Do We Need a NEW Dark Matter Model?

[@Saltyarticles]

Matt is Definately in my top 10 of science communicators. I would love to see more videos on the physics/ mathematics of superconductors

[@bennybundi9671]

Current or all time?

[@delawarecop]

Matt, like most delusional people, follows whatever the latest trend is in Science Fiction. There is no 'dark matter'. People pursue the 'dark matter' delusion because they cannot resolve the contradictions in their materialistic world view of the Natural Universe. If I said that Dark Matter was just a Scientific term that describes the Spirit of the Creator, then everyone would be up in arms about faith based religions; yet holding faith in a Science Fiction hypothesis about something that has never measured, tested, or observed like 'Dark Matter' is just a substitute faith based religion = pure unadulterated HYPOCRISY!

[@mastrtonberry2]

Infinitely better than that low IQ shill, Neil Degrasse Tyson.

[@gert-janbonnema]

Who are the other eight beside me and Matt?

[@jamieclarke2694]

I feel like I'd really enjoy just listening to Matt and Brian Cox having a conversation over dinner haha

[@MCsCreations]

I would love to see some FDM simulations. Should be very interesting. At the same time, perhaps we should consider hybrid solutions - those where dark matter isn't all the same, but perhaps a myriad of particles.

[@morgan0]

yea i was gonna suggest, do FDM models usually consider a single wavelength, or do they consider a distribution, like mostly one but a bit on either side

[@andrycraft69]

​@@ntdm25Pretty bad miscalculation for it to have remained unnoticed to thousands of physicists for decades.

[@jakublizon6375]

​@@ntdm25It's really not. There is something there, it's just extremely difficult to identify.

[@JCO2002]

@@ntdm25 Somewhat like cosmic inflation? ;-)

[@DFloyd84]

I tried to do an FDM simulation, but the nozzle went all BLEGH a couple hours into the printing and spat out something to do with string theory.😁

[@nuclearocean]

I can't say I understood everything, but the visuals are hypnotizing

[@hatuletoh]

I'm always amazed at physicist's ability to invent catchy names. Not all of their names are winners, but for a profession necessarily dominated by math people, physicists have a pretty good track record for coming up with memorable nomenclature.

[@ProfessorJayTee]

You mean a profession dominated by math people who have more imagination than ordinary mathematicians? If they didn't have imagination, they'd have ended up ordinary mathematicians.

[@Biden_is_demented]

Notice how there is a striking similarity between this theory, and your average Star Trek technobabble. It should raise red flags up the wazzoo! It is a conundrum of our times, that such smart people seem to turn off their inherent disbelief mechanisms, and choose to just follow the crowd, even when said crowd is following what is clearly gibberish! A form of matter that you can´t see, can´t measure, and can´t quantify, but because it fits the "model" then it has to be "real"? I would have thought that "magic" and "superstition" were left back in the dark days of the Dark Age! Get enough people to believe, and you can start a movement, that others will feel compelled to adhere to, even if your intellect tells you not to. Dark matter is the high IQ equivalent to Flat Earth. Just like the Big Bang. When you ask what caused that initial singularity to come into existence to start the Big Bang in the first place, they shake their heads and utter "LA LA LA LA" until you go away, implying that is was the will of a "supreme being", on a cosmic snap of the fingers! It´s technobabble of the highest order, i tells ya!

[@carnsoaks1]

Mathemphysicsers are human wereings too.

[@sparking023]

So long as it is good in describing them

[@dieselgeezer18]

@@Biden_is_demented Observations and mathematical models are driving us into believing that such an invisible and "magic", as you call it, form of matter exists. Its not something totally made up. Science is not as "exact" as many people think. There is a lot of trial and error and a lot of theorizing. OK, dark matter may not exist, but just because something seems crazy and impossible doesn't mean that we should just give up and say "nah thats nonsense, lets move on". As we've seen countless times with modern scientific discoveries, things that once seemed insane and crazy now have changed our society fundamentally. Let me give you some examples. We use solar panels to convert light from the sun into a "magic" substance that flows through metal and can make your stove cook food. Solid state drives store data using the quantum tunneling effect, where particles(electrons in this case) passes through SOLID matter. Solid state drives are used in your smartphone, your computer and almost anything that stores data. Nuclear power plants can power ENTIRE cities for a day and consume an amount of uranium that could be held on your hand, while a coal or natural gas powered power plant would consume TONS AND TONS of matter. They work by splitting in half the building block of matter which is so incredibly small that you cannot comprehend it. The examples could go on. People many decades ago would find all these insane and crazy. But just because it seems crazy does not mean its could not be real. The universe works in unconventional ways. Also you did not provide any real argument to falsify the claims on dark matter. You simply called it magic and superstition. I could also say that about electricity. " how is it possible for an invisible substance to flow through a non-hollow fully SOLID metal wire and power electric motors that can make cars move at 100 kilometers an hour and make computing devices that can simulate extremely realistic enviroments and solve mathematical equations in mindblowingly fast speeds?". Yet its real and has totally changed our society.

[@caffiend81]

I must have picked up a disturbance in Space Time because I randomly decided to open KZbin and saw this 27 seconds after it was posted. 🤣

[@gtbkts]

😂😅

[@Alex-qm6ig]

Or just that you are addicted to KZbin like everyone is nowadays

[@xpatrstarx]

Maybe you've become entangled with the channel?

[@kayakMike1000]

It wasn't a disturbance in spacetime, it was a sudden harmony provided by Dr. O'dowd.

[@kayakMike1000]

​@@Alex-qm6igI ain't addicted! I can quit anytime!

[@StarCh33se]

It'd be really cool to have dark matter's nature uncovered in my lifetime, but in the meantime I'll keep appreciating these updates on scientists' best guesses. Love the video!

[@alastorgdl]

Science is NO about GUESSING, dear scientism cannon fodder Science is about VERIFIED THEORIES You're in a cult and you don't even know it

[@jovetj]

I'll be happier when the "dark matter" "dark energy" theories are dead.

[@KekusMagnus]

@@jovetj propose an alternative then? It just means there's matter which we haven't discovered yet, that you find that unsettling is not the universe's problem.

[@StarCh33se]

@@jovetj climate change denier, i definitely think you have something valuable to add to the conversation!

