What is dark matter made of? Leading theories explained: Axion, Wimp, Machos
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Is dark matter real? What is dark matter made of?Axions, Wimps, Machos explained. (Part 2 will be "why dark matter may not be matter at all") One of the biggest questions in science is: What is the universe made of? There is about 6X more matter in the universe than we can see. This invisible matter is called dark matter. Without dark matter, we would not exist. If dark matter is invisible, how do we know that it is there? And what could it actually be?
The first evidence of Dark Matter came from Fritz Zwicky in the 1930’s, when he saw that the galaxies in clusters like the Coma cluster were moving at very high speed. They could not stay gravitationally bound and should get ripped apart unless they had 100 times the matter that he could see. He coined the term “Dark Matter.” In the 1970’s, Vera Rubin confirmed the idea of dark matter. She measured that the velocity of stars on the outer edge of galaxies was about the same as those closer to the center.
Near the center of the galaxy, there is enough visible matter to account for this speed, but at the edges, there is a greater and greater mismatch between the orbital speed of the stars and the visible matter.
How do we know that this dark matter is not just ordinary matter that is hard to see - MACHOS - massive compact halo objects. The distribution of dark matter based on the rotational curves gives us a clue. It appears to be distributed evenly as well as like a halo around the outer edge of galaxies, and not clumped up like visible matter is. This can be explained if we theorize that this matter interacts very weakly with itself. But ordinary matter does not interact weakly,
The bullet cluster is the best evidence. The majority of the matter, as indicated by gravitational lensing, is in the blue areas of the photo. This is the dark matter that simply did not interact with the ordinary matter or with itself, as the two clusters collided, and just passed right through.
Here are the properties a potential dark matter particle must have:
1) It must be dark, or does not emit light.
2) It must interact through gravity.
3) It must interact with itself weakly.
4) It must be cold. It is not moving at very high speeds.
5) It must be stable.
Could the particle be an ordinary particle in standard model? The only massive neutral particle in the standard model that is stable is the neutrino. But because neutrinos are so light, they are not cold. They move very fast.
If we invent a new particle that does not interact with electromagnetism, has no strong nuclear force interactions, but does interact through the weak nuclear force and through gravity, then we have just invented the WIMP or weakly interacting massive particle.
And there is a model in physics that predicts exactly such a particle - supersymmetry. It says for every kind of fermion particle, there would be corresponding boson particle with the same charge and mass, and the same strong and weak nuclear force interactions. But it would have a different spin and mass.
A perfect candidate exists in supersymmetry - the neutralino. The neutralino would be the lightest supersymmetric partner of the photon, the Z boson, and the Higgs bosons. But the biggest problem with the Neutralino theory is that we should have been able to detect it at the Large Hadron Collider, and so far we have not.
The axion is the second viable candidate to be the dark matter particle. The axion was invented to solve the charge conjugation and parity symmetry problem with the strong nuclear interaction, or "the strong CP problem."
CP symmetry basically means that the laws of physics should be the same if a particle is replaced by its antiparticle (C symmetry) and its spatial coordinates are inverted to its mirror image (P symmetry). The neutron has a property called a magnetic moment or spin. This means that if you put the neutron in a magnetic field, the neutron will have a spin. But the neutron should also have a spin in an electric field. But it does not. No one knows why. This is the problem. This lack of spin is dependent on one of the fundamental constants of nature, called Theta. Theta has to be zero. But theta should vary anywhere from negative pi to pi. This seems to be a huge fine-tuning coincidence.
#darkmatter
#axions
#wimps
In 1977, two physicists Roberto Peccei (pechchaye) and Helen Quinn proposed a theory which solved this problem, by creating a new field for theta instead of it being just a fundamental constant. And since most fields maintain the lowest possible energy state of zero, that’s what theta would also seek to be - zero. But it also means that this field will have a particle associated with it. This particle of the theta field is called the axion. Axion experiments are being done in Hamburg, Germany, and in CERN, but so far nothing has been detected. - วิทยาศาสตร์และเทคโนโลยี
Again you manage to take something I've been struggling for years to try and understand and explain it in such an easy to digest way.. These videos should be shown in all Schools!!
to show kids that all we know of the cosmos is what?
