I believe that the issue is that Science popularizers often underestimate the ability of people that have interest in science to do even basic arithmetic.The final result is that people end up with pretty bad models, but under the impression that they understand. I will say that is worse than before. Also smart people with a superiority complex notice the that model is wrong, do not study the actual science and end up starting a electro-pulsating-theory channel or any similar nonsense and getting a bunch of followers.
I feel like a lot of these books about "the physics of everything" make a tacit deal with the reader: the book will pretend to explain things, and the reader will pretend to understand
@@kumagoro That guy was a complete pseudo-scientist I debunked most of his bs theories on my channel and on my blog vasileffect.blogspot. The only one he got right is the mass-energy equivalence, and thats because he stole it from Poincare.
@@kumagoro That guy was a complete pseudo-scientist I debunked most of his bs theories on my channel and on my blog vasileffect. The only one he got right is the mass-energy equivalence, and thats because he stole it from Poincare.
Wow. For years I've heard about "the worst prediction in theoretical physics" and wondered how there could be such a ridiculous discrepancy (10¹²⁰) between theory and observation. And not once in all those years has anyone ever explicitly mentioned, "Oh by the way, in QFT we're disregarding gravity, so actually we can add any constant to our definition of energy density, so in fact, the vacuum energy density isn't really determined." I'm a "layperson", so I mostly have to TRUST in what scientists tell me. More & more I feel like I've been had! I mean, I've thought to myself before, "But hang on a sec, there's no gravity in QFT so how...?", but then stopped myself thinking "No, it's too bloody obvious, surely they've factored that in somewhere!" Unbelievable.
As an astrophysicist, what you are referring to is the field of quantum gravity which is literally the unification of quantum mechanics (and hence field theory) with Einstein's theory of gravity. It is not that we disregarded gravity altogether, we need to start with simpler models to start constructing more complex predictions. QFT relates to particles themselves (how particles form, particle-antiparticle production, how they interact etc.), so is like saying 'oh particle physicist don't consider gravity?' - no they don't, because that wouldn't be useful in the moment to build or discover what they need. So yeah, we are trying to add gravity now, that's where the whole theory of everything deal comes about, but the whole thing is probably the most complex problems we have ever approached as a scientific community. What might seem obvious is actually a problem that has been going on for decades BECAUSE so many theories are valid candidates but none of them has been proven for certain. For something to be considered valid it has to be proven so many times it leaves almost no room for doubt (that is in the context of a specific theory or regime). So yeah, you should continue to trust the scientific community, if we don't communicate something it's not because we are stupid or haven't thought of it, we simply need to be 100% sure of what we are saying, otherwise our reliability would really be questionable. Also our funding is shit, so many people don't see it worth it to work this hard for such low pay so we don't have too many people helping out, lots of promising young scientists drop out or go on to do something else which certainly does not help.
@@SabineHossenfelder it doesn't matter if it is real or not. It also doesn't matter if the Mach Effect and distant gravitational theory is real or not. Just studying this stuff by mathematicians and scientists can bring further understanding to our universe. Maybe find something useful that works on a different principle but you stumbled upon it in a dead end quest. I hope the following works, andvI don't care why. th-cam.com/video/0bp8fk5rosI/w-d-xo.html
@@SabineHossenfelder You are so on point, it's hot. 😳 Sabine, on a serious note, what's your take on Gerard Hooft's Cellular Automata interpretation of Quantum Mechanics? And doubly special relativity? (DSR would be an easy way to get SR from a CA.) Do you believe superdeterminism is farcical or does it only appear that way because the basis we currently use makes it look like free will / counterfactual arguments have merit? Is our basis inherently biased to look psychologically sound with regard to will - should we accept any fundamental interpretations of the universe that use arguments of freedom and what could have been done - or is this okay because the alternative is an incredibly grandiose conspiracy or universe with an entirely non-psychological basis, that creates strong mystical seeming correlations (entanglement) in a somehow naturalistic emergent way? Do you think entanglement is truly nonlocal, or do you believe it is local in higher dimensions (holographic boundary ?) or perhaps a different metric space basis more fundamental than spacetime (causal sets of causal dynamic triangulation?) Thoughts on Wolfram's graph theoretic model of the universe, and its notion of causal invariance? Thoughts on constructor theory? Is information the most fundamental concept of our conscious lives, and the universe itself? Action is Energy x Time , Joule-seconds. Thus Energy is Action Frequency, Action-hz. Could we look at absolute energy, including vacuum energy, as a computational substance with a fixed amount of compute per Joule? Essentially, each Joule is guaranteed to cause O(t*h) computational/informational changes every t seconds? library.oapen.org/handle/20.500.12657/27994 en.wikipedia.org/wiki/Doubly_special_relativity en.wikipedia.org/wiki/Holographic_principle en.wikipedia.org/wiki/AdS/CFT_correspondence en.wikipedia.org/wiki/Causal_sets en.wikipedia.org/wiki/Causal_dynamical_triangulation
@@danielmconnolly7 THE BALANCED, ULTIMATE, TOP DOWN, AND CLEAR MATHEMATICAL PROOF REGARDING THE FACT THAT E=MC2 IS F=MA: Time dilation ultimately proves ON BALANCE that E=mc2 IS F=ma, AS ELECTROMAGNETISM/ENERGY IS GRAVITY. Time is NECESSARILY possible/potential AND actual IN BALANCE, AS E=MC2 IS F=ma; AS ELECTROMAGNETISM/energy is gravity ON BALANCE. Gravity is ELECTROMAGNETISM/energy. Great !!!! QUANTUM GRAVITY !!!! E=MC2 IS F=ma. This NECESSARILY represents, INVOLVES, AND DESCRIBES what is possible/potential AND actual IN BALANCE. What are the EARTH/ground AND the SUN are CLEARLY E=MC2 AND F=ma IN BALANCE. Very importantly, outer "space" involves full inertia; AND it is fully invisible AND black. The stars AND PLANETS are POINTS in the night sky. GRAVITATIONAL force/ENERGY IS proportional to (or BALANCED with/as) inertia/INERTIAL RESISTANCE, AS E=MC2 IS F=ma; AS ELECTROMAGNETISM/energy is gravity. Gravity/acceleration involves BALANCED inertia/INERTIAL RESISTANCE, AS E=MC2 IS F=ma; AS ELECTROMAGNETISM/energy is gravity. BALANCE AND completeness go hand in hand. It does ALL CLEARLY make perfect sense. GOT IT !!!! THE SKY is BLUE, AND THE EARTH is ALSO BLUE. Great !!! Now, think about the man who IS standing on what is THE EARTH/ground. Perfect !!!! Energy has/involves GRAVITY, AND ENERGY has/involves inertia/INERTIAL RESISTANCE. "Mass"/ENERGY IS GRAVITY. ELECTROMAGNETISM/energy is gravity. E=MC2 IS F=ma ON BALANCE. Gravity/acceleration involves BALANCED inertia/INERTIAL RESISTANCE, AS E=MC2 IS F=ma ON BALANCE; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. (ACCORDINGLY, the rotation of WHAT IS THE MOON matches it's revolution !!!) Gravity IS ELECTROMAGNETISM/energy. TIME DILATION ultimately proves ON BALANCE that E=MC2 IS F=ma, AS ELECTROMAGNETISM/energy is gravity. News flash ! Gravity IS ELECTROMAGNETISM/energy, AS E=MC2 IS F=MA. The Earth (A PLANET) is a MIDDLE DISTANCE form that is in BALANCED relation to the Sun AND the speed of light (c), AS the stars AND PLANETS are POINTS in the night sky; AS E=mc2 IS F=ma. TIME is NECESSARILY possible/potential AND actual IN BALANCE, AS E=MC2 IS F=ma; AS ELECTROMAGNETISM/ENERGY IS GRAVITY !!! By Frank DiMeglio
You have become the most interesting physicist around! I love your channel and jokes and learn so much. Thank you for all that work. I couldn't even learn a second language let alone master it and teach physics using it! You are so intelligent and talented. Thank you sincerely!
Actually she and thunderf00t, are the only actual scientists I can think of with youtube science channels. Lots of science channels, but they're all operated by armchair scienticians. The absolute worst of them all is ridddle, he's scientifically illiterate and just straight up plagiarizes random things on the internet he thinks are obscure enough no one will notice.
Dr. Hossenfelder, thank you for taking the time to help break down these complex concepts. While I still don't completely understand it all, you do help me to get rid of misconceptions that I've had about some of these more difficult theories in astronomy and particle physics. Thank you for taking your expertise to the masses and making these very dense topics more approachable. Excellent work!
The last point about oversimplified analogies is, I think, also particularly relevant in school. Chemistry in particular springs to mind in that they never tell us how it IS, they tell us how it is LIKE. And then, in areas where this model diverges from reality, they give another example of how it is LIKE something else, further perpetuating the problem and making it frustratingly opaque to dissect. Analogies are a double edged sword because they allow someone to gain a foothold in a new area, or to understand the bigger overarching patterns, but when it is used as a substitute for the actual description it becomes more hindrance than help.
Well, we are just now able to simulate how these things at that scale actually might be working. When I was at school, 20y ago, I remember my chemistry teacher emphasizing: "the bohr model is just that: a model that works to explain our observations at our current stage of experimentation."
That's why I hate chemistry back in highschool because we were never taught the "first principle" (I guess in this case would be quantum mechanics) where everything else can be derived... That's why I chose physics and maths back then, thinking they are a bit more, like you said, dissect-able.
@@Philoreason Exactly! And while I fully get that quantum mechanics is probably a bit much for high school students, I feel that high school students are capable enough to understand concepts beyond the almost infantile analogies that teachers use. and the funny thing is that these analogies often end up backfiring because in order to use them, the teachers also inevitably have to explain all of the exceptions to the rule and it ends up feeling more like the grammatical rules of the english language than fundamental truths of reality.
Dr. Hossenfelder you have made me love science and physics more than ever so Thankyou for your concise and humorous studies. I’ve learnt more from you than anyone in the past and you answer most of the things I’ve wondered which makes the future more interesting and enjoyable. Education is key to freeing the mind to its full potential and I feel you are easy to understand on these complex topics. Great channel 👏 (Edit) probably best to comment after watching your video. You answered all my questions 🙏🏻 heading toward a star that is coming our way seems to be the quickest way to arrive when it catches us up.
yeah....She's really helping me nail down key aspects and terminology needed to explain some my own theoretical models. What is interesting her is she delves into the scientific topics most relevant to what I'm researching/trying to discover. Good Stuff!
One of my favorite things about your presentation of these fairly high level physics subjects is that you make it extremely clear where the gaps in our knowledge is and the clear delineation between what we know via observation and the theories we attempt to explain through inference. One of my favorite examples is dark matter. It's name is a misnomer. It's just a description of an aspect of astronomy we don't have a good explanation for when comparing our understanding of physics with our observations of galactic rotation. A lot of physicists thing it COULD be some type of particle because it's convenient and covers a lot of the observations they are making, but it's not even able to do that completely. Plenty of other science educators will tout it as THE answer but fail to break apart the complexities of what is wrong with the model or even mention alternative theories because the admission that our understanding of the subject is actually really limited doesn't SOUND like education, but I think for people seriously wanting to understand the sciences the admission of blank spots in our knowledge and limitations of observation are one of the most important things we can keep ourselves reminded of.
