How To Go Faster Than Light Speed (Seriously…)
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Nothing can travel faster than light - in a vacuum. But when light slows down, sometimes matter can blaze past that speed limit, creating a stunning glow called Cherenkov radiation. We can see this glow in a nuclear reactor as high-energy particles speed by. It offers us a window into a realm of the universe that is usually invisible to us.
Filmed at the J. J. Pickle Research Campus at the University of Texas at Austin
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0:00 A strange blue glow
1:24 How to slow light down
3:19 The right way to think about light
5:41 How to make a photonic boom
7:51 Who discovered this?
8:25 Why this matters
9:45 Extras!
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This episode of Be Smart is licensed exclusively to KZhead.
Nuclear reactors are cool. This might be the coolest thing about them. Thanks for watching! I hope I've earned your like and subscription. If you'd like to help me make videos like this one, check out the link to the Patreon in the description!
Ha ha
I mean, nuclear reactors are the exact opposite of cool... they're hot! that's the whole idea XD
Tacobell has the ability to travel faster then light speed.......
If neutrinos are producing Cherenkov radiation, they should be losing speed. Where are all the slow neutrinos? Why haven't we found them?
Sometimes I wonder why I watch these videos Most of the informations goes above my head 😂 but still these attract me and yeah I love biological videos rather than physics 🙃
Gotta love how Joe just casually sits atop a nuclear reactor
Why would that be an issue? Nuclear power is perfectly safe, and with that volume of water, the background radiation is much higher than what's coming from the reactor.
@@maxwyght1840 It's not perfectly safe, but yeah, water is blocking the radiation here.
@@maksphoto78 people swim those pools all the time to perform maintenance. So yeah, it's perfectly safe. As long as it wasn't built by communists.
Lol exactly. I was worried through the whole video that he was gonna fall in. Lol. I can't tell if it was just the way it was filmed, but could someone fall in there?!
This is small nuclear reactor, for test so it not much radiation, also water is the best shield
As a particle physicist, I appreciate this video. Cherenkov radiation can be used to measure the speed of a high energy particle traveling through a medium as well as to distinguish types of particles such as electron vs muon.
The muons just existing cuz of time dilation?
Cosmic ray muons are from economic necessity given how expensive particle accelerators are even if Inai has a Japanese patent on ground based muon particle beams to supply rocket engines in flight so for relativistic spaceflights a ship and crew would turn into meson particles to sink into gravity wells and burst with force of a supernova.
Just a random question of someone that isn't physicist: If Cherenkov radiation is the "echo" of the light of a high energy particle and can be used to measure the speed of that particle, why can't we break the uncertainty principle with it? Measuring it's position and then using the "echo" to determine its speed?
@@ThiagoFer93 No physical quantity can be measured with 100% precision. You can measure the position and the momentum, just cannot do it precise enough simultaneously to break the uncertainty principle.
does it work for neutral particles? because from the explanation from the video, it seems like it has something to do with its electric charge as well.
to anyone wondering how joe is still safe; the water between him the the rods is protecting him, even if he was in the water he would be alright, there's more than actually needed, to be extra safe
True water blocks radiation very well, why else is water inside space stations’ walls but to protect you inside, ask any person at nasa about radiation in space and the answer is just water, except the janito ofc
Hot tub :D
@@threemooseqateers9689 Forbidden hot tub
@@vaingloriantbut not cuz radioactivity, you just ain’t allowed cuz it’ll make the water dirty (also it’s more a cool tub)
This is why I quite like 'Speed of Causality' for light speed in a vacuum. I think its clearer, or at least gets people asking the right questions.
I agree 👍
True. My car can go faster than a Lamborghini... through a car wash.
@@CheatOnlyDeath i can go faster than any airplane, if we are both in water
Yes!
That‘s why it‘s called c, right?
I've seen the Cherenkov effect myself, on top of a pool of water with a small reactor core below too. It's beautiful. But I thought it had to do with neutrons shooting into the water, so you've corrected this mistake in my mind. Thank you. A shockwave of light, that's awesome!
I think that happens too. Like at the IceCube Neutrino Observatory in Antarctica...
@@Leboybandent I was thinking about neutrons, not neutrinos. Anyway, that is interesting, since I understood from the video that the effect is caused by charged particles.