So your brainwashing has finally reached the lie levels the scientists are telling us and you now understand something that doesnt exist.
Good job!
Unfortunately they still only teach Newtonian physics at school. I guess they don't want the kids thinking outside the box otherwise they won't want to work at McDonalds.
One of the best channels on YT
Hahahaa maybe you should ask tinker bell what her fairy dust made from i think its the same as your "magical" dark matter.. You people are a joke.
EU
@BBB H I agree with you except pbs spcaetime doesn't dumb it down..But I agree pbs spacetimes few videos are complicated to understand...
I'm a big fan too.
Yeah but sooo underrated. I actually think this channel is better than PBS space time
@@sIXXIsDesigns right!
I really enjoy the level of detail you put into your explanations. Your ability to put such complex topics into layman terms we can understand is impressive. I definitely follow along better without all the jargon. Some of us appreciate science, but aren't looking to earn degrees ourselves just to understand it! lol
Thanks, yes, that's exactly what I'm trying to do -- Give you enough details for you to understand it fully. Whenever possible, I try to explain the meaning of the equations rather, than derive the equations.
I very much agree thank you Arvin
@@ArvinAsh yhsrm. Thanks wax zee q,mlreaf gwà uy 0⁷⁷kn
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@@ArvinAsh But derivations in quantum physics can be very beautiful, and powerful, for proof is why, nogtwhat and how. My favourite is the derivation of the Schrodinger equation.
You are the first and perhaps the only content creator i will pay to keep these videos free of cost for everyone. Thank you for being such a wonderful and kind educator. Truly a physics dad.
Arvin.... I worked as a salesman for a year. And I sold products that I hated. Now after some years studying physics I look back at my sales... I feel sorry for some. I made them a offer , and sold things I don't think is good. Now I'm teaching physics at a high school, and "selling" knowledge about physics is good.
I think your videos are the best there is... ... (could and would repeat: the best)
I hope your commercials stand the same quality....
THE best explanation on dark matter theory I've ever seen.. amazing
Shouldnt it be dark gravity? Doesnt matter interact with stuff like light and other matter by definition?
Arvin, this really rounds up the arguments and explanations. Concise and easier to understand than most. Well done. Keep on.
Arvin I'm really glad to see that your are getting more and more subscribers. I'm subscribed from when this channel had ~15 - 20K subscribers, and I must say that your channel is one of the most quality ones. You explain extremelly complex matter in a way that even I can understand. Wish you all the best and thank you.
Thanks for being a long time fan my friend. I appreciate it.
I absolutely love your channel! You cover so many good things! I would love to see an episode listing the current problems people are working on today or what other things need to be answered, and maybe even what groups or individuals are working on them. I'm sure many people that are not in physics or science professionally are curious about this, but don't even know where to look or what to ask about. Thanks again for your videos!
Excellent in so many ways. It can’t be easy to edit something like this or to acquire the visuals. Thank you for the extreme effort.
Thanx for these videos man. I find your videos are far more clearer, exciting, entertaining than many other popular educational physics videos on youtube.
I wish I was smart enough to understand all of the fine details. It's such a fascinating subject matter. I love your videos Arvin!
@@sIXXIsDesigns Or something is wrong the way they see it.
@@sIXXIsDesigns Well, in my 3 books in copiright the big and the small work the same, the cosmos is not much diferent than DNA through our vains so we are big made by smalls so the day they match both only then they will be right, still we know the alphabet of chemestry but ignore the language or languages that it may speak. - Every thing of course vibrates, vibrations is the resistenses that all matter oppsses to the flow of electrisity or light through matter so maybe expressed in Hz. - I used to wonder but not that much, my interest stared by a Mayan Calender that decoded by hobby i am not a math person but all my work can easely be undertood by a 6th grader kid. - I just left that mission and is good enough to understand the cosmos including the small they get well togather the puzzle structure is done in most. found that the universe is metric with 3.1416, 1.618 and much more.
@@sIXXIsDesigns This numbers are in nature all over in Iin to many ways. - if you mean geometry. to me is all over as well.
@@sIXXIsDesigns every thing works about the same, like we are all about the same but each one is unique. - see: the Suns light takes 149.6 millions of Km to reach earth and 149.6 times 21 = 3141.6. - Earth around the sun does a common denominatoe too at the 21 years.
they are in galaxies, the sun, and all around us all we see is the same chemestry or DNA.
