Dark Energy and the Vacuum Catastrophe

[@JG-zs8tr]

when in doubt, just slap a cosmological constant onto the end of the equation

[@coolhand411luke6]

More alarming is leaving an infinity in the accepted academic cosmology lexicon. If you have an infinity in your work, you made a mistake.

[@gorantev]

@@coolhand411luke6 Yeah, but we can't fix that, yet. We simply don't know enough to know exactly where we are wrong, and why.

[@gorantev]

@@chri-k Thanks for letting me know.

[@jezer8325]

Yeah, that was kinda weird ngl

[@kiabtoomlauj6249]

@@gorantev If we don't know enough to know exactly where we are wrong and why, it is clear as night and day we can't and shouldn't say we know "matter" is exactly 5% of the universe, "dark matter" is exactly 25% of the universe, and "dark energy" exactly 70% of the universe, etc., etc. THAT is just idiocy committed by the most brilliant, most educated folks in civilization... similar to what Aristotle and countless others had done in previous generations (the brightest in society coming up with some of the most stupid "explanations" for how reality and the cosmos work, here on earth and "out there" in the far distance). For me, unless and until the contrasting explanations by Quantum Mechanics and General Relativity are brought to a seamless whole, like a perfectly fitted puzzle, things like (the "mysterious") "dark matter" and (the "even more mysterious") "dark energy" as well as "Inflation" (or "hyper-inflation," the Allen Guth imaginary energy) are just Planet Vulcan, Aether, Crystalline Sphere assertions, randomly & clever reverse engineering mathematical contraptions conjured up and invoked to make "theories" look plausible. It's not real science when X or Y or Z "must" have happened. Any time the word "MUST" is used, it's nothing more than Bronze Age religious fairy tale doctrines and beliefs...

[@Scrogan]

“Let’s take a deeper look at the vacuum of space” You say, pushing me out the airlock.

[@taufiqutomo]

James Barclay was not An Impostor. 2 Impostors remain.

[@shaunhumphreys6714]

that sounds like a Quark threat from deep space nine ''or i'll push you out the nearest airlock''

[@fnerXVI]

@@taufiqutomo hahahaha AMOGUS hahaha 😂🤭😆😅🤣

[@Jesus_Offical]

@@taufiqutomo Amogus

[@Jesus_Offical]

@@shaunhumphreys6714 i see youre a man of Culture aswell

[@Mechadude32]

Sure "the universe should have torn itself apart in a minute fraction of a second" sounds bad but I maintain that "ovens should produce limitless energy and radiation" is still the worse prediction.

[@theglitch312]

But it's the only explanation where I can still absolve myself of any blame when I burn something in my oven. So I'll stick with that one thank you very much.

[@WeirdMedicine]

Oh, you and your ultraviolet catastrophe ;-)

[@mihailmilev9909]

@@theglitch312 lmao

[@mihailmilev9909]

@@WeirdMedicine ohh so that what that is

[@watamatafoyu]

I think my stove is getting excess radiation from another universe because simmer should not boil an open pot of soup.

[@JC-zw9vs]

Loving the fact you get straight into the equations....and give really clear narrative about how they work and what they mean. I'm not a physicist, just have an interest. So many lectures aimed at folk like me avoid the equations; wrongly in my view. Keep it up!!!

[@PhysicsExplainedVideos]

Cheers!

[@brianl7321]

Agreed. The derivations make it very clear what the implications are and don't require anything more complex than some calculus (and a lot of algebra) to follow. Of course it's far easier to see it explained than do it yourself!

[@notspacekeeper]

Also a great way to weed out nonsense. Ask for the maths. "I have a theory about how it all works and no one will listen!" -> "Let's see your maths."

[@tomtom2891]

this is so true

[@BruceCarbonLakeriver]

@@PhysicsExplainedVideos I need to agree! I'm glad you went directly into the equations :D And you've produced a very well forged video! :D

[@appleslover]

This channel is a treasure

[@TylerSolvestri]

Especially for physic fanboys or interested

[@appleslover]

@@TylerSolvestri yeah I'm a medical student but still a physics nerd since high school 😁

[@miguichopemigui6736]

It is

[@jennyanydots2389]

@@TylerSolvestri He's on a list because fanboys who look 18 but turned out to be 12

[@smiley_1000]

agreed!

[@jakebramhall3479]

"We are now in a position to combine all of our previous results" Oh yeah, it's all coming together.

[@realcygnus]

Pretty much equivalent to about a dozen+ hours of Lenny Susskind's/Stanford lectures(which are superb in their own right imo) but amazingly condensed to well under an hour. A priceless EDU Gem !

[@ObjectsInMotion]

This entire video is literally only 3 pages in my cosmology textbook, it's not as condensed as you might think.

[@realcygnus]

@@ObjectsInMotion Yea, I don't doubt it. I tend to exaggerate, its still a gem though.

[@sdadsada8528]

@@ObjectsInMotion which cosmology book?

