Also the best (i.e. simplest and most correct) explanation of the Casimir effect I've ever heard.

Hi, sorry I'm late, but both explanation are wrong.

isodoublet shut up and leave

@@isodoublet I agree. WHat is the right explanation in your opinion? Maybe just external EM waves exerting pressure on plates? I mean, there is always some that are traveling from around - no need to pop into existence.

It's actually the only decent one I've ever heard.

Right? Incredible

...somebody has never seen, heard nor read Feynman, Walter Lewin, Judith Grabiner, Eric Kandel...

​@@crackakilla2506Some of us probably have, but that doesn't diminish this man's didactic skills in any way :)

@@BackflipBeaver ty for the new word!

@Pink Pyramids chill

I think I understand how you feel.

Sounds great

Agree!

yeah im sure they are pulled together not pushed. they are attracted to each other. they are of the same element.

that's great!

+Sixty Symbols why only the anti partical falls inside the black hole and not the partical?

+Amit r Could be the other way round - nothing is stopping that.

+NuclearCraft Mod sorry, what?

Amit r It isn't always the anti-particle that falls into the black hole - it can sometimes be the particle.

because he is a professor and lecturer

bertazoid lol

┌─┐ ┴─┴ ಠ_ರೃ >< And he's a dapper man. A true gentleman of the people.

It's also wrong though.

isodoublet elaborate upon your statement, from what I know is that the Casimir effect talks about a force caused by quantum fluctuation (F=π^2 hbar c)/240 d^4 that occurs in electrodynamical vacumm that fluctuates zero point energy fields, these fluctuations are a product of uncertainty principle, what did the professor say that was wrong?

When we say we notice them, we might also say we observe them, or we measure them. It means they have an effect. Between two transitions, that is to say between the origin and the end of the existence of a particle, it can be in any state. It can go infinitely many ways, and in some sense it does go all of them. That includes interacting with all kinds of other particles that may or may not be there, as long as the effect at the end is the same. Those other particles the original particle may interact with (or does interact with, depending on your take on things) can be anything, but the more energy they have, the shorter the duration during which they can affect the original particle. They are not measured themselves and as such are considered virtual. And because the sum of the energy between measurements must be zero, all these virtual particles must come with their respective anti-particle. Light is its own anti-particle. All this could be considered a philosophical red herring that originates from the mathematical description, except that the Casimir effect proves that there is more to it. These virtual particles can be made not-virtual. There are other applications that rely on the existence of virtual particles as well. And they are also the explanation for what is Hawking radiation, or in other words: They reconcile GR with thermodynamics. (Which is ironic, because QM (which describes virtual and other particles) and GR are still not reconciled with each other themselves.) Obviously there is more to it than is currently known.

Well, that's very simple. Bring your own accelerometer , like the kind in a smartphone and start measuring before acceleration and continue after deceleration, then compare with your Earthbound twin. OR Forget the Smartphone and go on a looong circular journey under constant acceleration. When you get back, compare your clock or calendar with your Earthbound twin.

Had a few PM designs back in the day. Prof. Casimir debunked them for me, and warned me not waste my entire life searching :). You can find them on my website for amusement. Still searching though...

Thinking perpetual motion is possible, no matter how small you think the odds are, demonstrates a fundamental misunderstanding of physics as a WHOLE. You need to invest your time in learning all of the fundamentals again before you attempt to pose or answer any questions. Thinking perpetual motion is possible at all and also believing in physics is just like believing in science and religion. Science and religion have direct contradictions to each other that makes their coexistence impossible unless you make logical or moral concessions or you just completely ignore certain conflicts and act like they don't exist. With science you don't have the luxury of being able to ignore or omit the parts that contradict because those things remain true whether you believe it or not, your belief in the matter doesn't change the outcome. Perpetual motion is 100% unequivocally impossible and you'd have to completely disregard some of the most well understood and fundamental build blocks of physics to rationalize the possibility of any system having 100% or higher efficiency. There are plenty of things that are highly efficient and appear to have perpetual motion, but the idea of true perpetual motion is absurd and ignorant.

