SPITE-VOTES is how Biden WON. This, Jerrymandering and a Billion other Problems are insta-solved by Ranked-Choice-Voting as explained by "Second Thought".
I love how this channel about high level astronomy and particle physics gets millions of views. You somehow have done the impossible and made physics break into the mainstream crowd. Incredible work every video.
@@captainmcawesome7908 For a channel like this to get 2.7M subscribes, they must be doing something right. Even if people can't always be bothered to watch full videos on subjects they barely understand ;)
Let's be honest here: I understand, maybe 2% of what is explained. Most videos are way over my head, but I see it as exposure. Maybe I'll have a better understanding the 25th time something is explained to me.
I don't try to measure my comprehension relative to what he is saying, just each time I learn _something_ I didn't know before I watched it. If I re-watch, maybe a little more. I envy you understanding 37%. 🙂
I used to be able to understand them 2-3 years back but nowadays their videos go way over my head, there's only so far my high school physics could go. But still interesting, i understand maybe 10%.
@@Cat_Woods Cat Woods, dont JUST let about Science in these hard times. KNOW WHY CRT is opposed? Because People know that teaching about History is literally always good and more importantly: they know the ABSOLUTE Fact of Factual Factness that teaching about R-cism is DECREASING R-cism according to all Data weve ever collecting on this Planet. Literally everything weve ever studied about this tells us this. Its obvious that N-zis literally dont want people to be able to identify N-zis. Good old Ted Cruz has literally said and made others say "We should be objective about History and THEREFORe not SAY N-ZIS are BAD GUYS. That would be taking-a-side and thats a No-No!". The Agenda behind this is so laugghablxy-obvious it implodes the very Concept of Obviousness. If the OLD Phrase "Those not learning from History are Doomed to Repat it" doesnt Do it for you, OK, then how about the Third GOP-Video of "Some More News" and his MLK-Video?
@@minotaurbison this has me laughing so hard... Sadly I can't share this joke with friends or family ... Oh what a lonely world for Higgs Bison believes
I have no formal education in physics. However, I put this channel on whenever it's late at night and I want to have my mind blown at what humanity has been able to deduce from observation, experimentation, documentation, and more imagination & hard work than any single person can fathom. Thanks for explaining topics in a way where you're completely true to the physics, yet make it light hearted and intriguing enough to keep me up, late into the night, learning new and exciting ways of shedding light on even the darkest topics in... SpaceTime.
As a person who earned their PhD in particle physics earlier this year I have to say I absolutely love this channel. Been watching it for years and it always keeps me thinking, fantastic work ✊🏾
This channel is intro undergraduate level. How do I know? Cuz that's what I am, and this is all stuff I understand and have taught myself. If you are speaking the truth, I just realized getting a PhD is going to be easy as f*ck (i'm going the theoretical route, double majoring in math and physics)
It's still a wonder to me that we have this giant loop through which we can aim accurately enough to collide subatomic particles, at speeds that break intuitive physics, then make out a whole tree of decaying particles, and identify each precisely enough to confidently know when something's off
@@svendkorsgaard9599 Well this throwing particles at each other still consists of collecting them in bunches that are 25 cm long and at the place of collision have 3.5 micrometers in diameter, aiming them so these 3.5 micrometer beams intersect in space, and timing them so they meet at that intersection in the center of the detector.
@@yudhistirs right. Your are obviously way smarter then the LHC guys, maybe you should call them and correct them before they build another one of those funny rings.
Wow! what exceptional restraint to not sensationalize and overhype what is undoubtedly an avenue of research highly worth pursuing! I expected the end of the video to be either 'we don't have the data yet' or 'this also didn't pan out'. But presenting the results so honestly and without fanfare and instead pointing to ongoing promising research was once again an example of how professional and scientific this channel is!
You're being sarcastic right? Did you hear him mention the exceedingly likely possibility that dark matter doesn't exist? No. This entire video presents dark matter as fact and reality pointing instead to the experiments not being done long enough or big enough. Do you know how many thousands of DM experiments have turned up nothing? Pay attention to this moment. This was the moment someone informed you that particle physics has become overwhelmed with group think and ideology. And in the future, presumably when we figure out what was wrong with our assumptions, you can look back and think someone warned you. I wouldn't care if there weren't millions and billions of US tax dollars being flushed down the drain to chase certain scientists' hubris.
I love you PBS spacetime, it was initially my childish and naive amazement with the complexity of GR and QFT, over the years I have more or less become an amateur mathematician in pursuit of understanding these theories, but even now, I still return to my ‘ sippy cup’ of PBS spacetime it is too good!
@@matroqueta6825 I just learned about the time cube meme and I’m sorry to say I got really deep into a manic phase once and kind of had similar experiences. Once I started getting medication for my type 1 bipolar these thoughts and other paranoid delusions disappeared. He’s probably just going through smth. {{ edit: sorry this was a grandiose delusion but it was heavily accompanied with paranoia }}
I love it too. And especially when he edges us by hinting it and then continuing the sentence. "And that's the story of everything within the entirety of... the fantastic expanse of... the colorful reality of everything in... such a wondrous thing we call... our collective home: Space Time." 🤣
I'm sure some channel's done it before, but I'd love to see a series on this channel where the videos discuss each type of subatomic particle. Not just the ones in the standard model, but ones like protons/neutrons, pions, kaons, pentaquarks, tetraquarks. One video at a time. You could make an entire series just about the standard model particles, too. You could discuss a particles' interactions, the history of its discovery, the implications of its discovery, the role it plays in physics etc. It might get to be a bit much watching (and making!) a 10-20 minute video for every particle, type of particle and combination of particle but I for one think it would be great fun.
I'm so used to dead end for finding out what Dark Matter is, that the branching fraction up to 0.26 had me jump on my armchair! Looking forward for future development on this topic.
The branching fraction up to 26% just means we don't detect anything, and we would have detected something if the branching ratio was larger than this. The Standard Model Higgs->invisible branching fraction is really, really small (0.1%), so unfortunately we'll never see this at the LHC.
My goodness I've been studying particle physics since late middle school, I'm going to college next year, Im aiming to work at an accelerator one day. This stuff is so exciting I reallllllly can't wait to learn more in college
college is overpriced. you could formulate your own curriculum and gather your own reading material to cut out the middle man who aims to steal your intellectual property for DARPA purposes.
@@niteshkumarsharma8305 That's awesome! What year are you right now, and are you jumping straight in, or did your IT background give you a headstart with prerequisites?
finding anything at all that reacts with dark matter in a way that visualises it in a way that we can detect it... that'd be like finding the holy grail
Would you rather discover what dark matter is or make contact with intelligent aliens? I'd go with the latter. Especially if they knew the answer. But not necessary.
@@aero1000 through gravity, but nothing else. As far as we can tell no, neutrinos barely interact with anything so it's likely that dark matter probably doesn't interact at all. Not in the same way at least.
I absolutely love the pace at which this was spoken compared to usual. I will be coming back again more often instead of assuming my mind won't keep up lol
So this might come from my gaps in understanding, but if we detect what is presumably the fundamental dark matter particle via the Higgs, are we assuming it's a solitary particle or could there potentially be an entire "dark model" that exists beside the standard model?
Most things in the standard model come in families of similar particles, and it has a tendency for groups of 3 or 6. We wouldn't call it a "dark model" or anything like that, but it could definitely add a big new dark section to the model we have.
It wont exist separately to the standard model, it coexists with the standard model. The Higgs particle / Dark matter is "Skin Theory" it exists in a Symmetrical balance with temperature plasma weight physics.
This is likely armchair science at best, but I believe there are as many as three dark sectors. If you count the broken symmetries related to particle interactions and assume they all had to link up at some point during the early stages of the big bang, then you can reduce until you are left with a few possible branches for the energy to have taken at the very beginning. All the particles and forces we can clearly see are based on only one of those branches. So if that energy persisted then you'd end up with different types of energy (i.e. particles) that shadow our existing particles but exist where the energy of our type cannot interact. If that is true, I would also expect to see the only interactions with dark matter being photophobic in nature and really only appearing in the apparent loss of energy in a system (which was in the video due to a shared Higgs) or in the slight altering of standard decay rates of other particles as the dark matter interferes with particles it contacts.
Exposition and delineation are marvellous and par-excellence as always. Dark matter and Dark energy both are really very tortuous and twisted concepts which impel every one to scratch their head .
What do you think about traveling back in time as fare time is moving forward and that's good for interstellar travel. What about warping to light speed and using that against rotation of the Galaxy to travel at the rate of time
Time travel is really a very exciting and bewitching sci-fi concept. But if we contemplate carefully and profoundly we are already experiencing the time travel . Although it is very teensy-weensy as in contrast to our macroworld but still it is there and we gauge that time off-set with a very groovy instrument called Atomic Clocks . As you know Gravitational effects are interplaying here . These gravitational effects give rise to something called Gravitational gradient which tells us about gravity's variation with altitude , with depth . Now as we ascends towards space we are little bit ahead in time which is very minute but still it is there and for people who are on the earth will experience a little bit lag in time as compare to ours . This is because of gravitational gradient effect. BTW this is the same phenomena which aid us to experience gravity on earth. So Aren't we already subject to time travel ? Although this is teensy-weensy but it's OK .Time travel at large scale is a horse of different color. Infact at macroworld time is nothing but just a unidirectional arrow running it's course . 😇😇😇
As far as warp to light speed is concerned and make use of this to create conducive conditions for instellar voyage is still need to get down the brass tacks for burgeoning the methods to achieve this quickly and at a rate of knots. Miguel alcubierre has already unravelled the equations which we can use to create a device called warp drive but our technology is not that much pullulated and developed which can give rise to such kind of device . All this is a matter of time . But For the time being we can only mock up about the real model of warp drive. But one day in future we will definitely have this kind of tremendous and top-notch device. 😊🙃🙃
I really wish you guys and galz would toss your brain power on making commercial Fusion at reality! I'd take that over the solution for DM any epoch of universe! But hey, thanks for what you ARE teaching us mere mortals. It helps flush the brain of other wurst insignificant dark matter.