[@ObjectsInMotion]

@@sdadsada8528 Barbara Ryden's

[@richardwebb9532]

👍🍻

[@monday223]

Love the way you show how the most important findings and problems in physics can be derived from basic equations. Thank you!

[@PhysicsExplainedVideos]

You're very welcome!

[@williamfritz189]

Quite quite true!! For the mathematically respectful but not accomplished, this has been like the experience of the kid who's been taught a half year of cello but never heard any music but blue grass gospel in church, who then gets seated before a professional orchestra performing Brahms. Impossible to comprehend but not, in awe, profoundly to appreciate.

[@JyChau]

Me preparing to sleep at 3am: youtube: DARK ENERGY AND THE VACUUM CATASTROPHE

[@scifino1]

Me, reading your comment from two hours ago: Huh? it's only ten minutes to eleven. *looks at symbols in your name*: oh, yeah, that explains it. I hope you have slept well, when you read this. Have a nice day!

[@badartgallery9322]

Same here.

[@pgzzz]

Me too. Just a pain in the arse when you choose a video with adverts which are broadcast at 3 times the volume of the actual video 👍

[@duprie37]

Same here. 3AM. Just about to put phone down & sleep...oh look here's an interesting news story about the EPA restoring scientific integrity post-Trump...article refers to Sharpie Gate...haha yea I remember that, let's watch a quick funny KZbin video to recall what that was all about...hahaha...oh look, there's a new video from Physics Explained about the Vacuum Catastrophe. Fascinating! ...damn now it's 5AM.

[@jamesbanq3660]

Same here

[@flockofwingeddoors]

As someone starting a physics degree soon, I just wanted to say that you are an incredible content creator. Your work is inspiring and clear, keep up the amazing effort!

[@PhysicsExplainedVideos]

Thank you for the feedback, it is much appreciated. Good luck with the Physics degree!

[@johnopalko5223]

Brilliant job! I was really disappointed when the video ended after only 49 minutes. I could have listened to you for another couple of hours, at least.

[@Dave5843-d9m]

Always keep them wanting more.

[@jeffk8019]

Thank you so much. This is incredible content. Your technical explanations are at a perfect level for a lot of us who enjoy deeper dives into physics. I hope your channel grows.

[@PhysicsExplainedVideos]

Glad it was helpful!

[@justanotherguy469]

Very very well said.

[@stuartclifton4764]

I'm absolutely abysmal at maths, but have such an interest in physics... This channel is a bloody godsend for me! Thank you so much

[@PhysicsExplainedVideos]

Great to hear!

[@jimlbeaver]

This must have taken an incredible amount of work to create. It was very thorough and clear. Thanks and great job!

[@PhysicsExplainedVideos]

Glad it was helpful!

[@digbysirchickentf2315]

And yet he is not even questioning the theory of expansion, and is quite happy to believe in theories of mysterious energy, a rather conservative mind.

[@ps200306]

@@digbysirchickentf2315 , expansion is an observational fact.

[@digbysirchickentf2315]

@@ps200306 It depends if your measurements are correct (they're not) and also depends how far you can see. Around the Laniakea Supercluster space appears to be contracting. Mathematical predictions of expansion do not match observations.

[@ps200306]

@@digbysirchickentf2315 , the Laniakea Supercluster is not gravitationally bound, therefore not contracting. Of course there are deviations from the Hubble flow on the scale of superclusters and below -- that's what you would expect.

[@scottrobinson4611]

I wish I had this video when I was in the middle of my cosmology module at university... I've always been bad at seeing the 'whole picture' as I'm learning and studying for an exam, but when I revisit summaries later on, it all fits together nicely. Your videos are excellent.

[@ps200306]

Same here. Always takes a couple of years to sink in ;-)

[@scottrobinson4611]

@@ps200306 5 years and a Master's later, and I still don't think I know E&M. I'm starting my PhD this year too, god help me

[@PhysicsExplainedVideos]

Thanks for the kind feedback

[@timvvs]

I dont have any physics background but you explain things in such an easy to understand way, without dumbing it down at all.

[@brianflaherty9054]

This is the only channel I’ve ever turned on notifications for

[@callmedd3494]

I followed this video for about 5 minutes. Which I think is a new record for me.

[@TheoriesofEverything]

Underrated channel. Great job.

[@PhysicsExplainedVideos]

Much appreciated!

[@dimitrijmaslov1209]

You both...

[@TheoriesofEverything]

@@dimitrijmaslov1209 Thanks, man.

[@richardsilva-spokane3436]

New sub: Back in the sixties when I attended high school, I was drawn to read Scientific American in spite of the fact that I comprehended very little of the content. In the same way-as a layperson-I am enchanted by the production values and teaching methods of this video.👍👍👍👍👍

[@PhysicsExplainedVideos]

Thanks for the feedback, glad to hear that you are enjoying the content

[@MosquitoValentineNH]

Aaaaaahhh… I get it!- “Dark Energy= Pi squared times energy mass velocity derivative factor over r factor multiplied by divided gravity squared plus Hawkings wheelchair minus Einstein’s whiskers” -thanks for clearing that up for a layman like myself!

