@kiya713 That's why he said "based on our current understanding of the world". If that turns out true then we need a new theory, and I would be extremely excited for that :D. Ah, I ♥ science.
Beautiful - colorful & so love the color digiPAD electronic blackboard pen like a prism color effect- that will really help faculitate through the psychological barriers I.e. The Thalamic Gate! Yet, this very week Einsteins theory re light as the fastest wave or particle are being challenged by modern-day physicist w/ the idea of Nuetrinos--particle acceleration! Love the clip art/graphics to further augment insights!
The statements at the beginning of the video that these things aren't fully understood by anyone is just wrong. Quantum Electro-dynamics (QED) really does explain all of the properties of electro-magnetism. Stating that this stuff is "truly mysterious" instead of "seemingly mysterious" is a disservice.
Golliwogg learnt quite a lot from this introduction to light, thank you. Although he also read recently about a new breakthrough in Europe showing that faster than light travel could well be possible.
Nothing faster than the speed of light huh? Seems to me Neutrinos broke it. Still needs some more testing but if it works, Good bye a to a very important pillar of physics! XD
@DeimosReborn Not really a pillar. No one... Well, no one with any sense imagined the theory of relativity was a pillar. Indeed, we've known since we had a problem uniting relativity and quantum mechanics, that relativity is definitely only an approximation to what is happening. Right in many respects, but far from the whole picture.
By no one, and we, I mean me. I'm not stupid enough to think a physics theory is more than an approximation of reality. That will always be true.
Odd he'd say there's nothing that could go faster than the speed of light. 2 years ago scientists made something to manipulate radio waves to exceed the speed of light.
@woo216 That's not true, that is useful information, radio-waves traveling faster than light? quicker radio signals, and other things. But he actually never says useful information, he says there is nothing known that can exceed the speed of light and as far as they know the speed of light is the fastest thing. He puts it rather evidently with concrete fact that there is nothing faster. He doesn't make any implications there isn't, but I was just pointing that out.
So... The properties of the light change depending on the frequency? Oh and I didn't see white on that color spectrum. Why? Since it is visible it should be a wave and it should have some kinda length?
I wonder if there really is a medium through which light travels? I mean isn't light considered pure energy? Suppose our universe was composed of these little spring like things on a lattice, that when disturbed could be conceived as corpuscles, as Newton saw them, but were really stationary in space-time, and only activated as a wave of energy passed through them?
@rhoadess in the 19th century it was postulated that there was this thing called "aether" (borrowed greek word) which was everywhere, basically a medium that allowed the propagation of light (and other e-m waves). This was proved to be an incorrect (or unnecessary) assumption by Einstein's theory of relativity. Wikipedia "Luminiferous aether".
@MrWebdrone Loop quantum gravity suggests that space can be viewed as an extremely fine fabric or network "woven" of finite quantised loops of excited gravitational fields called spin networks. Perhaps this fabric is the Aether through which all forms of energy that move at the speed of light traverse. String theory provides compacted dimensions.
@rhoadess I knew about the loop quantum gravity thing... actually i'm going for 1st year in theoretical physics in Imperial this year, so it's all pretty exciting for me! I will be able to grasp these concepts and have some more background in them in a few years (hopefully ;p)
Yeah Khan, do quantum mechanics. Like Photoelectric effect, De Broglie Wavelength, Schroedingers wave equation, Barrier Tunneling, Electron spin, Chaos and so on\
I am pretty sure light must travel over/through space time :) which is warped and compressed by matter leading to "lowering the speed of light" which is just an example of drawing more space time into a relatively small space (or making a larger distance to travel with a set relative distance), usually a super cooled tube of gas. So one could say light always travels at the speed of light- it just looks fastest in space hehe
Hold out your arm to represent the electromagnetic spectrum, and now if you were to take a nail file and strike once at your nail you have just removed the same amount of the spectrum as visible light, showing how much we really see.
Khan - I suggest doing some videos on de Broglie wavelengths, Compton Scattering, Young's Double Slit Experiment in order to appease all of the people who want to see quantum mechanics videos.
@elfmotat That's just introducing Quantum Mechanics. Actually getting into Quantum Mechanics is Schrodinger's Equation, Schrodinger's Cat, the Dirac Equation, Antimatter, the Klein-Gordon Equation, etc. There's a lot more than just de Broglie Wavelengths, Compton Scattering, and the Double-Slit Experiment.