Essentially 'dark matter/energy' is an explanation dreamed up to explain 'why don't stars and galaxies move the way the general theory predicts'. No one has detected or observed aaaaaaaaanything that they thought 'hey, I've found this new stuff'. The General theory is not fully coping with how things *actually* behave. Either the theory is wrong (it is) or there really is this mysterious, never detected or discovered or measured or isolated, new energy/matter that *just happens* to be 'the error amount in the general theory. Maybe "all" that is needed for dark matter/energy to work is a 9500% increase in the total matter in the universe. Or. The general theory doesn't work.
Would love to see an episode discussing vector portals following this one! Dark photon/additional U(1) vector bosons are frequently discussed in the DM literature, providing interesting coupling mechanisms for direct detection, such as kinetic mixing. Great stuff guys!
Great episode! You mentioned earlier that every neutrino is accompanied by a lepton when it's produced. Wouldn't that make it possible to track these leptons and account for the momentum of their corresponding neutrinos? That way they could conclusively determine that missing decay products are something new, and not a problem with how the branching fraction was calculated.
Finally a video that is unique and interesting. So tired of YT showing me the exact videos I have already watched. Not to mention, this is something I have not heard about so that is refreshing also. Thanks
Love these videos and love the fact that this information is now easily accessible to anyone and everyone that has an internet connection. You can accidentally stumble into these videos and learn or spark interest.
Hello sir I just wanted to tell you I've been watching your show since 2017 and the information provided has been invaluable to me. Just by watching your show and some other delving into hermetic teaching. Basically you've helped me achieve a fundamental and solid belief system through mainly a deep understanding of physics. Final words are this. I'm starting a tiktok because it's what's popular right now, anyway I plan to metaphorically scream your name from the internet rooftops. I assure people will know PBS spacetime by heart before I've had the final say. Cheers hope this finds you well and I'm doing this simply because I'm tired of wrong answers.
Very interesting! It would be quite ironic if the Higgs actually turned out to be this meaningful after everybody thought its detection was just veryfying the last missing bit of the standard model but wouldn't get us forward.
I feel like the discovery or explanation for dark matter will be the greatest scientific achievement of my own lifetime. The scientists who pull it off will get all the Nobel prizes
if physicists are correct, it's going to happen soon. with enough higgs collisions they can narrow down the branching fraction and detect the presence of particles that haven't been discovered yet - most likely dark matter. i expect this to be solved in the next decade or so unless the higgs decaying into dark matter is rare - which doesn't seem to be the case considering the overwhelming amount of dark matter in the universe.
This channel continues to churn out amazing videos with incredible production. I almost feel I understood this one :). Thank you for keeping science in the spotlight.
If we think detecting dark matter is difficult spare a thought for those on the dark side trying to detect the much much less abundant normal matter on the light side.
Funny :D Unfortunately, we know that DM does not form small-scale structures. We never observed stellar clusters with some part of them being invisible. Evidence points out that DM concentrations are diffuse and large ("halos"). Essentially, normal matter (a galaxy) sits in a larger, invisible DM halo, not the other way around (DM "clouds" flying inside galaxy).
@@denysvlasenko1865 If dark matter gravity is what’s stopping galaxies flying apart, and if this gravity is of the attractive variety then sufficient dark matter must be located within the boundary of the visible galaxy? I would like to hear your opinion on this.
@@hyperduality2838 I'm sorry I couldn't get through your whole comment, but no Dark Energy is not dual to Dark Matter, or at least there's no evidence to suggest such a thing. They are just both called dark because they are invisible (and I guess invisible matter wasn't catchy).
If this fails, then the best conclusion left would be that "dark matter" is not "matter" at all, but some other kind of space-time distortion other than matter.
like primordial black holes? my naive brain loves the idea of extending this to all particles being local scrumples of spacetime, but i know that's very inconsistent with physics as we know it.
Good @Pedro Andrade. More likely to go that way. The introduction of the nameholder 'Dark Matter' came into being in the first place observing a space-time distortion to which we desperately wanted to assign 'matter' to cause it. But when cause and effect are so separated with time, space retains the 'effect' as memory. Where does this vein take us to? Dark matter is a wrinkle in space-time or a memory registered as distortion. On the flip side, all memories fade in time. Wrinkles ironed. The universe expands. Thus, dark energy!
Very interesting, insomuch it's actually investing.. congrats Euan and Matt (collaborative writers), this episode is a preponderantly influential argument for a badass new particle collider.
As usual, fascinating! As usual, I watch every episode intently and hope 10% of the content sticks to my slimy little brain. Matt, who does your synthy background scores (not necessarily your theme tune, though I love that too!)
Talking about particle accelerators always brings the scene from the Simpsons to mind where prof. Frink gets a printout after running some accelerator and says something like "you can tell your grandchildren you were here when humanity learned.........that this accelerator is much too small to tell us anything important"
I remember in one episode of star talk, some asked Neil DeGrasse Tyson if dark matter gets its mass from the Higgs boson, he said "for all we know, dark matter could have its own Higgs boson."
If 2 force carrying particles eject a Higgs, and the Higgs may decay into dark matter, does that mean the dark matter created there is a force carrying particle? (Not all DM, but the particles from this interaction.) Is that possibly gravity? Might explain the relationship between mass and gravity.
@@sspectre8217 I am way too many years out of touch, but the diagram made it look like a force, and gravity is weak, so a force that weakly interacts with mass seemed like a fit Just wondering what I am missing.
@@randolphphillips3104 thats sound plausible. Having no real understanding of how the mechanics work I cant possible disprove this idea. Man that really would line up with a lot of things. No particle for gravity, no way for gravity to be included with QM, gravity being so much weaker, unexplained "dark" mass. While writing this I had idea, if we know the strength of the weak and higgs forces could we somehow find what the supposed "dark" force carriers would need to have?
I, for one, can’t wait to see what we find out about the universe next! As a kid I wanted aliens and monsters to be real, for there to be some legitimization to my desire for there to be things that elicit that feeling of wonder out there in the world and not just on the TV or computer screen. As I was getting older I kind of lost that for a while, but between PBS Space Time and Science and channels like Science and Futurism with Isaac Arthur I feel like I’ve kind of found a new version of that. I just love how there really are edges to our knowledge of the world, and there are still thing to be discovered. Those objects are just very small or very far away, or very well hidden… the ideas very obtuse or obscure or complex… but they’re out there.
I love SFIA as well! I feel the two channels complement each other's subject matter very well. Isaac has recommended PBS space time on at least a couple of occasions.
great simple video on explaining all tge way down to branching fraction and comparing theory with measurement (and kudos for acking error bar being large).
Is it possible to measure gravitational waves from the particle collision in LHC ? I mean, i think we don't have sensitive enough equipment for it yet, but if we develop it would dark matter potentially give up some kind of micro disturbance via gravitational waves or something like that ?
If gravitational waves are created due particle collisions, then it would be near impossible to detect it. It would be astronomically small There's an question on how fundamental particles experience gravity. So far we haven't tested it
We haven't even measured the gravitational waves of some black hole mergers that release large amounts of energy. There is no hope for measuring subatomic particles at such low energies
@@Haskellerz Gently whisk one cup of bose einstein condensate through two slits. Heat with a space laser until trajectory is solidified. Serve warm on rice or pilaf.
"Physic Girl" does a good episode on the gravitational detectors that measure the difference in phases of wavelengths when compared to another in a perpindicular direction. Might be a good channel to look up.
@@RADARTechie yeah i watch physics girl channel. Idk, maybe in the future it would be possible. Maybe curve the laser beam around the length of LHC a few times and have one really long perpendicular to it so it may detect something... I know we cant detect that now, because we can detect only the biggest of the bigges gravity waves, but with time maybe the "resolution" will get better.
Is total quantity of dark matter, or some dark charge associated to it conserved? If creating dark matter particles from ordinary matter is so rare and difficult, how come is there so much of it, or is in fact number of dark particles much smaller than number of barions, but WIMPs are many times more massive than proton?
Maybe the energy needed to create higgs bosons in the early universe was high enough, and dark matter is very stable which could explain why we have so much today but it is so hard to recreate.
@@GabrielACGama Can supernova explosions or AGNs convert convert some of matter to dark? Could we detect that quantity of dark matter was increasing over time in some galaxy?
It does seem likely that WIMPs, assuming they exist, are much more massive than the proton. Hundreds, or even thousands of times heavier. That may be why they haven't been detected in accelerators yes.