[@lobsterbark]

I love learning stuff by listening to stuff I don't really understand like that in the background while doing chores. I don't understand most of it, but slowly I start to, or I will connect something from one thing to another thing and it will start to make sense. I now know a little bit about basically everything, which is pretty useful.

[@ifrazali3052]

I love these detailed videos They are perfect for undergrad physics enthusiasts

[@jimpollard9392]

I make an error this big on my paper: get it marked wrong. PhD's make an error this big: write grant proposals.

[@channelsixtysix066]

😆

[@masstv9052]

TBF, Science is about trying to prove a hypothesis incorrect, not to prove something correct. So even wrong predictions and hypothesis are valuable information.

[@channelsixtysix066]

@@masstv9052 He was being satirical. 😊

[@big.atom37]

Being a physics noob I have several questions after watching this video: 1) Plank's length and time simply denote the limit of our ability to meaningfully measure something. They are not some fundamental constants so why are they used as such? 2) By dividing by acceleration and its derivative we automatically assume that the acceleration isn't zero and changes with time. If it's not true then doesn't the whole thing fall apart? 3) Using the fluid equation for the whole Universe seems like a stretch. Can we really know that the Universe doesn't lose or gain energy as it changes in size? 4) We know that time flow varies. Around the supermassive black holes, which amount to a significant part of the observable mass, time almost slows down to a halt. and so do all the processes. Knowing this how can time derivatives be simply applied to the whole Universe without being inspected more thoroughly? Can someone please explain?

[@spaghett5531]

Also being a physics noob i can't answer these with definite certainty 1. I think its because they are constants, the Planck length isn't going to change unless something fundamental with Newton's law of gravitation or the electromagnetic force changes. The Planck time isn't going to change unless the Planck length or the speed of light change, so I think because these numbers are already based on constants and equations that we know shouldn't change that we use them as constants. 2. Its because we've observed that the universe is accelerating and at an increasing rate, although I'm not sure how this would be justified before these discoveries were made. 3. It's due to the conservation of energy that we observe everywhere, so we assume (and probably have evidence I'm unaware of) that it applies to the universe as a whole. 4. I think that's due to using the cosmological principle to say that the universe is homogeneous and isotropic, so we kind of just ignore the regions of space that are particularly different like black holes.

[@TheoEvian]

I am in no way a professional so I might state some mistaken points but I will try to ellaborate on Spaghett's answers: 1)Planck units (natural units) are derived using gravitational constant, speed of light and planck constant: they are basically as fundamental as these things get. The reason why they were used there is because the fluctuations should constrained by the uncertainty principle, that is have a maximum value. Planck scale makes a logical cutoff. It is true that you can get Planck units derived slightly differently and those then are different from the standard size by a small coefficient, like 2pi or 4pi, but that doesn't matter too much in this case. 2) this actually shows that the universe CANNOT be static which was goal of Friedman in studying this equation. Remember, before 60s most people thought that the universe is static and this was one of the biggest blows to that idea.

[@JMnyJohns]

You killed this. Thank you so much! I've always wanted to be 'walked' through this math but never knew anyone who could. Instant sub!

[@germaindesloges5862]

32:46 One major problem with stating that energy fluctuation is limited by how much its duration is short is that when talking about density it poses the question "How much its duration is short compared to what?". If two of those fluctuations appear one after the other, its basicly a fluctuation which is twice as long. I wonder if taking that into account could somehow help to solve the problem. If i'm right, the computation of vacuum energy density assumes that all fluctuations happen all the time which just doesn't make sense because in that case it's the same as if it's a much longer fluctuation, and therefore should have much lower energy.

[@tiekoetter]

You just explain these things in a very intriguing and understandable way. The usage of the equations alongside your explanation helps to better understand how one comes up with these assumptions about the universe.

[@PhysicsExplainedVideos]

Cheers!

[@HeavyMetalMouse]

I have always been taught that, when your model makes an prediction that turns out false (particularly if it is wildly false), then your first order of business (after checking your math over) is to go back through the various assumptions you made in your model, both stated and unstated, to determine where something we take as obvious or reasonable might in fact not be so. Since the calculated value of the quantum vacuum energy depended on certain assumptions about using the Planck Time as a 'cutoff' for frequencies that could contribute to it, that seems like one plausible place we could have made an incorrect assumption. What 'cutoff' would we have to assume in order to match the observed energy density? What would that revised cutoff imply in a physical sense, and how might we justify or verify that?

[@meofamily4]

Yes, it seems that the smallest imaginable time produces an excessively large energy density, so that such small fluctuations are nonexistent, for some reason.

[@theshadow8900]

My professor asked me about what's ZPE and i found the best video on the web. Tons of thanks ❣️

[@PhysicsExplainedVideos]

Glad it was helpful!

[@TheZorbeck]

The best physics channel I know of. Frankly, it is the first time I hear clear definitions and explanations of most fundamental concepts of modern physics, up to their limits so to speak...But to me a scale factor of 10^120 in the discrepancy of calculated and predicted values is a clear sign there is a fundamental mismatch lying at the root, and a new Einstein is needed to create a new framework to overcome it...