Honestly, I really struggled with early school because so much stuff was simplified and analogised to the point it just didn’t make sense to my tragically over logic little brain. As I got deeper into subjects like physics I felt really betrayed. Now when I teach compsci, I am overly sensitive about being blindingly clear when I am simplifying; and I always try to do a “deeper dive for the interested”. We should never teach analogies as facts just as poor illustrations that allow us to access a deeper concept. Thanks so much for your approach.
@@Brianboy9494 Approximations are meant to make our lives easier. They have to be "good enough to be useful", which means that only the practitioner in a field can develop a good feeling for the range of applicability of an approximation. You are of course correct that physicists are usually able to smell an approximation from miles away while the layman is, at best, guessing what it is that he is looking at. That's a serious problem in science communications and not just in physics. That is my reason for pointing them out wherever I see somebody misusing them.
I really, really look forward to Sabines new videos every Saturday. Love this channel and Sabines sense of humour
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Sabine is the most uneven presenter on the internet. The one thing that is constant is she is completely honest. Sometimes she is wrong and sometimes her presentations are confusing. I subscribe because sometimes she hits a home run. Her explanation of Vacuum Energy was best physics presentation that I have every heard.
THANK YOU! Thanks for including the equations and explaining them as you go. Thank you for using more accurate / less confusing terms. And Thank you for your humor! That makes otherwise science more fun!
I love how Sabine is transparent about the science; often science reporters push one theory or paradigm without addressing it's flaws, but she seems to truly be impartial.
1) I love the Sabine 'listening/confused/puzzled' expressions, I was pulling the same at the reply. 2) I'm now off grid with a ZPM I found in the back of a dumped puddle jumper :)
Thanks Sabine! I have been trying to understand Vacuum Energy for a long time. I STILL don't understand it, but now I am more confident in my ignorance!
Ive got vacuum energy....every tuesday bout 10 am...out comes my vacuum and i use energy ..so vacuum energy..😁Dont know wat these scientists are on about saying its a hard problem etc...i sorted it in 2mins...WHERES MY NOBEL PRIZE 🤣🤣🤣🤣😍😍😍😍😍🤣🤣🤣🤣🤣🤣
Vielen Dank, Frau Hossenfelder für die klaren Erklärungen! Das ist der beste Kanal, der sich mit aktuellen Fragen der Astrophysik in wirklich für den Nicht-Fachmann verständlicher Sprache nachvollziehbar auseinandersetzt und vor allem die Widersprüche nicht ausklammert, der also nicht nur ex-kathedra doziert, sondern den Zuhörer in die Gedankengänge mitnimmt. Nochmals: Vielen Dank!
Space Time tried to explain several things which are not explained here for example where the cosmological constant comes from. But in this video it would have been misleading and rightfully Sabine go straight to the point.
this is even better... The "EM Field" or "Tesla's EM Gas" is an IDEAL BOSE GAS of EM DIPOLES or EM Quantum Kinetic Dipole Particles that kinetically collide in the vacuum causing "vacuum pressure". The Quantum Superfluid (QSF) flowing inside elementary particles are a Bose-Einstein Condensate of EM Quantum Kinetic Dipole Particles and each EM Dipole has a mass of about 10^(-90) kg each. There are about 10^(72) EM Dipole Particles per cubic meter of "Vacuum" in our solar system with a total mass of 10^(-18) kg /m^3. This is dark mass / matter!!! These dipoles have an RMS velocity of "c" and they carry all momentum/energy in the vacuum . This is vacuum energy. Like less than half a Watt! The vacuum is not empty it contains EM Dipole Particles! The speed of light is the "Speed of Sound" in the Quantum Ideal Bose Gas of EM Dipole Particles. Both My Father who helped launch Apollo 11 and Wernher von Braun said so in the 70's! NASA/DoD Black Projects used EM QKD Theory to make Warp Drives no in the skies in the UAPs. As soon as you DROP SPACETIME TRASH and use Ideal Bose Gas Laws with EM Dipoles as the particle, you will NEVER solve TTOE and design your own UFOs! We "finished" TTOE 3 years ago using Bose Gas Laws at it us only took 3 months to solve Gravity! The Mass/Energy Density Gradients in the Vacuum containing the Ideal Bose Gas of EM Dipoles causes a net momentum transfer in the direction of the gradient or DOWN!
@Joaquin Yeah, PBS spacetime is v solid. But I sometimes just don't understand it, esp when they get deep in the maths. Sabine is very clear to any ignoramus with a decent IQ and without a Journalism degree (which seem to make any kind of knowledge acquisition impossible).
I really enjoy your channel Sabine. I finally can understand some aspects of physics that perplexed me thanks to your presentations. Yours is a most excellent resource, and was most definitely worth my subscribing to!
I just started watching for less than half a minute and I am already having the best fun! This is physics explained in most entertaining way imaginable!
I feel like the explanation the editor gave goes something like this: "If we view a ball rolling because of the wind as a ball rolling off a slope, we would conclude that such a wind speed corresponds to such an inclination of the slope. And that's why balls move in the wind."
Thank you for your fascinating observations on mainstream science! It is very pleasant to hear real scientists make sense of what we don’t know. I would love to meet you and have coffee and talk about physics… I am a particle physicist too
The editor's reply is exactly the sort of text my prototype AI response generator regurgitates when trained on previous Q&A datasets. So I'm not entirely sure it was a human that replied.
I'm new to this channel. But both the reply in Scientific American and (especially) your facial expression in response to it was hilarious! As the Brits would say "Jolly good show!" Your response to inappropriate analogies reminds me of Mr. Feynman's critique of 'invisible rubber bands' as an analogy for gravity.
Thanks Sabine for your great insights. They are Invaluable and useful. You seem to be in a trajectory lately, to erradicate all the nonsense in this field and you are certainly not afraid to break some eggs. You have my support! There is no need to be kind to people in positions that they shouldn't be in, like that awful editor. Keep on doing the great work!
I would like to see Sabine debate Sean Carroll on this point. I watched a lecture from the Great Courses on candidates for dark energy and Carroll explains the vacuum energy in terms of QFT, which is where you get the outrageous prediction of 10^112 as opposed to 10^-8 for the vacuum energy. He explains these concepts very thoroughly so I’m surprised to see them dismissed here.
The thing is, General Relativity and QFT are different realms of Physics. With all this Cosmological constant and Vacuum Energy business many accounts mix them up, and that generates confusion. Look how careful Sabine has been in explaining the CC under GR, without need at all of QFT. If a Vacuum Energy consistent with the expansion of the Universe is never derived from QFT... well, GR is perfectly happy with the CC as a constant of nature the same way it is with the Gravitational Constant.
I expect that Sabine knows that the prediction from QFT, No? Does she disagrees with QFT? I have not seen her say that. And she would have mentioned that.
@@theta-rex explain these premises you describe as "wrong". E.g. where Sabine describes the term as simply a constant in the equation, this is undeniably true. How can you say it isn't?
@@theta-rex are you saying that the interpretation of the cc as representing something real is possibly just a conceptual convenience, employed only as a means of making sense of the models (GR particularly) we currently use to describe the universe, and that gr could just be insufficient at the scales in question?
I always thought it is weird that it is just generally _assumed_ that vacuum energy equals dark energy but no one has come up with feasible mechanism explaining _how_ the quantum boiling of vacuum would make spacetime expand on the largest scale. Thanks for clearing this up!
It is still an assumption that the vacuum energy is what is fueling the universe's expansion. It's an assumption that it will have constant density forever until even quarks rip apart. We've been testing and observing this a very short period of time. Hell, we're second guessing now whether we're even right about how fast it's expanding. We just need to keep in mind that these cutting edge theories are built on assumptions, which are built on other assumptions. The assumptions can be proven wrong. I recommend PBS Spacetime's video "How An Extreme New Star Could Change All Cosmology" as an example of this. Turns out we just might be wrong about the supernovae that we base a lot of cosmology on.
@@defenestrator9119 I get you. But the thing is, afaik, there isn't even a proper hypothesis for a mechanism how quantum vacuum fluctuations would cause a positive vacuum energy density, since quantum zero-point energy is zero on avarage. Given that and the problem of "vacuum catastrophe" it is likely that dark energy can't be explained by vacuum fluctuations alone. And yes, I've watched almost every episode of PBS Space Time ;-)
@@KennyT187 I tremendously agree. It's a great and huge step from the calculation of these virtual particles popping into existence for a very short time then annihilating, causing expansion. Meanwhile in their brief instant they leave a bit of gravitational attraction that cannot disappear. Cumulatively it's 10 to 120th greater than what's observed, according to latest news. But where do we get the minus sign? The inflation of space containing this gargantuan density, rather than the universe collapsing on itself. Need some 'splainin, Lucy.
This is comforting . So often Sabeens explanations seem closer to natural intuition than the ones you hear from other commentators as if many are trying to over sensationalise by making it more counter intuitive for which there really is no need
I am glad that there is somebody out there that explains this so clear. I always though that "vacuum energy" as result of "quantum fluctuations" was gobbledygook. On the other hand, if vacuum energy increases, because expansion of space, does that means that the mass of the Universe increases?
Good question, I figured there can never really be an increase of mass, but the scattered mass bodies in space merge together to become one body with more mass to achieve the mass-energy equilibrium, same as happens on quantum level. Black holes tend to have the same merging behavior as already has been discovered.
@@ronnyklingeleers2293 What does bodies merging together have to do with "achieving the mass-energy equilibrium"? And in what way is that the same as "happening on quantum level"?
good morning to my favorite teacher, today's first is queued up, and tonight i'll see where that leads; i've never had so many questions i want to ask, yet i would never ever wish to introduce a frown to a great teacher's day, 2:49 , sometimes it is the things that dont as much as the things that do and the whys that are the utmost illuminating, and i am at the point i realize something.......7.01....... and no idea what i am realizing, vacuum physics indeed,
This explanation raised a new question for me: If we agree that vacuum energy is a constant, non-fluctuating enery level from absolute zero, which is everywhere in space, and does not dilute as space-time expands or contracts. Then doesn't it mean that on its own, vaccum energy does not have any "preference" to either expand or contract the universe? All it does is just accelerate whichever state we are currently at. If spacetime is contracting in an area, it will assist in this contraction, and if its expanding in an area, it will assist in accelerating it. So, it does explain why space explansion accelerates, but it does not explain what is the initial thing that drove acceleration above the threshold where vaccum energy alone could keep up the acceleration going (and im not informed enough to confidently say it's the big bang, and that this event alone was enough to get us here), and also doesn't tell me what's stopping space time from locally contract and be accelerated in the other direction by the same vaccum energy principle, or why can't that spread/overtake the current acceleration outwards.
I’m unsure if this is a fact or a joke? Either way it’s quite funny and a reflection of how both publications have fallen into the political pit of despair.
As someone who used to routinely put closed refrigeration systems into a vacuum, I can say with experience the deeper the Vacuum the Harder the Suck, & with a large enough vacuum chamber you can extend that Suck. That's why the accumulated Gravity of all Universal Gravity Sources just comes up shy of overcoming the Massive Quantum Suck of an Eternity of Nothing
Would you mind talking about the Cauchy horizon and that result that says the GR equations don't work after a certain point? I remember reading about it in Quanta Magazine, and when I went to check in the paper it was based on I only got more confused.