Usually the pros talk about the eq. Principle that acceleration and gravitation are equivalent at a point. Tidal forces are infact a thing that distinquishes gravitation from acceleration. I find iy easier to see when we think about a very large and very looong object near a massive round body. It is falling towards it, but if the object is long, then it starts to bend (imagine this as the object being longer than the planet's diameter, and the object will start to "hug" the planet by bending to a sircular form, stretching from its far ends). That is another type of a tidal force, and there you can see your spaceship going from straight into a banana-looking shape, and you can say that you are in a Gfield. If the spaceship was just accelerating uniformly, it would stay straight.

In the case of gravity the force is radial ie pulls towards the centre of the Earth. This means that the gravitational force on your left side won't be quite parallel to the force on your right. If you were to hold a weight in each hand, stretch your arms out and drop the weights, the weights would hit the ground slightly closer together than when you released them. Obviously the difference will be tiny and will be masked by masses of other objects in the vicinity. In the case of acceleration the forces will be perfectly parallel on both sides so the weights would hit the ground exactly the same distance apart as when they were released.

+Udit Dey Somebody is actively avoiding the News...hehehe...

Accelerate faster than the speed of light? You're comparing two different nominal measurements, acceleration and velocity.

That was what I thought... maybe some smart intelligent friendly person could answer this question?

Actually if I've understood things correctly, a significant portion of the particles in the universe were created via this in the first place. When the cosmic inflation ended, the energy of it had to go somewhere and theories suggest that that energy went into the virtual particles that existed at that moment and turned them into real particles.

From what I know, I don't think so. Not in the same way as this. During inflation spacetime itself was expanding insanely fast, but not the particles in spacetime. Not saying that particles didn't get created, but I don't think it's thanks to this.

one interesting consequence of it would be clumps of antimatter and clumps of "ordinary" matter populating the universe, that have no causal interaction between one another because they would have been brought apart by the inflation acceleration. Such an eventuality would leave behind a specific imprint in the cosmic microwave background radiation for instance. Planck data is to this day being studied to test the validity of such models. We may live in a symetric matter / antimatter universe afterall :D

+SkrootNissu Yoctomind There's an experiment that can produce anti-matter and you can see sparks in the air where the anti-matter hits regular matter and gets converted to pure energy

+lawlerzwtf Sounds like a cool way a space ship engine could work. The Vibrator Engine!

From a pure mechanical viewpoint, these photons are created from the energy of the vibrating plate. This from one side of this duality way of viewing things - and both are correct. So it's merely a roundabout way to get electrons, or any other particle. If you need a lot of photons, use a led lightbulb, easier and cost less. ;)

Maybe the mass is 1/0? ( ͡° ͜ʖ ͡°)

Ramanujams identity won't work. Mass isn't negative

No.

it's just regular Deep Magicks

yes, but the effect would only be noticeable if the object was very very small.

I am wondering this too. I think it must do, these tiny forces would become imbalanced for a short period before naturally balancing.

I don't think so. If those virtual particles only borrow their energy from the vacuum energy, then their annihilation must not have ANY effect on anything else for the energy conversation to hold true. Because if they interact with anything else, they will lose energy and so give less energy back into the vacuum than they took out of it.

Regigigity yes and the geometry of said object can effect the ways in which it behaves, but the effect overall is so miniscule.

Not really. It would only be useful for studying the casimir effect and breaking particle and antiparticle pairings, but it wouldn't do much else for studying event horizons themselves. Black holes have a similar effect at their event horizons, but the casimir effect doesn't mimic the properties of an event horizon. It's kind of like how a black hole could theoretically have a charge, but studying... I dunno... say a balloon rubbed on a cat wouldn't explain much about what's going on inside a black hole. :P

I would like to know more about the balloon and the cat. I don't think there is any published data on balloons and cats, at least in a refereed journal. Though I may have missed a symposium or two.

I know. He actually does a really good job of explaining things, but it's hard to keep up with it sometimes. I had a lecturer like this in my freshman chemistry class way back when. It was kind of a maddening experience.

All you have to do is click the three dots upper right corner and slow him down.