[@spiritualawareness7736]

😊😊HUMAN SCIENCE is incomplete science in comparison with extraterrestrials science. Extraterrestrial science is HYPERDIMENSIONAL SCIENCE while on earth we have the wrong science Which is only based on the material physical part of our Reality but the HYPERDIMENSIONAL SCIENCE is focused on the two realities in which we exist, the MATERIAL PHYSICAL Reality and the SPIRITUAL ETHERIC REALITY. To have a complete theory of everything humans need to use HYPERDIMENSIONAL QUANTUM PHYSICS. How long will it take you to realize what I am telling you? A long time still Since 2006 I have told you by video and written that black holes are actually portals Dimensional tunnels to another reality completely different to our 3d reality with totally different and new laws of matter and energy that exist in that different reality 😊 Since 2006 i SAID THAT and Just last year is that Theoretical Quantum Physicists like MICHIO KACU are beginning to discover and talk about it, that i have been saying since 2006. 😊 HYPERDIMENSIONAL QUANTUM THEORY IS THE THEORY OF EVERYTHINGWhen will humans discover this? A lot of time at the pace at which they are advancing

[@GargantuanMonster]

Imagine living in one of these dark satellite galaxies, with only a few stars in them. The night sky would be almost black, save for a few whisps of the nearby large galaxies. Then after the discovery of the telescope the inhabitants find the sky is full of stuff. How do they make sense of it given their strange predicament?

[@albertodejuan6104]

With God, of course.

[@pierrotA]

If our mater is visible to them, they would have hypotesis and tehories on "shiny matter", and will think that their location is exeptionnal based on their observations, as we do too. They will have the advantage of knowing the structure of the dark mater, based on the observation of the region they can observe. They will know if the dark mater is mainly composed of black holes, particules, dead stars, or whatever. If our mater is not visible, and they can only see their own mater, they will have the same problem that us: why the univers seem more dense that we can observe ? That is, of course, if dark mater is mater... Maybe what we call dark mater is a distortion of gravity that is not link to any type of mater as we know it. Maybe space-time is distorded in way we fail to understand.

[@phoebepalydovas9881]

dark mater? i hardly knew'er!

[@sparking023]

Well, they would learn that the universe is much larger than they thought, just like us. The neat part about dark matter is that it is "transparent", so being inside a dense cluster shouldn't affect your observations, safe for the gravity distortion.

[@tigerpjm]

Wouldn't matter to them.

[@tommylakindasorta3068]

Great work -- this channel is phenomenal.

[@hayuseen6683]

Wonderful dive into the challenges of explaining things

[@kevincronk7981]

Wow 2.92 mil subscribers, this channel has really grown and I love that

[@JosePineda-cy6om]

i'm still not convinced an invisible particle is the key to everything. with each iteration, DM becomes weirder and weirder. I've always thought it doesn't have to be a "one theory fits all" situation, to me it seems a variation of MOND *plus* some invisible particle (or, more likely, *several* types of particles) will finally be the key. Once you modify the behaviour of gravity at ultra small accelerations, you don't need quite as much DM

[@tonywells6990]

There are huge problems with ideas like MOND. Even if MOND is correct you still need an enormous amount of DM to create large scale structures, but you may be right about a combination.

[@shawns0762]

There is a clear reason for the "missing mass". The answer has to do with what exists at the center of galaxies. Mainstream thought today is that singularities exist there. Most people don't know that Einstein said that singularities are not possible. In the 1939 journal "Annals of Mathematics" he wrote - "The essential result of this investigation is a clear understanding as to why the Schwarzchild singularities (Schwarzchild was the first to raise the issue of General Relativity predicting singularities) do not exist in physical reality. Although the theory given here treats only clusters (star clusters) whose particles move along circular paths it does seem to be subject to reasonable doubt that more general cases will have analogous results. The Schwarzchild singularities do not appear for the reason that matter cannot be concentrated arbitrarily. And this is due to the fact that otherwise the constituting particles would reach the velocity of light." He was referring to the phenomenon of dilation (sometimes called gamma or y) mass that is dilated is smeared through spacetime relative to an outside observer. "Time dilation" is one aspect of dilation. It's the phenomenon behind the phrase "mass becomes infinite at the speed of light". General Relativity does not predict singularities when you factor in dilation. Einstein is known to have repeatedly spoken about this. Singularities have always been a stubbornly persistent fictional term. Dilation will occur wherever there is an astronomical quantity of mass because high mass means high momentum. There is no place in the universe where mass is more concentrated than at the center of a galaxy. It can be shown mathematically that the mass at the center of our own galaxy must be dilated. In other words that mass is all around us. This is the explanation for the abnormally high rotation rates of stars in spiral galaxies. The "missing mass" is dilated mass. Einstein wrote about dilation occurring in "large clusters of stars" which is basically a very low mass galaxy. For a galaxy to have no/low dilation it must have very, very low mass. It has recently been confirmed in 5 very, very low mass galaxies to show no signs of dark matter. This is virtual proof that dilation is the source of the "missing mass", there can be no other realistic explanation for this fact. Dilation is the original and correct explanation for why we cannot see light from the galactic center.

[@atharvamirashi]

I'm currently studying about both these problems in college (the Too big to fail problem and the density diversity problem). One of the explanations for not seeing the sub halos is that in some of these ultra faint dwarf satellites their star formation stopped sometime during the epoch of reionization and therefore we receive much less amount of light from them. Either reionization or ram-pressure stripping could have pushed the gas out of those subhalos very efficiently. Although this "fix" isn't completely sufficient to solve the problem entirely it's one of the explanations why it could cause such variations.

[@nodarkthings]

have you ever considered that the model may be false and that this invented invisible material that no one can see.... actually.... doesn't exist?? surely this is what pseudoscientists do when their model is shown to be false?