@@thstroyur www.quantamagazine.org/mathematicians-disprove-conjecture-made-to-save-black-holes-20180517/ This is the article in question. The paper is referenced in it. The authors are Dafermos and Luk.
@@nooneinparticular3370 Read article+abstract--OK; first off, it seems to me the article itself did a good job explaining what's going on except for the title, "Mathematicians Disprove Conjecture Made to Save Black Holes", because the topic is the (strong) cosmic censorship, not the existence of BHs or something - a better title would'be some like "[...] to Save _the Intelligibility of_ Black Holes", IMO. Another slip they made is the popular mistake of equivocating space-time with the dynamical object considered by GR, as exemplified in the quote "[...] Einstein’s theory of general relativity [to] predict the evolution of the shape of space-time". In reality, what Einstein's theory does is to give us this thing called a _metric_ , which is a property of certain types of sets known as Riemannian manifolds that model space-time, yet in GR are seen as dynamical things that depend on matter content (in fact, physically speaking, they have to do with gravitational potentials, though not directly); then, to get these metrics, we solve the Einstein eqs using this "Cauchy" stuff by providing 1) a 3D "slice" (a "Cauchy surface") with a given, known 3-metric associated, and 2) information telling us how that slice is "imbedded" in the larger 4D space(-time) (often referred to as the "extrinsic curvature") (for the more technical details, check link.springer.com/article/10.1007/BF01645389 , or the famous book by Hawking and Ellis). With this, it is possible to solve for the Einstein eqs even numerically, except under certain circumstances - e.g., for a Cauchy surface between an event horizon and this "Cauchy horizon" the article mentions. The takeaway of what these guys claim is that yes, you can have a _metric_ manifold beyond this horizon (otherwise you could _still_ have a generic manifold there defined by hand, which in a sense would still be a "space-time", albeit highly unusual) - but the catch is, this metric is just C^0 - i.e., it doesn't have well-defined derivatives of 1st and higher orders, and as such you still can't find the metric beyond the horizon via the Cauchy method, using some Cauchy surface outside the horizon. Hope this technobabble might shed some light on all the mathematical mumbo-jumbo 😵
@@thstroyur I'm a mathematician actually, but you did help me. What I wasn't sure about was what exactly the "Cauchy horizon" was, since I couldn't find a proper definition. I wasn't sure if it was an actual hypersuface inside the black hole or some weird abstraction. And my actual question then would be: doesn't this then mean that speaking about a "singularity" (whether it be in the center or in a ring around it) is misguided, since the Einstein equations don't even really apply after a certain point? And what about ring singularity getting bigger as the black hole spins faster? Doesn't that mean at some point its predicted location would be outside the Cauchy horizon? What's the deal with all that? This is more precisely what I wanted Sabine to clarify. I didn't specify it since I wanted to leave a quick commment and go check the video. I imagine Sabine would naturally answer these questions of mine. If you can answer them yourself I'd feel very thankful though!
Before I saw this video, that math equation looked like a bunch of letters and numbers thrown together by my 18 month old granddaughter. Now it actually makes sense! Thank you Sabine! :)
Thank you for that explanation, which basically says vacuum energy is defined as zero, and must be zero, or else it would exert a gravitational field. I did a lot of research, in my early years, chasing down this elusive vacuum energy. Also people constantly interchange the terms energy, power or work, which they are not. We are really after power, or work provided by utilizing differences in energy states. I remember attending a lecture by Prof. Harold Puthoff in 1994. I spoke with him afterwards. He talked about these experiments which he carried out at UCSD, related to attempts to extract Vacuum Energy. He was able to create helical electron streams to extract work, from a force which must of had only the explanation of being created by the vacuum zero-point energy. Of course, this is one way to understand this acceleration. He used a calorimeter, in a closed system, to measure net energy gained and displayed microscopic images of the electrons' path to prove the existence of the force. He approached every sector of the energy industry, with the results. The nuclear industry leaders wanted to replace their expensive enriched uranium rods with these devices and said they would use these, as it would solve the problem of nuclear waste. The oil companies said they wanted to use this as well, since fossil fuels were becoming more expensive to extract and they were looking to diversify their investments to stabilize their profits. This shot down the idea than an evil conspiracy exists which colludes to stop the use of alternative power sources. (I won't say that there aren't some people who might not want more alternate power sources, but this list is far fewer and less powerful than those who do want it). ANYWAY, Puthoff realized, however that although he tried this experiment in many different configurations, it really never proved that net energy could be extracted from the vacuum in any usable form or at all. The energy extracted was very small, in the microwatts and of course, the energy required to put the electrons into a situation where they could spiral down, was orders of magnitudes higher than that. So, he devised the "One Watt Challenge," which meant a closed system must be able to demonstrate a net extraction of one watt of vacuum power for an indefinite period of time. No one has ever demonstrated this, because the laws of thermodynamics are fundamental to the stability of the universe. Its barking up the wrong tree to attempt to extract vacuum energy. Its better to chase elusive energy sources, like fusion, remote energy extraction or solar, wind, etc, than to attempt to extract energy from the vacuum. Because of what you said, we are not after Free Energy, but rather "Low Cost Power". Its power and not energy which does work. Its the "power company", not the "energy company." Even electrons display energy in their ground state. Brownian motion is a form of energy, but not power. Nothing is free; what we need are power sources which are worth the cost of creating the device used to extract it. At this point, we seem to be doing the best we can, which is sad in itself. Because then you realize what a great source of power fossil fuels really are, and they are becoming more difficult to extract, as time goes on. I am optimistic we will overcome all this and someday figure out how to transfer geothermal energy more efficiently, over a broader area of the Earth's surface, due to efficient graphene production methods. I also believe solar prices will continue to decline, due to cheaper electronics manufacturing methods. And ultimately, we will discover some method of focused fusion/fission which will prove useful in more compact systems. I don't put much stock in Tokamaks, because we've spent hundreds of billions on trying to create the conditions of the surface of the sun and are still 50 years from creating something usable. We've spent only millions on focused fusion/fission research. We've barely begun to try out the endless possibilities in that area, whereas the Tokamak route is only a question of optimizing its efficiency. A tokamak is only capable of extracting heat, which is inefficient. Focused fission/fusion has many possible routes, where electrical energy can be directly extracted without first being converted to heat.
Thank you, Professor. Years ago, I read literature and the physics text by Professor Richard Fynemann. Human understanding is very limited in our infinite universe.
You're so right about inappropriately oversimplified analogies, Sabine. I've spent my whole life trying to drag sense out of stupid pop-sci analogies. It's far harder work than it should be.
@@waldwassermann Much as I'd love to get into a semantic debate about the two separate meanings of "simple" we're using, (which is the same pitfall that overuse of Occam's Razor can lead to), "simple" and "intuitive" aren't the same thing.
This formula might reveal dark energy being the difference between n=0 (Black Hole?) and n=1 in the Schrodinger solution of the universal wavefunction. I try to combine the cosmological constant and the Schrödinger solution on the Planck scale. I used Planck units. At the end I went back to SI units to compare with the measured vacuum energy density (0.63 10^-9 J/m^3.) Combine: 1) Einstein, cosmological constant 2) Schrödinger solution 3) Planck units Result: - vacuum catastrophe solved? 1)Einstein, cosmological constant Λ = (8π 𝐺 ƐΛ)/(𝑐^4) Planck units: G=1 c=1 Λ (6.1871424 10^34)^-2 = (8π ƐΛ [PlanckEnergy/PlanckVolume] 1.1056 10^-52 (6.1871424 10^34)^-2 = 8π ƐΛ 0.001149 10^-120 = ƐΛ 0.1149 10^-122/ ƐΛ = 1 2)Schrödinger solution, n=1 (ℎbar^2 𝑛^2 𝜋^2) / (2𝑚𝐿^2) = E Planck units hbar=1 n=1 m= mPlanck =1 L= LPlanck=1 0.5 𝜋^2= E 1= E/0.5 𝜋^2 3)Einstein, Cosmological Constant = Schrödinger solution 0.1149 10^-122/ ƐΛ = 1 = E/0.5 𝜋^2 0.1149 10^-122 0.5 𝜋^2= ƐΛ EPlanck EPlanck =1 0.1149 10^-122 0.5 𝜋^2= ƐΛ 0.567 10^-122 = ƐΛ [PlanckEnergy/PlanckVolume] 0.567 10^-122 1.9561 10^9 /(1.61625502 10^-35)^3= ƐΛ [J/m^3] ƐΛ = 2.627 10^-9 [J/m^3] Measured: 0.63 10^-9 [J/m^3] I am looking forward to your response.
I don't know if Sabine ever considered merchandising, but if she does, she needs to make a shirt with a tasteful drawing of Einstein and the caption, "THAT GUY AGAIN".
Last time I was this early my vacuum had energy. I followed everything except the definition of the scale factor. Anyone care to explain the scale factor more thoroughly?
The scale factor is just a number, a measure, that tells us how much are the distances between objects in the universe increasing over time due to the expansion of the universe. Since the expansion is 'stretching' the empty space between objects and thus pulling them away from each other as a result in all directions, over time that means objects become more distant from each other. The scale factor is simply a number that tells you in what way that distance will change over time, in this case increase.
@@ThatCrazyKid0007 I'm still confused. So measuring the rate of expansion gives a proportional relationship to vacuum energy? Hmmm, if I understand this correctly, vacuum energy will increase exponentially with time. I guess the Big Rip is real.
MMM... another great presentation Sabine..... Much of the math is beyond my level, but the way you explain things means that I can get a handle on the ideas in an "analogue" kind of way. My knowledge of physics is pretty basic, but I find I can grasp your points quite well even on something as esoteric as this.... Thank you, you keep my 80 year old brain busy, and at my time of life that is a good thing... 🙂
interesting! if you refear to PlanckUnits as multi-brane resonance fluctuations it all might just be a Conway's Game of Life simulation on gods gaming rig!
Yeh, but only because units are an untangible element of measurement, not an actual thing. Yes, i am including Planck length. I mean if you have a ruler you'd find you need more notches. But then maybe you confuse plack length with an idea of universal 'pixellation' which is not what it is...you are free to speculate it is however, such as if the universe is a simulation, i suppose they could be incrementally growing more disk space 🤔
@@MrDlinch maybe not constant but more cept in check by gravity. On smaller scales interactions between particles are strong enough to not be pulled by expanding space, but I guess it doesn't mean the rug of spacetime isn't pulled from beneath our legs, but chemical and gravitational bounds are stronger. I don't know if the Planck unit should be derived from matter instead of the space grid?
You rock. Love the way that you break this down. Thank you. I’m still astounded at the constancy of the vacuum energy for a given volume despite the accelerating expansion of the universe. I imagine that this is a big question that once solved will lead to deeper understanding. Is there any relation between the expansion of the universe and any variable at all? Do you think the answer lies tied up in higher dimensional non-de sitter space?
PLEASE!! :'D Sabine gib uns mehr Reviews mit face-reaction xD deine Mimik ist so expressiv, sein ein Laie der im ersten Moment gar keine Ahnung hat worum es geht _fühlt_ sofort mit und ist "auf der selben Wellenlänge" -- und die die inhaltlich auch noch mitkommen, leiden synchron mit dir -- es ist einfach herrlich ^_^
Here, I show the math: th-cam.com/video/bl_wGRfbc3w/w-d-xo.html&lc=UgwaAqpQUOaoXE9bGvp4AaABAg It's just simple math - not as much any "real" physics...