[@scottrobinson4611]

For any fans of SixtySymbols, you may like to know that Ed Copeland refers to the Friedmann equation as the "Cool Dude" equation in his lectures and notes. You have to love him

[@samposyreeni]

You are unreally good at explaining this stuff. In the stuff I already understand as a total STEM nerd of 43 years, you basically nail the simplest explanation I've learnt or discovered, every single time, or you teach me somewhat more. This is a rare treat. Please continue. I'll correct, of course, if there's a reason, as the scientific and didactic process lies. But for now there hasn't been a *single* instance where I could intervene. Usually mind kind of polymath *would* intervene, but you're just too good and methodical. You cover all the bases. And you're TIGHT AS FUCK! The conciseness and preciseness of your presentation well out-shines anything I've ever seen, online, or off.

[@t3hjnz]

Amazing, as always. Thanks for taking the considerable time to cogently summarize and relate these concepts - I always learn something from your videos.

[@PhysicsExplainedVideos]

Great to hear!

[@TheSwartz]

This is one of the most interesting channels on KZbin; you do SO MUCH better with physics than many other channels. I do hope this channel starts posting more videos!

[@tim40gabby25]

If you walk into a room and find a pencil's standing on it's point - you're in a freefalling elevator! Who would have thought :)

[@himanshi0003]

If the elevator is freely falling wouldn't I be in air ? I am not sure my concepts aren't good and I haven't watched the video yet

[@kashu7691]

@@himanshi0003 you could be in an astronaut mall

[@flymousechiu]

I won't be able to walk then because my steps then accelerate me into the ceiling.

[@LuisAldamiz]

I see what you did here, Andrew. We should be thinking in GR terms, not QM ones.

[@BrightBlueJim]

But, no. If you are in a free-falling elevator, you are floating, and a pencil "standing on its point" wouldn't have any meaning, because there would be no up or down. How can a pencil be "standing" in this situation? It can't. It's just floating, like you are.

[@Darkiekurdo]

One of the best channels out there.

[@SreeKrishnaDeva]

Concepts explained in detail and illustrations are extremely helpful to imagine & understand, Thank you

[@PhysicsExplainedVideos]

Glad it was helpful!

[@fburton8]

Squeezing a billion trillion trillion trillion Andromeda galaxies into one cubic metre... He's 'avin a laugh!

[@baruchben-david4196]

It would be very expensive and time-consuming.

[@incription]

@@baruchben-david4196 Would be terrible for the economy!

[@PrivateSi]

I agree. This 4D unified, quantised subspace matter-energy field model provides a few possibilities. Exploding neutrino crystals... locally shrunk/expanded subspace cell width/gap... huge hole blown in the subspace matter-energy field... Black hole universes in black hole universe... -- Bottom-up Thought Experiment... Constraints: As few base forces and particles as possible to form a coherent, integrated 4D multi/universe model -- Subspace Charge Field: +ve charge cells (ball, quanta, +1) held together by free-flowing -ve charge. Matter-energy field conserves momentum -- Matter-Energy: Matter is focused energy.. Energy is mobile matter.. Momentum conserves velocity.. Force changes velocity and/or direction -- Positron/Up Quark/Graviton (p+): Free, out of place cell warps the field, radiating AC field cell vibration 'blip' spheres at C + 6 DC spin loops -- Electron/Down Quark (e-): Hole left behind warps the field, radiating AC field cell vibration 'blip' spheres of opposite phase at C + 6 DC spin loops -- Noton/Dark Matter (n+-): Exactly opposite phase close p+ and e- annihilate (ie. entangled pair created together (e_p) ), else a noton forms -- Nucleons: Proton: P=pep.. Neutron: N=P_e=pep_e.. Beta-: N-e>>P+e.. Beta+: P+e_p>>N+p.. Alpha: A=PNPN=PeP_PeP=(pep_e_pep)_(pep_e_pep) -- Heavier Fermions: Larger holes and chunks of subspace field rapidly disintegrate to p+s, e-s, n+-s and/or annihilate to regular = empty field -- Electrostatic Force: Recoiling blip spheres propagate. Opposite direction + and - blips form a vibrating AC bond, same sign=phase repel -- Instant-Off Long Force: AC (longitudinally blipping) subspace 'flux tube' as thin as 1 cell wide. Each cell and its -ve charge move in contrary motion -- Spin: e-s and p+s pull in the 12 surrounding cells, or -ve charge that pulls cells, that then bounce out, stabilising as a torus of 6 in/out (N/S) DC loops -- Strong Force: Spin loops merge and form flowing DC circuits between e-s and p+s -- Mass: Sum of the lengths of all strong force bonds + near electric field. Notons have compact strong force bonds, Protons' are long as 2 p+s repel -- Magnetism: Some spin-aligned atoms' p+s and e-s' strong bonds join in a shorter straight path. Energy conservation results in external force circuits -- Weak Force: Geometric structural charge balance instability. Possibly noton hits statistically tipping the balance -- Photon: Charged particles moving up and down (transmitter, atomic electron) form a radiating transverse wave blip pattern -- Double Slit: Laser light / particle centre's preceding, extended subspace distortion diffracts, interferes, forming wave guides observation destroys -- Dark Gravity: p+ traps 1 quantum of -ve charge so void cell size/gap grows (and matter's shrinks?) forming a macro -ve charge gradient -- Bang Expansion: Loss of -ve charge to the multiverse?.. Bang ejector velocity petered out, magnified in time by outward momentum conservation -- Gravity Wave: Longitudinal wave where the entire field in a large region is effected in unison for a duration -- Big Ping: A dark crystal universe collisions' intense gravity wave forms e- & p+ pairs inwardly at C that annihilate or form notons, Protons, Neutrons -- Big Bang: Ping wave collides centrally? Field blast forms matter + a large hole (then Big/Dark Refill)? Fast -ve charge loss? Noton crystal exploded? -- Black Hole: Absorbs matter and energy. Noton crystal (with a core returning to empty field)? Large hole in the field traps anything entering? -- Frame Dragging: Entire sphere of subspace cells rotating around a point in unison -- Time: Cell to cell blips take a constant time. Gravity shrinks cells so light slows but locally measures C as circuits lengthen in space & time, adding mass -- Makes more sense than making up bosons to carry force and mass, quarks that don't solve the anti-matter and dark matter problem, anti-neutrinos, loads of fundamental fields, extra spatial and temporal dimensions etc, that ultimately don't tie relativity and quantum mechanics together properly or well... They should at least be honest and call their 'spatial dimensions' geometric/field dimensions or something.. Magic Space is not my cup of tea.