[@shawns0762]

There is a clear reason for the "missing mass". The answer has to do with what exists at the center of galaxies. Mainstream thought today is that singularities exist there. Most people don't know that Einstein said that singularities are not possible. In the 1939 journal "Annals of Mathematics" he wrote - "The essential result of this investigation is a clear understanding as to why the Schwarzchild singularities (Schwarzchild was the first to raise the issue of General Relativity predicting singularities) do not exist in physical reality. Although the theory given here treats only clusters (star clusters) whose particles move along circular paths it does seem to be subject to reasonable doubt that more general cases will have analogous results. The Schwarzchild singularities do not appear for the reason that matter cannot be concentrated arbitrarily. And this is due to the fact that otherwise the constituting particles would reach the velocity of light." He was referring to the phenomenon of dilation (sometimes called gamma or y) mass that is dilated is smeared through spacetime relative to an outside observer. "Time dilation" is one aspect of dilation. It's the phenomenon behind the phrase "mass becomes infinite at the speed of light". General Relativity does not predict singularities when you factor in dilation. Einstein is known to have repeatedly spoken about this. Singularities have always been a stubbornly persistent fictional term. Dilation will occur wherever there is an astronomical quantity of mass because high mass means high momentum. There is no place in the universe where mass is more concentrated than at the center of a galaxy. It can be shown mathematically that the mass at the center of our own galaxy must be dilated. In other words that mass is all around us. This is the explanation for the abnormally high rotation rates of stars in spiral galaxies. The "missing mass" is dilated mass. Einstein wrote about dilation occurring in "large clusters of stars" which is basically a very low mass galaxy. For a galaxy to have no/low dilation it must have very, very low mass. It has recently been confirmed in 5 very, very low mass galaxies to show no signs of dark matter. This is virtual proof that dilation is the source of the "missing mass", there can be no other realistic explanation for this fact. Dilation is the original and correct explanation for why we cannot see light from the galactic center.

[@shawns0762]

Here is the explanation for dark matter/galaxy rotation curves - Wherever there is an astronomical quantity of mass the known, fundamental phenomenon of dilation (sometimes called gamma or y) will occur. Mass that is dilated is smeared through spacetime relative to an outside observer. It's the phenomenon behind the phrase "mass becomes infinite at the speed of light". Time dilation is just one aspect of dilation, it's not just time that gets dilated. A 2 axis graph illustrates the squared nature of the phenomenon, dilation increases at an exponential rate the closer you get to the speed of light. Dilation will occur wherever there is an astronomical quantity of mass because high mass means high momentum. This includes the centers of very high mass stars and the overwhelming majority of galaxy centers. It can be inferred mathematically that the mass at the center of our own galaxy must be dilated. This means that there is no valid XYZ coordinate we can attribute to it, you can't point your finger at something that is smeared through spacetime. More precisely, everywhere you point is equally valid. In other words that mass is all around us. Dilation does not occur in galaxies with low mass centers because they do not have enough mass to achieve relativistic velocities. It has recently been confirmed in 6 very low mass galaxies including NGC 1052-DF2 and DF4 to have no dark matter. In other words they have normal rotation rates. This also explains why all binary stars are normal rotation rates, not 3 times normal.

[@SomyCoal]

Always excited to see a new spacetime episode

[@Jondiceful]

This is one topic that never seems to get dull. I hope we get more episodes on the um... matter... to shine some more light on the um... dark mystery and the tweaked variations of the models meant to explain it all.

[@EMAngel2718]

I wonder if a mix of types of dark matter could be at play, with different mixtures having different properties; it does seem odd that so much of the universe's mass would be a single type of thing

[@Merennulli]

That is the obvious thing to try, but any model has to still solve the problem of what we've observed and a lot of the mixture options just don't fit, combining problems rather than solving them. Right now, Mixed Dark Matter (MDM) is mostly looking at mixing CDM and UltraLight Axionlike particles (ULAs).

[@castonyoung7514]

While that's what I'm hoping for, and perhaps have some very circumstantial reasons to think this is likely the case; I don't see how it would be unnatural at all for 80% of the universe to be one thing. After all, think of how much hydrogen there is compared to every other element, or how much of your body is made of water. I'd say transformations of the inverse square law are just as common as they are uncommon, if not more so.

[@rohrertech8882]

Not even a theory, just an idea, but what if the dark matter was as diverse as our common matter in terms of density and energy. Could there be 100 kinds of dark matter, with different speeds and energies. Would certainly make the calculations a nightmare, but if wimps were of differing mass,(or interactive strength) how would that affect the models? Would high energy wimps be less likely to interact with normal matter?

[@marckiezeender]

I agree. The thing about CDM is that it doesn't differentiate between WIMPs and any other non-relativistic particle. I.e. dark matter particles could be the size and/or mass of an entire planet, and it would still behave like CDM on a galactic scale.

[@marckiezeender]

@@rohrertech8882 All non-relativistic weakly interacting particles would behave like cold dark matter (see my other comment ^^^)

[@vinnieg6161]

every time a new space time video gets out I have to put on my thinking cap,

[@JonoSSD]

Quick question: do these models take into consideration dark energy at all? Or it doesn't make sense because at these scales (inside of galaxies) gravity wins over it anyway?

[@marckiezeender]

They do take dark energy into account. They generally model it using the cosmological constant assumption. In fact, dark matter halo radius is essentially defined as: anything outside this radius is being pulled away by dark energy/expansion, and anything inside this radius is being pulled in by gravity

[@misterlau5246]

That's the uppercase Lambda, the cosmological constant in general relativity, Expansion

[@Aut0mati0n]

The ‘Too big to fail’ problem is perfectly named

[@xzysyndrome]

Super String...."Too big to fail" Look at all the grant devourers who have spent millions producing nothing at all....Some real big names too....Michio (Cough) ooo...my bad.

[@peterb9038]

Sounds like a few other variables or events have been forgotten in those simulations. Look forward to hearing about results based on refinements.

[@mortyrickerson6322]

Love this channel so much

[@Lantalia]

I'm still betting that the real answer is "many of the above", with multiple dark matter candidates turning out to exist in meaningful quantities

[@unvergebeneid]

Eh, Occam's razor and stuff.

[@thelongestyoutubechannelev6433]

Yeh seems like it

[@thelongestyoutubechannelev6433]

Probably

[@w.o.jackson8432]

@@unvergebeneid Occam's Razor isn't a law of the universe.

[@milferdjones2573]

I love it in my far future Sci Fi there is a whole periodic table of Dark Matter and then the future discovery of Invisible Matter that being particles that don't interact with anything in normal space even Gravity instead forming a second universe we can not easily observe. Then many different types of Dark and Invisible Energy. Allows massively faster than Causality scanning and communication example invisible fields that if you provide a equal amount of energy to them to transfer back to matter and energy they interact with you get a non gravity bound sensor or communication that can't be detected by the things it interacts with. Fun part back to the serious is maybe we are actually right now dealing with NIMP's instead meaning Non Interacting Particles. Then we might not be able to solve the Dark Matter problem for a very long time if at all having to accept they exists even though we can't find them.