@@sIXXIsDesigns Take a look to my hannel and find out that everything is a HOLOGRAM kind of.
The way you say "that's coming up, rrriiight now," gets me pumped everytime.
😅😅😅
What's the matter? It's Mostly Dark!
Physics are in the DARK AGE.
@Muslimcel hahaha
@Muslimcel so do you think that God is evenly distributed throughout the whole universe...
That means God is in our milky way galaxy... Wow
It's mostly TRANSPARENT, and it mostly doesnt exist. Its SF matter, theres no proof whatsoever that it exists.
Science has nothing to do with God or any imaginary friend one has in our mind.
Ur videos are so good Arvin. Sometimes I stray to Other channels but just end up confused and tired in the head. Ur videos make me Hungry for MORE information! MORE learning! Love it!
Good to have you my friend. Stay curious. And thanks for watching.
Man, I wish I had more professors like you when I was back in the school!
Thank you for making such a complex and fascinating topic so accessible!
So far, this is the best explanation on "dark matter". You practically put into perspective the fact that "dark matter" is really invisible matter. It is a misnomer and quite misleading. Thank you.
Aside from a very clear explanation, I appreciate how you give a lot of background and some of the first information recorded about a subject. A lot of videos just jump in and skip over important facts and I end up having to watch multiple videos or Google it. Thank youuu!!!
You're very welcome!
How have i only just now found this channel? Been binching it all day today
Arvin you have always been able to talk about difficult subjects in physics and let us mire mortals take a look into the hardest findings possible and then help us make sense of it all. You always make my day sir. Thank God for your talent and knowledge and ability to pass it on to others.
Arvin: you are by far the best at explaining concepts and theories to laymen like me.... Thank you..
You make this stuff so easy to understand because everything just clicks when you describe Physics and it's unlike any other
Great channel. Such well thought out explanations for the material being presented.
Finally -- a good explanation of "axions" !! Thank you
excellent explanation, like all other Arvin's videos
This channel is amazing! I only understand about 80% of it so I like that some of your episodes overlap
Had to rewatch this a few times to understand it wish I was smart enough to know the details but awesome video stated things very clearly!
That picture of Fritz Zwicky is perfect lol.
Yeah :) I'm glad he finally did get his point across even posthumously.
hey Arvin , not sure if you read comments to your videos but I just wanted to let you know that you’ve just gained a new subscriber for life 😊 . I really love all of your content and specifically the way that you describe it .
I consider myself quite well-versed in the knowledge of the things you discuss but all of the insight you provide and the WAY you provide it is really great !
thanks again from all the way down here in melbourne australia 😊
Welcome aboard my friend! Good to have you.
Your show is really good. You can break down complex physics in a very understandable way and I appreciate that . Thank you.
I appreciate you and love you for this trial
I hadn't heard that Vera had died. So long, Vera. Thank you for your many valuable contributions. You were a great scientist and an example for us all.
I like how he doesn't yell at us- he has a nice, calm tone!
Great video, the detailing is so nice
There are lots of things I'm not a genius about, but here are some things that I think about when I think dark matter.
-Leftover residual phenomenon from the initial conditions of the universes beginning, when anti-matter and regular matter had more significance.
-Side effect of the universes expansion from dark energy, maybe even an effect from the mixing of fields and radiation for so long after the expansion.
-Something similar to the mechanism which gives way to gravity, or perhaps an unknown trait of gravity itself.
What if:
1) It’s just a miscalculation
2) It’s actually just matter that doesn’t interact with *visible* light
3) It’s matter in a slightly different dimension/plane of existence because of string theory’s multiple dimensions
4) It’s just too small to see through the telescope
5) The black holes at the centre are stronger than estimated
*?????*
Item 1 could be correct. 2 and 4 are unlikely as there are no viable ordinary matter candidates. 3 is possible in membrane theory. 5 would not explain the steady velocity on the outer edges.
