dark matter is not a theory

dark matter is not a theory.
I tried to increase the sound on this---let me know how it went? I keep getting comments that my sound is too low but it always sounds fine on my devices.
Professor David Weinberg dark matter rap:
www.astronomy.ohio-state.edu/...
Professor Adam Hincks visualization link:
adh-sj.info/bao_cmb.php
Job Geheniau’s dark matter measurement:
www.rtl-sdr.com/wp-content/up...

[@Phenpaii]

this video aged like a fine wine

[@bubbafug00gle51]

I think there's a problem with the model

[@TheBBQify]

I think these observations are a theory.

[@bubbafug00gle51]

@@TheBBQify Are you sure you don't mean hypothesis? I don't know what your science background is...

[@billyt8868]

@@TheBBQifyi’m not sure if you’re aware of the PROPER definition. so i will copy and paste it for you. “theory is a well-substantiated explanation of an aspect of the natural world that can incorporate laws, hypotheses and facts.”

[@somedudeok1451]

No. This video cannot age like anything, because there are no strong claims or statements.

[@vortalcombat4702]

Someone in the comments unironically just said "Thank you Physics Mommy"

[@mersilvaureus1525]

Definitely wasn't you, right?

[@nomchomsley854]

Thank You Physics Mommy

[@mygaffer]

That kind of sounds like an unwanted sexual comment. Hopefully it doesn't make her feel uncomfortable.

[@zeppie_]

Everyone don't forget to Thank our Physics Mommy Thank you Physics Mommy!

[@TheRashy2]

I hate this hellhole website

[@sigithesauropod3340]

POV: You're about to add an 'other' comment, thus changing the data until that which was presented in the second video is inaccurate for the future, thus aging it like milk.

[@sebastiangudino9377]

And she will make a follow up, because she reads every comment

[@Rc3651]

There's sometime therapeutic about "Dark matter isn't a theory, it's a list of observations"

[@senvr11]

yeah especially considering the borderline conspiracy that was string theory

[@sebastiangudino9377]

​@@senvr11It's not that drastic tho lol. It is just a pretty useless but honestly pretty interesting mathematical model that happens to be fundamentally untestable so even if it is true we just will not know

[@senvr11]

@@sebastiangudino9377 it's hyperbole and not like the graph

[@sebastiangudino9377]

@@senvr11 Yeah, I get it, but I think string theory is sometimes vilanized. It is not really physics, it is pure mathematics, but it is genuinely really interesting. People seem to think string theorists are all misleading douches and claim string theory is a waste if time. Which I feel is unfair

[@senvr11]

@@sebastiangudino9377 my issue is those who put it into physics, like i'm sure it's cool math but if it's not for this reality then i mean... cool? I can understand what you mean. My dad grew up in the string theory age and one of the consequenses is that he said quantum mechanics was just us not understanding physics. I don't blame the math for his ignorance but it's a setback

[@comment_section4766]

as a retired engineer who's good at math but doesn't really understand this, you must be wrong.

[@quinnocent]

As somebody who's moderately handy but barely understands engineering, I really have to question whether you're wrong about them being wrong

[@rayli.08]

@@quinnocent Original comment was likely a joke. It's a play on crackpots, mentioned in a previous video.

[@joed180]

​@@rayli.08 As someone whose friends tell him he's funny but tried and failed to be a comedy writer, I have to tell you that your evaluation of the comment you replied to as serious is 1000% wrong.

[@quinnocent]

@@rayli.08 I've told a joke before. In my expert-ish-esque opinion, I have to wonder if you're wrong about me being wrong about them being wrong about her being wrong

[@newdefsys]

Yeah, thats like French. I dont understand it but I can speak it pretty well.

[@DataIsBeautifulOfficial]

Dark matter: Do we need it? What is it? Where is it? How much? Do we need it? Do we need it? Do we need it? Do we need it?

[@junebunchanumbers]

I was hoping every comment would be this.

[@DevinDTV]

we don't need it, but general relativity does come up with a better theory and we can drop dark matter

[@machielste1]

@@DevinDTV Rip SG553

[@oliviapg]

This is going to be stuck in my head all day

[@keypo790]

whyt r u scribbling senseless numbers with letters on yer papyrus hamilton that just imaginary numbers? Do we need it?

[@Bohonk212]

"I'd rather have questions that can't be answered than answers that can't be questioned" Richard Feynman

[@chrywelch]

this.

[@jonathanbowers8964]

And I'd rather us all stop quoting and glorifying a certified creep and serial abuser who coerced and manipulated women into unsafe situations. Richard Feynman was the Harvey Weinstein of the science world and it is time we start acknowledging this reality.