I missed the part about your black hole question. So it's the same idea - mass bends spacetime (called gravity.) Think of this as bending all possible paths you or a particle or a photon could travel down. A black hole is an extreme case of this - at the event horizon, all possible paths bend inward. The black hole has bent spacetime so much that even the paths leading directly away from it end up pulled forward instead. So light still travels at c even in a black hole. But there is no way for it to go out because there is no such thing as out anymore. All paths inside the event horizon lead to the singularity.

+ForeverOfTheStars The black hole doesn't slow the light down. It can bend light but also it can change the wave length of the light. Think of it like the Doppler effect. When light is emitted from very close to the horizon of a black hole then it will appear to have a much longer wave length once it escapes the vicinity of the black hole. So blue light will appear more red. Eventually at the horizon light emitted would have an infinite wave length and hence a zero energy. This all ignore quantum effects though, which makes things a little more interesting.

+ForeverOfTheStars Gravitational redshifting is the answer you are looking for :)

Kevin Falls yep this effect is called Einstein shift, essentially it is the redshift of wavelengths due to gravitational radiation.

ForeverOfTheStars think about like light doesn't slow down but the path In which it's traveling if warped in away so that light seems to move slower. It's hard to explain over the phone but whatever Light follows the curvature of space time, if the curvature of space time is warped by gravity then the path in which light travels through is warped, think about like this, say you have to walk x distance this takes time y, if x distance is distorted or warped in a wavey like way then you have to travel the same x distance but now since it's distorted instead of being a straight path it's takes y+z time where z is the prolonged time due to the path being distorted, same behavior for light if say light travels x distance and it takes time y if it's straight path is distorted by gravity then it's the same amount of distance and speed but the time (y) is prolonged by a certain amount depending on the how much space time curves.

Yes it also happens in a gas or solid. Remember that almost all the space in a gas is empty space. The individual atoms are surrounded by vacuum and inside of them it's almost a perfect vacuum with only a few electrons being very far from the nucleus. Of course one could imagine some of these particles being absorbed by, say, the electrons, but in general they wouldn't even notice the presence of matter.

I see, so, since the annihilation of matter/antimatter takes place everywhere, and as a result, photons are emitted, since the interaction of photon-electrons of matter is unavoidable, can we conclude that matter is constantly receiving energy from the vacuum through the creation of this photons (except of course if the energy of the photon is so low that it can't promote electrons to higher energy states)?

That's a good question. It would seem like the matter should be getting energy for free this way, which obviously isn't the case. Saying that the photons do not have the energy to jump the electrons up to a higher orbit might help explain some, but we would still expect the nuclei to continuously gain energy from the virtual photons. By the way, the photons are not created by matter-antimatter annihilation in this case, but just spontaneously pop into existence because of the uncertainty principle.

Ok, sorry, I put it in the wrong words XD. That is actually the point, thing is, like you already said, I would expect matter to continuously gain energy because of these photon-electron interaction however I agree, that it shouldn't (isn't) happening. And the only way around it is either that they're unable to promote the electrons or that somehow these virtual photons aren't interacting with matter.

Yes it will be interesting to know the answer to this. I will try asking some physicists.

Don't mind if I do (nom nom). Now, did you have an actual argument?

No.

Uhm... both particles and antiparticles have a positive mass.

Anti particles and particles don't have opposing mass only opposing charge - that's why there's an "energy debt" in the first place as there is technically a net increase of mass (i.e. energy in the universe). Though the mechanics of the theory doesn't exactly work like this the simplest way to explain why the black hole loses mass is that once these twins are split, the one that falls into the black hole has a bountiful amount of energy to interact with to "repay the debt" while the other twin gets to roam the universe as a real particle (without the temporal grim reaper over it's head since the "debt" got repaid in the black hole).

Paulina Jonušaitė And? The antiparticle annihilates something inside the hole and the regular particle doesn't. The regular particle would then increase the mass. DarkenedYeastExtract What I don't get is that it's about particles and antiparticles, yet it doesn't matter which one enters the hole. Of course I assume nothing works the way you'd think inside a black hole, but if I just go by the particle-antiparticle logic, only the antiparticle would end up decreasing the mass of the hole, since it annihilates something within it.