After August 2014, due to EU rules, manufacture of vacuum cleaners with a power consumption greater than 1600 watts were banned within the EU, and from 2017 no vacuum cleaner with a wattage greater than 900 watts was permitted. [wikipedia]
@@PMA65537 That explains why British left the E.U. and some other smart countries like Switzerland and Norway don't want to join it. These Eurocrats want us now to clean our houses for longer time. Thanks God my vacuum cleaner was produced before 2014 and is 2200 Watt!
An omnipresent energy that's equal for any point in space can only have a net force of 0. If there's no change for point A to point B it has no effect. Also, there's a lot of volume in space, which either contains something is truly vacuous. If there's energy particles or mass particles or anything there, it's not vacuous. Also, if minus lambda g mu v does not dilute with the expansion of spacetime, then the sum can only be zero. If the sum of energy per volume is fixed, and spacetime streches to increase it's volume, then the energy would dillute. You can have either expansion AND dillution, or no expansion AND no dillution, mutually exclusive.. This extends to volume. expansion dillution volumetric change, or no expansion no dilution no volumetric change. What scientists perceive as volumetric change does not happen, only the positional changes of the content within the volume. There's no volume change, no dilution and no expansion. The matter and energy within change position but does not change the consistency of the volume. Since there's no change from point A to any other point B, the sum effect is zero. The only exclusion is when the vacuum energy does not exist, totalling zero. Then when the volume increases, the energy density remains unaffected. The universe is two things, the volume of space and the content. The apparent expansion, which does not happen, is caused by the motion of the content, not the volume. The filler is in motion and moves away from each other, which gives the apparent, yet non-existent, expansion, which gives the illusion of expanding volume.
They're terms in an equation. Often there's infinitely many like the geometric series for 1/(1-x). So everyday language isn't good enough, more precise language is necessary. A huge part of it is simply developing the language to describe it.
Sabine raises a very, very important point in that analogies are only that. They're there to further an idea towards the Eureka-moment, not define the science that explains it. Vacuum energy and the mysteries within that realm are probably some of the most confounding and exciting part of physics. Great video
My intrusive thought about dark energy: The universe severs itself due to the expansion of the universe eventually expanding faster than light. Like an event horizon it splits virtual particle pairs which is the force we call dark energy.
4:32 lambda is the energy density of the vacuum, which is energy per volume of empty space 4:41 vacuum energy doesn't dilute if the universe expands because it's a property of space-time 6:45 vacuum energy summary
Actually the 'p' in ∆U = -p∆V refers to the external pressure that the gas (or system) expands against. If an ideal gas expands into a vacuum it does no work and its internal energy remains constant. The assumption of zero forces between the particles of an ideal gas ensures that U is independent of volume unless the change in volume occurs in a way that the gas does work or has work done on it.
I have learned a lot about physics on this and other sites, but all of this incomprehensible to me. Sabine, you are the best. I like watching you for the humor.
Thanks for explaining this better than some books I've read and tried to understand this (vacuum energy/dark energy/cosmological constant). This includes books by Weinberg (First 3 Minutes, 1993); Barrow &Tipler (Anthropic Cosmological Principle, 1988, equations over my head!); Ross (Why the Universe is the Way it is? 2008, fine tuning argument); and Krauss (Universe from Nothing, 2012). Each seems to summarise the vacuum energy of the universe in different ways, that is confusing for a lay reader like myself. Some clearer explanations I've read were by Sean Carroll, the 10^120 difference between quantum field theory calculation (10^116 eV/cm3) and observed reality (10^-4 eV/cm3), The Particle At the End of the Universe (2013), pages 254-56. Others by Hawking & Mlodinow (Grand Design, 2010); Barrow (Book of Universes, 2012); and Kaku (God Equation, 2021, mentions assumptions of general relativity & quantum mechanics). They all explain it from different angles. I would still like a physicist to show me the maths step by step for how they get the huge 10^120 difference between the quantum field theory calculation and the observed reality? I hope Dr Hossenfelder could do a video, showing the maths step by step how physicists arrive at this huge 10^120 disparity? Even if I don't understand all the maths, I still like to know what each symbol represents and what assumptions are behind it? Anyway, big thanks Dr Hossenfelder for seeking to explain physics to the general audience and for pulling up physicists when they "leave scientific disciplines" and head off into hypothesis, aesthetics, philosophy, and belief statements. Nuff respect to Dr Hossenfelder, I appreciate your explanations greatly.
I always viewed that gravity is the result of the compression of space time such that when an apples fall towards the center of the earth, for the apple it is traveling at a constant velocity through the curvature of space time towards the center of the earth. But for an observer since space time gets more compressed towards the center of the earth they see it as as a accelaration of the apples speed. This acceleration phisically manifest its self as what we feel as gravity. Dark energy seems to be the opposite. As the universe expands from the center outwards to the void we are moving from higher gravity compression to a more decompressed gravity field. Such that the time dilation near the centre is slower than the time dilation of the outside void (where time dilation is faster) where the universe is expanding towards . This difference in time dilation is what we percieve as an accelaration, and it phisically manifest it self as dark energy. If we plot this by an xy graph where gravity is -y and dark enery is +y . And +x is time. As you move toward a gravity well -y the curvature is what we percieve as an accelaration. For dark energy +y as you move from the center of the universe towards the outside void there is also a curvature which we also percieve as an accelaration . All the galaxies are moving out ward at a constant velocity through the curvature of an expanding universe. But as an observer this curvature would appear as an accelaration. May be this is just too simplistic of a graphical representation and is completly wrong.
It’s more than a little nonsensical to ignore an error in the calculation that’s a whopping 120factor out of alignment, but no worries, we can ‘renormalise’ that and ignore it, it works everywhere else in today’s interpretation. =o/
Astronomy is in fact astrology in the sense that predictions in that field are extremely off, change radically very often and our understanding of the stars is no better than a horoscope.
As always common sense analysis Is your winning hand,why do some specialists seem so lost in the details,the forest is the trees and show this clearly.Thanks for that.
At 2:36, Peter should have been Paul. Sorry!
Sabine, did you forget the temperature term from the internal energy formula - or why does it vanish? Thank you!
dQ=0. If this doesn't answer your question I don't understand the question, sorry.
Peter, Paul and Mary were a great band though.
@@SabineHossenfelder , if we look empty space as an ideal gas and this ideal gas has an energy (density), shouldn't it then also have a temperature?
I believe that the issue is that Science popularizers often underestimate the ability of people that have interest in science to do even basic arithmetic.The final result is that people end up with pretty bad models, but under the impression that they understand. I will say that is worse than before. Also smart people with a superiority complex notice the that model is wrong, do not study the actual science and end up starting a electro-pulsating-theory channel or any similar nonsense and getting a bunch of followers.
I feel like a lot of these books about "the physics of everything" make a tacit deal with the reader: the book will pretend to explain things, and the reader will pretend to understand
TV news in the United States
I have a physics degree and I teach physics for a living. You are correct.
@@SeventhSaucer 😢
hmm yes yes, i understand
Sabine: you know nothing Jon Snow
"I didn't understand this answer"
Good to know that I'm not alone.
Its because the answer didnt adress gravity, right?
Answer didnt address any thing, as if it was meant for non physics people only. It was what a snake oil salesman would say, or maybe a fortune teller.
@@sukhdevujwal5126 Except that the seller/teller is a physicist.
No, you're not alone. I can barely understand any of the stuff she talks about, it's all way over my head. But she sure is cute.
Unfortunately I rarely understand Sabine's answers either lol
I am always totally happy when Sabine points to Einstein's picture, saying: "Yes, that guy again." What a magnificent running gag!
@@kumagoro That guy was a complete pseudo-scientist I debunked most of his bs theories on my channel and on my blog vasileffect.blogspot. The only one he got right is the mass-energy equivalence, and thats because he stole it from Poincare.
@@kumagoro That guy was a complete pseudo-scientist I debunked most of his bs theories on my channel and on my blog vasileffect. The only one he got right is the mass-energy equivalence, and thats because he stole it from Poincare.
Wow. For years I've heard about "the worst prediction in theoretical physics" and wondered how there could be such a ridiculous discrepancy (10¹²⁰) between theory and observation. And not once in all those years has anyone ever explicitly mentioned, "Oh by the way, in QFT we're disregarding gravity, so actually we can add any constant to our definition of energy density, so in fact, the vacuum energy density isn't really determined." I'm a "layperson", so I mostly have to TRUST in what scientists tell me. More & more I feel like I've been had! I mean, I've thought to myself before, "But hang on a sec, there's no gravity in QFT so how...?", but then stopped myself thinking "No, it's too bloody obvious, surely they've factored that in somewhere!" Unbelievable.
As an astrophysicist, what you are referring to is the field of quantum gravity which is literally the unification of quantum mechanics (and hence field theory) with Einstein's theory of gravity.
It is not that we disregarded gravity altogether, we need to start with simpler models to start constructing more complex predictions. QFT relates to particles themselves (how particles form, particle-antiparticle production, how they interact etc.), so is like saying 'oh particle physicist don't consider gravity?' - no they don't, because that wouldn't be useful in the moment to build or discover what they need.
So yeah, we are trying to add gravity now, that's where the whole theory of everything deal comes about, but the whole thing is probably the most complex problems we have ever approached as a scientific community. What might seem obvious is actually a problem that has been going on for decades BECAUSE so many theories are valid candidates but none of them has been proven for certain. For something to be considered valid it has to be proven so many times it leaves almost no room for doubt (that is in the context of a specific theory or regime). So yeah, you should continue to trust the scientific community, if we don't communicate something it's not because we are stupid or haven't thought of it, we simply need to be 100% sure of what we are saying, otherwise our reliability would really be questionable. Also our funding is shit, so many people don't see it worth it to work this hard for such low pay so we don't have too many people helping out, lots of promising young scientists drop out or go on to do something else which certainly does not help.
TRUST, but sceptically ;-)
[cf. Trust but Verify..]
Another video, I have 3 to watch, a great way to spend a Saturday afternoon, thanks for all the hard work.
Happy you enjoy them!
Same!
@@SabineHossenfelder it doesn't matter if it is real or not. It also doesn't matter if the Mach Effect and distant gravitational theory is real or not. Just studying this stuff by mathematicians and scientists can bring further understanding to our universe. Maybe find something useful that works on a different principle but you stumbled upon it in a dead end quest. I hope the following works, andvI don't care why.
th-cam.com/video/0bp8fk5rosI/w-d-xo.html
@@SabineHossenfelder You are so on point, it's hot. 😳
Sabine, on a serious note, what's your take on Gerard Hooft's Cellular Automata interpretation of Quantum Mechanics? And doubly special relativity? (DSR would be an easy way to get SR from a CA.)
Do you believe superdeterminism is farcical or does it only appear that way because the basis we currently use makes it look like free will / counterfactual arguments have merit? Is our basis inherently biased to look psychologically sound with regard to will - should we accept any fundamental interpretations of the universe that use arguments of freedom and what could have been done - or is this okay because the alternative is an incredibly grandiose conspiracy or universe with an entirely non-psychological basis, that creates strong mystical seeming correlations (entanglement) in a somehow naturalistic emergent way?