[@PrivateSi]

If space is infinite then any finite volume occupies an infinitely small volume, relatively speaking, even though it does have absolute size.. Even though our universe has expanded, if it is finite in size in an infinite space it still occupies a relatively infinitely small volume... A problem with maths or a feature of reality? I like a finite universal field occupying a finite amount of Real Space that is infinite and propertyless.. My 4D EM Field is all that is needed to explain a coherent universe.

[@pipertripp]

speaking of compactification...

[@justanotherguy469]

This is one of my favorites videos on KZbin, so well explained and simplified, and enables you to visualize what is going on inside of the equations... You can actually see the output and you can see the transformation from concept to concrete reality.

[@FarFromEquilibrium]

Your explanations are amazing. I do have to watch several times to start to get it most of the time. Can't wait to hear the ones you have planned. Who are some of your favorite physicists, alive and dead?

[@PhysicsExplainedVideos]

James Clerk Maxwell is perhaps my favourite..

[@FarFromEquilibrium]

@@PhysicsExplainedVideos Perfect.

[@danielhaslam5179]

Currently completing research for an essay regarding the cosmological constant. Your explanation of the cosmological constant problem is by some distance the best I've seen. Thanks so much and keep it up!

[@tomcook2311]

Awesome video. Excellent wrap up at the end. While the math was over my head the basic problem was very well explained. Thanks for posting this.

[@Markoul11]

@Physics Explained Your videos are a real treasure for youtube. Honestly, you should be given an award for the best physics video content creation in youtube. You breathtaking high quality presentation in your videos and unambiguous in depth and detail formal explanations and physical interpretation given, is leaving really no room for misunderstanding and is an amazing achievement. Be sure your videos are not only educational but are being used also as a review material by scholars and academics. People watching your videos not only appreciate more physics but also mathematics and how these two are entangled together the one pushing forward the other and controlled by logic. Really, best physics scholar literature content in long memory currently on KZbin or any other public electronic media. You have risen the bar to a much higher new level . Bravo!

[@albadarqamar7380]

Thanks again man for this quality content

[@guig008]

I'll be really sincere here and say that I didn't know what dark energy is and was too lazy to search for some boring explanation, and you, sir, made me understand what dark energy and dark matter is without being boring, and for that I must say thank you very much!

[@scdesign1565]

The single most mind blowing and important presentation I’ve seen in some time. How inspiring, not to attempt to solve the problem, of course! One might try to calculate the size of brain you might need to attempt it, but just thinking about these equations is a trip. I suspect Ill be referring to this video for years to come. Many thanks!

[@feekygucker2678]

Watched this on recommendation of one of my profs after explaining that fascination with the vacuum catastrophe was a major reason I was studying physics. Good recommendation prof! Particularly fascinated by the observed/classical/quantum relationship for lambda values. It's got me thinking, 'how does one go about predicting a value for lambda-classical from first principles?' It's a good job I'm well aware (and only a tiny bit scared) that there is no bottom to the question well :). Nice work PE. Easily the most rigorous, compressed coverage I've yet sampled on YT.

[@samw3086]

An incredible channel. Mind blowing stuff. Thank-you for presenting it so well. It would be amazing if and when this problem is resolved. Hopefully in my lifetime.

[@PhysicsExplainedVideos]

Thank you very much!