@OniLinkPlus Thank you captain obvious. I suggested those topics because they only require algebra and Khan has a tendency to stick to algebra-based topics in his physics videos.
@elfmotat Quantum Mechanics is, in most people's opinions, harder than Calculus. So he doesn't need to restrict himself to just the stuff that uses algebra, since you're probably not going to understand it anyways without an understanding of Calculus.
@OniLinkPlus What? Khan has only done a couple of videos on calculus-based physics, and none (as far as I can remember) involving differential equations (neither ordinary or partial - even in the SHM videos). I suggested algebra based topics because they are easy to cover and will (probably) appease the large number of people who commented here asking for QM.
To be honest, I'm really not even sure what point you're trying to make.
@elfmotat The point I'm trying to make (although I'll admit I worded it poorly) is that Quantum Physics is one of the most complicated parts of physics. If he's going to teach any of it, there's no reason to limit himself by only teaching the parts that use algebra.
Also, I can guarantee almost everyone who requested Quantum Mechanics wants to learn the calculus of it.
@OniLinkPlus I'm not suggesting that he limit himself; on the contrary, I'd like to see calc & diff-eq based QM as well. I merely noted the trend of his videos and suggested topics that fit. I also don't know the feasibility of teaching rigorous QM over a series of 10 minute videos - it would be a big beast to try and tackle.
If he's doing light and its mysterious properties, then he is likely doing Quantum Mechanics. Light's mysterious properties are how we started to learn Quantum Mechanics, so you tell me, if he's doing how we got into Quantum Mechanics, wouldn't he also do Quantum Mechanics itself?
It's incorrect to say that the speed of light is the highest speed possible. The correct limit is that you can't accelerate past the speed of light. But there is nothing that forbids something from moving faster than the speed of light if it were to start out above that speed without accelerating past it. We don't know about anything that moves that fast as far as I know but there is nothing that theoretically forbids it.
@armpitpuncher That's not what I've been taught. There has been lots of theoretical work regarding things like tachyons within the scope of relativity. There are other restrictions on the possible properties of faster than light particles relating to causality etc. but not something that outright forbids their existance. I've only studied relativity at an undergraduate level but I would be surprised if there was something at advanced levels that would disallow it given how it was taught to us.
@petercourt Light has no mass (photons). We have a mass. If we were to get to the speed of light then we would need to have an infinite mass. (vague response but i've not done much of this yet in my physics class)
@mrtnHD That's incorrect, if we wanted to get to the speed of light what we would need is an infinite energy not infinite mass, but having said that since e=mc^2 an infinite energy would require an infinite mass; considering any given mass is a finite amount, I would think for any given amount, like the mass of a spacecraft, a huge but finite amount of energy is need to achieve the speed of light, only an infinite given mass would require an infinite energy to achieve the speed of light.
@petercourt I think technically and probably literally light is made of definite objects called photons, which were mentioned in the video. Referring to your second question, I'm pretty sure there exists some mostly or completely theoretical answer to it, but based on my experience regarding my interest in the same whole answer, I pretty confidently assume it is based on relatively high and advanced Physics, and therefore it is too complex to comprehend without proper wide preliminary knowledge.
@petercourt Light (photons) behave like a particle. A baseball or space probe also acts as a wave flying through space but at a MUCH MUCH longer wavelength because of it's mass and velocity. Frames of reference involve not going faster than c.To any observer a certain spaceship can never go faster than c and vice versa. You can try to accelerate to the speed of light in space but you will only approach c.The observer watching you pass by will see a stretched version of your spaceship. crazyness.
@raydredX Quantum Mechanics is feasible, as it only requires a little bit of new math. In order to do GR, he'd have to do a whole playlist on tensors and tensor calculus, a section on differential geometry, and then a section covering the tensor formulation of SR. It's a lot of new (and very difficult) math.
For relativity theory you can watch the videos in the “Relativity Theory” playlist. For quantum mechanics you can watch the videos in the “Quantum Physics / Quantum Mechanics” playlist. Both playlists can be found on the Best0fScience Channel.
@igankyoumaybe Generally speed of light (c) as a speed limit mainly applies to particles and anything with mass, and its because as the object approaches c it becomes energy, meaning no information can be carried at thins speed
Nice, I enjoy this stuff.. If radio waves are perceived as sound, but invisible to our eyes, does this mean that the visible spectrum may have sound associated with it as well, but perhaps we just can not perceive it?