Arvin Ash thank you I hadn’t realised that. As you can probably tell I’m still in school so haven’t been learning about this so I just watch science videos (yours) to learn. I’m gonna go and watch another one of yours now 👍
I bet its number 3
FINALLY!!
was waiting for this one!
i liked how you also explained the symmetry and also the particle part
thankyou
Wow great explanation, space is absolutely mind boggling but amazing at the same time.
i wish you millions of subscribers
You have good videos that I really enjoyed watching. and some more complicated, almost boring ones too. But, This is one of the good videos. Well done
I can’t get over how amazing these videos are.
"What is dark matter made of?"
That's easy, it's made of pixie dust and ground up unicorn horns.
More like PIXEL dust... and horny unicorns!
From your first couple of minutes, it seems that neither light nor darkness can exist without each other. Just as Bad does not exist without a standard of Good.
Very good video Arvin!
Thanks for sharing this interesting subject.
Cheers Arvin, been mystified about the issue!
Very clear & understandable. Gratitude!
I like the way you explain things. They make me think.
Fantastic video! A pretty difficult material presented in an easy way. I’m truly impressed!! As for neutrinos, could there be a 4th neutrino that could explain the dark matter? In principle, there could be more than 3 generations of quarks and leptons in the Standard Model. The 4th generation would consist of heavy particles that simply haven’t been observed yet.
it's possible. There is just no evidence for it currently though, so we are trying to fit dark matter within what is currently known.
What if dark matter is indeed just an invention to "make" general relativity work?
Could be. Next video will address this.
General relativity does work and works very well. It will always be true in the regimes it is valid in. We also know it is incomplete, as it is a classical theory that does not unify with quantum mechanics.
GR and the standard model aside, whatever DM is ,its a fact, if it did not exist galaxies would fly apart as the gravity of the normal baryonic matter is not even close to enough to hold them together. Just one example of why it must exist:/
@@TheZacdes The point is that the statement "not even close to enough to hold them together" is based on general relativity and gravity equations. It is not an undeniable truth so it is not an argument to support that DM MUST exist...
It is just that.
Love the way you explain.
Subscribed.
Arwin, you are the best scientific concept explainers i have ever seen. You explains things more calmly and perfectly that even normal people can understand. Your explaining way is that perfect and simple. Hope you will make more videos.😊
10:40 so here is a literal miracle, in our maths, which already predicts things which are true, but since we "can't see the particle in our particle collider" it's a big problem. I'll tell you the real problem, that collider isn't doing the correct things to get the reading which will represent the truth. The mistake is somewhere within the technology, or how it's translated. The intense match up between theorized math, and real life, is too much of a coincidence. Super symmetry, or whatever it's polished successor will be called, is a true wonder of mathematics.
You make a very good point! The problem is that the energies needed to create the theorized supersymmetric particles are achievable by the LHC. But since 2012, nothing has been detected. However, to your point, it is possible that these darn things interact so weakly with other particles, that we can't see it even if it has been created.
exactly 👌👌
Nice work. My gut feel is no dark matter. Something else at work here.
You'll like next week's video then, "why dark matter may not be "matter" at all."
Thank sir for your videos about fundamental questions of physics
Hands down the best channel on TH-cam!!!!!! Outstanding material in every video!!!!
It's a field. Light passes through it. You said it. It's an ocean.
As pretty much everything has a field underlying it, its pretty certain that DE and DM have fields at their core, why we have not found the associated particles is probably because we dont have the needed power in our colliders. DM could be a very weird "thing" that is spread out over large distances, mostly within large amounts of baryonic matter accumulations. It interacts poorly with normal baryonic matter except for its gravitational effect on it. Like gravity its transparent to light of any frequency. Gravity is a very weak force, yet has a very strong effect over large distances. DE is going to be harder to find, a sort of "anti" gravitational effect. Whatever it is, its very strange! To find either of these will take a lot more energy than we have available with even our most powerful colliders. An "ocean" describes any of the quantum fields as a good analogy. It took a long time to find the Higgs, and a lot of power, but it only accounts for a part of mass. Quark confinement accounts for more.
