#CuriousAboutLight: 🤔 Have you ever wondered why light is so special in Physics? Let me break it down for you!
Hey there! 👋 I couldn’t help but get curious about what makes light so unique in the world of Physics. I mean, it’s not just fast – it’s the speed limit of the entire universe! 🚀 Plus, it holds a key role in so many equations and theories. But why is it always light calling the shots? 🤷♀️
You see, when we look at the fabric of space-time, it’s like a big, stretchy blanket. And how fast you’re going compared to the speed of light can really change the shape of that blanket! 🌀
So why does light have all this power? Why is it THE phenomenon that shapes most of what we know in Physics? 🤔
Let’s dive deeper into the world of light together and uncover what makes it so special. 🌟 Share your thoughts in the comments below! Let’s solve this mystery together! 💡 #LightMystery #PhysicsFun #LetsLearnTogether
Light isn’t special, at least not in the way you’re asking it to be.
The speed of light is, in fact, the speed of *causality.* It’s the speed that *any* massless particle, or field wave, will travel. Gravitational waves also propagate at *c* (in other words, if the sun suddenly disappeared, Earth would continue orbiting it for eight minutes). If something is one light-year away, there is absolutely nothing you can do that will have any effect on it in less than one year.
We call it “the speed of light” because light was the first thing we realized was going that speed.
We call it the speed of light because we only later realised that the speed is much more fundemental.
Any massless particle will be traveling at the speed of light, and massive ones will always be slower. It is more appropriate to call it the cosmic speed limit or maximum possible speed. As often in science what stuff is called is affected by our history of discovery.
The second part is where light is special is in particle physics. There forces need particles to transmit them. Here the electromagnetic force just so happen to be transmitted by photons.
In general light just interact with alot of things, making it very important for exploring the world, whether you are going for a walk or determining the elemental composition of a distant galaxy.
Because light is a very good reference point when talking about something like relativity. No matter what speed you’re going, the speed of light stays *constant.*
A good example I always heard was the baseball metaphor. Pretend you’re standing at the back of a moving bus going 20mph. You throw the ball towards the front at 20mph. Well, relative to you it’s going 20mph, but to somebody on the outside, the ball is going 40mph.
Light does not do this. Lets say the bus is still going 20mph and you are standing in the back and shine a flashlight towards the front. Well, according to the baseball method of adding it, the light should be going 20mph+C, right? No, it doesn’t since nothing can necessarily exceed the speed of light, and you cannot really ‘accelerate’ light, so the beam cannot go faster than the speed of light already is. The difference between this and the baseball metaphor, relative to you ***and*** the person outside the bus, the light is moving at the exact same speed.
This is why it’s super important, it’s essentially the only thing in the universe that stays constant no matter the reference point. Just like you said, it stays constant across every formula and equation you can think of.
Light(=photon) is massless (as of today), and it’s possibly the only fundamental particle that have this characteristic. I’d it’s what it makes light so special. That said, any fundamental particles are special.
As far as know there are 4 fundamental forces in the universe. Every other “force” is based on these 4. Two of those fundamental forces act on VERY small ranges (ie less than the size of atoms). The other ones are gravity and electromagnetism.
Gravity requires a LOT of mass to work but it extends to very long distances. It keeps planets orbiting stars, gives us the weight we feel on earth. Because of this, at human levels, gravity is generally felt as a “constant”. For us, it pulls us and all the stuff on earth towards the ground. We don’t “feel” the gravity of the sun etc because earth’s gravity is large enough to make all other sources of gravity generally irrelevant day to day (except for tides – caused by the moon in ELI5 terms)
The last remaining force electromagnetism is what causes all the other interactions that we study. Electromagnetic forces can operate at “medium distances” and “medium strength”. This is very useful because nearly everything humans do are at this scale. Things like chemical reactions, why we don’t fall through our chairs, what makes electricity and magnets work, radio waves, light, human biology and physics – all of these are basically various forms of electromagnetism in operation. The object that “carries” electromagnetic forces is the photon. Some photons interact with our eyes and we call it light. Many other varieties of photons are not visible to humans. Since pretty much everything that we experience except gravity operates through photons, knowing how it works is pretty much the bulk of physics.
Now this doesn’t explain WHY it is this way. It is this way because the universe appears to work this way.