@sausage4mash this sounds a little out there, but i've heard of cases where veterans with shrapnel embedded in their heads are able to perceive radio waves. can't say for sure, but regardless radio waves, despite the speaker as the "middle man", are heard and not seen...
@petventures radio waves are part of the electromagnetic radiation. So basically it's "light" and not sound. The sound you hear con a radio was converted from the radio signals. The radio waves are converted to an electrical signal which later goes to the speaker. It's not that we "hear" the radio waves.
@petventures To expound on what nicohunger said, the frequencies of the radio waves themselves are well beyond the tuning of the human ear. By altering, or modulating, high frequency waves like radio waves, either their amplitude (am) or the frequency (fm), they can carry within them lower frequency waves like sound. Look up modulation on wikipedia.
@petventures Radio waves are not sound. Sound happens because of disturbances in air. Radio waves are still photons traveling at the speed of light regardless of air. They get converted with a radio device to electric pulses pushed to a speaker which creates the sound waves. It just so happens the 'radio waves' are named after 'radio devices' because of their use.
@CodeWarriorx0539 light or photons of the EM spectrum always travel the same speed but the wavelength can change depending on your frame of reference. See the Doppler effect. Slow light is the propagation of an optical pulse or other modulation of an optical carrier at a very low group velocity. I think the photons still travel at speed of light though. At black holes the wavelength stretches out like a spaghetti string with the closer end to the black hole pulling with more force.
could there be parts of the Electromagnetic Radiation spectrum that we dont know of yet? like something beyond radio, or gamma ray?
Ken11091990 2 weeks ago
great intro..
HostingReviews1 1 month ago
Light needs the Higgs field to travel through. That's it's medium.
AdmiralMorningWood 1 month ago
Awsome, now I know why the sun is yellow :P!
TheProoMas 1 month ago
smtimes his voice gets deep because he talks without taking in O2
anonymusdevil 2 months ago
i do like 2 dwnload alllllllll Sal's video
anonymusdevil 2 months ago
I'd love to see a whole optics lecture series!
aianyoung 2 months ago
I must admit, I only clicked on this because it looked pretty.
411KB 2 months ago
Are you sure that human perception light varies from planet to planet? It doesn't make sense
visu119 2 months ago
@ 8:15
"You might say Hey Sal How can we..."
Dude... if your name Sal?
Freaky, my name is Sal.
Just found Khan Academy today, this was the first vid I watched cuz I just took Physics last session and I was explaining it to a classmate.
So weird, this never happens with my name lol Are you sure you haven't traveled back in time to teach me physics?
UDKoder 3 months ago
Darkness is faster than light.
axelrock007 3 months ago
Neutrinos can't go faster than light
alainchriste 3 months ago 2
@alainchriste its not fully tested yet but it is believed to be able to
micky23451 3 months ago
Barman says: Sorry we don't serve faster than light particles in here
A neutrino walks in to a bar.
decorations 4 months ago
@decorations I don't get it, but I want to so please explain. The barman perceived the neutrino before it was visible?
Hashishin13 2 months ago
Pretty colors
FreshieB23 4 months ago
its grat
trollstomper242 4 months ago
the cake is a lie
TheMike393 4 months ago 7
@TheMike393 What does the cake or portal have to do with this video?
Hashishin13 2 months ago
@Hashishin13 lol idk :D
TheMike393 2 months ago
4:53 Neutrino says "LOLNO"
Gigatless 5 months ago
what about neutrinos?..they say it can travel faster than light..............?
kiya713 5 months ago
@kiya713 That's why he said "based on our current understanding of the world". If that turns out true then we need a new theory, and I would be extremely excited for that :D. Ah, I ♥ science.
LoliWolf 4 months ago
@kiya713
That has yet to be confirmed ^^
SJentZ 4 months ago
Beautiful - colorful & so love the color digiPAD electronic blackboard pen like a prism color effect- that will really help faculitate through the psychological barriers I.e. The Thalamic Gate! Yet, this very week Einsteins theory re light as the fastest wave or particle are being challenged by modern-day physicist w/ the idea of Nuetrinos--particle acceleration! Love the clip art/graphics to further augment insights!
silverfoxidm 5 months ago
The statements at the beginning of the video that these things aren't fully understood by anyone is just wrong. Quantum Electro-dynamics (QED) really does explain all of the properties of electro-magnetism. Stating that this stuff is "truly mysterious" instead of "seemingly mysterious" is a disservice.
jpgoldberg 5 months ago
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Golliwogg learnt quite a lot from this introduction to light, thank you. Although he also read recently about a new breakthrough in Europe showing that faster than light travel could well be possible.