[@ModernStupidity-qm3rj]

answers that can't be questioned? Try religion.

[@Bohonk212]

@@ModernStupidity-qm3rj I've known many highly religious people who love to engage in debating everything within their religion. If you don't, you need to associate with smarter people, religious and otherwise.

[@buckets3628]

that's a definition of Philosophical thinking

[@coreyalexbarker]

The fossil analogy was actually perfect! Fossils aren't the actual organisms anymore (ignoring stuff trapped in amber etc), but give us a detailed picture of what the bones (and sometimes skin and feathers/hair) looked like.

[@astemet]

how many light years does is the distance from center of galaxy to edge.. -> There is no dark matter.. its a illusion of time..

[@spvillano]

And in some cases, what the internal structures look like at a cellular level. An example being dinosaur marrow, whose structure was preserved down to the cellular level, despite the loss of the majority of proteins and DNA.

[@derrickcox7761]

​@@astemetit's "an"...not "a".

[@derrickcox7761]

The Big Bang was not a theory...oh, wait!

[@ChristopherSadlowski]

​@@spvillano I'm still salty that the DNA has decomposed. I would punch myself in the face no more than 3 times to see a real dinosaur! I was such a huge dinosaur nerd as a kid. Okay, well, no, that's not accurate; I'm still a huge dinosaur nerd.

[@straka-art]

Dr Weinberg was my professor for cosmology, and he gave us a flawless performance of the dark matter rap during lecture. He got a standing ovation. It was effervescent and hearing that at the beginning of this video made my day

[@neanda]

that's so fkn cool 😀

[@acollierastro]

I'm so jealous you saw a live performance of my favorite song.

[@motoko_kusanagi_]

Steven Weinberg was a bigot, got to sit through him bringing a female Iranian graduate student to tears during a lecture q&a by berating her and then implying his supremacist stance by pointing out how the Muslim countries have never won a Nobel prize and probably never will while his people have a plethora. Look at his quotes on the Palestinians if you have any doubts about his supremacist views. Also saying Dark Matter has been observed and only a 'crackpot' would protest since all physicists agree on dark matter being observed is just completely wrong. You can find quotes of counterexamples everywhere from top physicists who will tell you its not been observed. Once you can prove you've measured a signal of dark matter then it will be observed. The currently fruitless search for measuring dark matter on the particle physics side doesn't look good though. Playing word games with 'directly' and 'observed' just misinforms the public and applying the repetition over and over in the video on your stance is not the best approach to such a controversial subject.

[@corrinflakes9659]

There’s a reason Eminem has yet to diss Dr Weinberg’s flow.

[@bluemonstrosity259]

I thought you meant Steven Weinberg for a sec

[@FollowSmoke]

I'm not a student, engineer, chemist, or scholar; I'm a truck driver with a high school education. I just want to say I love your content. Your ability to communicate is wonderful and make the topics more interesting.

[@lettersnstuff]

no one should ever let their job title keep them from learning about something they find interesting. good shit, homie.

[@kim15742]

I love her definition at the end. We can all be into science for the love of it

[@denim_ak]

Hello fellow trucker

[@keeperMLT]

@FollowSmoke, I agree! I have heard the spiral galaxy explanation for dark matter but couldn't understand why it wasn't just a bunch of rocks. If we can't find Planet X in our solar system, despite gravitational evidence, why do we need "magic matter" for galaxies. The WMAP explanation finally offered an answer for how we know that a 'weird' form of matter exists and has since the Big Bang.

[@anilaxsus6376]

i agree, i think she can just re-explain physics concepts, that stuff has potential.

[@sigithesauropod3340]

This aged like wine

[@JasonWelch]

I was just trying to explain this to my son earlier (who's 6) and told him that while we haven't figured out what dark matter or dark energy is, we can observe the effects of it. He had far too many questions though. I study computer science, not astrophysics, so I had to basically tell him I just don't know enough or understand enough to give him better answers. I think admitting "idk" is unfortunately lacking in society. Anyway, maybe one day he'll be able to explain it to me!

[@Jake-0011]

My dad and I have had so many debates about this stuff and it usually ends with him getting hung up on something, then me trying to explain why it works in that way, and then him not listening even when I give him a source. Good times.

[@L2p2]

fortunately scientist say 'we just dont know" often enough. Too often too my liking because it does not explain what i want to understand. But this is good for science as it keeps it honest and we know where need to focus attention.

[@eggsalts4243]

It’s just a record player bro, Diamond tip on a vinyl blank pits and valleys and highs, dark matter, Liquid Metal, come on man. We know this stuff

[@Josecannoli1209]

We do know what dark energy is… don’t tell him we don’t. Dark energy is the energy of the the vacuum state.