Do you think entanglement is truly nonlocal, or do you believe it is local in higher dimensions (holographic boundary ?) or perhaps a different metric space basis more fundamental than spacetime (causal sets of causal dynamic triangulation?)
Thoughts on Wolfram's graph theoretic model of the universe, and its notion of causal invariance? Thoughts on constructor theory?
Is information the most fundamental concept of our conscious lives, and the universe itself? Action is Energy x Time , Joule-seconds. Thus Energy is Action Frequency, Action-hz. Could we look at absolute energy, including vacuum energy, as a computational substance with a fixed amount of compute per Joule? Essentially, each Joule is guaranteed to cause O(t*h) computational/informational changes every t seconds?
library.oapen.org/handle/20.500.12657/27994
en.wikipedia.org/wiki/Doubly_special_relativity
en.wikipedia.org/wiki/Holographic_principle
en.wikipedia.org/wiki/AdS/CFT_correspondence
en.wikipedia.org/wiki/Causal_sets
en.wikipedia.org/wiki/Causal_dynamical_triangulation
I got a bunch more to go😅, more recently discovered her channel and the analysis is pretty extensive, I like it🧐👍
Sabin's photo of herself "not understanding" is hilarious. I love this channel.
Dr. Hossenfelder, I love your channel and your sense of humor. Thank you for making the hard stuff comprehensible.
I appreciate those aspects too but for me they are just bonuses to the best science channel on YT.
There is no such thing as gravity.
@@danielmconnolly7 I guess the mean the warp factor of mass. Whatever that means.
@@danielmconnolly7 THE BALANCED, ULTIMATE, TOP DOWN, AND CLEAR MATHEMATICAL PROOF REGARDING THE FACT THAT E=MC2 IS F=MA:
Time dilation ultimately proves ON BALANCE that E=mc2 IS F=ma, AS ELECTROMAGNETISM/ENERGY IS GRAVITY. Time is NECESSARILY possible/potential AND actual IN BALANCE, AS E=MC2 IS F=ma; AS ELECTROMAGNETISM/energy is gravity ON BALANCE. Gravity is ELECTROMAGNETISM/energy.
Great !!!! QUANTUM GRAVITY !!!! E=MC2 IS F=ma. This NECESSARILY represents, INVOLVES, AND DESCRIBES what is possible/potential AND actual IN BALANCE. What are the EARTH/ground AND the SUN are CLEARLY E=MC2 AND F=ma IN BALANCE. Very importantly, outer "space" involves full inertia; AND it is fully invisible AND black. The stars AND PLANETS are POINTS in the night sky. GRAVITATIONAL force/ENERGY IS proportional to (or BALANCED with/as) inertia/INERTIAL RESISTANCE, AS E=MC2 IS F=ma; AS ELECTROMAGNETISM/energy is gravity. Gravity/acceleration involves BALANCED inertia/INERTIAL RESISTANCE, AS E=MC2 IS F=ma; AS ELECTROMAGNETISM/energy is gravity. BALANCE AND completeness go hand in hand. It does ALL CLEARLY make perfect sense. GOT IT !!!! THE SKY is BLUE, AND THE EARTH is ALSO BLUE. Great !!! Now, think about the man who IS standing on what is THE EARTH/ground. Perfect !!!!
Energy has/involves GRAVITY, AND ENERGY has/involves inertia/INERTIAL RESISTANCE. "Mass"/ENERGY IS GRAVITY. ELECTROMAGNETISM/energy is gravity. E=MC2 IS F=ma ON BALANCE. Gravity/acceleration involves BALANCED inertia/INERTIAL RESISTANCE, AS E=MC2 IS F=ma ON BALANCE; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. (ACCORDINGLY, the rotation of WHAT IS THE MOON matches it's revolution !!!) Gravity IS ELECTROMAGNETISM/energy. TIME DILATION ultimately proves ON BALANCE that E=MC2 IS F=ma, AS ELECTROMAGNETISM/energy is gravity. News flash ! Gravity IS ELECTROMAGNETISM/energy, AS E=MC2 IS F=MA. The Earth (A PLANET) is a MIDDLE DISTANCE form that is in BALANCED relation to the Sun AND the speed of light (c), AS the stars AND PLANETS are POINTS in the night sky; AS E=mc2 IS F=ma. TIME is NECESSARILY possible/potential AND actual IN BALANCE, AS E=MC2 IS F=ma; AS ELECTROMAGNETISM/ENERGY IS GRAVITY !!!
By Frank DiMeglio
ha ha like you understand any of the hard stuff now
Thank you for starting where we must always start in order to sort ourselves out: "terminology", it is tempting to skip, but it is crucial!
Absolutely right. Absolutely.
You have become the most interesting physicist around! I love your channel and jokes and learn so much. Thank you for all that work. I couldn't even learn a second language let alone master it and teach physics using it! You are so intelligent and talented. Thank you sincerely!
I never thought of it in that way. My respect for Sabine has grown.
Actually she and thunderf00t, are the only actual scientists I can think of with youtube science channels. Lots of science channels, but they're all operated by armchair scienticians. The absolute worst of them all is ridddle, he's scientifically illiterate and just straight up plagiarizes random things on the internet he thinks are obscure enough no one will notice.
Dr. Hossenfelder, thank you for taking the time to help break down these complex concepts. While I still don't completely understand it all, you do help me to get rid of misconceptions that I've had about some of these more difficult theories in astronomy and particle physics. Thank you for taking your expertise to the masses and making these very dense topics more approachable. Excellent work!
The last point about oversimplified analogies is, I think, also particularly relevant in school. Chemistry in particular springs to mind in that they never tell us how it IS, they tell us how it is LIKE. And then, in areas where this model diverges from reality, they give another example of how it is LIKE something else, further perpetuating the problem and making it frustratingly opaque to dissect. Analogies are a double edged sword because they allow someone to gain a foothold in a new area, or to understand the bigger overarching patterns, but when it is used as a substitute for the actual description it becomes more hindrance than help.
So analogies are analogous to a double edged sword?
Well, we are just now able to simulate how these things at that scale actually might be working. When I was at school, 20y ago, I remember my chemistry teacher emphasizing: "the bohr model is just that: a model that works to explain our observations at our current stage of experimentation."
That's why I hate chemistry back in highschool because we were never taught the "first principle" (I guess in this case would be quantum mechanics) where everything else can be derived... That's why I chose physics and maths back then, thinking they are a bit more, like you said, dissect-able.
Why don't they just give the model that matches reality...
@@Philoreason Exactly! And while I fully get that quantum mechanics is probably a bit much for high school students, I feel that high school students are capable enough to understand concepts beyond the almost infantile analogies that teachers use. and the funny thing is that these analogies often end up backfiring because in order to use them, the teachers also inevitably have to explain all of the exceptions to the rule and it ends up feeling more like the grammatical rules of the english language than fundamental truths of reality.
Dr. Hossenfelder you have made me love science and physics more than ever so Thankyou for your concise and humorous studies. I’ve learnt more from you than anyone in the past and you answer most of the things I’ve wondered which makes the future more interesting and enjoyable. Education is key to freeing the mind to its full potential and I feel you are easy to understand on these complex topics. Great channel 👏 (Edit) probably best to comment after watching your video. You answered all my questions 🙏🏻 heading toward a star that is coming our way seems to be the quickest way to arrive when it catches us up.
Obviously, vacuum is not easy to understand: nothing. Just like "space". There is also no "potential" and no "energy" "inside"-)
This helped clear up some misconceptions I didn't even know I had
Thank you so much Sabine, your clarity is so helpful
yeah....She's really helping me nail down key aspects and terminology needed to explain some my own theoretical models. What is interesting her is she delves into the scientific topics most relevant to what I'm researching/trying to discover. Good Stuff!
One of my favorite things about your presentation of these fairly high level physics subjects is that you make it extremely clear where the gaps in our knowledge is and the clear delineation between what we know via observation and the theories we attempt to explain through inference.
One of my favorite examples is dark matter. It's name is a misnomer. It's just a description of an aspect of astronomy we don't have a good explanation for when comparing our understanding of physics with our observations of galactic rotation. A lot of physicists thing it COULD be some type of particle because it's convenient and covers a lot of the observations they are making, but it's not even able to do that completely.
Plenty of other science educators will tout it as THE answer but fail to break apart the complexities of what is wrong with the model or even mention alternative theories because the admission that our understanding of the subject is actually really limited doesn't SOUND like education, but I think for people seriously wanting to understand the sciences the admission of blank spots in our knowledge and limitations of observation are one of the most important things we can keep ourselves reminded of.
Honestly, I really struggled with early school because so much stuff was simplified and analogised to the point it just didn’t make sense to my tragically over logic little brain. As I got deeper into subjects like physics I felt really betrayed.
Now when I teach compsci, I am overly sensitive about being blindingly clear when I am simplifying; and I always try to do a “deeper dive for the interested”.
We should never teach analogies as facts just as poor illustrations that allow us to access a deeper concept.
Thanks so much for your approach.
Physics is the art of approximation. If you don't know how to teach approximations properly, then you shouldn't be talking about physics.
@@lepidoptera9337 Not every approximation is meaningful and sensible. Some are even misleading. It's a physicist's job to distinguish between those.
@@Brianboy9494 Approximations are meant to make our lives easier. They have to be "good enough to be useful", which means that only the practitioner in a field can develop a good feeling for the range of applicability of an approximation. You are of course correct that physicists are usually able to smell an approximation from miles away while the layman is, at best, guessing what it is that he is looking at. That's a serious problem in science communications and not just in physics. That is my reason for pointing them out wherever I see somebody misusing them.
@@lepidoptera9337you're talking bs
@@Nat-oj2uc Hey, Ma! There is a lonely kid who wants attention. Let me give him some. ;-)
I really, really look forward to Sabines new videos every Saturday. Love this channel and Sabines sense of humour
Sabine is the most uneven presenter on the internet. The one thing that is constant is she is completely honest. Sometimes she is wrong and sometimes her presentations are confusing. I subscribe because sometimes she hits a home run. Her explanation of Vacuum Energy was best physics presentation that I have every heard.
"That guy" also taught us to make things as simple as possible but no simpler.
Thnx Sabine.
… but not simpler
@@fkeyvan both are ok.
Depends on what you are reflecting on.
THANK YOU! Thanks for including the equations and explaining them as you go. Thank you for using more accurate / less confusing terms. And Thank you for your humor! That makes otherwise science more fun!
I love how Sabine is transparent about the science; often science reporters push one theory or paradigm without addressing it's flaws, but she seems to truly be impartial.
That's what happened with the theory that brain makes consciousness. Lovers of this theory didn't want to examine its flaws.
Supersymmetery left the chat
1) I love the Sabine 'listening/confused/puzzled' expressions, I was pulling the same at the reply.
2) I'm now off grid with a ZPM I found in the back of a dumped puddle jumper :)
I see you are a man of culture as well
Thanks Sabine! I have been trying to understand Vacuum Energy for a long time.
I STILL don't understand it, but now I am more confident in my ignorance!