[@Locut0s]

It's good that we are starting to get a HUGE flood of new data from all the new telescopes and surveys that are going to be coming on line in the near future. There have been just WAY too many neatly fine tuned models over the recent decades that are hard to disprove because we just haven't had a lot of new data. Both in particle and astrophysics.

[@GregorBarclay]

@@satan899I will never understand what accounts like yours are trying to achieve.

[@TheDarkToes]

​@@GregorBarclaythey are trying to achieve... The ability to watch and comment on KZbin.

[@nelson_rebel3907]

@@GregorBarclay Same thing yours is? Discussion and conversation? Or is the general disdain for any comment your only notable achievement in life?

[@GregorBarclay]

@@nelson_rebel3907 @TheDarkToes Sorry guys, think you're white-knighting for a comment you've not read - I'm replying to @satan899, who appears to have now deleted their post, which was encouraging us to repent our sins and kneel down to their particular god. But yeah, I've got some achievements! I came second in a hundred metre running race on a beach when I was nine. Admittedly, there were only two kids competing but chalk up the wins where you can, right?

[@yishakibrahim]

Great Episode as always! Just being picky at 6:25 Galaxy rotation must be the other way round🧐

[@yyyy-uv3po]

The mystery thickens and attracts more mystery in the process.

[@Galadonin]

I've been a sub for some time now, and I'll always click on the notification, thanks for everything

[@mixstudio-sham1463]

Great job Matt, interesting as always.

[@sir.games7668]

This is so interesting, like how modern physics changed classical and how gravity was defined at first and how it is now by general relativity or even how we interpret it at quantum level. It's so fascinating and it shows how scientific knowledge is ever growing. First, draw a wild deduction from an observation and then work on it until it is more plausible and until it is the truth, and I like how many theories were rejected and many taking its place. It's an ever-growing pool of knowledge, and I am here for it.

[@Kevin-p2l5b]

Awesome.

[@sjoncb]

Yes a 'new' model. *ELECTRIC UNIVERSE* protons are everywhere!!

[@MartinH81]

Every time CDM is discussed I get more confused. not only about the how/why, but also about the scientific conduct surrounding this topic. I work in biomedical sciences, a different field of science, but the scientific principle is a pretty universal one and I have a lot of difficulty accepting CDM as being truly scientific. If I'd grow cells in a lab and they grow weird and my professor asks me which serum I use and I'd answer "don't worry, it's just 20% of the medium" he would tell me I'm an idiot and he would be totally right. It's a simplistic example perhaps, but I was flabbergasted to just learn that phycisists made this flaw in the simulations and that you are so forgiving about it in this video. Though I know/understand why you are, as these are your colleagues. I have always assumed normal matter was included, because that would make the most scientific sense and to my memory it was never mentioned that these were CDM-only w/o normal matter. Especially because the other 80% is so vaguely defined you'd definitely want to add the 20% of the mix which you know most about. If so, then you did an absolutely great job unveiling this. I'm not the first who argues it's strange scientific conduct to invent a particle, which is completely invisible, only interacts gravitationally, then tweak the parameters of this elusive particle in such a way that it fits observations again and then fully adopt its existence and validity. Then more particles with more assumptions are added into the mix and simulations, those also being tweaked based on...nothing?...no experimental validation or whatsoever. How's that scientific? I'm not surprised simulations show similarity with reality, as the simulation is biased by the same assumptions. This whole field of research on CDM seems to lean heavily on circular reasoning to me. We are being educated that a scientific theory is not just an idea as many think of when they hear theory. A (good) scientific theory not only describes reality, but also makes correct predictions. CDM does neither, for decades. I'm totally fine with the idea that I'm not a cosmologist, therefore it's likely way over my head and that I simply don't understand enough about it, but the scientific conduct of this whole field of science is so alien to me. I'd love to see a video which discusses the scientific argumentation and especially scientific validity for each step in the development of this model.

[@legitskilz901]

Your speaking on too many different levels of applicability for a good answer to be given. The hard part is there’s about 3 levels for sure for sure. I explain it like 1. Black holes being undefined unmetered pure energy. 2. The show “futurama” black holes to alow easier explanation of string theory, time travel, and choice/love 3.

[@fewwiggle]

Your concerns mirror my own (by about 10% :-) I wish they would present this type of stuff as more "speculations", than as "theories"

[@chuckschillingvideos]

The notion of "dark matter" is as far from actual science as you can get. It is somewhere on a scale between wild speculation and hopelessly wishful thinking.

[@benblas164]

I remember learning in Physics history that is was commonly accepted that heat was a "thing" that flowed between objects rather that a property of the object itself. I've always drawn parallels between that and dark matter. I've always wondered about Dark matter just being regular old matter, maybe not as simple as a bunch of hydrogen atoms, but what about a "soup" of subatomic particles (Bosons, Hadrons, and Fermions) flying through space weakly interacting with more rigid atomic structures we can observe. I agree that inventing a new form of matter and then just tweaking it until it fits our observations is a bit backwards, however astrophysics does not have the luxury of the scientific method, there is no way to empirically test hypotheses, the best we can do if start with our observations and invent reasons for why that may be. I would really love for someone to tell me why dark matter could not be just regular old dispersed matter :)

[@fewwiggle]

@@benblas164 In most cases, astrophysics can't be 'tested', but a theory has consequences, so it inevitably makes predictions about what we will observe. And, when a prediction is falsified, that theory should be kaput.

[@ryewaldman2214]

I'm glad you touched on the gravitational coupling between dark matter and baryonic matter, and how baryonic matter acts as a third party mediator to communicate electromagnetic interaction. It's like dark matter can, in the presence of baryonic matter, interact with (influence) other matter. electromagnetic interaction with extra steps? The more dark matter you have, the more baryonic matter you'll gravitationally attract, which in turn gravitationally influences dark matter. The forces of interaction amongst baryonic matter will modulate gravitational effects felt by dark matter. In fluid mechanics we use can use field equations to describe fluids as a continuum when the Knudsen number is sufficiently small (the length scales of molecular integrations is small compared to the length scales of the flow that we're interested). This allows us to drastically simplify our calculations by replacing the need to consider molecular dynamics with a simple constitutive model of the fluid. In this case, i presume that dark matter can be treated as a continuum, defined by the local density and temperature, with the interactions due to gravity a function of the density. Is there a length scale that is large enough that we treat all baryonic matter as a continuum with a simple constitutive model? I can't imagine the need to simulate the dynamics of star formation, death, and supernova directly in these universe-scale models just to account for the gravitational influence of baryonic matter on dark matter. I assume that there is some statistical representation that would give a relationship for pressure, temperature, charge, internal energy, density, viscosity, etc of baryonic matter and we would have a set of governing field equations for the dark matter and the baryonic matter that would be coupled by way of gravitational interaction. Otherwise, the range of length and timescales required to couple dark matter and baryonic matter in single calculation seems like it would be as ridiculous as trying to simulate a 747 flying in icy weather using molecular dynamics. Is there a "Knudsen number" for baryonic matter at universe length scales where it can be treated as a continuous field and what would its constitutive model look like?

