Etimology "Червен|ков" - Червен- means "red" in many Slavic languages, and "ков" is put at the end of Slavic names to indicate belonging, a direct translation would be "Red's". I find this a bit ironic since he wont a Noble price for finding the energized blue glow, named after him but, which in fact is blue. lol
Cherenkov was not the first who explained this phenomenon, he was the first to observe it. The theoretical explanation of the phenomenon was given by I. Tamm and I. Frank in 1937.
@fermilabvms (1-2) "The ratio between c and the speed v at which light travels in a material is called the refractive index n of the material (n = c / v). For example, for visible light the refractive index of glass is typically around 1.5, meaning that light in glass travels at c / 1.5 ≈ 200,000 km/s; the refractive index of air for visible light is about 1.0003, so the speed of light in air is about 90 km/s slower than c." ~Wikipedia cont...
Basically, in oil say, light can only go a certain speed. Not as fast as the actual speed of light in a vacuum. So when a particle enters the oil from a vacuum, it is momentarily travelling to fast. Not faster that the fastest speed of light, but faster than the light can go in that medium. Was that an all right explanation?? So it must lose energy, and it does so by the emission of a photon.
that awkward moment when a duck swims by, effectively ruining your experiment, while you're demonstrating cerenkov light with pebbles and a body of water
This helped explain the 'why' and 'how' of Cerenkov radiation, but to the layman, the 'what' is totally unaddressed. Thirty seconds of the Penn State or the Advanced Test reactor explaining that there are no light sources on in the pool, yet the core glows brightly due to Cherenkov Radiation would have accomplished this. Tack it on to the beginning and you're all set.
Several years ago, I worked on some electronics for a high energetic particle instrument that used a Cerenkov detector. The detector used a crystal instead of water or oil. Never found out what the crystal was, Maybe you might know?
Can this effect happen in gases? Can it happen in air? And since, as we are told by physicists, space is not total vacuum can it happen in space, possibly when particles are pulled in by a black hole?
what gives light its thrust to move at the speed of light. Or is light moving at light speed at the moment of creation. Ive always wanted to know why light moves at that high rate of speed without a motor or energy source?
Forget black hole idea since everything would be getting pulled in at the same rate then there would be no travelling through any medium, since the medium would be under the influence of gravity of the black hole. But I would still like to know what densities does this effect come into play. Can it happen in a solid or perhaps plasma?
Are you trolling? I think you got the formulas wrong. The refraction index of a medium is bigger or equal to 1. n = c/v, so what I'm saying is that v (the speed of light in that medium) is always less the c (speed of light in vacuum). So if I have v < c, I can have a particle with a velocity (let's call it vp) bigger than v and also smaller than c. What I think you did is mixing the velocities of light in a medium (v) and the velocity of a particle traversing the medium.
Basically, in oil say, light can only go a certain speed. Not as fast as the actual speed of light in a vacuum. So when a particle enters the oil from a vacuum, it is momentarily travelling to fast. Not faster that the fastest speed of light, but faster than the light can go in that medium. Was that an all right explanation??
I don't get it. So if there was a mechanism set up to transmit two things in opposite directions but was somehow made so you don't know exactly which directions it will go in then "information" is being transferred between the two things being set off? I thought it just depended upon the mechanisms involved? Hence no need for the photon to 'know' the other photon is going in a particular direction as its set up to be launched in the direction that it's going to go in with the mechanism just happening to determine that its partner will go in the opposite direction. Now maybe there is no physical evidence of mechanisms but they could be so microscopic we can't detect them. Although the entanglement thing I get how that's information going faster than light.
Yes, energy is being given off from the interaction of the photons with the atoms of whatever medium they are passing through, which 'creates' the light from the atoms losing energy. Photons just kind of spring into existence when electrons move from energy levels in the atom. Its weird quantum stuff
One weak spot of the explanation, at 4:00 the narrator says that particles produced are traveling faster than the speed of light in the water or oil. He should explain that the speed of light is slower in some mediums (like water or oil). The particles aren't actually going faster than "the speed of light" but rather faster than the light can go in the liquid medium.
light travels about 25% slower and if you can accelerate a particle (such as an electron) above that phase velocity of light, then it is technically traveling faster than light. Sorry it took so long for you to get a response.
@fermilabvms (2-2) The refectory index of water is n ≈ 1.33881 which is NOT less than one. There is no known medium with a refractive index less than 1, therefore your statement: "Actually, the particles ARE moving faster than the speed of light in a medium (pure oil or water) " is false. My source: refractiveindex [dot] info
The problem is that the narrator uses a sentence whose syntactic structure is ambiguous, permitting two non-equivalent interpretations. The intended structure has [the speed of light in that medium] as a constituent, but an equally possible structure, which many listeners arrive at, has [traveling ... in that medium] as a constituent. I.e., it's not unambiguous whether [in that medium] is (i) a prepositional modifier of [the speed of light], or (ii) of the verb phrase headed by [traveling].