I love that I woke up this morning and watched @veritasium talk about the DAMA/LIBRA detector and now I have Matt rooting that experiment in some robust theory. If there's some dark headmaster designing this RUclips syllabus, they have wonderful taste in professors!
I admire very much the clarity of the explanations, video after video I’m very grateful to PBS space time for giving me an opportunity to grasp these concepts so fluidly ; this channel is a gem !
Could there be a whole dark matter universe, with DM stars and DM life within our spacetime that we just see as this gravity discrepancy? Made out of particles that only interacts with the same kind and with gravity. The same way they do not see us and we are dark matter for them :) The kind of StarTrek "other dimension" stuff. Maybe even more than one?
Ordinary matter clumps together because of electromagnetic interaction, not gravity; dark matter does not have electromagnetic interaction, only gravity, so it can’t clump together to form larger objects. If it did, it wouldn’t be “dark” and we’d see it.
Did we ever rule out that Einstein's field equations could predict the large scale anomaly in galaxy movement? AFAIK it hasn't got an exact solution other than the Kerr metric for singular black holes.
@@StefSubZero270 Pilot wave seems to be the best. Look at Cymatics and Lycopodium powder to understand why dark matter would not even be needed nor would Dark energy more than likely but Dark matter is a definite given and is unneeded.
The problem with that (and MOND) is that different galaxies have a different 'dark effect'; some seem to have no dark matter and behave as we'd naively expect, while others seem to be more than 99% dark matter. A single solution to the field equations doesn't suffice to explain this variation (Even one that varies with the amount of matter present.) And the sheer SIZE of the effect is an issue as well. Getting an exact solution is difficult, but getting an approximate one is pedestrian. If we're missing 4/5 of the spacetime warp in a system it's probably not because we need a more exact solution.
Is it possible to digitally purchase the "soundtrack" of PBS Space Time? I love it and it would be awesome to have it as background music while working.
well not really because with anti matter it has to be the same amount as regular matter. From the known matter, we have same as antimatter however dark matter probably reacts with antimatter. if we come to know that there is a lack of gravity(gravitons) in the universe then that could make a good point as dark matter counteract gravitons in some ways, therefore limiting its quantity.
In general what's decaying into dark matter in these models is high energy particles, more energetic than would be found at the cores of massive stars. If dark matter itself decays we might see LESS of it over time as its production rate is likely very low in our current universe.
Isn’t it still possible that “dark matter” is simply an expression of gravity that we just don’t understand yet? That there isn’t missing matter, but rather gravity that we cannot currently account for because of our lack of understanding.
Because we don't know what it is, I guess the answer is, yes, maybe, but because the don't know, we say "dark matter is just an expression of matter that we don't understand yet."
These theories all have a lot of issues and are a bit of a stretch compared to those that just assume missing matter that doesn't interact via the electromagnetic force (and potentially not via the nuclear forces either). en.m.wikipedia.org/wiki/Alternatives_to_general_relativity
No, they assume dark matter exists because things don't behave the way they expect it too based on observations of distant galaxies. To me this is very sketchy ground and "dark matter" is only a place holder for our ignorance. Personally I think in the future this will be solved by further development of our knowledge of what's out there and explained by other means than a mysterious heavy particle that seems to only influence things by gravity. Personally I think tweaking our formulas for gravity and accounting for the influence of everythings gravity on everything else {such that gravity is a multi way street and not a one or two lane road} and a better inventory of matter in what's being studied will account for the discrepancies that led to this idea of dark matter. We have barely left the solar system in terms of probes and the earth in terms of our selves so to say we know how gravity works in the greater universe is really premature and irresponsible. The depth of human ignorance has always been a major hangup. On multiple levels.
Great science news broadcast! I am a particle physicist and I believe that I can’t do better. The fact that Higgs makes it possible to exist a coupling to any fermion in a particle-anti-particle pair. The sea of Higgs can give mass to particles in this way.
How many more years of experiments resulting in non-detection does it take before physicists can agree that the model is probably wrong, and you need to allocate more resources to better research of galaxy formation and the behavior of gravity (and other forces) on cosmic scales? The Lamba-CDM model is in dire need of replacement with something better.
Given the limited energies of all our accelerators, it will be a very long time indeed before WIMPs can be completely rules out. Also, galactic rotation curves are not the only evidence for missing mass. Remember, it took fifty years to find the Higgs, and about as long to find gravitational waves.
Before the Higgs was discovered, people said the same thing as you. And then we found the Higgs. Scientists aren’t just making stuff up to please themselves. They are trying to figure out how the universe actually works. That takes time. And our current theories are very good. The Standard Model and General Relativity are both very accurate descriptions of our universe. The missing pieces, like dark matter and dark energy, are how we are going to push our understanding further. We have very good reason to believe dark matter is made of particles, just like regular matter. Proving, or disproving, this will take a long time. It took 48 years to prove the Higgs existed, and it took 100 years to prove gravitational waves existed. Time will tell about dark matter.
@@michaelsommers2356 And yet, the dark matter hypothesis has been around since Zwicky (what, 90 years ago?), even before getting serious traction by the '70s, with Rubin et al. The OP still raises an important logistical point: how many null results are required before the community recognizes the fruitlessness of the approach? We're not even saying, drop DM altogether - just put it in the backburner and try other things out. It seriously frustrates me that the only alternative to DM (and indeed the EFE) we seem to hear about is MOND and variations thereof, as opposed to dividing and conquering with a wider exploration of different ideas. I'm about to do a shameless plug, but since IIRC you have a PhD in Physics or something, lemme tell you I wrote an e-print (rejected by the arXiv for no good reason - I had endorsement and everything) of a non-MOND alternative to GR based on pure differential geometry - the idea being dropping the Riemannian dynamics of Einstein's theory, and instead use _post_ -Riemannian structure for the gravitational degrees of freedom, which seems more amenable to quantization and other things [posted as "Gravidynamics of an Affine Connection on a Minkowski Background" on viXra - [viXra:2204.0115] ]. I don't claim like a crackpot it's a final solution and I have everything figured out, because I simply don't and I'm not even published yet - but my point is that the community does not explore ideas like this, and instead inertially stick to 'pre-approved' ways of thinking, which ultimately ends up stalling the progress of 'puzzle-solving science', to use Kuhn's terminology. Diversity of ideas is key - doubly so in the sciences.
@@thstroyur _"how many null results are required before the community recognizes the fruitlessness of the approach?"_ That is not a sensible question. It's not a question of how many. It would be a good question if, and only if, we knew exactly what we were looking for, and we knew exactly how to find it. We know neither regarding dark matter. We have no idea, or at least not much of an idea, whether the experiments conducted so far should have been able to detect dark matter. Recall how long it took to find the Higgs. Gravitational waves were looked for for forty years before they were found. It took about twenty years to find neutrinos. And so on. I just don't get why some people are so certain that WIMPs can't exist. The first elementary particle to be discovered was the electron in 1897. That's just 125 years ago. It is supremely arrogant to think that in those 125 years we have discovered all the particles that there are to be discovered. One could also turn the question above around. How many times will various modifications of gravity have to be tried before that idea is shelved? _"IIRC you have a PhD in Physics or something"_ I have never claimed to have an advanced degree in anything.
@@michaelsommers2356 "That is not a sensible question" And that is not a sensible answer; DM (not the phenomenology) either is real or it is not - if it isn't, no amount of detection will ever tell you that. In the end, you just reiterate yourself - but the truth is that, in spite of the many ideas poured everyday in the arXiv, physicists have no real leads, so they keep beating on their dead horses - like DM and MOND. But I suppose you won't be impressed even by the list shown in Veritasium's video "The Absurd Search For Dark Matter", @0:27-0:37; no, it doesn't matter how many experiments fail to find DM - we don't have to learn anything from them, we just need more, so let's keep truckin' to infinity. "I just don't get why some people are so certain that WIMPs can't exist" And I don't recall dogmatically saying they _can't_ exist - but one may note in passing that they are an _ad hoc_ construct whose only _raison d'être_ thus far is to fix the LCDM concordance - it _reeks_ of epicycle. Rather than postulating new entities blindly, it is more conservative to review what we think we understand about gravity. "How many times will various modifications of gravity have to be tried before that idea is shelved?" This is rich; in case you don't know, the crushing majority of "modifications" in the literature published after 1915 are basically PPN foils to the EFE - just look up the Wikipedia page; this includes even MOND, in the form of TeVeS. So far, pretty much everybody has cowered in the shadow of Einstein, as one either adds to his original field equations, or massages variables around as to reduce to that theory (e.g., the teleparallel equivalent of GR). So no - I don't think alternatives have been sufficiently explored for that possibility to be "shelved" already. "I have never claimed to have an advanced degree in anything" Neither did I; but there are a few people in this channel who _do_ have degrees (I myself have a BSc, Chemistry), and I'd hope having a convo about this paper. It is a huge bummer not having anyone to talk about it because generic lack of interest - so it seems I'm supposed to either hold to the truth of this idea o'mine like a crank, or carry it with me to the grave. Meanwhile, let's keep watching videos saying the same things and reporting the same failures; great times.
We barely understand spacetime and why matter bends it, we don't have any idea how space works on the quantum scale, and we have no idea the relationship between space and matter. Once we answer these questions then I feel like this elusive "Dark Matter" will reveal itself. Personally I don't think it's any form of matter at all, simply a gaping hole in our understanding of physics. I simply refuse to believe that there is some invisible form of matter that only interacts with the fabric of spacetime. It sounds ludicrous.