@@gastonpossel Oh I misread.. but yeah that is interesting.. need to look up how the emission from the neutrons passing through water happens!
Photonic wave
@@Leboybandent "Neutrinos are detected in water Cherenkovs when they interact by W exchange, converting into the equivalent charged lepton (muon or electron for νμ or νe respectively), or when they elastically scatter off electrons (when the recoil electron can be detected)."
Cherenkov radiation in a spent fuel pool is genuinely one of the most beautiful things ive seen, truly unforgettable
It's also one of the most horrifying. Considering you're talking about spent fuel that means we can't use it's energy for anything useful anymore even breeding useful material through neutron bombardment. It's still way too energetic to just store without active cooling & supervision & even after the blue glow disappears we have to store it far enough from anything it could possibly contaminate and spread to affect the environment for longer than all of human history.
@@dieseltechie7830 Wow, that is utterly untrue. Spent fuel from traditional reactors is actually about 5% consumed. There is enough energy in 'spent' fuel reserves to power humanity for about 500+ years with more efficient reactors. The best and ONLY practical way we have to get rid of nuclear fuel waste is fast neutron reactors. Why didnt we use them in the first place? they dont produce enough of the nuclear waste they wanted to make weapons.
@@mycosys And when the technology was finally explored, anti-nuclear activists were not happy, for some reason. Like, here in France we had two, Phénix and Superphénix, two prototypes of fast neutron reactors, and inarguably two successes. During its construction, Superphénix was the target of an unclaimed terrorist attack. With a rocket launcher. It was shut down in 1997, despite a stellar 1996, because of the "ecologists"
@@mycosys That's not entirely correct reasoning, fast spectrum reactors are perfectly capable to produce weapon material via breeding. Matter in fact they are much better at it than the commercially used moderated reactors, because those don't necessary need fuel reprocessing or at least not as extensive to acces the materials.
When I was a kid, my friend Todd used to steal Red Bull from his dad and we would ride our bikes faster than the speed of light. We had fun observing the relativistic effects as our velocity increased. Time always seemed to fly by. We'd get started in the afternoon, and by the time we got home, dinner had been over 40 years ago. Those were good times.
I thought red bull gave you wings, not bike powers?
fr fr i can relate
@funkytrickster618 It’s the new line of Redbull they released, didn’t you hear?
@@SuperMarioOddity red bull breaks realityyyyy~
This read like a quote from a novelist
I absolutely love that you also showcase how chill you can be around a nuclear reactor. Yes, it's small, but ALSO it's built such that you can absolutely sit right there and be perfectly fine, even if you did fall in. I'm also giggling a lot, because the first time I learned about Cherenkov radiation was after it was mentioned a little (possibly infamous) article called "Man of Steel, Woman of Kleenex" by Larry Niven...
You can showcase getting a lethal dose of radiation while remaining absolutely chill 😂 Filming it without camera distortion is harder though.
@@singularityscanwell it’s still not lethal in most cases; I’ve been to a reactor; I’m not even in university/college
Great video, Dr. Joe!!! Just one thing: at 8:27 it's implied that you can use Cherenkov radiation to detect neutrinos, but technically neutrinos can't produce Cherenkov radiation because they have no charge. The neutrino has to decay in other particles in order to be able to produce Cherenkov radiation.
You can use it for neutrinos, in that case muons or electrons are first created which in turn do have a charge and thus it can be detected the same way
this is sure the best time to be living in, just think how much information we normal people have access to, which would be a dream for a scientists back then, thank you for explaining such a complex thing in a very easy way
One of the most beautiful things I have ever seen. Going to a nuclear power plant while studying Physics at university. Cherenkov radiation makes all the water light up. Really magical.
9:41 as a fellow dude i can confirm we all wanted to jump into it
Thanks for giving me that '"click" Oh, I get it now!' moment. Such a great feeling
The best!
Superbly well explained. Well done😊
Pretty enlightening.
Thank you so much! I have said this before but everything having to do with light/EM-radiation and colours and wave-physics is my all favourite! I had heard all the false explanations before and realized that they couldn't be true but never knew the true explanation, thanks again for that! And what a great addition it was to talk about the Cherenkov detector used to study the cosmic high-energy particles. Keep up the good work Joe and team
I love these quirks of physics!