[@agusr32]

Yes, these simulations usually have millions or billions of different "particles" that represent dark matter, gas, stars, etc. For instance, a single gas particle's mass can be of millions of solar masses. Thus these simulations need to use algorithms that "create" stars, heat the gas, produce supernova feedback, etc. whenever certain conditions are met, because it is impossible to resolve these processes with the simulation's resolution. These "length" scales are basically the simulation's resolution.

[@SpaceMan-f6d]

I'm afraid dark matter does not exist at all. We're somewhere wrong about the nature of our Universe. But I'm a great fan of dark energy, which is hidden somewhere behind our regular matter. As soon as we understand dark energy, we can speculate on the nature of our Universe, thus putting everything together - light, energy, matter, gravitation, quantum, etc. Otherwise we are blind. And creating artificial realities. Nothing personal. I'm just not a fan of Multiverse either. Our Universe is fair enough for String Theory, probability, causality etc.

[@AustinFeltron]

@@SpaceMan-f6d if it’s not axions then I doubt dark matter is even real either. Axions fix the strong CP problem and would just be another scalar boson like the Higgs. I don’t have real physics qualifications, but it seems like a piece of the puzzle that would fit very nicely. If we prove dark matter isn’t axions I think it might be time to seriously reconsider our theory of gravity, which some have done already.

[@SpaceMan-f6d]

@@AustinFeltron Bull's Eye! Not a fan of Higgs either. I prefer gravitons to axions and it all makes more sense. Hypothetical too, but more realistic in SF or just NEW physics. Gravitational theory must be rewritten. Fully agreed.

[@angelmendez-rivera351]

@@AustinFeltron​​⁠​​⁠ *...but it seems like a piece of the puzzle that fits very nicely.* Saying "it seems like a piece of the puzzle that fits very nicely" is not a valid argument for any conclusion. It amounts to nothing more than "X is true because I like the idea of it being true." *If we prove dark matter isn't axions, then I think it seriously might be time to reconsider our theory of gravity...* Sorry, but this is not how it works. You not liking the case where dark matter is not constituted by axioms has no actual implications with regards to how empirically accurate our dark matter model is. *...which some have done already.* This defeats your previous point, especially as these alternatives do not fit the observations either.

[@ShawnPitman]

Maybe the real dark matter is the friends we made along the way.

[@kelbb1404]

Lmao

[@a6hiji7]

Or those files you keep hidden in your PC.

[@fkret3707]

great video as always! i wanted to ask how sure we are that dark matter is only made out of 1 type of matter and not a combination of the different suggested dark matter types?

[@castonyoung7514]

No, I think it's been hypothesized that every standard particle might have a dark counterpart; however, starting from some random number of dark matter components and then simulating every possible combination of properties they have is going to be much harder than forming one theory that describes the statistical mechanics of dark matter as a whole. Even if we found a combination of particles and properties that matched the data perfectly, we'd have to throw all of it out in favor of the properties they have as a whole, as that is the only thing that can be measured with certainty at the moment. Everything else would just be speculation. That being said it might be a good idea to try simulating mixtures of particles that are already predicted by other theories as dark matter candidates.

[@reubenpreciado]

it would be really neat to see an episode on gravitational atoms! thanks for the great work

[@TheArtofFugue]

We need revised models on almost everything. Dogmatism runs deep in science (as a post doc) as I’ve recently realized.

[@TheGr8scott]

Thank you Matt for keeping it real and not being a sellout like many public figure "scientists" these days who speak on all kinds of irrelevant topics outside their field or whatever is popular on tiktok.

[@alansnyder8448]

Really appreciate these deep dives in the Dark Matter debates. When we finally come to a solution, hopefully in my lifetime, I'll appreciate having known the details of how we got there.

[@KieranLeCam]

Hahaha me too :)

[@johnboze]

IF PBS SPACETIME STOPPED CENSORING ME THIS VIDEO WOULD NOT HAVE BEEN MADE: @FiringRoom1 Ambient EM Field Inertial Dipole Planck Particles in Vacuum ARE DARK MATTER AND ENERGY AND CAUSE VACUUM PRESSURE AND GRAVITY!

[@james6401]

Indeed.

[@shawns0762]

There is a clear reason for the "missing mass". The answer has to do with what exists at the center of galaxies. Mainstream thought today is that singularities exist there. Most people don't know that Einstein said that singularities are not possible. In the 1939 journal "Annals of Mathematics" he wrote - "The essential result of this investigation is a clear understanding as to why the Schwarzchild singularities (Schwarzchild was the first to raise the issue of General Relativity predicting singularities) do not exist in physical reality. Although the theory given here treats only clusters (star clusters) whose particles move along circular paths it does seem to be subject to reasonable doubt that more general cases will have analogous results. The Schwarzchild singularities do not appear for the reason that matter cannot be concentrated arbitrarily. And this is due to the fact that otherwise the constituting particles would reach the velocity of light." He was referring to the phenomenon of dilation (sometimes called gamma or y) mass that is dilated is smeared through spacetime relative to an outside observer. "Time dilation" is one aspect of dilation. It's the phenomenon behind the phrase "mass becomes infinite at the speed of light". General Relativity does not predict singularities when you factor in dilation. Einstein is known to have repeatedly spoken about this. Singularities have always been a stubbornly persistent fictional term. Dilation will occur wherever there is an astronomical quantity of mass because high mass means high momentum. There is no place in the universe where mass is more concentrated than at the center of a galaxy. It can be shown mathematically that the mass at the center of our own galaxy must be dilated. In other words that mass is all around us. This is the explanation for the abnormally high rotation rates of stars in spiral galaxies. The "missing mass" is dilated mass. Einstein wrote about dilation occurring in "large clusters of stars" which is basically a very low mass galaxy. For a galaxy to have no/low dilation it must have very, very low mass. It has recently been confirmed in 5 very, very low mass galaxies to show no signs of dark matter. This is virtual proof that dilation is the source of the "missing mass", there can be no other realistic explanation for this fact. Dilation is the original and correct explanation for why we cannot see light from the galactic center.