So either dark matter can be a WIMP, an Axion, or something that we just can't detect yet. My question is whatever this dark matter is made of, why haven't we discovered yet? We've done so many experiments around the world to detect dark matter, from the LHC to IceCube (icecube.wisc.edu/) , and we've still found absolutely nothing. If dark matter is a WIMP or an Axion, don't you think we should've discovered it by now? :/
Also, gotta point out that this is a great video for explaining dark matter, very clear. Thanks Arvin! :)
It's because they're just a predicted invented solutions to bigger unsolved mysteries. And that's how science works. You come across a phenomenon that is unexplained. You want to explain and measure it purely in terms of mathematics. When you cant do so, it becomes a problem to be solved. You then find surrounding theories to see what's missing and the missing pieces are either invented to match characteristics or you predict values. Call dibs on these predicted values and fund millions to produce experiments that research on this to confirm them.
Along the research you either confirm your dibs or find something else that solves/ confirms another theory.
I too have seen all the major videos on this kind of stuff and even as awesome as some of my favorites like PBS Space Time/Fermilab/Veritasium/Sean Carrol are, I too came here to say that hands down, you explain it the best both visually and verbally, thank you so much for making these. Found you by your QFT video and was blown away, then Quintessence, now this; really feel like I've developed a much deeper understanding of these topics. Gonna binge watch you. Science rules, and you fkn rock dude!
Glad you enjoyed it! I appreciate your kind words.
Yes he and Anton are great. Wonder his education.
The best informative physics channel I have ever seen , sir believe me you are amazing and thank u for share your priceless knowledge with us . God bless u
If theta is a constant
Then why does it value vary from -pi to +pi
Ahh yes, you have to take advanced physics to really get this one. I was debating whether to even put this equation on this video. Essentially, theta could have varied anywhere from -pi to +pi based on the possibilities, but it didn't. It is very close to zero. And no one knows why is zero. The field proposal is a possible solution.
IF dark matter doesn't interact with each other, then DOESN'T it means that Dark matter can't form clump?? 👀
Yes, it doesn't clump, and is likely smooth. However its gravitational effects affects ordinary matter.
@@ArvinAsh sounds interesting. 💫
The universe is full of wonders. 💖
It could just be a charged area of space that is large enough to create a gravitational field, much like when you rub a balloon and hold it next to your hair
@Rata 4U EVery mystery has an answer...
Let's be optimistic about the future.😊✌
Mr. Ash, time and again you prove the ability to bring critical physics issues away from the complicated esoteric, and directly into the hands and minds of us "common" folks. Thank you very much.
I always like the Arvin Ash videos. Great.
SUPERSYMMETRY ALSO EXPLAINS ABOUT THE ABNORMAL SIZE OF HIGGS BOSSONS.
IT ALSO PROVIDE BETTER UNIFICATION OF FORCES.
AND YEAH,ABOUT DARK MATTER.
Cant wait..🤣
keep up the great work man
Great video as usual arvin
Dark matter and dark energy has created the universe.
Yep, they both played a large role.
@@ArvinAsh Arvin, are we in a holographic simulation?
@@jayrodriguez84 I don't think so.
@@ArvinAsh so you don't believe this is any type of simulation? Or a hologram projected from a 2D surface? It seems like both ideas are irrefutable to me. It appears as if all life on earth is programmed to me.
@Enigma You have no way of knowing you're not in one and can't prove that you're in a non-simulated/"natural existence". So, that doesn't advance the discussion. Bostrom and Musk and other intellectuals propose the argument. I just happen to collect all information(which is what everything is anyways, just information coded in a physical reality) and wonder if that's how it things fundamentally are. I see fine tuning everywhere in this existence which leads me to believe none of it was accidental or "natural phenomenon".
It's popular because axion is so clean
Lol
When you say "coming up right now" - the most brilliant ❤
Your analogies really help understand, better than my professor that for sure. Cheers
My gut feeling tells me that this is the real McCoy. But my stupid brain isn't smart enough to get the fine print.
THE HALO THAT galaxies have are part of the electromagnetism that all matter posses.
Same thing makes light bend, the picture is shown flat but it is like a eel fish.
I really enjoyed the lecture! Thanks!
Awesome channel! Just found it and subscribed immediately!
Welcome aboard!
dark matter is a mathematical patch for a good but flawed theory.
I agree with the general concept of you statement, but how come a flawed theory is a good theory?... Thanks to this "flawed theory", which is called the STANDARD MODEL, Astrophysics has not had any major breakthrough since Einstein. The development of the science is at full stop.
@@tomasramirez4985 it is good in a sense that it is working for what we do at our scale. it is useful to us and helped us achieve a lot.