GolliwoggMusic 5 months ago
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GolliwoggMusic 5 months ago
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GolliwoggMusic 5 months ago
Sal!!! You need to update this video!!! Scientists just found a sub atomic particle to be 60 nano seconds faster than the speed of light!!!!
zhunathaniel 5 months ago 2
@zhunathaniel *cough* they suspect its faster, it's not a fact as of yet, nor is anything else we know in existence :D
757sportbikes 5 months ago
@757sportbikes Good point. Although, it would be quite amazing if it comes through.
zhunathaniel 5 months ago
@zhunathaniel Absolutely agreed :D
757sportbikes 5 months ago
my mom makes me watch this but im getting use to it i actually like it:)
cheesymccheezer 5 months ago
oh my god it's begun!!!!!!!!!!!!!
EltBerserker 5 months ago
Nothing faster than the speed of light huh? Seems to me Neutrinos broke it. Still needs some more testing but if it works, Good bye a to a very important pillar of physics! XD
DeimosReborn 5 months ago 11
@DeimosReborn Not really a pillar. No one... Well, no one with any sense imagined the theory of relativity was a pillar. Indeed, we've known since we had a problem uniting relativity and quantum mechanics, that relativity is definitely only an approximation to what is happening. Right in many respects, but far from the whole picture.
By no one, and we, I mean me. I'm not stupid enough to think a physics theory is more than an approximation of reality. That will always be true.
theantiantichrist 2 months ago
@DeimosReborn It was an error, neutrinos are fast but not quite c
david52875 2 months ago
@DeimosReborn they forgot special relativity when measuring neutrinos.
jfusion10 2 months ago
@DeimosReborn Or it was an error in measurement, as pretty much everyone involved thinks.
kayaman132 1 week ago
@DeimosReborn Apparently this was actually due to some faulty wiring! So Einstein's still okay about this.
EnglishPh0t0grapher 21 hours ago
Genesis 1:14 and God said let there be light and there was light.
anad667 5 months ago
@anad667 your god has no place in the classroom of science.
usmcpound 5 months ago
Genesis 1:14
anad667 5 months ago
One more thing though. I don't think there is other life on other planets.
anad667 5 months ago
@anad667 plants can grow of other plant if the quantum photothinsis rays are split
cheesymccheezer 5 months ago
@anad667 reality doesn't care what you think
zinkerled 5 months ago
What about an X ray or a cats scan how much radiation do they have.
anad667 5 months ago
PLEASE MAKE PLAYLISTS FOR SPECIFIC SUBJECTS!!
xbsl123x 5 months ago
Odd he'd say there's nothing that could go faster than the speed of light. 2 years ago scientists made something to manipulate radio waves to exceed the speed of light.
Tripple w(dot)universetoday(dot)com/33752/device-makes-radio-waves-travel-faster-than-light/
MrScorn 5 months ago
@MrScorn no, michio kaku said that no USEFUL information can travel faster than light
woo216 5 months ago
@woo216 That's not true, that is useful information, radio-waves traveling faster than light? quicker radio signals, and other things. But he actually never says useful information, he says there is nothing known that can exceed the speed of light and as far as they know the speed of light is the fastest thing. He puts it rather evidently with concrete fact that there is nothing faster. He doesn't make any implications there isn't, but I was just pointing that out.
MrScorn 5 months ago
So... The properties of the light change depending on the frequency? Oh and I didn't see white on that color spectrum. Why? Since it is visible it should be a wave and it should have some kinda length?
valdas0 5 months ago
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randomwindowsstuffz 5 months ago
@valdas0 The white light was refracted. Which in basic terms means that it was split up.
randomwindowsstuffz 5 months ago
That was really informative, awesome :D
IdoloR 5 months ago
Do you think the RF spectrum could repeat at a higher or lower scale?
DanielJDukat 5 months ago
I wonder if there really is a medium through which light travels? I mean isn't light considered pure energy? Suppose our universe was composed of these little spring like things on a lattice, that when disturbed could be conceived as corpuscles, as Newton saw them, but were really stationary in space-time, and only activated as a wave of energy passed through them?
rhoadess 5 months ago
@rhoadess in the 19th century it was postulated that there was this thing called "aether" (borrowed greek word) which was everywhere, basically a medium that allowed the propagation of light (and other e-m waves). This was proved to be an incorrect (or unnecessary) assumption by Einstein's theory of relativity. Wikipedia "Luminiferous aether".