[@swatch_goblin]

Matt looks kinda evil in this video, almost like a Dark Matt. If he becomes more evil, he will be Dark Matter.

[@patton72010]

Love this channel. Was hoping for LK-99 video though.

[@Number8Soft]

"The Wimp miracle" might be my new favorite term in physics

[@KraigoryFilms]

please do a space time podcast, i would love to listen to matt speak with others more :)

[@King-Ender]

Great video man👍🏻👍🏻! I’m currently getting a bachelors degree in physics and then going for a masters and a PhD in Astrophysics and videos like this helps out a lot for me. Thank you for making these kind of videos.

[@pacotaco1246]

Did you get to the Virial Theorem yet?

[@stevenverrall4527]

TIP: Don't climb on the DM or string theory bandwagons because they are tipping over!

[@pacotaco1246]

@stevenverrall4527 bandwagoning is always a bad idea, especially in science. Stay skeptical, seek evidence

[@King-Ender]

@@pacotaco1246Now I’m curious, what do you mean by tipping over?

[@King-Ender]

@@pacotaco1246Thank you for the advise, I will keep that in mind. I was actually planning on studying other stuff like black holes, white holes, and DM & DE. That stuff interests me a lot and would love to learn more about them.

[@stevevermeer1797]

I agree with Edwin, would love an update on the latest on superconductors. Great job Matt, interesting as always.

[@ArtVandelayLTEX]

You're so good at this I need to watch it 3 times.

[@stevenverrall4527]

That's right. Keep adding unobservable adjustable parameters. Sounds like epicycle theory...

[@J-A-A-K]

This video was extremely well written and presented for such a complex subject matter. Thank you!

[@lordoftherings999]

Actually dark matter is much older than we’d think. It was first conceived by Lord Kelvin in 1870s (the same scientist who first theorised universal Heat Death in 50s and a very “euristic” form of Big Rip). A lot of things have changed since these years, but still dark matter and energy remain a fascinating mystery.

[@trumpingtonfanhurst694]

Considering recent observations are blowing up some of science's most closely held beliefs, I'd say we need a new model for most things.

[@narfwhals7843]

Nothing is being "blown up". Interesting results are being misreported as paradigm shifts for profit.

[@DrOtto-sx7cp]

🤣👍

[@imwelshjesus]

Baby jesus?

[@Scion141]

@@narfwhals7843 Sounds like @trumpingtonfanhurst694 has been reading news headlines and taking them as facts.

[@danmallery9142]

6:25 As the density increases, would it not begin to heat up and effect the cusp-core problem? (If anyone reacts to this post, please realize that I am not a scientist, so use small words. 🙂 )

[@geniej2378]

Reading through the comments, I think it’s worth a mention of why Baryonic matter was excluded from earlier simulations. My guess is that computer simulations and compute power available to scientists to run these simulations has vastly improved over the years, and it wasn’t a “lazy” oversight.

[@garynicolson5192]

It's because normal matter has complex interactions, such as stars, novas etc. Dark matter is easily simulated as a non-interactive fluid/gas modeled just with gravity.

[@PajamaMan44]

I don’t consider 20% to be a small fraction tbh. Seems silly to ignore it

[@sciencegeekgrandpa8]

And then there's the most important problem of all: ENC (Emperor's New Clothes)--the problem caused by people forgetting that the only thing we have for certain is some observations that can't be explained, and that Dark Matter is just a hypothesis until some smart person can actually demonstrate the existence of the billions of particles that are supposed to be sheeting through us every second. Until then, it will remain the finest of fabric!

[@StreakyBaconMan]

Dark matter isn't a hypothesis, it's merely what we call the source of the extra gravity we can observe out in the universe. What is a hypothesis is the potential explanations for what dark matter actually is - like dark matter being weakly interacting massive particles is a hypothesis that hasn't been demonstrated. But the fact that dark matter (unexplained sources of gravity) exists is not a hypothesis - you can run an experiment to confirm that unexplained sources of gravity do or do not exist, and we've done those experiments repeatedly and made the same observations that they do exist. That's just not a hypothesis anymore when you have that level of evidence.

[@StreakyBaconMan]

@@palladium1083 Dark matter is just a name - it doesn't necessarily mean that it's matter. I think you're just getting hung up on the name of these phenomenon as though they are attempting to describe the cause of the phenomenon when it's simply a name for the phenomenon itself. In your head just replace the words "dark matter" with "unexplained source of gravity" and "dark energy" with "unexplained source of energy causing the expansion of the universe to accelerate". If you think scientists are ruling out the possibility that dark matter is something other than matter you're just wrong - plenty of scientific research has been done trying to offer alternate explanations for dark matter which don't involve it being matter, they are just less accurate at making predictions than the explanation that dark matter is some type of weakly interacting massive particle.

[@feynstein1004]

Could it be that in the beginning, there were equal amounts of matter, antimatter and dark matter but because of the asymmetry of the weak force, the antimatter got converted into dark matter while normal matter remained? This reminds me, does dark matter also have its anti- counterpart i.e. anti-dark matter? 🤔

[@resistancefm5133]

I don't think so, because Dark Matter doesn't interact with the electromagnetic force it can't have an electric charge, and the relationship between matter and anti-matter is defined by having opposite electric charges.

[@flambambam]

@@resistancefm5133 Where are you getting this from? The three flavors of neutrinos are all neutral and still have anti-particles.

[@michaelsommers2356]

@@resistancefm5133 There is more to antimatter then opposite electric charge. After all, there are anti-neutrinos, and neutrinos have no charge.

[@20ZZ20]

maybe there is anti-dark matter but it is irrelevant because it doesn't interact with anything

[@angelmendez-rivera351]

@@flambambamNeutrinos have chirality. Antimatter also flips the chirality.

[@vicentecastro7148]

This is so informative..tnx Man😁

[@iavdortmunder8132]

Loved this breakdown of the problems with modelling Dark Matter, keep up the great work I'm sure you guys will figure it out :) One is forced to consider what Matt would be like as a dark matter simulation and would we be able to see and hear him I guess not but you'd have to wonder what part if any of Matt would persist?

