My best mate in the navy is guard one of these. He told me "you know how in cartoons, nuclear reactors are shown with green lighting? Well in real life they are blue" amazed to finally see it.
This is called Vavilov Cherenkov radiation (commonly just called Cherenkov radiation for short.) The important concept to grasp before I explain it is that “the speed of light” is a misconception. When people say “nothing travels faster than the speed of light” the part they leave off is that “nothing travels faster than the speed of light in a vacuum.” The “speed of light” depends on what the light is traveling through, for instance light is slower to travel through water or a gas than it is traveling through “empty space.” So what you are seeing here is the effect that occurs when a physical particle holding a charge (like an electron or proton) being emitted by the reactor travel faster than the phase speed of light travels through the coolant of the reactor. The phenomenon was first theorized by an English scientist in the late 1800’s but wasn’t recorded to be experimentally produced until over 50 years later by two Russian scientists.
The speed of light IS constant. It's just that when it travels through material it has to take a longer path around the atoms. The photon itself never slows down.
Hmmm... yes and no. There is ongoing research into that very fact, and many are currently theorizing that it is not. Even Einstein wasn’t explicit that C in vacuum was constant. But if we put that asides- when we refer to c, we are not referring to the particle speed of light, but the propagation of light waves. In a vacuum- c is thought to be a universal constant. However, when light travels through a material, the refractive index of that material alters the speed at which light may travel through it. Light travels almost 100,000kl/s slower through most glass than through most air for instance. This is the “bending” of light we can see from things like a lens or light shining through water. It takes light an almost imperceptibly longer time to reach you through the glass of a bulb that the spark of a lighter activated at the same time. We can even “freeze” light in experimental conditions. The speed of light in a vacuum has not been disproven as constant. The speed light...
.... travels a given distance has been proven to be able to be altered based upon what the light is traveling through. Currently we do not have proof that undernidentical circumstances (ie: light traveling through the same pane of glass) that subsequent light travels at a different speed through identical media- but “the speed of light” is still dependent on what that light travels through, and not all light in all circumstances will be going the same speed as all other light in the universe.
I would not entirely agree. The fact that it takes light longer to travel through a medium does not mean that the photon is actually slowing down. It wouldn't make sense for light to slow down just because it enters a cluster of molecules (unless it's extremely dense and able to warp spacetime). The photon doesn't care what's around it as long as it doesn't run into anything. Given that a photon is masless and thus forced to move at the speed of light it makes more sense that rather than slowing down it gets reflected, absorbed and re-emitted by surrounding atoms. The act of which takes time and that's the measured decrese in speed.
You make a good point, but we are not discussing the speed of a photon, “the speed of light” refers to the speed at which a light wave crosses a certain distance. Imagine that you and I are both going to the same place. We take alternate routes that are the same distance, but my route has lots of pot holes. You arrive in 10 minutes, I arrive in 20. Since we traveled the same distance, but I took longer- I would be “slower” getting there than you, and my average speed would be half of yours. If we use the analogy of a “maze” in which you may go from point A to B unobstructed, but I must navigate a labrynth to do the same- if we are traveling the same “speed” you would only get to point B before me if the maze was a longer distance right? But we can measure that over the same distances traveled that in different mediums, light waves will take different times to go identical distances from point A to B.
Of course, I am but a stranger o the internet, and it is your inherent right to disagree regardless of my status. It so happens though the good people at the physics department at UC riverside research, and most others in the field would agree with my assessment. If you have some compelling evidence to the contrary however, you could revolutionize our understanding of physics, and I would be quite interested. There is a character limit, so Here are some sources with interesting information on the not so constant speed of light waves:
http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/speed_of_light.html https://io9.gizmodo.com/scientists-freeze-light-for-an-entire-minute-912634479
As a kid I always think that nuclear power is something fancy like magnet or something like that.
But as I grew up I learned that its just boil the water and spin the turbine.
I know what you mean. When you are young you think there’s some special kind of high tech gizmo that somehow “extracts” “nuclear energy” like an old sci fi show. Then you learn that “nuclear reactions are hot. We boil water with the heat, the steam turns a generator...” and you’re just like..... “really? That’s what the big deal is about?” It falls to the universal rules of life that without “luck” or privelage everything we want is either more effort than it is really worth, or more effort than we think it should take, and all returns are diminishing. For a 2x improvement it takes 8x effort, and once you have that 2x improvement it will take 16x effort to get another .08 improvement.
http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/speed_of_light.html
https://io9.gizmodo.com/scientists-freeze-light-for-an-entire-minute-912634479
But as I grew up I learned that its just boil the water and spin the turbine.
Gotta turn it into electricity somehow.