Ive got vacuum energy....every tuesday bout 10 am...out comes my vacuum and i use energy ..so vacuum energy..😁Dont know wat these scientists are on about saying its a hard problem etc...i sorted it in 2mins...WHERES MY NOBEL PRIZE 🤣🤣🤣🤣😍😍😍😍😍🤣🤣🤣🤣🤣🤣
It's all about love... seriously... it takes some time to figure it out...
Vielen Dank, Frau Hossenfelder für die klaren Erklärungen! Das ist der beste Kanal, der sich mit aktuellen Fragen der Astrophysik in wirklich für den Nicht-Fachmann verständlicher Sprache nachvollziehbar auseinandersetzt und vor allem die Widersprüche nicht ausklammert, der also nicht nur ex-kathedra doziert, sondern den Zuhörer in die Gedankengänge mitnimmt. Nochmals: Vielen Dank!
Such a better explanation than when PBS space time did an episode on it. I love the clarity of the way you explain things.
I was just about to say that!
Yes, but what matters is the amount of hand waving and emphatic gestures, not clarity.
Space Time tried to explain several things which are not explained here for example where the cosmological constant comes from. But in this video it would have been misleading and rightfully Sabine go straight to the point.
this is even better... The "EM Field" or "Tesla's EM Gas" is an IDEAL BOSE GAS of EM DIPOLES or EM Quantum Kinetic Dipole Particles that kinetically collide in the vacuum causing "vacuum pressure". The Quantum Superfluid (QSF) flowing inside elementary particles are a Bose-Einstein Condensate of EM Quantum Kinetic Dipole Particles and each EM Dipole has a mass of about 10^(-90) kg each.
There are about 10^(72) EM Dipole Particles per cubic meter of "Vacuum" in our solar system with a total mass of 10^(-18) kg /m^3. This is dark mass / matter!!!
These dipoles have an RMS velocity of "c" and they carry all momentum/energy in the vacuum . This is vacuum energy. Like less than half a Watt!
The vacuum is not empty it contains EM Dipole Particles!
The speed of light is the "Speed of Sound" in the Quantum Ideal Bose Gas of EM Dipole Particles.
Both My Father who helped launch Apollo 11 and Wernher von Braun said so in the 70's! NASA/DoD Black Projects used EM QKD Theory to make Warp Drives no in the skies in the UAPs. As soon as you DROP SPACETIME TRASH and use Ideal Bose Gas Laws with EM Dipoles as the particle, you will NEVER solve TTOE and design your own UFOs!
We "finished" TTOE 3 years ago using Bose Gas Laws at it us only took 3 months to solve Gravity!
The Mass/Energy Density Gradients in the Vacuum containing the Ideal Bose Gas of EM Dipoles causes a net momentum transfer in the direction of the gradient or DOWN!
@Joaquin Yeah, PBS spacetime is v solid. But I sometimes just don't understand it, esp when they get deep in the maths. Sabine is very clear to any ignoramus with a decent IQ and without a Journalism degree (which seem to make any kind of knowledge acquisition impossible).
This is just a beautiful mind and an incredible teacher. Dr. H, thank you for your work.
This was an excellent explanation, It clarified some things for me and showed the dangers of arguing through analogies. Thank you.
I really enjoy your channel Sabine. I finally can understand some aspects of physics that perplexed me thanks to your presentations. Yours is a most excellent resource, and was most definitely worth my subscribing to!
Happy you find it useful!😊
I just started watching for less than half a minute and I am already having the best fun! This is physics explained in most entertaining way imaginable!
Theoretical Physicist’s Hocus Pocus.
I didn’t know what to think of this channel at first. Now I’m addicted. Good work!
I feel like the explanation the editor gave goes something like this: "If we view a ball rolling because of the wind as a ball rolling off a slope, we would conclude that such a wind speed corresponds to such an inclination of the slope. And that's why balls move in the wind."
for me his explanation is pretty ok
Thank you for your fascinating observations on mainstream science! It is very pleasant to hear real scientists make sense of what we don’t know. I would love to meet you and have coffee and talk about physics… I am a particle physicist too
Sabine is married, yeah?
6:58 why add here that it doesn't fluctuate? arent virtual particles bubbling off vacuum as dEdt < k ?
This deeper dive past what seems more intuitive on surface is especially appreciated, since otherwise I likely would have thought otherwise ^^
The editor's reply is exactly the sort of text my prototype AI response generator regurgitates when trained on previous Q&A datasets. So I'm not entirely sure it was a human that replied.
I would so laugh if your AI secretly knew exactly what it was talking about,
I mean, maybe your AI just achieved consciousness?
Your AI has just summed the group intelligence of humans is less than one human or the many is less than one
A.I. Correctly parsed gobbledygook in, correctly parsed gobbledygook out.
@@thomasnaas2813 As one expert in AI fairly recently said computers can't actually read yet.
I'm new to this channel. But both the reply in Scientific American and (especially) your facial expression in response to it was hilarious! As the Brits would say "Jolly good show!"
Your response to inappropriate analogies reminds me of Mr. Feynman's critique of 'invisible rubber bands' as an analogy for gravity.
Haha! No we wouldn't!
Thanks Sabine for your great insights. They are Invaluable and useful. You seem to be in a trajectory lately, to erradicate all the nonsense in this field and you are certainly not afraid to break some eggs. You have my support! There is no need to be kind to people in positions that they shouldn't be in, like that awful editor. Keep on doing the great work!
I would like to see Sabine debate Sean Carroll on this point. I watched a lecture from the Great Courses on candidates for dark energy and Carroll explains the vacuum energy in terms of QFT, which is where you get the outrageous prediction of 10^112 as opposed to 10^-8 for the vacuum energy. He explains these concepts very thoroughly so I’m surprised to see them dismissed here.
The thing is, General Relativity and QFT are different realms of Physics. With all this Cosmological constant and Vacuum Energy business many accounts mix them up, and that generates confusion. Look how careful Sabine has been in explaining the CC under GR, without need at all of QFT.
If a Vacuum Energy consistent with the expansion of the Universe is never derived from QFT... well, GR is perfectly happy with the CC as a constant of nature the same way it is with the Gravitational Constant.
I expect that Sabine knows that the prediction from QFT, No? Does she disagrees with QFT? I have not seen her say that. And she would have mentioned that.
@@theta-rex If you have a better model that describes the Universe on the largest scales than please put it forth.
@@theta-rex explain these premises you describe as "wrong". E.g. where Sabine describes the term as simply a constant in the equation, this is undeniably true. How can you say it isn't?
@@theta-rex are you saying that the interpretation of the cc as representing something real is possibly just a conceptual convenience, employed only as a means of making sense of the models (GR particularly) we currently use to describe the universe, and that gr could just be insufficient at the scales in question?
wishing you love and peace, dear Sabine. Keep well.
Omg the look on your face when the editors reply is up. 😂
I remember my teachers didn’t appreciate that look. But sometimes it’s impossible to suppress it since it comes from deep within.
I always thought it is weird that it is just generally _assumed_ that vacuum energy equals dark energy but no one has come up with feasible mechanism explaining _how_ the quantum boiling of vacuum would make spacetime expand on the largest scale. Thanks for clearing this up!
It is still an assumption that the vacuum energy is what is fueling the universe's expansion. It's an assumption that it will have constant density forever until even quarks rip apart. We've been testing and observing this a very short period of time. Hell, we're second guessing now whether we're even right about how fast it's expanding. We just need to keep in mind that these cutting edge theories are built on assumptions, which are built on other assumptions. The assumptions can be proven wrong. I recommend PBS Spacetime's video "How An Extreme New Star Could Change All Cosmology" as an example of this. Turns out we just might be wrong about the supernovae that we base a lot of cosmology on.
@@defenestrator9119 I get you. But the thing is, afaik, there isn't even a proper hypothesis for a mechanism how quantum vacuum fluctuations would cause a positive vacuum energy density, since quantum zero-point energy is zero on avarage. Given that and the problem of "vacuum catastrophe" it is likely that dark energy can't be explained by vacuum fluctuations alone. And yes, I've watched almost every episode of PBS Space Time ;-)
@@KennyT187 I tremendously agree. It's a great and huge step from the calculation of these virtual particles popping into existence for a very short time then annihilating, causing expansion. Meanwhile in their brief instant they leave a bit of gravitational attraction that cannot disappear. Cumulatively it's 10 to 120th greater than what's observed, according to latest news.
But where do we get the minus sign? The inflation of space containing this gargantuan density, rather than the universe collapsing on itself. Need some 'splainin, Lucy.
@@theta-rex We don't know. But it apparently does.
@@theta-rex I think you need to reread what I wrote. I was basically agreeing with everything you just said. That those things are assumptions.
thank you for this brilliant mind-bending short video, which helps you fall back in love with Physics if you need to
Sabine is just brilliant! Love the snarky explanations!
*Sabine reads editors response
Sabine: I'm about to end this man's whole career.
Sabine's followers: HUZZAAAAHHH!
@@CAThompson It's "Hossa!!!" in german (x)
@@ListenToMcMuck 😄
Hossa for Hossenfelder! 🤪
The editor did themselves no favours.
Science editors need to start looking over their shoulders and checking their facts, maybe not both at once though.
This is comforting . So often Sabeens explanations seem closer to natural intuition than the ones you hear from other commentators as if many are trying to over sensationalise by making it more counter intuitive for which there really is no need
I am glad that there is somebody out there that explains this so clear. I always though that "vacuum energy" as result of "quantum fluctuations" was gobbledygook.
On the other hand, if vacuum energy increases, because expansion of space, does that means that the mass of the Universe increases?
Good question, I figured there can never really be an increase of mass, but the scattered mass bodies in space merge together to become one body with more mass to achieve the mass-energy equilibrium, same as happens on quantum level. Black holes tend to have the same merging behavior as already has been discovered.
@@ronnyklingeleers2293 What does bodies merging together have to do with "achieving the mass-energy equilibrium"? And in what way is that the same as "happening on quantum level"?
After reading the daily news, I need a dose of Sabine to retain my sanity. Thanks!
good morning to my favorite teacher, today's first is queued up, and tonight i'll see where that leads; i've never had so many questions i want to ask, yet i would never ever wish to introduce a frown to a great teacher's day, 2:49 , sometimes it is the things that dont as much as the things that do and the whys that are the utmost illuminating, and i am at the point i realize something.......7.01....... and no idea what i am realizing, vacuum physics indeed,
Thank you Sabine for another great video! I appreciate your critical thinking skills that seem to be lacking by those who profess to be experts.
Lol I’ve fallen in love with your channel. Your sense of humor is fantastic. Thanks for doing what you do.
This explanation raised a new question for me:
If we agree that vacuum energy is a constant, non-fluctuating enery level from absolute zero, which is everywhere in space, and does not dilute as space-time expands or contracts. Then doesn't it mean that on its own, vaccum energy does not have any "preference" to either expand or contract the universe?
All it does is just accelerate whichever state we are currently at. If spacetime is contracting in an area, it will assist in this contraction, and if its expanding in an area, it will assist in accelerating it.
So, it does explain why space explansion accelerates, but it does not explain what is the initial thing that drove acceleration above the threshold where vaccum energy alone could keep up the acceleration going (and im not informed enough to confidently say it's the big bang, and that this event alone was enough to get us here), and also doesn't tell me what's stopping space time from locally contract and be accelerated in the other direction by the same vaccum energy principle, or why can't that spread/overtake the current acceleration outwards.