MrWebdrone 5 months ago
@MrWebdrone Loop quantum gravity suggests that space can be viewed as an extremely fine fabric or network "woven" of finite quantised loops of excited gravitational fields called spin networks. Perhaps this fabric is the Aether through which all forms of energy that move at the speed of light traverse. String theory provides compacted dimensions.
rhoadess 5 months ago
@rhoadess I knew about the loop quantum gravity thing... actually i'm going for 1st year in theoretical physics in Imperial this year, so it's all pretty exciting for me! I will be able to grasp these concepts and have some more background in them in a few years (hopefully ;p)
MrWebdrone 5 months ago
can you do hydrolysis reaction please?
xXAkitokunXx 7 months ago
Yes please do quantum mechanics...I have a final coming up and this chapter is literally killing me :/
Sweetcupcakes23 7 months ago 2
and nothing goes slower than my internet connection/. i did the math
tIs4gatorbait 7 months ago
sal plexx do QM.....please.,....we all beg u
420hassam 7 months ago
For everyone that wants him to do QM, go read Feynman.
FreemanFighter94 7 months ago
I push my fingers into my eyes, it's the only thing that slowly stops the ache.
But it's made of all the things I have to take, Jesus it never ends it'll work it's way inside.
If the pain goes on, I'm not gonna make it.
Oh whoops, wrong duality.
paesanng 7 months ago
Yeah Khan, do quantum mechanics. Like Photoelectric effect, De Broglie Wavelength, Schroedingers wave equation, Barrier Tunneling, Electron spin, Chaos and so on\
paesanng 7 months ago
Sal, what is darkness?
rinwhr 7 months ago
@rinwhr the absence of light
hairypineapplewoo 7 months ago
@rinwhr The absence of light
randomwindowsstuffz 5 months ago
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chocobofarmer2021 7 months ago
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chocobofarmer2021 7 months ago
I am pretty sure light must travel over/through space time :) which is warped and compressed by matter leading to "lowering the speed of light" which is just an example of drawing more space time into a relatively small space (or making a larger distance to travel with a set relative distance), usually a super cooled tube of gas. So one could say light always travels at the speed of light- it just looks fastest in space hehe
EgadsNo 7 months ago
DOUBLE RAINBOW ALL THE WAY!!!
moondustyperson 7 months ago
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Evolution now makes sense :)
aljoshabre 7 months ago
This makes more sense than all my science courses. Thanks for posting!
motogpslider 7 months ago
Hold out your arm to represent the electromagnetic spectrum, and now if you were to take a nail file and strike once at your nail you have just removed the same amount of the spectrum as visible light, showing how much we really see.
bradkey98765 7 months ago 2
Khan - I suggest doing some videos on de Broglie wavelengths, Compton Scattering, Young's Double Slit Experiment in order to appease all of the people who want to see quantum mechanics videos.
elfmotat 7 months ago 2
@elfmotat That's just introducing Quantum Mechanics. Actually getting into Quantum Mechanics is Schrodinger's Equation, Schrodinger's Cat, the Dirac Equation, Antimatter, the Klein-Gordon Equation, etc. There's a lot more than just de Broglie Wavelengths, Compton Scattering, and the Double-Slit Experiment.
OniLinkPlus 7 months ago
@OniLinkPlus Thank you captain obvious. I suggested those topics because they only require algebra and Khan has a tendency to stick to algebra-based topics in his physics videos.
elfmotat 7 months ago
@elfmotat Quantum Mechanics is, in most people's opinions, harder than Calculus. So he doesn't need to restrict himself to just the stuff that uses algebra, since you're probably not going to understand it anyways without an understanding of Calculus.
OniLinkPlus 7 months ago
@OniLinkPlus What? Khan has only done a couple of videos on calculus-based physics, and none (as far as I can remember) involving differential equations (neither ordinary or partial - even in the SHM videos). I suggested algebra based topics because they are easy to cover and will (probably) appease the large number of people who commented here asking for QM.
To be honest, I'm really not even sure what point you're trying to make.
elfmotat 7 months ago
@elfmotat The point I'm trying to make (although I'll admit I worded it poorly) is that Quantum Physics is one of the most complicated parts of physics. If he's going to teach any of it, there's no reason to limit himself by only teaching the parts that use algebra.