Wait how was this 2 days ago
Its not a quirk of physics. Light is not decelerating
quark quirks!
@@tri-ify8852 Patreon innit.
@@rykehuss3435 light changing speed when it changes medium is a quirk of physics.
Great, just great visuals. Thank you for the constant quality!!
I'd need to watch it twice or even thrice to understand it better. Also the analogies were great especially the duck going at turbo speed and the ripples behind it bunching together. Something just clicked in my head then. (English is not my native language so my bad if something feels off in my wording) I love these videos.
Your English is amazing! I wish I could speak more languages. As an American, foreign languages aren’t taught well here. I know most other places teach a few languages throughout all of their schooling. In America, we touch on Spanish a couple times and move on.
9:35 what did he say? Shedding light. Oh. Shedding. That's not what I heard at first.
The reason my brain isnt hurting is because youve done an excellent job at explaining it
This is really cool! I knew about Cherenkov detectors (although not necessarily by that name) and how they give off light when particles pass through the water, but I'd never had a detailed explanation of *how* and *why*!
I think we should call it a superluminal shock wave, it sound cooler than photonic boom, and its also a better description of what is actually happening
I’d love to see a collaboration with Be Smart and PBS space time.
Excellent video. It's astonishing how you (all of you, include the animators!) succeed to explain such complicated issues.
This was an excellent explanation of light and Cherenkov radiation!
Finally needed a tutorial on this.
A video on neutrino detection would be awesome! Great video btw.
At 6:02 the positive partial charges of water are at the hydrogen atoms. Wouldn't the molecules turn their positive parts (hydrogen) to the passing electron (which is negative).
Great video. I had no idea this is how Neutrino detectors work.
That's the warp core
Like the video, one quick correction would be the graphic at 6:00 is slightly off, the positive end of water is the hydrogens, so that's the thing that would be attracted to the negative electron, not the oxygen as is shown.
So clearly explained! Thanks 🙂
I'd love it for Joe to explain more about microcurrent in a longer form video! The foreo bear explaination was wonderful
One interesting thing to think about is that the Cherenkov effect in case of the nuclear reactor is due to the interaction of the charged particle and the water molecules and the subsequent "piling up of the ripples of light", then how do the Cherenkov detectors work in case of neutrinos which do not interact with matter? Actually, they DO interact with matter, albeit rarely. The neutrinos interact through weak force which is very short range. And since these neutrinos are high energy as well, one can imagine the rarity of these interactions.
sience like this always gets me hyped up like a jet turbine
You have the most amazingly good job - and you're incredibly good at it too. Staying curious.
Such an amazing episode!
This video has the best clickable but not clickbait title in the history of KZhead! It's immensely provocative and on its face, seems easily disprovable and yet it's 100% accurate and scientifically provable. Prodigious! You are clearly a man of sagacity and wit. 😎
This Danish lady professor slowed down light so much you could walk past it, Joe. I don't think this is what people have in mind when they talk about "traveling" faster than the speed of light 😀
Thanks for this bro.
I feel like more people need to see this just to understand how safe nuclear reactors are
Hey! Great video! I have 2 questions: 1. In the portion where you explain Cherenkov radiation with electrons (5:58 to 6:25) the water molecules are re-orienting themselves due to the electric field the electron is giving off. I was just wondering whether the re-orientation of the water molecules was correct, since the e- is negative, and the water molecule being polar, the positive side (Hydrogen side) would be facing the e- as it went by. In the video the negative side of the water (2 pairs of e- on the O) face the e- as it goes by. Let me know if I am wrong or if it is due to other facotrs, such as the magnetic field the moving charge produces, or perhaps the field the e- produces is very small compared to the field the other water molecules produce and so it is a relativley small change etc. 2. Lastly, I don't fully understand why the neutrinos produce Cherenkov radiation. I understand the e- doing it, since it interacts with the Electromagnetic force with it's neighbours (water), producing EM waves. However, as you stated in the video, neutrinos don't interact electromagnetically (since they are neutral charge), therefore I don't see how they can produce light. Perhaps it is a different sort of Cherenkov radiation, produced by other mechanisms such as the weak force, which eventually produces EM waves (Cherenkov radiation) Many thanks, again great video I enjoyed it alot!