The thumbnail is hilarious 😂😂😂😂
The editor is now working for the NYT.
I’m unsure if this is a fact or a joke? Either way it’s quite funny and a reflection of how both publications have fallen into the political pit of despair.
As someone who used to routinely put closed refrigeration systems into a vacuum, I can say with experience the deeper the Vacuum the Harder the Suck, & with a large enough vacuum chamber you can extend that Suck. That's why the accumulated Gravity of all Universal Gravity Sources just comes up shy of overcoming the Massive Quantum Suck of an Eternity of Nothing
Respect the Suck, one day you'll have to deal with it
That sucks!
Would you mind talking about the Cauchy horizon and that result that says the GR equations don't work after a certain point? I remember reading about it in Quanta Magazine, and when I went to check in the paper it was based on I only got more confused.
Can Sabine explain everything please thank you, the Universe might actually make sense then. 🙂
What paper?
@@thstroyur www.quantamagazine.org/mathematicians-disprove-conjecture-made-to-save-black-holes-20180517/
This is the article in question. The paper is referenced in it. The authors are Dafermos and Luk.
@@nooneinparticular3370 Read article+abstract--OK; first off, it seems to me the article itself did a good job explaining what's going on except for the title, "Mathematicians Disprove Conjecture Made to Save Black Holes", because the topic is the (strong) cosmic censorship, not the existence of BHs or something - a better title would'be some like "[...] to Save _the Intelligibility of_ Black Holes", IMO. Another slip they made is the popular mistake of equivocating space-time with the dynamical object considered by GR, as exemplified in the quote "[...] Einstein’s theory of general relativity [to] predict the evolution of the shape of space-time". In reality, what Einstein's theory does is to give us this thing called a _metric_ , which is a property of certain types of sets known as Riemannian manifolds that model space-time, yet in GR are seen as dynamical things that depend on matter content (in fact, physically speaking, they have to do with gravitational potentials, though not directly); then, to get these metrics, we solve the Einstein eqs using this "Cauchy" stuff by providing 1) a 3D "slice" (a "Cauchy surface") with a given, known 3-metric associated, and 2) information telling us how that slice is "imbedded" in the larger 4D space(-time) (often referred to as the "extrinsic curvature") (for the more technical details, check link.springer.com/article/10.1007/BF01645389 , or the famous book by Hawking and Ellis). With this, it is possible to solve for the Einstein eqs even numerically, except under certain circumstances - e.g., for a Cauchy surface between an event horizon and this "Cauchy horizon" the article mentions. The takeaway of what these guys claim is that yes, you can have a _metric_ manifold beyond this horizon (otherwise you could _still_ have a generic manifold there defined by hand, which in a sense would still be a "space-time", albeit highly unusual) - but the catch is, this metric is just C^0 - i.e., it doesn't have well-defined derivatives of 1st and higher orders, and as such you still can't find the metric beyond the horizon via the Cauchy method, using some Cauchy surface outside the horizon. Hope this technobabble might shed some light on all the mathematical mumbo-jumbo 😵
@@thstroyur I'm a mathematician actually, but you did help me. What I wasn't sure about was what exactly the "Cauchy horizon" was, since I couldn't find a proper definition. I wasn't sure if it was an actual hypersuface inside the black hole or some weird abstraction. And my actual question then would be: doesn't this then mean that speaking about a "singularity" (whether it be in the center or in a ring around it) is misguided, since the Einstein equations don't even really apply after a certain point? And what about ring singularity getting bigger as the black hole spins faster? Doesn't that mean at some point its predicted location would be outside the Cauchy horizon? What's the deal with all that?
This is more precisely what I wanted Sabine to clarify. I didn't specify it since I wanted to leave a quick commment and go check the video. I imagine Sabine would naturally answer these questions of mine. If you can answer them yourself I'd feel very thankful though!
Would love for you to chat with Sean Carroll on his Mindscape podcast
About Multiverses and Boltzman's brains? I'll bring the popcorn.
I’d love to see her shut him down in that.
Am a big fan of Sean... but love how Sabine don't take no $%!+ 🙂
Amazing video. Your scientific approch is quite necessary in the media.
Before I saw this video, that math equation looked like a bunch of letters and numbers thrown together by my 18 month old granddaughter. Now it actually makes sense!
Thank you Sabine! :)
Maybe your granddaughter is the new Einstein!
LOL, I’m still trying to make sense if it myself personally😅
Thanks so much for this short clarification Sabine. Great! That was really necessary.
Thank you for that explanation, which basically says vacuum energy is defined as zero, and must be zero, or else it would exert a gravitational field.
I did a lot of research, in my early years, chasing down this elusive vacuum energy. Also people constantly interchange the terms energy, power or work, which they are not. We are really after power, or work provided by utilizing differences in energy states.
I remember attending a lecture by Prof. Harold Puthoff in 1994. I spoke with him afterwards. He talked about these experiments which he carried out at UCSD, related to attempts to extract Vacuum Energy. He was able to create helical electron streams to extract work, from a force which must of had only the explanation of being created by the vacuum zero-point energy. Of course, this is one way to understand this acceleration.
He used a calorimeter, in a closed system, to measure net energy gained and displayed microscopic images of the electrons' path to prove the existence of the force. He approached every sector of the energy industry, with the results. The nuclear industry leaders wanted to replace their expensive enriched uranium rods with these devices and said they would use these, as it would solve the problem of nuclear waste. The oil companies said they wanted to use this as well, since fossil fuels were becoming more expensive to extract and they were looking to diversify their investments to stabilize their profits. This shot down the idea than an evil conspiracy exists which colludes to stop the use of alternative power sources. (I won't say that there aren't some people who might not want more alternate power sources, but this list is far fewer and less powerful than those who do want it).
ANYWAY, Puthoff realized, however that although he tried this experiment in many different configurations, it really never proved that net energy could be extracted from the vacuum in any usable form or at all. The energy extracted was very small, in the microwatts and of course, the energy required to put the electrons into a situation where they could spiral down, was orders of magnitudes higher than that.
So, he devised the "One Watt Challenge," which meant a closed system must be able to demonstrate a net extraction of one watt of vacuum power for an indefinite period of time.
No one has ever demonstrated this, because the laws of thermodynamics are fundamental to the stability of the universe. Its barking up the wrong tree to attempt to extract vacuum energy. Its better to chase elusive energy sources, like fusion, remote energy extraction or solar, wind, etc, than to attempt to extract energy from the vacuum. Because of what you said, we are not after Free Energy, but rather "Low Cost Power". Its power and not energy which does work. Its the "power company", not the "energy company." Even electrons display energy in their ground state. Brownian motion is a form of energy, but not power. Nothing is free; what we need are power sources which are worth the cost of creating the device used to extract it. At this point, we seem to be doing the best we can, which is sad in itself. Because then you realize what a great source of power fossil fuels really are, and they are becoming more difficult to extract, as time goes on.
I am optimistic we will overcome all this and someday figure out how to transfer geothermal energy more efficiently, over a broader area of the Earth's surface, due to efficient graphene production methods. I also believe solar prices will continue to decline, due to cheaper electronics manufacturing methods. And ultimately, we will discover some method of focused fusion/fission which will prove useful in more compact systems. I don't put much stock in Tokamaks, because we've spent hundreds of billions on trying to create the conditions of the surface of the sun and are still 50 years from creating something usable. We've spent only millions on focused fusion/fission research. We've barely begun to try out the endless possibilities in that area, whereas the Tokamak route is only a question of optimizing its efficiency. A tokamak is only capable of extracting heat, which is inefficient. Focused fission/fusion has many possible routes, where electrical energy can be directly extracted without first being converted to heat.
Thank you, Professor.
Years ago, I read literature and the physics text by Professor Richard Fynemann. Human understanding is very limited in our infinite universe.
It must have been a long time ago because you don't even properly remember his name!
You're so right about inappropriately oversimplified analogies, Sabine. I've spent my whole life trying to drag sense out of stupid pop-sci analogies. It's far harder work than it should be.
I am not so sure about that... truth is more simple then it appears.
@@waldwassermann Much as I'd love to get into a semantic debate about the two separate meanings of "simple" we're using, (which is the same pitfall that overuse of Occam's Razor can lead to), "simple" and "intuitive" aren't the same thing.
@@musicalfringe Dear Musical Fringe. Thank you. Just going by the Latin definition which says that the origin of the word Simple is One. 🙏
@@musicalfringe If all things appeared from the Big Bang it can only mean that...
You Sabine, are truly awesome. Thanks for making the difficult easier to understand.
I only just discovered you also made music videos.
Beautiful, Intelligent and talented 😍
My life goal for now is to catch up with her.
Whaaaat, she makes music videos?
Ok, I looked in her channel page, and she DOES make music videos. A pretty decent job of it too.
Great job as usual. Enlightening. Services like NordVPN require the same hard look at what they say and what their reality actually means.
This formula might reveal dark energy being the difference between n=0 (Black Hole?) and n=1 in the Schrodinger solution of the universal wavefunction.
I try to combine the cosmological constant and the Schrödinger solution on the Planck scale.
I used Planck units.
At the end I went back to SI units to compare with the measured vacuum energy density (0.63 10^-9 J/m^3.)
Combine:
1) Einstein, cosmological constant
2) Schrödinger solution
3) Planck units
Result:
- vacuum catastrophe solved?
1)Einstein, cosmological constant
Λ = (8π 𝐺 ƐΛ)/(𝑐^4)
Planck units:
G=1
c=1
Λ (6.1871424 10^34)^-2 = (8π ƐΛ [PlanckEnergy/PlanckVolume]
1.1056 10^-52 (6.1871424 10^34)^-2 = 8π ƐΛ
0.001149 10^-120 = ƐΛ
0.1149 10^-122/ ƐΛ = 1
2)Schrödinger solution, n=1
(ℎbar^2 𝑛^2 𝜋^2) / (2𝑚𝐿^2) = E
Planck units
hbar=1
n=1
m= mPlanck =1
L= LPlanck=1
0.5 𝜋^2= E
1= E/0.5 𝜋^2
3)Einstein, Cosmological Constant = Schrödinger solution
0.1149 10^-122/ ƐΛ = 1 = E/0.5 𝜋^2
0.1149 10^-122 0.5 𝜋^2= ƐΛ EPlanck
EPlanck =1
0.1149 10^-122 0.5 𝜋^2= ƐΛ
0.567 10^-122 = ƐΛ [PlanckEnergy/PlanckVolume]
0.567 10^-122 1.9561 10^9 /(1.61625502 10^-35)^3= ƐΛ [J/m^3]
ƐΛ = 2.627 10^-9 [J/m^3]
Measured: 0.63 10^-9 [J/m^3]
I am looking forward to your response.
I don't know if Sabine ever considered merchandising, but if she does, she needs to make a shirt with a tasteful drawing of Einstein and the caption, "THAT GUY AGAIN".
I want a portrait of the Art-Deco Sabine Disappointed Face from 09:30 . in oils, nice ash frame... This needs to happen.
Last time I was this early my vacuum had energy.
I followed everything except the definition of the scale factor. Anyone care to explain the scale factor more thoroughly?