Particles pop into existence, leaving an energy "debt" in their stead. Normally, the "debt" is returned by both particles annihilating again, however, if one of the particles flies away due to extremely warped space-time curvature, the "debt" has to be repaid from other sources, namely, the mass that created the warped curvature. Thus, black hole loses energy and, by extension, mass, because mass *is* energy when speaking about black holes. You seem to think of mass and energy as two separate things, which is just incorrect for black holes. There is no matter or antimatter inside the black hole, that information is completely obliterated, so there is nothing annihilating inside of it either.

I could be totally wrong here but here's what I think of it; If the positive(real) falls in and the negative(anti) remains out, the negative would have to annihilate because it's existence added matter to the black hole. But it can't just vanish. It'd need to pair with a nearby particle, and being as though there are particles being created and annihilated around it constantly, it'd pair with a positive half & annihilate, leaving another anti-particle half there, and would continue to chain until one falls into the black hole, restoring the energy. If that is right then we'd only get "real" photons emitted while over time the black hole reduces in mass to account for the energy released as hawking radiation. Again, could be wrong it's just my interpretation.

i am gonna assume the explanation is way more complicated than this but probably they just do. Maybe they interact with the background radiation or the magnetic field or the higgs field but pretty much they just pop out of nowhere and disappear in a matter of femtoseconds

zach miller you should look into quantum mechanics, and different dimensions, essentially these particles are just going in and out of different dimensions...

zach miller Do you remember when the guy said that when the photon falls into the black hole, it loses mass? Another way you can think of that is by saying that the photon has negative mass and negative energy. When you think of it that way, you realise that virtual particles never violate conservation of energy - when they form, one has positive energy, one has negative energy, and so the total energy sums to zero. As to how and why they form, that's a difficult question, and I probably don't know enough to answer. It's a result of the Uncertainty Principle, as the professor said. The common formulation of the UP follows thusly - the momentum and position of a particle cannot be determined to high precision at the same time. Without a lot of work, the UP can be rearranged to state that, also, the energy and the time interval a particle has existed for cannot be determined to high precision at the same time as well. The vacuum of space - we know exactly how long it has been in existence, at least in theory. 13.75 billion years. Theoretically, we could determine that number to an incredible accuracy. We also know how much energy it has. It's a vacuum, so zero energy. So for the vacuum, we know the time interval and we also know its energy precisely. But by the UP, that's impossible. So one of those two has to be wrong. We aren't wrong about how long its been in existence, so therefore we must be uncertain about its energy. All we know is that it can't have zero energy, because that's too precise a value. This implies that there's energy embedded in the vacuum itself, which we can't measure. I don't know why the particles form, but at least I can tell you where they get their energy from. It's best to stop thinking of the vacuum as a zero energy system. Instead, think of it as the lowest energy state of a system, and by the UP, that lowest energy value is forbidden from being zero. Hope it helped.

+Vai *...essentially these particles are just going in and out of different dimensions...* I just read this and thought, "Hmmmm that sounds an awful lot like pseudo-science to me. Especially since that would be something we cannot observe to be true by any means."

+Yokai Seishinkage He asked where these particles came from so I told him what I knew about it, unfortunately no knowledge is absolute. What makes you think that my statement cannot be observed or tested, you don't have a degree in quantum physics to my knowledge.

┌─┐ ┴─┴ ಠ_ರೃ s >< c\_/ Yes. Yes it was.

i just watch physics videos on youtube - i'm not an expert at all. that's an interesting thought but my understanding is that this casimir effect produces photons which are mass-less particles. Dark matter is a source of unknown gravity in the universe implying that the cause of dark matter has a mass. then again e=mc^2 says mass and energy are interchangeable so what do i know?

***** it can also produces particals with mass like a proton, but the chances are way less than for a photon...

+Melodic Guitar Rock/Metal GuiltyGearRockYou Yes, that is true, and they also exist incredibly briefly. This prevents it from entangling with even nearby particles, and dark matter operates at an extremely long range, from what I gather anyways.

They actualy DO interact with nearby objects, as was shown in the plate experiment.