I feel like you must have skipped a lot of early SpaceTime episodes on the nature of matter, mass, space, and time. It's not really all that mysterious anymore. It might do your head in, but to the extent that it's possible to answer _why_ matter exhibits gravity, we have done so. In general, science asks "how?" (by what means?) and not "why?" (for what purpose?).
I don't think you should call these things "Dark matter detectors". It's really putting the cart before the horse. They haven't detected anything yet, let alone a particle that makes up 5/6 of the matter in the universe, let alone a particle that solves the numerous problems with single-particle theories of dark matter.
Their purpose is to detect dark matter; therefore, that’s what they are named. In the future if/when we’ve discovered dark matter, either with the same or different machines, we can always change the terminology then.
@@i_booba Just because we hope that this time it will be different is no reason to call them "Dark matter detectors" as if they were already on the job busily detecting dark matter. That's in additional to all the theoretical problems with single-particle theories that should make us wary of expecting success with this.
@@Tehom1 Isn't it though? I mean dowsing rods are fancy sticks rather than water detectors, but they're still named after what they're intended to do. Failing at a purpose doesn't seem to have much bearing on nomenclature.
Excellent video. Very very very very interesting. It makes you wonder if particles from the dark sector can interact with each other with forces that do not interact with particles from the standard model... THere may be other forces we're not aware of. Keep the hard work.
I believe there is an error starting at 5:47. Should be discussion about which particles could decay into dark matter rather than which could decay into Higgs.
A noob question about mass: So, mass is a result if interactions on subatomic levels, and a property of mass is to resist acceleration. Maybe for educational purposes mass of a particle can be likened to gyro. Movement inside a gyro will influence how the gyro itself can be accelerated. So, maybe mass is just a result of one way (or all) that units of energy can move or interact with other units of energy.
I like the symmetry of the vector boson fusion model which creates the Higgs, however, if it then decays into dark matter particles, I have a feeling they will, like you said, become not just two equal dm particles but, like the quark and lepton families, unveil a whole family of dark matter particles. Truly fascinating! I then wonder if they in turn decay into the infamous dark energy? However, I feel that dark matter must be quite stable for it to be so abundant in the universe.
All the discussion of Black Holes, Dark Matter, and Dark Energy has me thinking of the video that got me first hooked on PBS Space Time - "The Real Meaning of E=mc²". In that video Gabe concludes at 7:53 that "mass is a property that all energy exhibits". My questions: Is there a real difference between what we call Mass and what we call Energy? 1) Once mass/energy enters a Black Hole, can we tell what it is any more? Could everything the enters a Black Hole become Energy and if it does, would it still have the same same gravitational attraction? 2) If Mass is a property of Energy, does Dark Energy have mass? Does it create gravitational attraction like Dark Matter does? How are they different?
Very basically, mass as we define it is contained energy, energy that cannot simply zip away at light speed. PBS has a video on this: ruclips.net/video/gSKzgpt4HBU/видео.html 1.) Once something enters a black hole, we cannot tell what it is anymore. This is part of the black hole information paradox; in theory even after a black hole evaporated, we wouldn't be able to tell what it had been made of, which violates information conservation. 2.) Dark energy should have mass and thus create gravitational attraction. HOWEVER, since it is evenly spread throughout the universe there would be no center for this gravity to pull towards, the gravitational force in any direction would be balanced by an equal and opposite force. This leaves only dark energy's repulsive effect unbalanced, which is why it can have a positive energy yet cause expansion.
@@mrmonkeboy nice catch! Experiments show that neutrinos have mass but in the Standard Model they are very peculiar and don't get a mass from the interaction with the Higgs field. There are many hypothetical ways to describe massive neutrinos, the one that I find most fascinating is the existence of the right-hand neutrino. In the theory, charged leptons are described with a pair of a left-handed and a right-handed field. The Higgs mechanism introduces the mass terms of the fermions as interactions between left and right-hand fields (when breaking the electroweak symmetry). The Standard Model does not contemplate the right-handed neutrino and therefore there is no mass term. Why are the right-handed interesting? As they have no electrical charge and only the left-handed fields interact weakly, a right-handed neutrino will not interact with any other boson but the Higgs making them impossible to detect. This solution is simple as they would get mass from the Higgs field, the same as the rest of particles. However, this brings the question on why does the Higgs interact so specially weakly with the neutrinos and their differences in mass are around the eV, when the other leptons have masses between 0.5-1.7 GeV. Maybe it gets the mass from a new mechanism, if neutrinos are their own anti-particle (a Majorana particle instead of the others, Dirac fermions), they would get a new mass term and, together with the seesaw mechanism, would explain the small masses their small differences.
Dark-matter particles don't interact electromagnetically, so how could the annihilation of a pair of such particles produce any photons? Since momentum is a vector, an inequality like "p_out < p_in" is meaningless. Conservation of momentum does not mean that "total momentum never increases or decreases" (also meaningless).
Can you do an episode clarifying the discovery of large structures that are older than should be posible under the current model of the big bang by the JWST?
![The Dark Matter Mystery [4K]](http://i.ytimg.com/vi/5iA7wZfxglE/mqdefault.jpg)
The fact that we have machines so precise that we can casually discuss tracking subatomic particle collisions is incredible.
Literally! i could not begin to understand the complexity of machines like the LHC
no its stupid and who is "We". 'We' doesn't include ME because these people do not help me or want to help me.
We've had such machines for decades. The neutrino was detected in 1956 because of missing momentum.
Good point, yeah, that's not something chances are most of us ever give any real thought.
SPITE-VOTES is how Biden WON. This, Jerrymandering and a Billion other Problems are insta-solved by Ranked-Choice-Voting as explained by "Second Thought".
I love how this channel about high level astronomy and particle physics gets millions of views. You somehow have done the impossible and made physics break into the mainstream crowd. Incredible work every video.
Most videos have
Been my favourite physics youtuber by far for a while now, props to Dr Matt
@@captainmcawesome7908 For a channel like this to get 2.7M subscribes, they must be doing something right. Even if people can't always be bothered to watch full videos on subjects they barely understand ;)
It's not impossible. People just actively reject the knowledge because they find calculating taxes more important.
Let's be honest here: I understand, maybe 2% of what is explained. Most videos are way over my head, but I see it as exposure. Maybe I'll have a better understanding the 25th time something is explained to me.
My favorite line yet, “Physicists are very stubborn; and very good at finding ways to do things they should not be able to.”
Kinda like speedrunners.
Ignorance about something is really a blessing in disguise which forces us to go all out and unravel the mystery. 😃🙃
Just like Sith Lords.
@@Kwisatz_HaderachXIII precisely. 🙃
@@SkinnyBlackout I mean speed runners are technically finding exploits in a game’s physics engine, so…
I've been subbed to PBS Space Time for so long now, I can watch entire episodes and understand at least 37% of what Matt is telling me.
I don't try to measure my comprehension relative to what he is saying, just each time I learn _something_ I didn't know before I watched it. If I re-watch, maybe a little more. I envy you understanding 37%. 🙂
I used to be able to understand them 2-3 years back but nowadays their videos go way over my head, there's only so far my high school physics could go. But still interesting, i understand maybe 10%.
@@Cat_Woods Cat Woods,
dont JUST let about Science in these hard times.
KNOW WHY CRT is opposed? Because People know that teaching about History is literally always good and more importantly: they know the ABSOLUTE Fact of Factual Factness that teaching about R-cism is DECREASING R-cism according to all Data weve ever collecting on this Planet. Literally everything weve ever studied about this tells us this. Its obvious that N-zis literally dont want people to be able to identify N-zis. Good old Ted Cruz has literally said and made others say "We should be objective about History and THEREFORe not SAY N-ZIS are BAD GUYS. That would be taking-a-side and thats a No-No!". The Agenda behind this is so laugghablxy-obvious it implodes the very Concept of Obviousness. If the OLD Phrase "Those not learning from History are Doomed to Repat it" doesnt Do it for you, OK, then how about the Third GOP-Video of "Some More News" and his MLK-Video?
Ha! I got you beat! I understand 37.5%,
I was subbed since around 5th upload. I can uderstand it pretty well back then. I'm still watching now but can only understand about 10%. xD
I mean if the Higgs boson would be ever so kind as to show us what dark matter is, that would be very nice of them.
Maybe it is just one...
I'm still looking for the Hoggs Bison, I'm starting to think I may be the victim of a typo.
@@minotaurbison The Snorting Buffalo is an enigma.
@@minotaurbison this has me laughing so hard...
Sadly I can't share this joke with friends or family ...
Oh what a lonely world for Higgs Bison believes
It*
I have no formal education in physics. However, I put this channel on whenever it's late at night and I want to have my mind blown at what humanity has been able to deduce from observation, experimentation, documentation, and more imagination & hard work than any single person can fathom. Thanks for explaining topics in a way where you're completely true to the physics, yet make it light hearted and intriguing enough to keep me up, late into the night, learning new and exciting ways of shedding light on even the darkest topics in... SpaceTime.
As a person who earned their PhD in particle physics earlier this year I have to say I absolutely love this channel. Been watching it for years and it always keeps me thinking, fantastic work ✊🏾
I didn't know Cracker Jacks gave out Physics degrees...