He said "a particle going faster than the speed of light in that medium", which can easily happen. According to relativity, nothing can go faster than light in vacuum, but if light is in a medium, it is slower depending on the refractive index of the medium.
you never know if a particle or some sorrt of unknowen can travel faster its like people hundreds of years ago said its imposible that the world is a sphere until someone has proven different so never say something is imposible!
He said "a particle going faster than the speed of light in that medium", which can easily happen. According to relativity, nothing can go faster than light in vacuum, but if light is in a medium, it is slower depending on the refractive index of the medium.
Assuming c is the cosmological speed limit (and especially as the neutrino is not massless). Cerenkov Light, as defined in this video, can never have been observed. But 'Cerenkov Light' has been observed. Therefore the mechanism presented here as to how Cerenkov Light is caused cannot be correct. If it were correct, then the existence of ftl-neutrinos would not be a supposed anomaly recently detected(maybe) by OPERA but, rather, an already well established, observable fact. But it isn't. FAIL.
This is not good reasoning. If the light propagates in the glass at v_l=c/1.5=~0.66c and the particle moves at the speed close to c (lets say v_p=0.9c), then v_p>v_l , rendering your argument invalid.
He said "a particle going faster than the speed of light in that medium", which can easily happen. According to relativity, nothing can go faster than light in vacuum, but if light is in a medium, it is slower depending on the refractive index of the medium.
That was a well made video, educational, no bullshit and quick to the point , awesome
This was one of the most lucid explanations I have ever seen on CZcams. Thank you.
Are there anymore videos with this narrator ? I like it very much and it's very clear to understand.
Thanks!
Etimology "Червен|ков" - Червен- means "red" in many Slavic languages, and "ков" is put at the end of Slavic names to indicate belonging, a direct translation would be "Red's". I find this a bit ironic since he wont a Noble price for finding the energized blue glow, named after him but, which in fact is blue. lol
Cherenkov was not the first who explained this phenomenon, he was the first to observe it. The theoretical explanation of the phenomenon was given by I. Tamm and I. Frank in 1937.
@fermilabvms
(1-2)
"The ratio between c and the speed v at which light travels in a material is called the refractive index n of the material (n = c / v). For example, for visible light the refractive index of glass is typically around 1.5, meaning that light in glass travels at c / 1.5 ≈ 200,000 km/s; the refractive index of air for visible light is about 1.0003, so the speed of light in air is about 90 km/s slower than c."
~Wikipedia
cont...
Basically, in oil say, light can only go a certain speed. Not as fast as the actual speed of light in a vacuum. So when a particle enters the oil from a vacuum, it is momentarily travelling to fast. Not faster that the fastest speed of light, but faster than the light can go in that medium. Was that an all right explanation?? So it must lose energy, and it does so by the emission of a photon.
that awkward moment when a duck swims by, effectively ruining your experiment, while you're demonstrating cerenkov light with pebbles and a body of water
This helped explain the 'why' and 'how' of Cerenkov radiation, but to the layman, the 'what' is totally unaddressed. Thirty seconds of the Penn State or the Advanced Test reactor explaining that there are no light sources on in the pool, yet the core glows brightly due to Cherenkov Radiation would have accomplished this. Tack it on to the beginning and you're all set.
The narrator, Bob Sauer, sounds great in this video.
Several years ago, I worked on some electronics for a high energetic particle instrument that used a Cerenkov detector. The detector used a crystal instead of water or oil. Never found out what the crystal was, Maybe you might know?
Thank you for uploading this! :)
Loved this video! Many thanks!
Take into account that light travels around 25% slower in say... water, this means it is possible for some particles to travel faster than light.
Can this effect happen in gases? Can it happen in air? And since, as we are told by physicists, space is not total vacuum can it happen in space, possibly when particles are pulled in by a black hole?
0.56 also explains doppler effect .
This video is fantastic, it makes me feel smarter =D
Awesome,really educational !!!!!
what gives light its thrust to move at the speed of light. Or is light moving at light speed at the moment of creation. Ive always wanted to know why light moves at that high rate of speed without a motor or energy source?
I've never thought of that.
@brockunc hehe, you may want to rethink that statement in view of new findings at the LHC.
Forget black hole idea since everything would be getting pulled in at the same rate then there would be no travelling through any medium, since the medium would be under the influence of gravity of the black hole. But I would still like to know what densities does this effect come into play. Can it happen in a solid or perhaps plasma?
Are you trolling?
I think you got the formulas wrong. The refraction index of a medium is bigger or equal to 1. n = c/v, so what I'm saying is that v (the speed of light in that medium) is always less the c (speed of light in vacuum). So if I have v < c, I can have a particle with a velocity (let's call it vp) bigger than v and also smaller than c.