Also, I can guarantee almost everyone who requested Quantum Mechanics wants to learn the calculus of it.
OniLinkPlus 7 months ago
@OniLinkPlus I'm not suggesting that he limit himself; on the contrary, I'd like to see calc & diff-eq based QM as well. I merely noted the trend of his videos and suggested topics that fit. I also don't know the feasibility of teaching rigorous QM over a series of 10 minute videos - it would be a big beast to try and tackle.
elfmotat 7 months ago
@elfmotat If anyone can do it, Sal can.
wittsmith 7 months ago
If he's doing light and its mysterious properties, then he is likely doing Quantum Mechanics. Light's mysterious properties are how we started to learn Quantum Mechanics, so you tell me, if he's doing how we got into Quantum Mechanics, wouldn't he also do Quantum Mechanics itself?
OniLinkPlus 7 months ago
It's incorrect to say that the speed of light is the highest speed possible. The correct limit is that you can't accelerate past the speed of light. But there is nothing that forbids something from moving faster than the speed of light if it were to start out above that speed without accelerating past it. We don't know about anything that moves that fast as far as I know but there is nothing that theoretically forbids it.
ingsve 7 months ago
@ingsve Actually, yes, the theory of relativity, if correct, does forbid anything from traveling faster than the speed of light.
armpitpuncher 7 months ago
@armpitpuncher That's not what I've been taught. There has been lots of theoretical work regarding things like tachyons within the scope of relativity. There are other restrictions on the possible properties of faster than light particles relating to causality etc. but not something that outright forbids their existance. I've only studied relativity at an undergraduate level but I would be surprised if there was something at advanced levels that would disallow it given how it was taught to us.
ingsve 7 months ago
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chocobofarmer2021 7 months ago
Khan told Quantum mechanics how to work.
xuijing 7 months ago
can't wait for upcoming videos on this subject
cosminx2003 7 months ago
you rule
imrama 7 months ago
Wait, so nothing could go faster than the speed of light?
gamemaster014 7 months ago
How exactly does light (not made of anything) pass through a vacuum (which is made of nothing)?
Why can't we go faster than light, what's stopping us?
petercourt 7 months ago
@petercourt Light has no mass (photons). We have a mass. If we were to get to the speed of light then we would need to have an infinite mass. (vague response but i've not done much of this yet in my physics class)
mrtnHD 7 months ago
@mrtnHD That's incorrect, if we wanted to get to the speed of light what we would need is an infinite energy not infinite mass, but having said that since e=mc^2 an infinite energy would require an infinite mass; considering any given mass is a finite amount, I would think for any given amount, like the mass of a spacecraft, a huge but finite amount of energy is need to achieve the speed of light, only an infinite given mass would require an infinite energy to achieve the speed of light.
advers1078 7 months ago
@mrtnHD But why, exactly, would we need infinite mass?
petercourt 7 months ago
@petercourt I think technically and probably literally light is made of definite objects called photons, which were mentioned in the video. Referring to your second question, I'm pretty sure there exists some mostly or completely theoretical answer to it, but based on my experience regarding my interest in the same whole answer, I pretty confidently assume it is based on relatively high and advanced Physics, and therefore it is too complex to comprehend without proper wide preliminary knowledge.
AA10Megaviv 7 months ago
@petercourt Light (photons) behave like a particle. A baseball or space probe also acts as a wave flying through space but at a MUCH MUCH longer wavelength because of it's mass and velocity. Frames of reference involve not going faster than c.To any observer a certain spaceship can never go faster than c and vice versa. You can try to accelerate to the speed of light in space but you will only approach c.The observer watching you pass by will see a stretched version of your spaceship. crazyness.
chocobofarmer2021 7 months ago
Pigeons can see UV light
Cats can see infra red
MrValzen 7 months ago
PLEASE DO QUANTUM MECHANICS
igankyoumaybe 7 months ago 126
@igankyoumaybe That'd be an awesome idea! Maybe he could do Classical Relativity and what not! Sounds exciting.