"Study of Excited Cascade Baryons and Preliminary Cross-Sections for Ξ(1530) Using Data from the GlueX Experiment" - I see
This channel is intro undergraduate level. How do I know? Cuz that's what I am, and this is all stuff I understand and have taught myself. If you are speaking the truth, I just realized getting a PhD is going to be easy as f*ck (i'm going the theoretical route, double majoring in math and physics)
@Flust Is that your argument? The irony is immense
@@pyropulseIXXI They never said they used this channel to study. Read harder.
It's still a wonder to me that we have this giant loop through which we can aim accurately enough to collide subatomic particles, at speeds that break intuitive physics, then make out a whole tree of decaying particles, and identify each precisely enough to confidently know when something's off
And do it zillions of times a second, and process each collision fast enough to be able to safely discard most of them.
Well i don't think it "aims accurately", it's more like, "throw particles at eachother enough times and eventually they collide"
@@svendkorsgaard9599 Well this throwing particles at each other still consists of collecting them in bunches that are 25 cm long and at the place of collision have 3.5 micrometers in diameter, aiming them so these 3.5 micrometer beams intersect in space, and timing them so they meet at that intersection in the center of the detector.
It is still a juvenile approach of breaking things to study their internals, not a smart way to go about it though
@@yudhistirs right. Your are obviously way smarter then the LHC guys, maybe you should call them and correct them before they build another one of those funny rings.
Wow! what exceptional restraint to not sensationalize and overhype what is undoubtedly an avenue of research highly worth pursuing! I expected the end of the video to be either 'we don't have the data yet' or 'this also didn't pan out'. But presenting the results so honestly and without fanfare and instead pointing to ongoing promising research was once again an example of how professional and scientific this channel is!
You're being sarcastic right? Did you hear him mention the exceedingly likely possibility that dark matter doesn't exist? No. This entire video presents dark matter as fact and reality pointing instead to the experiments not being done long enough or big enough. Do you know how many thousands of DM experiments have turned up nothing?
Pay attention to this moment. This was the moment someone informed you that particle physics has become overwhelmed with group think and ideology. And in the future, presumably when we figure out what was wrong with our assumptions, you can look back and think someone warned you. I wouldn't care if there weren't millions and billions of US tax dollars being flushed down the drain to chase certain scientists' hubris.
This was an amazingly well written episode, managed to keep me hooked on a subject I know nothing about and seems incredibly complex. Well done !
Couldnt agree more, terrific episode.
First time here? Lol
I love you PBS spacetime, it was initially my childish and naive amazement with the complexity of GR and QFT, over the years I have more or less become an amateur mathematician in pursuit of understanding these theories, but even now, I still return to my ‘ sippy cup’ of PBS spacetime it is too good!
Checking whether "sippy cup of PBS Space Time" can be added to the merch store...
Let’s talk about string theory
@@hyperduality2838 real Time Cube vibes over here
@@pbsspacetime adding...
@@matroqueta6825 I just learned about the time cube meme and I’m sorry to say I got really deep into a manic phase once and kind of had similar experiences. Once I started getting medication for my type 1 bipolar these thoughts and other paranoid delusions disappeared. He’s probably just going through smth. {{ edit: sorry this was a grandiose delusion but it was heavily accompanied with paranoia }}
I know this is a small thing, but I love that every episode ends with the words _space time_ .
I love it too. And especially when he edges us by hinting it and then continuing the sentence. "And that's the story of everything within the entirety of... the fantastic expanse of... the colorful reality of everything in... such a wondrous thing we call... our collective home: Space Time." 🤣
Ain't it grand?
And now that you have said that we will have to pick a new word or phrase to end on. See you next time on Raid Shadow Legends.
I'm sure some channel's done it before, but I'd love to see a series on this channel where the videos discuss each type of subatomic particle. Not just the ones in the standard model, but ones like protons/neutrons, pions, kaons, pentaquarks, tetraquarks. One video at a time. You could make an entire series just about the standard model particles, too. You could discuss a particles' interactions, the history of its discovery, the implications of its discovery, the role it plays in physics etc. It might get to be a bit much watching (and making!) a 10-20 minute video for every particle, type of particle and combination of particle but I for one think it would be great fun.
They have an entire playlist breaking down the standard model constituents.
I'm so used to dead end for finding out what Dark Matter is, that the branching fraction up to 0.26 had me jump on my armchair! Looking forward for future development on this topic.
The branching fraction up to 26% just means we don't detect anything, and we would have detected something if the branching ratio was larger than this. The Standard Model Higgs->invisible branching fraction is really, really small (0.1%), so unfortunately we'll never see this at the LHC.
My goodness I've been studying particle physics since late middle school, I'm going to college next year, Im aiming to work at an accelerator one day. This stuff is so exciting I reallllllly can't wait to learn more in college
All the best for you!
It's amazing, I will be switching from IT to Physics next year :)
college is overpriced. you could formulate your own curriculum and gather your own reading material to cut out the middle man who aims to steal your intellectual property for DARPA purposes.
Amazing! Please report back to us when you're working at that particle accelerator and let us know if you find any dark matter particles!
@@niteshkumarsharma8305 That's awesome! What year are you right now, and are you jumping straight in, or did your IT background give you a headstart with prerequisites?
@@h7opolo I need degrees to work on particle accelerators (I think) :(
This was brilliant, one of the most interesting I’ve seen recently. What a gold mine channel!
finding anything at all that reacts with dark matter in a way that visualises it in a way that we can detect it... that'd be like finding the holy grail
Doesn't dark matter react with the whole universe the same way that matter does?
Would you rather discover what dark matter is or make contact with intelligent aliens? I'd go with the latter. Especially if they knew the answer. But not necessary.
@@douglasauruss
You just wanna have sex with Martians -_-
@@aero1000 through gravity, but nothing else. As far as we can tell no, neutrinos barely interact with anything so it's likely that dark matter probably doesn't interact at all. Not in the same way at least.
@@douglasauruss I agree
I absolutely love the pace at which this was spoken compared to usual. I will be coming back again more often instead of assuming my mind won't keep up lol
So this might come from my gaps in understanding, but if we detect what is presumably the fundamental dark matter particle via the Higgs, are we assuming it's a solitary particle or could there potentially be an entire "dark model" that exists beside the standard model?
yes there could be an entire "dark sector"
We just don't know. It could be one particle, it could be 100, it could be zero.
Most things in the standard model come in families of similar particles, and it has a tendency for groups of 3 or 6. We wouldn't call it a "dark model" or anything like that, but it could definitely add a big new dark section to the model we have.
It wont exist separately to the standard model, it coexists with the standard model.
The Higgs particle / Dark matter is "Skin Theory" it exists in a Symmetrical balance with temperature plasma weight physics.
This is likely armchair science at best, but I believe there are as many as three dark sectors. If you count the broken symmetries related to particle interactions and assume they all had to link up at some point during the early stages of the big bang, then you can reduce until you are left with a few possible branches for the energy to have taken at the very beginning. All the particles and forces we can clearly see are based on only one of those branches. So if that energy persisted then you'd end up with different types of energy (i.e. particles) that shadow our existing particles but exist where the energy of our type cannot interact. If that is true, I would also expect to see the only interactions with dark matter being photophobic in nature and really only appearing in the apparent loss of energy in a system (which was in the video due to a shared Higgs) or in the slight altering of standard decay rates of other particles as the dark matter interferes with particles it contacts.
This is one of the dopest channels out there… and it just keeps getting better. Good stuff
Exposition and delineation are marvellous and par-excellence as always. Dark matter and Dark energy both are really very tortuous and twisted concepts which impel every one to scratch their head .
What do you think about traveling back in time as fare time is moving forward and that's good for interstellar travel. What about warping to light speed and using that against rotation of the Galaxy to travel at the rate of time
Time travel is really a very exciting and bewitching sci-fi concept. But if we contemplate carefully and profoundly we are already experiencing the time travel . Although it is very teensy-weensy as in contrast to our macroworld but still it is there and we gauge that time off-set with a very groovy instrument called Atomic Clocks . As you know Gravitational effects are interplaying here . These gravitational effects give rise to something called Gravitational gradient which tells us about gravity's variation with altitude , with depth . Now as we ascends towards space we are little bit ahead in time which is very minute but still it is there and for people who are on the earth will experience a little bit lag in time as compare to ours . This is because of gravitational gradient effect. BTW this is the same phenomena which aid us to experience gravity on earth. So Aren't we already subject to time travel ? Although this is teensy-weensy but it's OK .Time travel at large scale is a horse of different color. Infact at macroworld time is nothing but just a unidirectional arrow running it's course . 😇😇😇
As far as warp to light speed is concerned and make use of this to create conducive conditions for instellar voyage is still need to get down the brass tacks for burgeoning the methods to achieve this quickly and at a rate of knots. Miguel alcubierre has already unravelled the equations which we can use to create a device called warp drive but our technology is not that much pullulated and developed which can give rise to such kind of device . All this is a matter of time . But For the time being we can only mock up about the real model of warp drive. But one day in future we will definitely have this kind of tremendous and top-notch device. 😊🙃🙃
I really wish you guys and galz would toss your brain power on making commercial Fusion at reality! I'd take that over the solution for DM any epoch of universe! But hey, thanks for what you ARE teaching us mere mortals. It helps flush the brain of other wurst insignificant dark matter.