The scale factor is just a number, a measure, that tells us how much are the distances between objects in the universe increasing over time due to the expansion of the universe. Since the expansion is 'stretching' the empty space between objects and thus pulling them away from each other as a result in all directions, over time that means objects become more distant from each other. The scale factor is simply a number that tells you in what way that distance will change over time, in this case increase.
@@ThatCrazyKid0007 I'm still confused. So measuring the rate of expansion gives a proportional relationship to vacuum energy? Hmmm, if I understand this correctly, vacuum energy will increase exponentially with time. I guess the Big Rip is real.
MMM... another great presentation Sabine..... Much of the math is beyond my level, but the way you explain things means that I can get a handle on the ideas in an "analogue" kind of way. My knowledge of physics is pretty basic, but I find I can grasp your points quite well even on something as esoteric as this.... Thank you, you keep my 80 year old brain busy, and at my time of life that is a good thing... 🙂
If space expands between e.g. galaxies and stay constant on Earth, does it mean Planck's lengh changes or "give birth" to new units of space?
why do you think space stays constant on earth?
interesting! if you refear to PlanckUnits as multi-brane resonance fluctuations it all might just be a Conway's Game of Life simulation on gods gaming rig!
Yeh, but only because units are an untangible element of measurement, not an actual thing. Yes, i am including Planck length. I mean if you have a ruler you'd find you need more notches.
But then maybe you confuse plack length with an idea of universal 'pixellation' which is not what it is...you are free to speculate it is however, such as if the universe is a simulation, i suppose they could be incrementally growing more disk space 🤔
@@naotamf1588 Hope God's Mother doesn't think he is spending too much time on his computer and unplugs it!
@@MrDlinch maybe not constant but more cept in check by gravity. On smaller scales interactions between particles are strong enough to not be pulled by expanding space, but I guess it doesn't mean the rug of spacetime isn't pulled from beneath our legs, but chemical and gravitational bounds are stronger. I don't know if the Planck unit should be derived from matter instead of the space grid?
You rock. Love the way that you break this down. Thank you. I’m still astounded at the constancy of the vacuum energy for a given volume despite the accelerating expansion of the universe. I imagine that this is a big question that once solved will lead to deeper understanding. Is there any relation between the expansion of the universe and any variable at all? Do you think the answer lies tied up in higher dimensional non-de sitter space?
Truth is simple... it is not good for one to be alone. Blessings.
PLEASE!! :'D Sabine gib uns mehr Reviews mit face-reaction xD deine Mimik ist so expressiv, sein ein Laie der im ersten Moment gar keine Ahnung hat worum es geht _fühlt_ sofort mit und ist "auf der selben Wellenlänge" -- und die die inhaltlich auch noch mitkommen, leiden synchron mit dir -- es ist einfach herrlich ^_^
The answer was indeed confusing, the link between pressure and energy density was lacking and the sounding question was demanding a proper answer
Here, I show the math: th-cam.com/video/bl_wGRfbc3w/w-d-xo.html&lc=UgwaAqpQUOaoXE9bGvp4AaABAg
It's just simple math - not as much any "real" physics...
The editor's comments sounded rather like the justification of astrology.
Quantum astrology!
@@CAThompson Quantum gemini space polarity
The danger lies in the fact that some people (myself included) are unaware of what they don’t know.
@@123Shel12 I realised after following Sabine that whole chunks of what I 'knew' wasn't even true. :-9
@@CAThompson True. It hurts a bit at first but then you find new things to not understand and that distracts from the pain. 😉
I mean...the best analogy for this is the beating heart, blood pressure and the function of valves...and analogies are key to understanding physics.
care to elaborate on the analogy?
My wife has about ten vacuums and spends a lot of energy on them.
After August 2014, due to EU rules, manufacture of vacuum cleaners with a power consumption greater than 1600 watts were banned within the EU, and from 2017 no vacuum cleaner with a wattage greater than 900 watts was permitted. [wikipedia]
*vacuua
@@PMA65537 That explains why British left the E.U. and some other smart countries like Switzerland and Norway don't want to join it. These Eurocrats want us now to clean our houses for longer time. Thanks God my vacuum cleaner was produced before 2014 and is 2200 Watt!
Is one of them a Dyson sphere :)
Sucks to be her, I guess.
An omnipresent energy that's equal for any point in space
can only have a net force of 0.
If there's no change for point A to point B it has no effect.
Also, there's a lot of volume in space, which either contains something is truly vacuous.
If there's energy particles or mass particles or anything there, it's not vacuous.
Also, if minus lambda g mu v does not dilute with the expansion of spacetime,
then the sum can only be zero.
If the sum of energy per volume is fixed, and spacetime streches to increase it's volume,
then the energy would dillute.
You can have either expansion AND dillution, or no expansion AND no dillution, mutually exclusive..
This extends to volume.
expansion dillution volumetric change, or
no expansion no dilution no volumetric change.
What scientists perceive as volumetric change does not happen,
only the positional changes of the content within the volume.
There's no volume change, no dilution and no expansion.
The matter and energy within change position but does not change the consistency of the volume.
Since there's no change from point A to any other point B, the sum effect is zero.
The only exclusion is when the vacuum energy does not exist, totalling zero.
Then when the volume increases, the energy density remains unaffected.
The universe is two things, the volume of space and the content.
The apparent expansion, which does not happen, is caused by the motion
of the content, not the volume.
The filler is in motion and moves away from each other, which gives
the apparent, yet non-existent, expansion, which gives the illusion of expanding volume.
I imagine virtual particles to be like some sort of quantum pop-corn.
held together by quantum butter with a sprinkling of quantum salt?
@@bubbathelonepotato2208 I like Caramel Matter.
They're terms in an equation. Often there's infinitely many like the geometric series for 1/(1-x). So everyday language isn't good enough, more precise language is necessary. A huge part of it is simply developing the language to describe it.
I love how Sabine explains things
Always at ease.
You're reactions starting @1:22 are everything!!!
I'm so biased by daily life that when you said "vacuum energy" I've heard "vaccine energy".
Haha 😅
I'm looking forward to getting my first vacuum injection next week. 😆
@@CAThompson congrats, I've already had the 2 Sinopharms of my own.
@@CAThompson the Dyson or Hoover ?
@@jorgepeterbarton The new General Electric one.
Peter or Paul? We'll forgive the occasional misread when the content is so superb. Nice to see feet and inches too.
Ah, right. I meant to put this in info. Thanks for reminding me!
Dr. Hossenfelder, your explanations are direct and amazing. I’m hooked!
04:15 "The arse quantify the curvature of space time." J-LO approves.
That's what she said!
I knew I couldn't be the only one who snickered at "arse"
The world needs a better theory for describing the universe (ToE ).
Thanks for explaining evidence based science.
Sabine raises a very, very important point in that analogies are only that. They're there to further an idea towards the Eureka-moment, not define the science that explains it. Vacuum energy and the mysteries within that realm are probably some of the most confounding and exciting part of physics. Great video
My intrusive thought about dark energy: The universe severs itself due to the expansion of the universe eventually expanding faster than light. Like an event horizon it splits virtual particle pairs which is the force we call dark energy.
That might be regarded as the technical explanation, always thought it was an explanation of repulsion😅
*Yes
4:32 lambda is the energy density of the vacuum, which is energy per volume of empty space
4:41 vacuum energy doesn't dilute if the universe expands because it's a property of space-time
6:45 vacuum energy summary
@@paulthomas963 Hi, Paul. I don't understand what you mean by "space doesn't expand" and "spacetime doesn't exist."
I was kinda expecting her to say: "But don't despair, at the end of this video, you will also be very very confused about what vacuum energy is."
Actually the 'p' in ∆U = -p∆V refers to the external pressure that the gas (or system) expands against. If an ideal gas expands into a vacuum it does no work and its internal energy remains constant. The assumption of zero forces between the particles of an ideal gas ensures that U is independent of volume unless the change in volume occurs in a way that the gas does work or has work done on it.
I have learned a lot about physics on this and other sites, but all of this incomprehensible to me. Sabine, you are the best. I like watching you for the humor.
Thanks for explaining this better than some books I've read and tried to understand this (vacuum energy/dark energy/cosmological constant). This includes books by Weinberg (First 3 Minutes, 1993); Barrow &Tipler (Anthropic Cosmological Principle, 1988, equations over my head!); Ross (Why the Universe is the Way it is? 2008, fine tuning argument); and Krauss (Universe from Nothing, 2012). Each seems to summarise the vacuum energy of the universe in different ways, that is confusing for a lay reader like myself. Some clearer explanations I've read were by Sean Carroll, the 10^120 difference between quantum field theory calculation (10^116 eV/cm3) and observed reality (10^-4 eV/cm3), The Particle At the End of the Universe (2013), pages 254-56. Others by Hawking & Mlodinow (Grand Design, 2010); Barrow (Book of Universes, 2012); and Kaku (God Equation, 2021, mentions assumptions of general relativity & quantum mechanics). They all explain it from different angles. I would still like a physicist to show me the maths step by step for how they get the huge 10^120 difference between the quantum field theory calculation and the observed reality? I hope Dr Hossenfelder could do a video, showing the maths step by step how physicists arrive at this huge 10^120 disparity? Even if I don't understand all the maths, I still like to know what each symbol represents and what assumptions are behind it? Anyway, big thanks Dr Hossenfelder for seeking to explain physics to the general audience and for pulling up physicists when they "leave scientific disciplines" and head off into hypothesis, aesthetics, philosophy, and belief statements. Nuff respect to Dr Hossenfelder, I appreciate your explanations greatly.
Never got closer to clear understanding than with your videos and your book
I always viewed that gravity is the result of the compression of space time such that when an apples fall towards the center of the earth, for the apple it is traveling at a constant velocity through the curvature of space time towards the center of the earth. But for an observer since space time gets more compressed towards the center of the earth they see it as as a accelaration of the apples speed. This acceleration phisically manifest its self as what we feel as gravity. Dark energy seems to be the opposite. As the universe expands from the center outwards to the void we are moving from higher gravity compression to a more decompressed gravity field. Such that the time dilation near the centre is slower than the time dilation of the outside void (where time dilation is faster) where the universe is expanding towards . This difference in time dilation is what we percieve as an accelaration, and it phisically manifest it self as dark energy. If we plot this by an xy graph where gravity is -y and dark enery is +y . And +x is time. As you move toward a gravity well -y the curvature is what we percieve as an accelaration. For dark energy +y as you move from the center of the universe towards the outside void there is also a curvature which we also percieve as an accelaration . All the galaxies are moving out ward at a constant velocity through the curvature of an expanding universe. But as an observer this curvature would appear as an accelaration. May be this is just too simplistic of a graphical representation and is completly wrong.
oh why haven’t you turned up in my view list before? a pleasure to watch - thanks
It’s more than a little nonsensical to ignore an error in the calculation that’s a whopping 120factor out of alignment, but no worries, we can ‘renormalise’ that and ignore it, it works everywhere else in today’s interpretation. =o/
Astronomy is in fact astrology in the sense that predictions in that field are extremely off, change radically very often and our understanding of the stars is no better than a horoscope.
As always common sense analysis Is your winning hand,why do some specialists seem so
lost in the details,the forest is the trees and show this clearly.Thanks for that.
Congratulations from Brazil. Thanks for the channel. 🇧🇷
I cant stop watching the beginning of this clip. Your facial expressions are simply priceless.