Energy to Light
You are emitting light, just in the infrared spectrum. We also emit glow for a little as the side effects of our metabolism, which is simply an exchange of forms of energy.
The most common way to emit light is through blackbody radiation. For example, if you see lava as red and orange or sometimes yellow, you see their hot temperatures emitting that kind of light. For example, our Sun, which is 5,778 K in temperature, emits across the visible spectrum.
But how can a computer, which is not scorching hot, glow in the dark? That’s because they use electric energy instead of thermal energy. Remember? Any forms of energy can convert into light because light itself is energy.
How to emit light
To see the process of emitting light, you need to zoom in to the atomic scale. An atom is made of neutrons, protons, and electrons. When an electron absorbs energy and jumps to a higher energy level, it needs to get rid of it to be more stable. They emit photons to carry the energy they have removed.
The Properties of Light
In the instant of creation, the photon already travels at the speed of light. This limit is a constant, but different mediums can slow light down. For example, light moves at 0.4 c, which is the speed of light, in diamonds.
Also, light is a wave created by a photon and has perpendicular electric and magnetic fields. As a wave, it can be refracted, reflected, and scattered. For example, Earth’s atmosphere scatters light with shorter wavelengths: Blue, violet, UV, etc. We can see Earth’s Moon and the planets because of the reflected light from the Sun. Also, light is bent in water, resulting the image being distorted.
Talking about wavelengths, if light has a shorter wavelength like X-rays and gamma rays, it is more energetic. They can even Tear Atoms Apart or trigger Nuclear Fusion! They are also very harmful to our eyes. Radio waves and microwaves have long wavelengths, meaning it carries less energy. That’s why we use infrared instead of ultraviolet for remote control because we don’t want to hurt our eyes in this scenario.
It can also produce Doppler shifts, which is very useful for observations. When an object is going away from us, we see it having a longer wavelength, and vice versa. When it is heading towards us, we see it having a shorter wavelength. That’s because light loses energy as they travel.
Light is the carrier of the electromagnetic force. That means, for example, a proton and an electron exchange photons to keep them attracted.
Credits
- Kurzgesagt — In a Nutshell, “What is Light”, Oct 15 2015, Youtube, https://www.youtube.com/watch?v=IXxZRZxafEQ
4 comments
Is black color exist?
Is black color exist?
Well, it is both a colour and not. While we see black as a colour, we are actually seeing no or little photons going into our eyes.
Well, it is both a colour and not. While we see black as a colour, we are actually seeing no or little photons going into our eyes.