Essentially 'dark matter/energy' is an explanation dreamed up to explain 'why don't stars and galaxies move the way the general theory predicts'.
No one has detected or observed aaaaaaaaanything that they thought 'hey, I've found this new stuff'.
The General theory is not fully coping with how things *actually* behave.
Either the theory is wrong (it is) or there really is this mysterious, never detected or discovered or measured or isolated, new energy/matter that *just happens* to be 'the error amount in the general theory.
Maybe "all" that is needed for dark matter/energy to work is a 9500% increase in the total matter in the universe.
Or. The general theory doesn't work.
Would love to see an episode discussing vector portals following this one! Dark photon/additional U(1) vector bosons are frequently discussed in the DM literature, providing interesting coupling mechanisms for direct detection, such as kinetic mixing. Great stuff guys!
Great episode! You mentioned earlier that every neutrino is accompanied by a lepton when it's produced. Wouldn't that make it possible to track these leptons and account for the momentum of their corresponding neutrinos? That way they could conclusively determine that missing decay products are something new, and not a problem with how the branching fraction was calculated.
Finally a video that is unique and interesting. So tired of YT showing me the exact videos I have already watched. Not to mention, this is something I have not heard about so that is refreshing also. Thanks
i remember staying up to watch the live announcement of higgs discovery and getting teary-eyed. has it really been 10 years?!
Love these videos and love the fact that this information is now easily accessible to anyone and everyone that has an internet connection. You can accidentally stumble into these videos and learn or spark interest.
Love when Matt gets Higgy wit' it.
Higgy ahh 💀
Nah nah nah~ nah~, nah NAH nah
Hello sir I just wanted to tell you I've been watching your show since 2017 and the information provided has been invaluable to me. Just by watching your show and some other delving into hermetic teaching. Basically you've helped me achieve a fundamental and solid belief system through mainly a deep understanding of physics. Final words are this. I'm starting a tiktok because it's what's popular right now, anyway I plan to metaphorically scream your name from the internet rooftops. I assure people will know PBS spacetime by heart before I've had the final say. Cheers hope this finds you well and I'm doing this simply because I'm tired of wrong answers.
Very interesting! It would be quite ironic if the Higgs actually turned out to be this meaningful after everybody thought its detection was just veryfying the last missing bit of the standard model but wouldn't get us forward.
From watching PBS Arthur as a kid to PBS space time, PBS has come a long way🙌
arthur thoma
I feel like the discovery or explanation for dark matter will be the greatest scientific achievement of my own lifetime. The scientists who pull it off will get all the Nobel prizes
if physicists are correct, it's going to happen soon. with enough higgs collisions they can narrow down the branching fraction and detect the presence of particles that haven't been discovered yet - most likely dark matter. i expect this to be solved in the next decade or so unless the higgs decaying into dark matter is rare - which doesn't seem to be the case considering the overwhelming amount of dark matter in the universe.
Such a good writing of this episodes! Very nice build up towards the end.
Great, accessible episode! Thanks, Space Time team 🙂
For the first time in a while I've learned something new in the subject. Great work!
After decades of thinking I finally figured out that the Emperor's new clothes are actually made of dark matter....
This channel continues to churn out amazing videos with incredible production. I almost feel I understood this one :). Thank you for keeping science in the spotlight.
If we think detecting dark matter is difficult spare a thought for those on the dark side trying to detect the much much less abundant normal matter on the light side.
Your line made me wonder...
(if "souls" and sh*t are a thing)
Do "we" just become dark matter when we die?
Underrated comment
Funny :D
Unfortunately, we know that DM does not form small-scale structures. We never observed stellar clusters with some part of them being invisible. Evidence points out that DM concentrations are diffuse and large ("halos"). Essentially, normal matter (a galaxy) sits in a larger, invisible DM halo, not the other way around (DM "clouds" flying inside galaxy).
@@denysvlasenko1865 If dark matter gravity is what’s stopping galaxies flying apart, and if this gravity is of the attractive variety then sufficient dark matter must be located within the boundary of the visible galaxy?
I would like to hear your opinion on this.
@@hyperduality2838 I'm sorry I couldn't get through your whole comment, but no Dark Energy is not dual to Dark Matter, or at least there's no evidence to suggest such a thing. They are just both called dark because they are invisible (and I guess invisible matter wasn't catchy).
You make all this very easy to follow. It's almost like we are on the hunt with you. On the cutting edge. Excellent work. Waiting on the next one.
If this fails, then the best conclusion left would be that "dark matter" is not "matter" at all, but some other kind of space-time distortion other than matter.
yes ! but only IF
like primordial black holes? my naive brain loves the idea of extending this to all particles being local scrumples of spacetime, but i know that's very inconsistent with physics as we know it.
Good @Pedro Andrade. More likely to go that way. The introduction of the nameholder 'Dark Matter' came into being in the first place observing a space-time distortion to which we desperately wanted to assign 'matter' to cause it. But when cause and effect are so separated with time, space retains the 'effect' as memory. Where does this vein take us to? Dark matter is a wrinkle in space-time or a memory registered as distortion. On the flip side, all memories fade in time. Wrinkles ironed. The universe expands. Thus, dark energy!
Careful now.
Next you'll be suggesting that the General Theory.........isn't quite right.
@@Tao_Tology 😂😂😂
Very interesting, insomuch it's actually investing.. congrats Euan and Matt (collaborative writers), this episode is a preponderantly influential argument for a badass new particle collider.
I wouldn't be surprised if Matt actually had a particle collider in his basement.
That'd make for one massive basement.
What sense would that make? You think he works from home with that kind of job?
I have one in mine. The lowest powered ones are pretty compact.
As usual, fascinating! As usual, I watch every episode intently and hope 10% of the content sticks to my slimy little brain. Matt, who does your synthy background scores (not necessarily your theme tune, though I love that too!)
Talking about particle accelerators always brings the scene from the Simpsons to mind where prof. Frink gets a printout after running some accelerator and says something like "you can tell your grandchildren you were here when humanity learned.........that this accelerator is much too small to tell us anything important"
Stuff’s gonna get crazy we’ve all been waiting for this. I wonder if Matt is personally excited for what’s to come.
I remember in one episode of star talk, some asked Neil DeGrasse Tyson if dark matter gets its mass from the Higgs boson, he said "for all we know, dark matter could have its own Higgs boson."
If the Higgs ends up not decaying into dark matter particles, perhaps this is an alternative explanation. I guess time will tell.
@@hyperduality2838 Please stop posting this utter gibberish.
I've heard the Higgs has two energy states. I wonder if dark matter is connected to the other energy state.
The information and it's presentation are absolutely astonishing. Thank you so much for your work.
If 2 force carrying particles eject a Higgs, and the Higgs may decay into dark matter, does that mean the dark matter created there is a force carrying particle? (Not all DM, but the particles from this interaction.) Is that possibly gravity? Might explain the relationship between mass and gravity.
That’s definitely an interesting thought, so if I understood you right the theoretical graviton could be dark matter or a part of it at least
@@sspectre8217 I am way too many years out of touch, but the diagram made it look like a force, and gravity is weak, so a force that weakly interacts with mass seemed like a fit
Just wondering what I am missing.
No
@@randolphphillips3104 thats sound plausible. Having no real understanding of how the mechanics work I cant possible disprove this idea.
Man that really would line up with a lot of things. No particle for gravity, no way for gravity to be included with QM, gravity being so much weaker, unexplained "dark" mass.
While writing this I had idea, if we know the strength of the weak and higgs forces could we somehow find what the supposed "dark" force carriers would need to have?
@@skop6321 I mean gravity is kind of already intimately tied to Higgs as it calculated by taking an acceleration and multiplying by the Higgs force.
That conservation of momentum method of detecting invisible particals is pretty slick
Wouldn't it be wonderful if the Higgs opened a portal and a big ' WELCOME TO LEVEL 2' sign appeared...
wow, thx for that. We are getting closer to having a full explanation of the universe.
I, for one, can’t wait to see what we find out about the universe next! As a kid I wanted aliens and monsters to be real, for there to be some legitimization to my desire for there to be things that elicit that feeling of wonder out there in the world and not just on the TV or computer screen. As I was getting older I kind of lost that for a while, but between PBS Space Time and Science and channels like Science and Futurism with Isaac Arthur I feel like I’ve kind of found a new version of that. I just love how there really are edges to our knowledge of the world, and there are still thing to be discovered. Those objects are just very small or very far away, or very well hidden… the ideas very obtuse or obscure or complex… but they’re out there.
I love SFIA as well! I feel the two channels complement each other's subject matter very well. Isaac has recommended PBS space time on at least a couple of occasions.
Very straightforward explanation! Keep it up!
Me: Who is Zed?
Matt: Zed’s dead baby, zed’s dead.
THERE it is! 8^D
I came here for this comment too.
great simple video on explaining all tge way down to branching fraction and comparing theory with measurement (and kudos for acking error bar being large).
Is it possible to measure gravitational waves from the particle collision in LHC ?
I mean, i think we don't have sensitive enough equipment for it yet, but if we develop it would dark matter potentially give up some kind of micro disturbance via gravitational waves or something like that ?