1. I think you're right. 2. "Neutrinos are detected in water Cherenkovs when they interact by W exchange, converting into the equivalent charged lepton (muon or electron for νμ or νe respectively), or when they elastically scatter off electrons (when the recoil electron can be detected)." I got this from another comment.
Would the temperature of the water affect the color? I love how out of the entire spectrum it just happens to have the right energy to be bluish white instead of most of the spectrum being not visible.
No, at least not in the perceived wavelength. There is a correlation of refractive index and temperature and a correlation between the refractive index and the maximum frequency that is emitted. But this would have no effect in the perceived colour of the glow.
The charged particles are moving toward the top of the tank so the light is blue shifted. If you could see the particles moving downward through the water they would be red shifted since they are moving away from the observer. 😉
Wanted to know that thanks, actually much more straight forward than I expected
Learned so much from this video. Thanks.
But Joe, nothing can travel faster than the speed of light!
I see what you did there...
To go faster than the speed of light you just need to be r34 artist
I want to understand this, but something tells me it’s better I don’t
@@joshuaosei5628 good intuition.
The speed of darkness on steroids.
@@joshuaosei5628 Rule 34: If it exists, there is porn of it. You can commission a "r34 artist" to create pornographic images of whatever you want. That being said, drawing pornographic matter going faster than the speed of light isn't the same thing as actually being faster than the speed of light, so I must admit I don't really understand what the joke is either, even though I know what a r34 artist is.
@@ryangainey94 Thanks for the explanation. I guess the joke was that people must be very quick to make the porn of that fandom or idea, and so they’re so fast they “go faster than the speed of light”
Great video thank you 🙏🏻
I just learned so much!
I like that since it's 2023 it's completely acceptable to casually use stock death metal music in your science education video
Oh I've been droppin' death metal stings since at least 2019
We only need more stock death metal in science education :))
@@besmart oh you know what you're right LOL
A light-boom?🤔🧐 Makes sense. Also, I never new there was anything that could move faster than the speed of light. That’s pretty cool.
Flash: am i a joke to u?
Actively, not cause the e= mc² But space could technically could be faster. Like light has no mass, space doesn't really need (added) energy to exist or accelerate. It's in homeostasis technically.
This idea intrigued me and I searched a bit, it seems the term used is "photonic boom". Although maybe "photonic flash" would better capture the redundancy present in the original term
This is fascinating 👍
amazing I never knew about this awesome!
Imaging going faster than light speed and not even be able to flex about breaking the laws of physics
Light does not decelerate. Its still traveling at c, even in water. It just takes more time since the photons are constantly being absorbed and re-emitted by the atoms of said medium.
The speed of light is already variable.
The speed of light != C C is not always equal in all space, as gravity affects the local constant, because all dimensions change and distort.
My theory dwarfs all of the vaccum, constant & dimensional limitations. I can actually prove it with a small diagram, but ideally, I'd like to further test on a simulator.
@@wolvenar Wrong. The speed of light is always the same, even in mediums. It is not variable. Photons in water still travel at c, they just bump into atoms and get absorbed, re-emitted and then sent on their way. Photons cannot decelerate, anything with rest mass will ALWAYS travel at c. If you disagree then go ahead and disprove theory of special relativity.
@@rykehuss3435 You might want to find out what happens mathematically to C and all the dimensions as you approach a gravity well, now work that relative to a second observer from a position well away from the gravity well.
@@wolvenar Nothing happens to it. You might want to find out about general and special relativity.
The opening scene is soo satisfying...
Thanks for your sharing
The trick is not going faster than c. The trick is slowing down light in water...
…………..god forbid they make a video to educate people that don’t know…………
@@MNSalty Then maybe without such pathetic clickbait
@@phoenixsmaug1568 agree
@@phoenixsmaug1568 just 1:30 into the video he clarifies the meaning of the statement
@@phoenixsmaug1568 Meeh it's ok if more people are going to learn because of it, I think
I feel clickbaited
Great video, that glow is so cool and now I have a better idea of how those giant detectors work.