[@TheRealSpiderMew]

What if Dark Matter is the Weight of Time generated by all the mass of everything else in the space, and Time does have a Particle but we can only observe the effect at a distance?

[@fab.9629]

i guess i should agree on some time-axis but probably wouldn’t call it weight..moments collected do not weigh, my best example is a campfire where our known elements come together to form a permanent stream (licking flames, glowing embers) of perpetual now in a very nuanced fashion. i‘d love to live and see cdm explained as invisibly ( to us ) shaping manifest moments of matter

[@michaelsommers2356]

What if dark matter is unicorn droppings?

[@Merennulli]

@@michaelsommers2356 Professor Farnsworth's smell-o-scope has largely ruled out that possibility. Unless the odors are weakly interacting, meaning only whatever dealt it can have smelt it.

[@JustinLe]

that's not consistent with experimental observations I think, so it doesn't quite work out

[@thezipcreator]

what? time is a dimension, there can't be "particles of time". like, there's not particles of the X Y and Z axes. time is the same as the other ones just with a sign flipped.

[@a3d4e]

What if dark matter does not exist, and the current gravitational model just needs to be revised at scale?

[@StreakyBaconMan]

Alternate theories of gravity aren't anything new, people have even used them to try and explain away dark matter before - the problem is that dark matter isn't uniformly spread across the universe and we've observed galaxies with hardly any dark matter, and other galaxies that are almost entirely dark matter. That's where modified theories of gravity fall apart - they start failing to make accurate predictions about such galaxies, when if it was an accurate theory of how gravity works it should make accurate predictions about all galaxies and not just galaxies that have average amounts of dark matter. It's also just unlikely we've got gravity that wrong considering how accurate the predictions we can make using that theory - like using the theory of gravity scientists were able to predict that black holes would exist decades before we had the technology to confirm they did in fact exist.

[@xBINARYGODx]

I demand you do an episode dedicated to the anti-science people that keep inundating the comments section with their drivel.

[@xBINARYGODx]

And I don't mean like the young-earth variety, some of these people seem rather scientistic until you mention DM or DE and then they throw the scie3ntic method out the windows and act no different the alt-fact-ers. Anyway, just watching this entire video silenced a lot of their (non-)points, but maybe a video directed at this nonsense would be helpful.

[@thstroyur]

I haven't seen any one such "anti-sciencer" here; plenty of people critical of DM and how its research is conducted - but not a single call for the overthrow of science as such. As for the unnecessary dig at creationism, I'll have you know that most creationists with scientific degrees nowadays have probably put more thought on this than you ever did - you're just parrotting diatribes you were socially conditioned to - and ironically enough, you're likely to approach the arguments with the same closemindedness of the people you're criticizing here. Fundamentalism is not exclusive to religion, as so happens.

[@pcarter1989]

I sense some underlying emotion in that delivery of "gravity wells."

[@funpotatoman]

I am chronically addicted to these videos

[@AlexanderGee]

Sidebar. Imagine if for april fools we could get a hitchhikers guide to the galaxy episode with Matt's actual galaxy facts and Journey of the Sorcerer for intro music.

[@bishwajitbhattacharjee-xm6xp]

Very crucial in this epoc .

[@kailomonkey]

To Big To Fail is such a meme naming

[@silentcaay]

Matt: "Ordinary matter... matters." Me, a construct of ordinary matter: 🥰🥰🥰

[@thedouglasw.lippchannel5546]

Great job Matt!

[@thebclpoonilli3098]

gravitational waves pushing on gravitational waves, make gravitational rivers

[@legitskilz901]

Life is a frequency

[@FacepalmProduction7]

I'm so gladf this show exists, signed up for the patreon :)

[@paulcoy9060]

6:30 That spiral galaxy moving in a counter-clockwise manner really hurts my eyes, with the arms facing the wrong way.

[@queueeeee9000]

It's always cool to see new ways of breaking youtube compression. Love it 😂

[@HupfderFloh]

0:49 it turns out that matter matters

[@patrickwumbo8271]

Please cite the papers you mention/get the information from in the description, thx!

[@PlanetXMysteries-pj9nm]

I was born with many difficulties in my life. Although I am not fully educated, I have a strong love for science and the universe. Thank you for bringing it to me. Love you

[@michaelsetter3647]

Great topic, I thoroughly enjoyed this one!

[@juustokasajuustokasa6109]

The acronym for Weakly Interacting Massive Particles must be one of the most spot on acronyms in science. I bet it gave a good chuckle to those who started calling these type of particles Weakly Interacting Massive Particles.

[@Killerbot-jn6xi]

Maybe blackholes in the center of galaxies have more of an effect on the dark matter density than we think?

[@richardaversa7128]

Another fabtastic episode. Does anyone know how to listen to the audio on the go? I wish PBS Spacetime would upload to Spotify.

[@Dagobah359]

GR: The faster something's relative speed is, the higher the apparent mass. The length also contracts. (Assuming the CG is in/near the middle) When something is going fast enough that the apparent length is less than 2x the Schwarzschild radius of the apparent mass ... would it appear as a rapidly moving black hole?

[@ditzykunoichi]

MAKE A VIDEO ABOUT UAPS!!!! You are one of my favorite science youtube guys, and I MUST know your opinions.

[@kittywampusdrums4963]

My wife's cooking turns into dark matter after she burns it on the stove every time.

[@bungalowjuice7225]

Regarding the inconsistency with supernova rich history and yet high dark matter in the middle could be that different galaxies simply have different amounts of dark matter

[@CACBCCCU]

You should consider El Gordo much like it's a compound lens system with a weak foreground field and a local condensing lens. Lensing patterns often have uniquely reduced divergences growing over distance, they can seem dissociated positionally from primary lenses. A single simple lensing mass is not particularly good at reconverging, let alone mirror-like reversing with doubling. With a compound lensing system one can imagine a removable screen in front of a secondary lens viewed beyond focus distance. Adding a rippled lens simplifies a lot of things, including explaining mirror-doubled near-parallel flat lensing image arcs, using radially-oriented projections for ripple-spanning galaxies seen edge-on.

[@Thanhatos]

Thank you ! :)

[@inujosha]

"Wimp miracle" my nickname in gym class in high school.