Swetlana0 7 months ago
@igankyoumaybe I want Quantum Mechanics and General Relativity.
raydredX 7 months ago
@raydredX Quantum Mechanics is feasible, as it only requires a little bit of new math. In order to do GR, he'd have to do a whole playlist on tensors and tensor calculus, a section on differential geometry, and then a section covering the tensor formulation of SR. It's a lot of new (and very difficult) math.
elfmotat 7 months ago
@elfmotat That's partially new info for me. Thanks.
raydredX 7 months ago
@igankyoumaybe
For relativity theory you can watch the videos in the “Relativity Theory” playlist. For quantum mechanics you can watch the videos in the “Quantum Physics / Quantum Mechanics” playlist. Both playlists can be found on the Best0fScience Channel.
LWRD 7 months ago
Why is the speed light the fastest speed possible?
igankyoumaybe 7 months ago
@igankyoumaybe Generally speed of light (c) as a speed limit mainly applies to particles and anything with mass, and its because as the object approaches c it becomes energy, meaning no information can be carried at thins speed
BigVic000 7 months ago
12 more vidz to go for 2500
nafaylodhi 7 months ago
Khan , you have a brain the size of a small planet :)
sausage4mash 7 months ago 66
@sausage4mash and planets is cools
webmastertool 7 months ago
@sausage4mash you mean large planet
paesanng 7 months ago
@sausage4mash and a heart of a big one :D
EndureFocusEngageDie 5 months ago
@sausage4mash
no joke
Kaleetos 5 months ago
Can you do a quantum mechanics playlist before september? I have an important physics exam and your videos always help a LOT.
nicochunger 7 months ago
Mantis shrimp... can see ten different colors.
jfusion10 7 months ago
Nice, I enjoy this stuff.. If radio waves are perceived as sound, but invisible to our eyes, does this mean that the visible spectrum may have sound associated with it as well, but perhaps we just can not perceive it?
petventures 7 months ago
@petventures sound waves from a radio come to you via a speaker pushing air ,we humans can not perceive radio waves without some device .
sausage4mash 7 months ago
@sausage4mash this sounds a little out there, but i've heard of cases where veterans with shrapnel embedded in their heads are able to perceive radio waves. can't say for sure, but regardless radio waves, despite the speaker as the "middle man", are heard and not seen...
petventures 7 months ago
@petventures radio waves are part of the electromagnetic radiation. So basically it's "light" and not sound. The sound you hear con a radio was converted from the radio signals. The radio waves are converted to an electrical signal which later goes to the speaker. It's not that we "hear" the radio waves.
nicochunger 7 months ago
@petventures To expound on what nicohunger said, the frequencies of the radio waves themselves are well beyond the tuning of the human ear. By altering, or modulating, high frequency waves like radio waves, either their amplitude (am) or the frequency (fm), they can carry within them lower frequency waves like sound. Look up modulation on wikipedia.
armpitpuncher 7 months ago
@petventures Radio waves are not sound. Sound happens because of disturbances in air. Radio waves are still photons traveling at the speed of light regardless of air. They get converted with a radio device to electric pulses pushed to a speaker which creates the sound waves. It just so happens the 'radio waves' are named after 'radio devices' because of their use.
chocobofarmer2021 7 months ago
Light has been shown that it can be slowed down... then can light accelerate? for instance in the presence of a black hole?
CodeWarriorx0539 7 months ago
@CodeWarriorx0539 light or photons of the EM spectrum always travel the same speed but the wavelength can change depending on your frame of reference. See the Doppler effect. Slow light is the propagation of an optical pulse or other modulation of an optical carrier at a very low group velocity. I think the photons still travel at speed of light though. At black holes the wavelength stretches out like a spaghetti string with the closer end to the black hole pulling with more force.
chocobofarmer2021 7 months ago
when are you going to start talking about cats being in and out of boxes?
disbandedNinja 7 months ago
sal plx...............M WAITING from years....that u ll make vid on photoelectric effect,realtivity
420hassam 7 months ago
sal....pls make vids abt quantum physics aor at least theory of relativity
420hassam 7 months ago
@420hassam I think he's heading there.
jfusion10 7 months ago
@jfusion10 bt i cnt wait anymore sal.....plxxx
420hassam 7 months ago
Thanks for uploading this Sal, it was great and so helpful
MTajvidi 7 months ago
Could you make a vid about why the speed of light is the maximum?Coz I really don't get it!
SuperLLL 7 months ago
Comment removed
okazam97 7 months ago
MORE PHYSICS!!
go khan!!
RTRVII 7 months ago
thx sal
cool70200 7 months ago
im 1st
monitanator 7 months ago
@monitanator you wish!
CJhakeV 7 months ago
light is amazing
okazam97 7 months ago