@@tomasramirez4985 classical mechanics is a flawed theory but at low speeds and large scales it makes accurate predictions that have been well tested. The same is true for general relativity and the standard model as they are remarkably consistent and enable us to accurately predict outcomes at their respective scales.
Yes we know that neither can be fundamental but they are useful. Without general relativity GPS satellites would not work due to giving incorrect ballooning errors, without quantum mechanics and the standard model transistors and thus modern computers would not exist. You directly benefit from the technologies made possible by these theories which is the best evidence that they are good theories even if "flawed".
If dark matter is just a "fudge factor," then why do we see a few galaxies that seem to have little or none of it? If our theory were wrong, you'd expect to see every galaxy defy our calculations, yet IRL a few select ones seem to behave like we'd expect them to.
@@tomasramirez4985 A model not so standard they missing the 4th gear that is the basement of the model: GRAVITY thats why they cant go any way from it, the standard model soon will be out taking with them most of the basement that is GR.
What’s the matter? It’s so dark!
This man blows my mind a little more every video.
Dear Mr. Arvin Ash. You are great and this is a great video also, as every time.
Well, if you did, you would have broken causality, because we just finished making the video yesterday.
who likes spaghetti? - - I am not a Tycoon.
Dark matter was totally and theoretically made up to correct some formulas and to explain things we see. Now we hunt for it like trying to find the stash of gold at the end of the rainbow.
Yep...but, isn't this how all discoveries begin. We see something we can't explain, we put a temporary label on it. And then people work hard to figure out how to explain it. And then prove their explanation with experiments.
So we shouldn't theorize about the things we see? You're analogy is stupid, no one is seriously believing there's gold at the end of the rainbow while there's a bunch of possible explanations for dark matter. While it's possible it doesn't exist, we won't know until we look.
No such thing as Dark Matter.....it's all explained even predicted in the Electric Universe.....people just need to f****** wake up !!
Thank you sir for your easier explaination.
Fantastic breakdown 👌 I needed it explained ta me like this, thank u so much, I just had to subscribe (n rang that bell)🤘
Please don't keep premieres. It's very annoying
Why? Premieres are fine
What r u talkin about, i love premieres
Well, it gives me a chance to interact in real time with viewers, which I enjoy, and hope they enjoy it too. But, if enough fans agree with you and your comment gets a lot of likes, I will consider it.
What are you talking about? Premieres are fun. We get to talk with Arvin live. If you don't like it don't come for the premiere
The premieres are finde. He would upload it anyway, now people just have the chance to get a live chat with Ash.
Lucid and thorough!!
Your channel is severely underrated my friend..
I subscribed. Love your ability to teach
Like this guy a lot. Great teacher, likeable personality.
THANK YOU DR.ARVIN ASH...!!!
Best ,simple explanation ever.thanks
Thank you sir for this amazing explanation of this advanced topic.. Sir If you don't mind then can you tell something about your education and specialised subjects?? Please..
Great videos Arvin!
Is there to little matter around the center to make time go clearly slower than the outer edge, thus making the center appear to spin slower than the edges?
Oh, already questioned that.. sorry..
Amazing video as always Arvin..I think you are right, we might not have the right tools to detect it..I Think its in another dimension for which we need other tools to detect it
Thanks for sharing. There is more out there we dont know.
Great video! Keep on!
Great video! Thank you.
Wow. This is the best explanation of dark matter on the internet. You truly do explain complex things simply, unlike that dude on PBS Space Time. As soon as he opens his mouth I'm lost. But with you, I get it. Thumbs up.
I enjoy the detailed elegant explanations from a foundational perspective. It becomes obvious over time how we are so dependent on the accuracy of predetermined concepts. This leads to ever growing complexity leading to an abyss of ignorance. My favorite is Kirchoff's blackbody work, which has been completely invalidated by Dr. Pierre-Marie Robitaille. Dr. Robitaile is likely unmatched in his absolute refusal to bend the laws of physics. To the best of my knowledge no one has seriously contested this man, and he is going to single handedly sink astronomy. He has already.
I still don't understand why something exists rather than nothing. I'll always wait for your videos about biggest question of human civilization
Arvin Ash should get a Nobel Prize just for being able to translate this advanced physics into English.