Melodic Guitar Rock/Metal GuiltyGearRockYou

Okey.. Now I feel stupid .. I did a bit of research and found the quite obvious explanation that The anti-particle that were sucked into the black hole, sending it's lone, ex-paired ex-virtual particle partner to fly through the galaxy as a real particle in the form of hawking radiation, would simply annihilate with a particle in the black hole's singularity, and thus making it lose mass. Quite obvious actually, and that's why i feel so stupid.. But… It still doesn't answer some questions.. like.. how come ONLY the anti-particle is sucked in and not the other way around? Why isn't it completely random which one from the virtual-particle-pair that's being sucked in.. I mean, the only difference between a particle and it's anti-particle is it's electric charge. So why does that have effect which of the two particles in the pair is being sucked into the black hole? And also, when a particle and an anti-particle annihilate, they create pure energy in the form of photos (that travels in the speed of light), and since whatever is inside the event horizon has to go Faster than the speed of light to escape, (something that is impossible) means that the energy Still can't Leave to black hole. So I still don't see where the loss off mass comes in.. So I still don't understand the basis for the claim that black holes evaporate.

Dahxelb The mass of a black hole will increase whether an electron or positron enters it. When an electron/positron pair (or any other matter/antimatter particles) come into existance just outside the event horizon and just one of the pair falls in, the black hole increases by the mass of that particle but the mass is also reduced by the energy required to separate that particle pair so there is a net loss of mass to the black hole. To summarize:- Electron/positron pair comes into existance electron falls into black hole, positron flies away. Universe now has gained the mass of one positron. Black hole has gained the mass of one electron but lost the mass of separating the electron positron pair which will be eqivalent to the mass of two electrons so the black hole has effectively lost the mass of one electron.

bob s Thank you for trying to explain. But it still doesn't explain exactly how something with mass actually leave the black hole. The energy that separates the particle pair comes from the black holes gravitational pull. And gravity doesn't "lose" energy just because something is pulled by it.

Dahxelb Nothing actually leaves the black hole, the particle that "leaves" (Hawkings radiation) originates just outside the event horizon. Mass and energy are equivalent (e=mc^2). The energy to separate the pair must come from somewhere.

Dahxelb I agree with you in that it doesn't make sense at least to us. All these people say that it takes energy to separate them but I see the world as you in that gravity doesn't lose energy by pulling. My guess is that the problem lies in the fact that we (no one really) don't know how to link quantum mechanics with gravity. It was mentioned in the video. That there is something that is missing in the puzzle.

chasem007ify The Casimir effect is measurable with boson force carrying particles like photons that are the boson particles of the electromagnetic field. These bosons have no mass, so an infinite amount of them can exist in the exact same space at the same time. A blue whale is made of fermion particles, that have mass and are matter particles, only one fermion particle can be in the same space at the same time. The Casimir is a quantum sub-atomic effect that thankfully does not measurably happen to us or blue whales.

I know, it's a hitchhiker's guide to the galaxy reference

chasem007ify LOL I should see that show.

chasem007ify well, 42.

Not so much because of this but that is possible if there is an infinite multiverse thanks to quantum mechanics.

And proof that you can't use the correct their.

It's a correct description. Scientists use the word "theory" in a way that's much closer to the colloquial meaning of theory than the one you've been told is the "scientific definition of theory".

avicenna the definition of a scientific theory is correct, but when scientists are talking (especially to the lay person, but even among themselves) then they will often use the colloquial form of the word just like everybody else does

No, it isn't. Scientists don't have a special snowflake ivory tower definition of "theory". They use it just like everybody else, when talking to themselves or to the public. This top-down enforcement of "theory" as necessarily having evidence behind it is not based on any kind of fact.

"es the word theory does have a very specific scientific definition and use, are you a creationist? " Nope, I'm a physicist and I see the usage of the word in person every day. This fiction that the word somehow means the current pinnacle of scientific understanding seems in fact to have been invented to combat creationists, but the correct response to creationism is not to say "evolution is a theory so shut up stop asking questions", but rather to give the evidence in support of it.

"a game theory'