[@Ameu-dude]

This was satisfying as it didn't leave much mystery

[@johnpfeiffer4978]

Another short message about thermodynamics you said that cold matter moves slowly. Under the law of thermodynamics only heat moves to fill the void of the cold to bring it to a moderate temperature

[@projectarduino2295]

Hey, I don’t know if you do requests, but I was thinking. I don’t know a lot about quantum physics, but I had a thought experiment: Suppose you have a particle and an antiparticle at rest. They annihilate, and conserving momentum, the photons now carrying momentum should sum to a net zero, so a radiating distribution summing to zero. But now suppose the two particles are at some velocity, there exists some direction of momentum, so when the particles annihilate, the photons summed should maintain that momentum, so their distribution should be biased to compensate. How does a particle “know” how to compensate? Is this even how it works? What does the energy release look like? If you think of a spherical surface around the particles, the photons escape radially through it after annihilation. If measuring the intensity of each photon as it passes through this surface, and there exists some variance of distribution, does this simply exist because of some reference frame shenanigans? TLDR: Sorry if this is a bit of a ramble, but I was just curious about the exact mechanics of particle-antiparticle annihilation at velocities and what the emissions as photons would look like in the absence of any other matter to absorb momentum.

[@garethdean6382]

This is something we've tested. When two particles annihilate they nearly always produce a pair of photons (which are their own antiparticles) moving in opposite directions. These carry equal and opposite momentum, spin and the like. For a MOVING pair of particles the same thing happens, but the two photons will not be equal; one will have more energy, more momentum than the other. It will be 'bluer'. Now, if we begin moving away from the bluer photon and towards the redder one we'll see the bluer one redshift and the red one blueshift, at some point they'll become equal. What point is this? When we're moving as fast as the annihilated particles were, on average. When the particles would have been still from our viewpoint, both photons will look identical!

[@Ice_Karma]

Have you guys been using some new audio processing... thing for the last month or two? It makes it sound like the host is speaking directly into a close mic, but there's some odd audio artifacting going on, too. I've noticed this on a couple other KZbin channels I'm subscribed to, too.

[@realmless4193]

I was hoping this video would mention the role of magnetism in the formation of gas clouds and the secondary effect it would have on galactic structure through the gravity of said gas clouds, but I guess I must wait for another day before I see a serious discussion of the gravitational effects of intergalactic wind.

[@drillpenguin]

I'm pleased to find out I matter!

[@chetbobo4481]

This video goes well with the oologies podcast episode on dark matter

[@Engineer1980]

I don’t see why there is so much confusion over dark matter. Everyone know dark matter is formed when the dryer eats one of a pair of your good socks.

[@wallysponagle2426]

Yes , Science is not Science without being questioned by opposition.

[@aaron2709]

Well done.

[@frankharr9466]

That's really interesting. I wonder what'll happen.

[@AppNasty]

Just a thought...probably going to sound stupid but....what if it's not a particle and there are different versions of gravity? 1. Regular gravity. Take some dust pack it together and you get reg gravity. Pack in enough for some boulders and it's stronger. Pack Boulders into asteroids and asteroids into planets...stronger. 2. Dark Gravity. This requires galaxies to start it's effects. A small galaxy is like the dust packing. It shows up. Medium sized galaxy like more dark gravity shows up. Allowing massive things to pack. Then you have a 3rd version. Super Dark Gravity. This is the stuff that holds the WEB of galaxies together. Only shows up when enough galaxies pack in tight and it causes this version to appear and it allows that WEB throughout the universe. Stupid idea but sounded logical to me lol. If reg gravity isn't there then suddenly you have a space ship fly by....gravity is around that ship out of nowhere but it took mass to appear. What if these super gravities operate the same way but require Ultra Mass?

[@garethdean6382]

There's a few issues. For example, while large galaxies have about the same amount of dark stuff, smaller ones sometimes don't. Some are more than 99% dark, (Dragonfly 44) while others seem to have NO dark stuff. (NGC 1277) This doesn't seem to relate to their mass either. That's tricky t explain as something relating to normal matter gravity.

[@AppNasty]

@@garethdean6382 ahhh so if what I'm saying is true than large galaxies should have MORE.....hmmm...what if there's a cap? Meaning what if once enough mass happens, a specific amount, this effect happens. Say the mass is a quadrillion trillion tons.....just making up numbers here....but say at exactly a quadrillion trillion tons this effect happens and even if you times it 20, the effect is the same. Would explain why the small galaxy with x amount of dark gravity and the large galaxy with about the same amount acts the same. I don't think it's a particle. I think its an effect that happens at a certain point. When a certain something happens. Thats my point. That on galactic scales, new physics happen. Just like in the quantum realm neww physics happens. Micro world 0hysics is different than macro, and macro world physics could be different than super macro, and the last could be ultra macro meaning the universe itself where it expands faster than light etc. If we 8gnore all I just said, then I would just ask "is it possible that it isn't a particle and instead just a new effect we hadn't known of that happens only on large scales?"

[@123wordbird321]

I enjoyed this from my bed which is traveling ............. through space time.

[@zacharywong483]

Superb video, as always!

[@Binyamin.Tsadik]

This is now the 100th time I'm writing this (not actually but it feels this way) Dark matter is just high entropy matter Dark energy is just high entropy energy

[@temestokles5214]

Been a long time since I watched a vid here. Thrilled about the title. Let‘s see what it has in store :) My believe before watching is that they won’t ever find a dark matter particle. I think it‘s more a lack of understanding on gravity. In direction of mond, but not Mond either.

[@Merennulli]

The problem with modified gravity is that the observed effect doesn't strongly correlate with baryonic mass. When you have gravitational lensing where there's no visible matter, and galaxies that don't show signs of extra mass, it doesn't really work for a misunderstanding of gravity.

[@TheArtofFugue]

Yea! We do!

[@TimeBucks]

Always excited to see a new spacetime episode

[@vennilamahavlogs1924]

Very nice

[@sandeepshrivastav7874]

Nice

[@nihaakter4040]

Nice

[@johnboze]

IF PBS SPACETIME STOPPED CENSORING ME THIS VIDEO WOULD NOT HAVE BEEN MADE: @FiringRoom1 Ambient EM Field Inertial Dipole Planck Particles ARE DARK MATTER AND ENERGY AND CAUSE VACUUM PRESSURE AND GRAVITY!

[@EzazulGaming]

Nice