If gravitational waves are created due particle collisions, then it would be near impossible to detect it. It would be astronomically small
There's an question on how fundamental particles experience gravity. So far we haven't tested it
We haven't even measured the gravitational waves of some black hole mergers that release large amounts of energy.
There is no hope for measuring subatomic particles at such low energies
@@Haskellerz Gently whisk one cup of bose einstein condensate through two slits. Heat with a space laser until trajectory is solidified. Serve warm on rice or pilaf.
"Physic Girl" does a good episode on the gravitational detectors that measure the difference in phases of wavelengths when compared to another in a perpindicular direction. Might be a good channel to look up.
@@RADARTechie yeah i watch physics girl channel.
Idk, maybe in the future it would be possible. Maybe curve the laser beam around the length of LHC a few times and have one really long perpendicular to it so it may detect something...
I know we cant detect that now, because we can detect only the biggest of the bigges gravity waves, but with time maybe the "resolution" will get better.
You had me at Dark Portal. Please continue.
Is total quantity of dark matter, or some dark charge associated to it conserved? If creating dark matter particles from ordinary matter is so rare and difficult, how come is there so much of it, or is in fact number of dark particles much smaller than number of barions, but WIMPs are many times more massive than proton?
Maybe the energy needed to create higgs bosons in the early universe was high enough, and dark matter is very stable which could explain why we have so much today but it is so hard to recreate.
Dark charge the Tesla for literal ludicrous speed
@@GabrielACGama Can supernova explosions or AGNs convert convert some of matter to dark? Could we detect that quantity of dark matter was increasing over time in some galaxy?
It does seem likely that WIMPs, assuming they exist, are much more massive than the proton. Hundreds, or even thousands of times heavier. That may be why they haven't been detected in accelerators yes.
@@hyperduality2838 That's still gibberish.
I love that I woke up this morning and watched @veritasium talk about the DAMA/LIBRA detector and now I have Matt rooting that experiment in some robust theory. If there's some dark headmaster designing this RUclips syllabus, they have wonderful taste in professors!
Using the "God" particle to open "portals" to contact the "Dark Universe" sounds like the premise of a sci-fi horror movie, but here we are 😂
You *WANT* Event Horizon to be real, don't you? 😉
Or a horrible sci-fi movie.
I admire very much the clarity of the explanations, video after video
I’m very grateful to PBS space time for giving me an opportunity to grasp these concepts so fluidly ; this channel is a gem !
Could there be a whole dark matter universe, with DM stars and DM life within our spacetime that we just see as this gravity discrepancy? Made out of particles that only interacts with the same kind and with gravity. The same way they do not see us and we are dark matter for them :)
The kind of StarTrek "other dimension" stuff. Maybe even more than one?
Ordinary matter clumps together because of electromagnetic interaction, not gravity; dark matter does not have electromagnetic interaction, only gravity, so it can’t clump together to form larger objects. If it did, it wouldn’t be “dark” and we’d see it.
Stoked for the era of Higgs physics!
Did we ever rule out that Einstein's field equations could predict the large scale anomaly in galaxy movement? AFAIK it hasn't got an exact solution other than the Kerr metric for singular black holes.
MOND so far seems to be good
@@StefSubZero270 Pilot wave seems to be the best. Look at Cymatics and Lycopodium powder to understand why dark matter would not even be needed nor would Dark energy more than likely but Dark matter is a definite given and is unneeded.
The problem with that (and MOND) is that different galaxies have a different 'dark effect'; some seem to have no dark matter and behave as we'd naively expect, while others seem to be more than 99% dark matter. A single solution to the field equations doesn't suffice to explain this variation (Even one that varies with the amount of matter present.) And the sheer SIZE of the effect is an issue as well. Getting an exact solution is difficult, but getting an approximate one is pedestrian. If we're missing 4/5 of the spacetime warp in a system it's probably not because we need a more exact solution.
This one was surprisingly easy to understand. And wow.
That would be pretty neat if I live to see dark matter figured out
Is it possible to digitally purchase the "soundtrack" of PBS Space Time? I love it and it would be awesome to have it as background music while working.
Could dark matter be linked to the lack of antimatter in the universe?
no
well not really because with anti matter it has to be the same amount as regular matter. From the known matter, we have same as antimatter however dark matter probably reacts with antimatter. if we come to know that there is a lack of gravity(gravitons) in the universe then that could make a good point as dark matter counteract gravitons in some ways, therefore limiting its quantity.
12:35 the error bars are how large? I don't see the paper linked either, that'd be awesome thanks!
if things decay into dark matter, we would see more and more of it over time, right?
Not if the dark matter decays back into ordinary matter.
maybe yes if there's a big source of the precursor. we might have used it all up by now.
@@michaelmicek then we should see matter popping up out of nowhere
@@HoD999x that is covered at 4:11
In general what's decaying into dark matter in these models is high energy particles, more energetic than would be found at the cores of massive stars. If dark matter itself decays we might see LESS of it over time as its production rate is likely very low in our current universe.
Great video! Actually managed to understand everything said in the video for once
Isn’t it still possible that “dark matter” is simply an expression of gravity that we just don’t understand yet? That there isn’t missing matter, but rather gravity that we cannot currently account for because of our lack of understanding.
Because we don't know what it is, I guess the answer is, yes, maybe, but because the don't know, we say "dark matter is just an expression of matter that we don't understand yet."
These theories all have a lot of issues and are a bit of a stretch compared to those that just assume missing matter that doesn't interact via the electromagnetic force (and potentially not via the nuclear forces either). en.m.wikipedia.org/wiki/Alternatives_to_general_relativity
I’ve been waiting for this video since I last saw your dark sector video!
Let's not forget: we already detect dark matter via the gravitational measurements that cause us to think it is there.
No, they assume dark matter exists because things don't behave the way they expect it too based on observations of distant galaxies. To me this is very sketchy ground and "dark matter" is only a place holder for our ignorance. Personally I think in the future this will be solved by further development of our knowledge of what's out there and explained by other means than a mysterious heavy particle that seems to only influence things by gravity. Personally I think tweaking our formulas for gravity and accounting for the influence of everythings gravity on everything else {such that gravity is a multi way street and not a one or two lane road} and a better inventory of matter in what's being studied will account for the discrepancies that led to this idea of dark matter. We have barely left the solar system in terms of probes and the earth in terms of our selves so to say we know how gravity works in the greater universe is really premature and irresponsible. The depth of human ignorance has always been a major hangup. On multiple levels.
Great science news broadcast! I am a particle physicist and I believe that I can’t do better. The fact that Higgs makes it possible to exist a coupling to any fermion in a particle-anti-particle pair. The sea of Higgs can give mass to particles in this way.
Could dark matter have played a part in the matter/antimatter discrepancy of our visible universe?
Always excellent videos with clear presentations of complex physics.
How many more years of experiments resulting in non-detection does it take before physicists can agree that the model is probably wrong, and you need to allocate more resources to better research of galaxy formation and the behavior of gravity (and other forces) on cosmic scales?
The Lamba-CDM model is in dire need of replacement with something better.
Given the limited energies of all our accelerators, it will be a very long time indeed before WIMPs can be completely rules out.
Also, galactic rotation curves are not the only evidence for missing mass. Remember, it took fifty years to find the Higgs, and about as long to find gravitational waves.
Before the Higgs was discovered, people said the same thing as you. And then we found the Higgs.
Scientists aren’t just making stuff up to please themselves. They are trying to figure out how the universe actually works. That takes time. And our current theories are very good. The Standard Model and General Relativity are both very accurate descriptions of our universe. The missing pieces, like dark matter and dark energy, are how we are going to push our understanding further. We have very good reason to believe dark matter is made of particles, just like regular matter. Proving, or disproving, this will take a long time.
It took 48 years to prove the Higgs existed, and it took 100 years to prove gravitational waves existed. Time will tell about dark matter.
@@michaelsommers2356 And yet, the dark matter hypothesis has been around since Zwicky (what, 90 years ago?), even before getting serious traction by the '70s, with Rubin et al. The OP still raises an important logistical point: how many null results are required before the community recognizes the fruitlessness of the approach? We're not even saying, drop DM altogether - just put it in the backburner and try other things out.
It seriously frustrates me that the only alternative to DM (and indeed the EFE) we seem to hear about is MOND and variations thereof, as opposed to dividing and conquering with a wider exploration of different ideas. I'm about to do a shameless plug, but since IIRC you have a PhD in Physics or something, lemme tell you I wrote an e-print (rejected by the arXiv for no good reason - I had endorsement and everything) of a non-MOND alternative to GR based on pure differential geometry - the idea being dropping the Riemannian dynamics of Einstein's theory, and instead use _post_ -Riemannian structure for the gravitational degrees of freedom, which seems more amenable to quantization and other things [posted as "Gravidynamics of an Affine Connection on a Minkowski Background" on viXra - [viXra:2204.0115] ]. I don't claim like a crackpot it's a final solution and I have everything figured out, because I simply don't and I'm not even published yet - but my point is that the community does not explore ideas like this, and instead inertially stick to 'pre-approved' ways of thinking, which ultimately ends up stalling the progress of 'puzzle-solving science', to use Kuhn's terminology. Diversity of ideas is key - doubly so in the sciences.