Whoa dude. Youre blowing my mind right now
Can't help but imagine you oops-ing right into that reactor.
I simply just run really fast.
Or take the shortcut.
WOW, EPIC video!!! Thank You!
Today I learned more about light. Thank you.
Thank you for teaching us about Cherenkov "thingies".
Great video Thank you
Now that is fascinating!
Just found your channel from the rainbow video and have commenced my weeklong binge of the backlog. Great stuff keep up the great work Joe!
I wish I had you as a science teacher! ❤
Like how you went full glowing Mr Burns at the end there! Lol
the swan segment was good. this pleases me
That a channel like this has almost 5 million subscribers makes me happy
Excellent video.
Does light instantly get back up to speed after leaving the medium? Or is the speed "slowly" building up to lightspeed in the vacuum?
thank's hank ❤
Great video!
The explanation is already very good and thorough for a short KZhead video, but the effect that of the light slowing down in a medium is only almost right. Indeed the electromagnetic wave tugs on the (mostly) electrons in the material, which moves along with the light and therefore, being an oscillating charge, creates its own wave, called a polarization wave. But then, this newly created field doesn't "tug" on the other field, because ligth does not actually interact with light. Instead, basically create a moving interference pattern, which is the light we observe going through the medium. The reason that the final wave is slower than the speed of light in vacuum is that the electrons (and other charged particles) have mass and therefore don't respond instantly. So the polarization wave therefore laggs behind the original wave as well.
Lol, you completely blew my mind. I thougt i was not possible
Fascinating!
Your electric wave and magnetic wave animation isn't the line right. The magnetic and the electric are not at a maximum at the same time but rather are 90° skewed
Thanks for shedding light on weird physics, Joe
Since light goes slower than c in a medium, do photons start having mass when they're moving through a medium? To my knowledge, massless particles tend to go at the speed of light while particles with mass go slower, so that would make it seem as though moving through a medium gives a photon mass
Excellent work... I started this video thinking "'faster than light'? I don't (expletive deleted) think so!" and finished it thinking "Oh... so that's why neutrino detectors are in gigantic buckets of water".
4:45 that's kinda like the sledge going into mud analogy. Why did u dismiss that away?😂
The mud analogy is assuming that we are still using friction, and since there would be no friction once as you exit said thing that is slowing you down ( that is if you were light) then you would immediately start going your original speed.
Like a Shockwave with the speed of sound, but with the speed of light. Love it. Also love when you explain something and i get excited because it makes sense, then say "if your brain hurts right now its okay." When my brain isnt hurting!
I had not understood the magnetic and electrical fields that make us light until seeing this video!
Thanks bro
Really happy that I randomly landed on this video.😊
Another great video. Thanks. However, I think your animation of an electron passing through a bunch of water molecules was slightly wrong. As the electron passed, you showed each molecule rotating so that its oxygen side was closer to the electron. I think the torque on the dipole would actually turn the hydrogen side towards the electron.
this is what i was searching for my teachers would n't be able to explain my curiosity hats off to Joe Thank you !
Nobody can explain curiosity.
@@BariumCobaltNitrog3n thankyou!! for letting me know this
@@pratibhakumari4118 Never stop being curious.
@@BariumCobaltNitrog3n I'll remember your wise words.
Great video 👍😃.
That magical blue glow is so pretty, what I wouldn't give to see that in person.
Thank you for the great video,. One question: if we would put together an anode/catode system with the catode in air and the anode submerged into wafer, and we would accelerate electrons from the catode to the water/anode, would we see the Cherenkov radiation in the water? Provided of course that the electron speed is high enough. Or is this phenomenon only possible with nuclear reactors due to the very high energy demand for the electrons?
Really like to watch your videos
Of course matter travelling faster than the speed of light IS a tremendous teaser, but tbh... ...you already had me just with the cool, blue glow. 🤗
Another good way to explain the speed of light in different mediums could be. Your walking on a stopped moving walkway, that's speed of light in a vacuum and once light goes through glass or water, the walkway moves against your walking slowing your movement speed but your walking speed to yourself doesn't change. Just a lil shower thought
I want a clarification please, isn't light "travelling" slower in, for example glass, because it takes a longer path in between atoms?