Light, is the connection between us and the universe. Through light, we could experience distant stars and look back at the beginning of existence itself. But, what is light? In a nutshell Light, is the smallest quantity of energy that can be transported A photon, an elementary particle without a real size That can't be split, only created or destroyed. Light also has a wave-particle duality being kind of a particle and a wave at the same time (although this is a lie) Also when we say light, we actually mean visible light which is a tiny part of the electromagnetic spectrum: energy in form of electromagnetic radiation. Electromagnetic radiation consist of an enormous range of wavelengths and frequencies. Gamma rays have the smallest wave lengths because they are the highest energy photons. But most gamma rays are just under ten picometers, which is still way smaller than a hydrogen atom. For reference, a hydrogen atom compared to a cent is about as big as a cent compared to the Moon. Visible light is in the middle of the spectrum in a range of about 400 nanometers to 700 nanometers: about the size of a bacteria. On the other end of the spectrum, radio waves can be up to 100 kilometers in diameter. The biggest wave lengths we know exist can span from 10,000 kilometers to a baffling 100,000 kilometers, way larger than Earth. From a physics stand point, all these different waves are the same. They all have the wave-particle duality and travel at 'c', the speed of light, just at different frequencies. So what makes visible light special, then? Well... Absolutly nothing. We just happen to have evolved eyes, that are good at registering exactly this part of the electromagnetic spectrum. This is not a complete coincidence though. Visible light is the only set of electromagnetic radiation that propagates when in water, which happens to be where most eyes first evolved, millions of years ago. That was a smart move, because light not only interacts with matter, it's also altered by it and can be used to gather information about the world around us,with almost no delay. Which is arguably really helpful for survival. Okay, where does light come from? A vast range of electromagnetic waves are created when atoms or molecules drop from a higher state of energy to a lower one. They lose energy and emit it in the form of radiation. At the microscopic level, visible light is created when an electron within an atom in an excited state drops to a lower energy state and loses this excess energy. The same way, incoming light can elevate an electron to a higher state of energy by being absorbed by it. Macroscopically, the moving charge of the electron creates an oscillating magnetic field, Which creates an oscillating electric field perpendicular to it. These two fields move themselves through space, transferring energy from one place to another, carrying information about its place of creation with it. Why of all the things in the universe is light the fastest thing there is? Let's change the question: What is the fastest way to travel through space in the universe? It's c, exactly two hundred ninety-nine million, seven hundred ninety-two thousand, four hundred and fifty-eight metres per second in a vacuum, one billion kilometres per hour. Electromagnetic radiation just happens to move this fast. Any particle that has no mass travels at c, without acceleration or any in between. The light that has released from a candle does not speed up until it reaches light speed, At the very instant of its creation, its speed is c. So why is c, the speed of light, finite then? Well, nobody knows. Our universe is just built this way. We don't have the smart answer here. So light is part of a spectrum, an elementary particle that also behaves like a wave, Propelled by two perpendicular fields, travelling at the speed limit of the universe. Okay, that's nice and all, but what about the crazy stuff about travelling at the speed of light, and time, the twin paradox, quantum stuff, things like that? We would have to save them for another video. For now, let's be happy that we've evolved eyes that pick up waves of information permeating the universe. Making us see things and put our existence into perspective.
I love the play on hexagons way too much. It looks so fun.
Edit: Mind telling us what the killed video was about? I'm curious.
Some honest feedback:
This video spits out a lot of information about light and photons. While watching the video, I couldn't really determine what the goal of the writers was, other than ramble some facts about photons and light. I don't think I could've followed this if I didn't know it already. I also think the video didn't do a very good job of explaining what the "frequency" of light is, and how the frequency has nothing to do with the speed of the photon.
Other than the writing I have a small remark about the animation around 1:00. I feel like 'switching pages' isn't helping in visualizing the different scales of the wavelengths. Maybe they could've zoomed in and out. I felt the asteroid was very small until I read "~100 kilometers".
Note: I didn't dislike the video, I just think these things could improve :)
Love the Distance to scale scene.
Oh love the new style. Hexagons are my spirit shape, they are so stackable. Also, done with translation!
I love this series! Very interesting so far!
Baby don't hurt me.
Hmmm
You sure do manage to explain a lot in a very short amount of time. Although I'm sure this is generally a good thing, I think that this video seemed to give too much information. Many people have no background in physics and are surely confused by a lot of the terms you throw at them. There's a lot of really advanced physics involving light and the propagation of it, and if you have no reference for all of this physics, you might just get confused and won't understand much of what's going on.
I think you tried to pack a bit too much physics into this video (Understandable - it's all so freaking awesome) but thereby making it less understandable to the general public.
Or it might just be me, I 'unno :/
Awesome video as always. But I have a suggestion: is there any way you can include the subtitles with the video? Not the automatic captions, but subtitles identical to the script. This will help a lot anyone willing to perform further researches on the content, and I am talking here about non native English speakers. Thanks for enLIGHTening us ;)
Light? That's a word!