@@thstroyur _"how many null results are required before the community recognizes the fruitlessness of the approach?"_
That is not a sensible question. It's not a question of how many. It would be a good question if, and only if, we knew exactly what we were looking for, and we knew exactly how to find it. We know neither regarding dark matter. We have no idea, or at least not much of an idea, whether the experiments conducted so far should have been able to detect dark matter.
Recall how long it took to find the Higgs. Gravitational waves were looked for for forty years before they were found. It took about twenty years to find neutrinos. And so on.
I just don't get why some people are so certain that WIMPs can't exist. The first elementary particle to be discovered was the electron in 1897. That's just 125 years ago. It is supremely arrogant to think that in those 125 years we have discovered all the particles that there are to be discovered.
One could also turn the question above around. How many times will various modifications of gravity have to be tried before that idea is shelved?
_"IIRC you have a PhD in Physics or something"_
I have never claimed to have an advanced degree in anything.
@@michaelsommers2356 "That is not a sensible question" And that is not a sensible answer; DM (not the phenomenology) either is real or it is not - if it isn't, no amount of detection will ever tell you that. In the end, you just reiterate yourself - but the truth is that, in spite of the many ideas poured everyday in the arXiv, physicists have no real leads, so they keep beating on their dead horses - like DM and MOND. But I suppose you won't be impressed even by the list shown in Veritasium's video "The Absurd Search For Dark Matter", @0:27-0:37; no, it doesn't matter how many experiments fail to find DM - we don't have to learn anything from them, we just need more, so let's keep truckin' to infinity.
"I just don't get why some people are so certain that WIMPs can't exist" And I don't recall dogmatically saying they _can't_ exist - but one may note in passing that they are an _ad hoc_ construct whose only _raison d'être_ thus far is to fix the LCDM concordance - it _reeks_ of epicycle. Rather than postulating new entities blindly, it is more conservative to review what we think we understand about gravity.
"How many times will various modifications of gravity have to be tried before that idea is shelved?" This is rich; in case you don't know, the crushing majority of "modifications" in the literature published after 1915 are basically PPN foils to the EFE - just look up the Wikipedia page; this includes even MOND, in the form of TeVeS. So far, pretty much everybody has cowered in the shadow of Einstein, as one either adds to his original field equations, or massages variables around as to reduce to that theory (e.g., the teleparallel equivalent of GR). So no - I don't think alternatives have been sufficiently explored for that possibility to be "shelved" already.
"I have never claimed to have an advanced degree in anything" Neither did I; but there are a few people in this channel who _do_ have degrees (I myself have a BSc, Chemistry), and I'd hope having a convo about this paper. It is a huge bummer not having anyone to talk about it because generic lack of interest - so it seems I'm supposed to either hold to the truth of this idea o'mine like a crank, or carry it with me to the grave. Meanwhile, let's keep watching videos saying the same things and reporting the same failures; great times.
This is actually super exciting
We barely understand spacetime and why matter bends it, we don't have any idea how space works on the quantum scale, and we have no idea the relationship between space and matter. Once we answer these questions then I feel like this elusive "Dark Matter" will reveal itself. Personally I don't think it's any form of matter at all, simply a gaping hole in our understanding of physics.
I simply refuse to believe that there is some invisible form of matter that only interacts with the fabric of spacetime. It sounds ludicrous.
I feel like you must have skipped a lot of early SpaceTime episodes on the nature of matter, mass, space, and time. It's not really all that mysterious anymore. It might do your head in, but to the extent that it's possible to answer _why_ matter exhibits gravity, we have done so. In general, science asks "how?" (by what means?) and not "why?" (for what purpose?).
Neutrinos are basically invisible, yet we KNOW they exist. Dark matter isn’t really all that different.
Brilliant explanations and visuals as always!
I don't think you should call these things "Dark matter detectors". It's really putting the cart before the horse. They haven't detected anything yet, let alone a particle that makes up 5/6 of the matter in the universe, let alone a particle that solves the numerous problems with single-particle theories of dark matter.
Their purpose is to detect dark matter; therefore, that’s what they are named. In the future if/when we’ve discovered dark matter, either with the same or different machines, we can always change the terminology then.
@@i_booba Just because we hope that this time it will be different is no reason to call them "Dark matter detectors" as if they were already on the job busily detecting dark matter. That's in additional to all the theoretical problems with single-particle theories that should make us wary of expecting success with this.
@@Tehom1 Isn't it though? I mean dowsing rods are fancy sticks rather than water detectors, but they're still named after what they're intended to do. Failing at a purpose doesn't seem to have much bearing on nomenclature.
@@garethdean6382 Not the greatest example, though. We don't call them "water detectors" and if you did people would think you thought they worked.
Thanks. Well explained and illustrated.
Excellent video. Very very very very interesting. It makes you wonder if particles from the dark sector can interact with each other with forces that do not interact with particles from the standard model... THere may be other forces we're not aware of. Keep the hard work.
I imagine Matt smashing his matchboxes together with high pressure air, doing smashing noises, and catches the particles of the collision with a net.
Long time fan of the show. First time commenter.
I believe there is an error starting at 5:47. Should be discussion about which particles could decay into dark matter rather than which could decay into Higgs.
Thank you for an excellent and informative presentation!
A noob question about mass:
So, mass is a result if interactions on subatomic levels, and a property of mass is to resist acceleration. Maybe for educational purposes mass of a particle can be likened to gyro. Movement inside a gyro will influence how the gyro itself can be accelerated. So, maybe mass is just a result of one way (or all) that units of energy can move or interact with other units of energy.
I like the symmetry of the vector boson fusion model which creates the Higgs, however, if it then decays into dark matter particles, I have a feeling they will, like you said, become not just two equal dm particles but, like the quark and lepton families, unveil a whole family of dark matter particles. Truly fascinating! I then wonder if they in turn decay into the infamous dark energy? However, I feel that dark matter must be quite stable for it to be so abundant in the universe.
Human ingenuity will never cease to amaze me.
Sure, these particles are undetectable, but that ain't going to stop us from detecting them.
Always fascinating!
7:47 that's an exciting way to phrase it
All the discussion of Black Holes, Dark Matter, and Dark Energy has me thinking of the video that got me first hooked on PBS Space Time - "The Real Meaning of E=mc²".
In that video Gabe concludes at 7:53 that "mass is a property that all energy exhibits". My questions: Is there a real difference between what we call Mass and what we call Energy?
1) Once mass/energy enters a Black Hole, can we tell what it is any more? Could everything the enters a Black Hole become Energy and if it does, would it still have the same same gravitational attraction?
2) If Mass is a property of Energy, does Dark Energy have mass? Does it create gravitational attraction like Dark Matter does? How are they different?
You need to watch the episode about the true nature of matter and mass.
Very basically, mass as we define it is contained energy, energy that cannot simply zip away at light speed. PBS has a video on this: ruclips.net/video/gSKzgpt4HBU/видео.html
1.) Once something enters a black hole, we cannot tell what it is anymore. This is part of the black hole information paradox; in theory even after a black hole evaporated, we wouldn't be able to tell what it had been made of, which violates information conservation.
2.) Dark energy should have mass and thus create gravitational attraction. HOWEVER, since it is evenly spread throughout the universe there would be no center for this gravity to pull towards, the gravitational force in any direction would be balanced by an equal and opposite force. This leaves only dark energy's repulsive effect unbalanced, which is why it can have a positive energy yet cause expansion.
Finally you're back!!
Great Video , excited can't wait for more on this.
As a physicist working on VBF at ATLAS, is great to see you guys showing these numbers :D
Matt said that most things get mass from the highs field. What particles don't and where does the mass come from?
@@mrmonkeboy nice catch! Experiments show that neutrinos have mass but in the Standard Model they are very peculiar and don't get a mass from the interaction with the Higgs field. There are many hypothetical ways to describe massive neutrinos, the one that I find most fascinating is the existence of the right-hand neutrino.
In the theory, charged leptons are described with a pair of a left-handed and a right-handed field. The Higgs mechanism introduces the mass terms of the fermions as interactions between left and right-hand fields (when breaking the electroweak symmetry). The Standard Model does not contemplate the right-handed neutrino and therefore there is no mass term. Why are the right-handed interesting? As they have no electrical charge and only the left-handed fields interact weakly, a right-handed neutrino will not interact with any other boson but the Higgs making them impossible to detect. This solution is simple as they would get mass from the Higgs field, the same as the rest of particles.
However, this brings the question on why does the Higgs interact so specially weakly with the neutrinos and their differences in mass are around the eV, when the other leptons have masses between 0.5-1.7 GeV. Maybe it gets the mass from a new mechanism, if neutrinos are their own anti-particle (a Majorana particle instead of the others, Dirac fermions), they would get a new mass term and, together with the seesaw mechanism, would explain the small masses their small differences.
@@adriasalvador3536 thank you for the detailed reply
Dark-matter particles don't interact electromagnetically, so how could the annihilation of a pair of such particles produce any photons?
Since momentum is a vector, an inequality like "p_out < p_in" is meaningless. Conservation of momentum does not mean that "total momentum never increases or decreases" (also meaningless).
yes.. everybody forgot about me mate HB, the most important discovery of the 21st century.
Definitely one of my favourite subscriptions 🙏🙏👍👍
Can you do an episode clarifying the discovery of large structures that are older than should be posible under the current model of the big bang by the JWST?