[@demoa0414]

Writing this while tackling it 🕳️ I'll make you proud prof 🔥

[@vincenthubschmann6512]

Will you ever do a video on the Schrödinger equations, where it’s derived from, what’s it comprised of and what it’s useful for? Or is that not your field at all?

[@flymousechiu]

also, requesting a vid on inflation theory! Really, really large numbers really excite me!

[@klausstock8020]

Yes, would like that as well. Including how the Fock we can make the Schrödinger equations work in relativistic quantum mechanics. Ouch. Thanks, I'll see myself out.

[@mskEduTech]

Very few channels provide mathematical concepts related to fundamental problems in physics as you did , I also have made few lecture videos based on equations on KZbin , but yours are very good. Keep doing this good work as it helps people who are interested in physics.

[@IJustMadeAComment]

Seems like the way were thinking about the production of quantum vacuum “energy” is erroneous and that not all probabilistic fluctuation states possible which do occur cause sustained probabilistic entropic processes (i.e. energy).

[@TheoEvian]

you are mistaken, energy has nothing to do with entropy in this case, THE CHANGE IN DENSITY of energy does. If you have constant energy density (like that one of the vacuum energy) no entropy will change (fluctuations don't cause information transfer since they are completely random, that is another way how to think about it). This is why you can't mine energy out of vacuum with Zero Point Modules like in SG: Atlantis, because that would mean a change in entropy. The vacuum has some energy value: you can see that in the cassimir effect etc. The problem with the vacuum catastrophy is that our naive predictions predict in that case either: infinite value for the energy or with plank scale constraints an unreasonably high value for this energy. Which means: our thinking about the contributions must be mistaken (after all it isn't that different from the thermal radiation problems that created quantum mechanics in the first place), there must be some other effect suppressing the contributions or we are completely mistaken in some other way, the existence of some vacuum energy however is completely sure.

[@alphaomega1089]

Loved the math lesson. One or two commentators raised an excellent point: what can be contained and not what is measured. We occupy a timeframe (channel) which can't see the others. We can only infer those other versions do exist using the math. Compact these and it fits the predicted value. Like your mobile phone ignoring those other numbers being dialled, our universe does the same.

[@VarroTigurius-u1f]

You are always the center of your own observable universe.

[@BrightBlueJim]

Unless you are near the edge of the actual universe.

[@dennisbrown5313]

First off, I accept your challenge. Second, fantastic and very well done presentation on a very complex topic. A very clear approach; obviously, someone without basic physics and some calculus would not be able to follow all the arguments but certainly the general approach. As you have shown the issue becomes a problem due to the uncertainty principle when applied to the vacuum energy. There, I feel, lies both the issue and solution. I am certainly interested in solving this problem and do feel it can be done. Obviously, any solution has to use and agree with existing physics but additional extensions must be incorporated to allow a viable solution. This I do believe is possible and some aspects that I have worked out both have experimental proof (for the assumptions) and follow current physics. Time will tell (and calculation) if my approach is valid. Your youtube topic has really help me with this problem - thank you

[@dennisbrown5313]

Up date: I've actually made some real progress in addressing these and other aspects of gravitation theory, as well (like what space curvature really is) - and my basic idea as extended to gravity does agree with experimental data and is falsifiable; it solves these and other issues but I am still a long way off but aspects are falling into place

[@furinick]

I am horrible at math and when you got into numbers i got a bit (a lot) lost, but at least the colourfull letters and numbers + the calm voice were pretty epic

[@justanotherguy469]

I love your cadence and your ability to take such a complex process and explain it in mathematical terms as well as in in laymen terms and make it totally understandable.

[@duprie37]

This is great! As a non-physicist interested in this stuff, I've heard the massive discrepancy between the energy density prediction & observation mentioned many times, but getting an explanation as to why there's such a massive disagreement is much harder to come by. The string theory anthropic explanation seems very unconvincing. How do we even know those 10^500 other universes really exist in the first place? You may as well say God is watching the quantum pot and making sure it never boils. Surely with that many universes to choose from, in at least one of them God would exist too?

[@crank1985]

Well, for some the universe's laws and theories there is a need of an external observer... or the equations will take a different turn.

[@crank1985]

@Gerard Moloney I'm speaking only from the point of quantum physics that the life is the best self improving and self replicating machine. One that you need a decade of intense study to just realise how vast and complex it is and how much more is to discover. The metaphysical context is not needed here. Especially that I didn't declare that the life is ruled by randomness and started spontaneously.

[@duprie37]

@Gerard Moloney Thanks, but I've read the Bible. In fact I was raised in a good Evangelical household and my Dad was a pastor for a time. The obsession with sin, the hostility towards the sciences, the bigotry and divisiveness did me a lot of damage and really held me back while I dealt with the emotional fallout. In fact I consider Christian indoctrination a form of child abuse. In any case, definitely not for me!

[@dorhinj23]

Q: if you draw a picture of a tree in a field, are you automatically IN that picture? Cheers!

[@johnnilson9039]

That was one of if not the best physics videos I have ever seen. Amazing. Great job.

[@PhysicsExplainedVideos]

Glad you liked it! Thanks for the kind words

[@rushianokun]

LOVE this content! DO NOT STOP PLEASE!