What I think you did is mixing the velocities of light in a medium (v) and the velocity of a particle traversing the medium.
Basically, in oil say, light can only go a certain speed. Not as fast as the actual speed of light in a vacuum. So when a particle enters the oil from a vacuum, it is momentarily travelling to fast. Not faster that the fastest speed of light, but faster than the light can go in that medium. Was that an all right explanation??
I don't get it. So if there was a mechanism set up to transmit two things in opposite directions but was somehow made so you don't know exactly which directions it will go in then "information" is being transferred between the two things being set off?
I thought it just depended upon the mechanisms involved? Hence no need for the photon to 'know' the other photon is going in a particular direction as its set up to be launched in the direction that it's going to go in with the mechanism just happening to determine that its partner will go in the opposite direction.
Now maybe there is no physical evidence of mechanisms but they could be so microscopic we can't detect them.
Although the entanglement thing I get how that's information going faster than light.
They have said recentely that Opera has comitted an error and neutrinos can't depass light speed..
Why is the light emitted? Is it like conservation of energy or something?
nice explanation
Yes, energy is being given off from the interaction of the photons with the atoms of whatever medium they are passing through, which 'creates' the light from the atoms losing energy. Photons just kind of spring into existence when electrons move from energy levels in the atom. Its weird quantum stuff
One weak spot of the explanation, at 4:00 the narrator says that particles produced are traveling faster than the speed of light in the water or oil.
He should explain that the speed of light is slower in some mediums (like water or oil). The particles aren't actually going faster than "the speed of light" but rather faster than the light can go in the liquid medium.
THANK YOU!
I still don't get it. How come it can go faster than the speed of light (in that medium).
Nothing can beat light on speed.
light travels about 25% slower and if you can accelerate a particle (such as an electron) above that phase velocity of light, then it is technically traveling faster than light. Sorry it took so long for you to get a response.
very nice and almost self explainatory
@fermilabvms
(2-2)
The refectory index of water is n ≈ 1.33881 which is NOT less than one.
There is no known medium with a refractive index less than 1, therefore your statement:
"Actually, the particles ARE moving faster than the speed of light in a medium (pure oil or water) "
is false.
My source:
refractiveindex [dot] info
The problem is that the narrator uses a sentence whose syntactic structure is ambiguous, permitting two non-equivalent interpretations. The intended structure has [the speed of light in that medium] as a constituent, but an equally possible structure, which many listeners arrive at, has [traveling ... in that medium] as a constituent. I.e., it's not unambiguous whether [in that medium] is (i) a prepositional modifier of [the speed of light], or (ii) of the verb phrase headed by [traveling].
Dude, as a non-native English speaker I didn't understand what have you wrote while I understood the video about some sort of quantum mechanics.
this music sounds at the start reminds me of shenmue.
fuck i miss my dreamcast for tht game
but the charge is not accelerating !
its misspelled.
I have been taught that NOTHING, absolulety NOTHING in this ff universe can travel faster than the speed of light. Has that CHANGED?
He said "a particle going faster than the speed of light in that
medium", which can easily happen. According to relativity, nothing can
go faster than light in vacuum, but if light is in a medium, it is
slower depending on the refractive index of the medium.
nothing moves faster than the speed of light IN VACUUM! When we are not in a vacuum, light moves slower.
To be quite honest it can be any particle.
you never know if a particle or some sorrt of unknowen can travel faster its like people hundreds of years ago said its imposible that the world is a sphere until someone has proven different so never say something is imposible!
But I thought nothing can go faster than the speed of light.
He said "a particle going faster than the speed of light in that
medium", which can easily happen. According to relativity, nothing can
go faster than light in vacuum, but if light is in a medium, it is
slower depending on the refractive index of the medium.
Only in the vacuum.. (but also this theory is invalidate by recent discoveries)
lol my family name is derenkov
Assuming c is the cosmological speed limit (and especially as the neutrino is not massless). Cerenkov Light, as defined in this video, can never have been observed. But 'Cerenkov Light' has been observed. Therefore the mechanism presented here as to how Cerenkov Light is caused cannot be correct. If it were correct, then the existence of ftl-neutrinos would not be a supposed anomaly recently detected(maybe) by OPERA but, rather, an already well established, observable fact. But it isn't. FAIL.
This is not good reasoning. If the light propagates in the glass at v_l=c/1.5=~0.66c and the particle moves at the speed close to c (lets say v_p=0.9c), then v_p>v_l , rendering your argument invalid.
Why am I watching this? I got lost in the depth of the Internet
you had me until you mentioned a particle going faster than the speed of light.
He said "a particle going faster than the speed of light in that medium", which can easily happen. According to relativity, nothing can go faster than light in vacuum, but if light is in a medium, it is slower depending on the refractive index of the medium.