[@evilotis01]

god, these videos are SO GOOD. also: i know basically everyone hates it at school, but it's fucking incredible how powerful a concept as simple as algebra is.

[@MrYukon2010]

I love your excersizes in 'equation substitution' . Together with a nice dose of logic thinking one can go a long way.

[@nihlify]

Thinking the universe should be logical to a human is setting yourself up for failure though.

[@doodelay]

Thank you so much for this, there is not enough quality physics derivations on KZbin

[@jacobburges1374]

Forgive my humanities degree: When the maximum energy density of the vacuum was calculated, was that not the hypothetical maximum energy which could occur at the maximally small length of time? I understood this to mean that that huge number was possible for very short periods of time. You did some fancy stuff with derivatives w/respect to time, but I think that this point stands outside of that: If we were to quantify the probability of that energy density occurring, we could say that on average, across the entire universe, the vacuum energy density could be whatever we wanted it to be. That is, knowing hubbles constant as we do and the predictions that makes for the energy density of the universe, we should be able to model the probability of vacuum energies. I imagine it would be a very low probability that the maximum energy would spontaneously appear, so say its 0.0001% (or however small you need to make it fit our current observations).

[@DrDeuteron]

that's a good point, given the simplified explanation here. In regular quantum mechanics, the vacuum is a stationary state: it does not evolve with time, so the vacuum fluctuations are baked in, so-to-speak. In quantum field theory terms, we'd say to get from an initial vacuum state to an identical final vacuum state, the electron, photon, quark, etc fields coherently take all possible configurations that conserve energy and momentum and are allowed by boundary conditions (see: Casimir force). So the fluctuations are here, there, and everywhere, all the time, with negative and positive energies all adding to zero. The idea that particles are randomly popping in and out at different places for limited times with real probabilities (as opposed to coherent superpositions of complex probability amplitudes) is just too classical to be realistic.

[@carlosgaspar8447]

@@DrDeuteron i'm not even convinced of the conservation of energy hypothesis in the universe, but it does make a convenient and accurate solution to local phenomena.

[@MilitanT07]

A physics channel that is not just about concept and philosophy, amazing!

[@catronimator6265]

50 minutes of awesomeness right here

[@billzemek5707]

This is absolutely the most brilliantly explained and visualised video that I have ever seen, and I have watched a lot of them. What a wonderful contribution to public education. We are all richer for the author's efforts.

[@jamescarnevale3312]

Great video. Seems quantum mechanics has more development ahead - it's vacuum energy is not observed nor possible.

[@PhysicsExplainedVideos]

Thanks for the feedback, much appreciated

[@Richard.Holmquist]

More gold. Who would’ve thought that the upload of this video and a successful static fire of Starship SN11 would occur on the same day!

[@Greenmachine305]

So basically, we barely understand a fraction of the 5% of the universe we can see. This is incredibly comforting to me.

[@AngryCanadian3]

Quality content. I like they way you describe with equations which other channels fail to do.

[@김정-n4d]

Whenever I just want to play. This channel helps me to study math and science. And makes me go a little closer to the goal I have in my life. Thanks for making these informative and inspiring videos 👍

[@haartmannlepak5817]

Boy, that's why I subscribed to this channel. Magnificent explanation of one of the most astonishing facts about our universe. Thanks again for the vídeo!

[@Martin_Taylor_UK]

Beautiful graphics and crystal clear explanations. I’m not a physicist but I actually feel that I understand a little more about the magnitude of the problems facing cosmologists now. Thanks.

[@brianl7321]

Great explanation. As soon as I saw the difference between the predicted and observed I knew the math was going to show some crazy things going on. It sure does seem like the answer lies in getting a better understanding of how dark energy operates beyond "it's the energy of the vacuum". Maybe it's somehow tied to something in quantum mechanics we haven't found yet.

[@PhysicsExplainedVideos]

Glad it was helpful!

[@utzius8003]

I understand nothing, but yet I still watch the video. Weird. Fluctuation, addition, equation, density, interpretation, constants, it feels like my mind is melting.

[@lapisdust]

First rate job of explanation, a real joy to sit back and watch, with pausing and catching up with my thinking. Also, I appreciate the use of yellow, blue, and white colors in the plots and equations, and at least the reds and greens are saturated enough for my Red-Green color blindness. I'm relearning forgotten physics from my youth!

[@PhysicsExplainedVideos]

Glad it was helpful!

[@ricardoraimundo4762]

I have a question. The theoretical value we found for the energy density of vacuum isn't simply its maximum value, not its actual value? Why should we take ∆t=t_p and not one of its multiples? This would probably reduce the theoretical value by intire magnitudes, no?

[@Think_Inc]

This channel has even more subscribers than some other science channels out there, EVEN if it it’s pure math. That shows how good it is. It has also achieved that, within a year, while other channels, which have been around for YEARS, still come nowhere close to this channel’s subscribers.

[@jauhueitang6879]

Excellent presentation! I have solved both the vacuum catastrophe paradox and the mystery of fine structure constant. My paper will be published soon!

[@narfwhals7843]

This was a great, detailed explanation of a topic i have never seen a good video on, thank you very much! But when you derive the acceleration equation you still just take it as a given that the universe is expanding in the first place, right? A cause of the expansion itself is never given. Will a contracting universe "bounce" back to expansion? So solving the ultraviolet catastrophe leads to the vacuum catastrophe... Can't this(and other divergences in QFT from infinite contributions) be solved in a similar manner? Quantizing the amplitude contributions to the energy density? I had a discussion with Zap Physics about this in terms of Feynman Diagrams and they say it would be hard to motivate such an approach given how well the current theory with renormalization works.

[@fawziekefli2273]

15-year old me slapping current me on the head: This; this is what we studied for.

[@not_yet_implemented]

Great video! I wonder if there are any other explanations possible for the red shift..

[@johndef5075]

I thought light was the same speed relative to anything. I dont understand the red or blue shifts.

[@shreyansengupta2594]

@@johndef5075 wavelenth

[@brandonkillham1744]

I have literally, always had difficulty with math, I understood the concept of swapping stuff via division and subtraction etc. But never why; this video, made me understand WHY this is so important and how it helps us understand the universe. Thank you for being a better teacher than 20 years of school and tutoring

[@3Space1time]

Op 👍🏻👍🏻 great video

[@AstradTheCynic]

I can't believe how much I understood With just basic calculus under my belt. Your explanations are superb.

[@chriszachtian]

You are my most-thumbs-up-channel by sure! One thought on vacuum energy: what, if it is not "fair" to put the highest possible energy into the lowest possible volume, then we obviously get an extreme. What, if there are more useful magnitudes for energy and length, maybe similar to Planck's deviation for radiation?

[@aszhara2900]

25:33 This is the most Phycisist move I've ever seen "The equation shouldn't be negative, let's slap a constant at the end that makes it positive" It was actually quite ingenious tho since it worked

[@narfwhals7843]

It is actually completely mathematically rigorous. Adding the constant gives a more general expression of which the form where the constant is 0 is a special case. If Einstein had _started_ with the more general expression his equations would actually have had more predictive power. Instead he started with the special case, saw that it didn't match observation, and expanded it.

[@oyibechibundu628]

Your videos rock!!! Your explanations are better than DR PHYSICS A. I love the way you add math to your explanations Can you do a video on einstein field equations?

[@PhysicsExplainedVideos]

Thanks for the kind words! Einstein's field equations are on the list

[@monday223]

Do you plan an explanation of the standard model and the latest news from CERN?

[@casimirronnlof7396]

Extremely well made video! Thank your for keeping on making these videos, I might even think of becoming a patreon in the future :)

[@PhysicsExplainedVideos]

Much appreciated! Thanks for the kind words of encouragement

[@johndegroot3124]

My cat runs under the bed when I turn on the vacuum.

[@CoreyKatouli]

Another amazing video. I would love it if you do a video that explains why general relativity does not mathematically fit into quantum mechanics.

[@gabelluc9573]

Absolutely agree, looking at why the perturbative method fails for general relativity would be a blast

[@mojtabajahandideh9188]

The best physics channel I have ever seen in youtube!

[@nebulasy8]

Another masterpiece! 👏🏼🏆 Thank you for the excellent videos and the excellent channel! P.S. Could you do a video explaining the electron orbitals? How are they derived from first principles? Their shapes from first principles.

[@Saturnium_]

I was amazed, shocked, and perplexed by this the whole way through. Well done on the explanations!

[@tumelondaba4659]

Great video. Please make a video on the basics of string theory

[@PhysicsExplainedVideos]

Great suggestion, on the list

[@beaconofwierd1883]

36:40 Why would we assume plank length of the cube? :S Aren't we looking at the energy density in the entire universe? Would it not be more reasonable to assume that the plank length is the smallest wavelength we can have and that the volume is the entire universe? If we sum over all frequencies up to a wavelength of the plank length and divide it by the volume of the universe we get around 2.85 * 10^-28 J/m^3. Granted, it's still way off, but interestingly it's very close to the mass density of the universe (9.9 * 10^-27 kg/m^3. Maybe there's a c^2 factor missing somehow? :S Still, my main question is what's the reasoning behind shoving the highest possible frequency into the smallest possible volume? To me it feels like that would simply be the highest possible energy density locally possible, not in any way an estimate of the energy density of the universe :S

[@chcknshznt1319]

KZbin, please recommend this channel to as many people as possible. All it takes is the interest of the right person, it could be any of us!

[@ff00005]

yep but not me, i'm just looking at a physicist pushing dt around. it strangely amuses me

[@mosesgunn6937]

You are an exceptionally gifted teacher.

[@PhysicsExplainedVideos]

Thank you, glad you enjoyed the video

[@tupublicoful]

Fantastic tour the force through 20th century physics and it’s implications for cosmology. This is very hard to do well. Thank you.

[@PhysicsExplainedVideos]

Glad it was helpful!