[@ReapingTheHarvest]

​@@L2p2 That's not true at all. The majority of scientists simply submit to whatever the consensus of their high priests is. It's a top down authoritative structure that has a lot to do in common with religions. If you question things, or apply critical thinking or alternative explanations for data, you are mocked, ridiculed, suppressed, and thrown to the fringes as a quack. If they were more honest most of the current theories wouldn't even exist.

[@lattice737]

It's funny: some creators use these powerful engines and elaborate animations to try and convey complicated topics more intuitively. You simply talk to us like we're in a conversation, using your hands and the occasional picture, and I always end up with a clear and manageable (even if not totally complete) understanding. You are an amazing communicator! Thank you for your content

[@Nvenom8.]

Good communicators are good. Shows both a deep understanding of/comfort with the subject matter and great awareness of the audience.

[@lattice737]

@@Nvenom8. exactly

[@Houshalter]

Anyone can make a video just talking to the camera. People put so much effort into animations and editing because it's the only way to stand out. It's lucky the algo picked up a channel like this over a thousand others

[@zackhall984]

New Existential Dread Just Dropped ROFL

[@lattice737]

@@Houshalter that’s literally the point

[@Binyamin.Tsadik]

I like that you included the point about the systematic error. That the expectation vs measurement does not have the same discrepancy in every galaxy. Very important addition.

[@PopeGoliath]

That single clarification actually totally changed my view on dark matter. I very much tend to lean towards systematic errors and underlying misconceptions as explanations for things, but that can't be the case here.

[@randomnobody660]

I don't get it. Why can't it just be that our understanding is wrong? In general when our observation doesn't fit understanding, how can you *ever* conclude it must be observation that's missing purely based on *how* they don't fit?

[@rianczer]

damn hello Binyamin. fancy seeing you here.

[@GuyNamedSean]

@@randomnobody660 Our understanding being wrong is one of the theories. Modified Newtonian dynamics is a set of theories relating to us just not understanding how gravity works on large scales as an explanation to dark matter observations. So far, many of the proposed MOND theories fall short on adequately explaining the variety of different observed dark matter amounts just like the systematic error theory.

[@robpaige4122]

@@jamesbyrd3740 and yet there were tides. Saying there are no tides because you did not believe in Posidon did not make the tides go away. Dark matter is a tide you can't explain.

[@perplexedon9834]

"so this is when we- well not us, we werenyt there...this was before stars..." Something about this line is just hauntingly beautiful and terrifying to me

[@OzymandiasWasRight]

Fun fact about Vera Rubin? Her husband would drive her to class, eat dinner in the car, then drive her home. They were both pretty busy brilliant people but found a way to spend time together every day. I just find that incredibly adorable.

[@gorgonzola86]

This got unexpectedly very emotional for me at the end. Today was the funeral of an aunt of mine, who was one of the best hobby gardener I know. And as a matter of fact I told the people who were there how honoured I feel to have all her gardening books now here at my place to take care of them. And it was also a rough day because we couldn't take my dad with us who is at very poor health both physically and mentally. And coincidentally to how you ended your video my dad has been a ham radio enthusiast for 30 years. So very strangely I feel like somehow if I have been hugged by this video and it somehow makes me want to hug it back. This must sound strange... but I feel very strange after watching the end of your video, but actually a lot better. Just had to have you know that.

[@honjon666]

Takeaways from this video: 1. Dark Matter is not a theory 2. Dark Matter is an observation 3. You can't just throw away Dark Matter 4. 1980's Casio keyboard midi drum tracks still slap in 2023

[@DJWESG1]

It's true. 4 is true.

[@manictiger]

Number 3 sounds like a hoarding problem. Next time on hoarders: cosmic being can't let go of dark matter

[@bakters]

" *1. Dark Matter is not a theory* " True. It's a hypothesis. " *2. Dark Matter is an observation* " False. People were searching for Dark Matter for decades and found nothing so far. What she shows as the "evidence for dark matter" is circular reasoning at its worst. "Gee, the Galaxies move too fast for their masses!" "Hmm, maybe they are way heavier than we thought? Due to some dark matter, you know?" "Dark Matter exists! Q.E D." " *3. You can't just throw away Dark Matter* " True. Just throwing it out won't work. The trouble is we simply can't find it, so some people start digging very deep into our actual theories.

[@bakters]

Okay, I've found a better summary, I think: 1. Luminoferous aether is not a theory. 2. Luminoferous aether is an observation (not true, obviously). 3. You can't just throw away luminoferous aether. 4. 1860 Brahms still grooves.

[@lieferservicemitreis6178]

She is right and wrong at the same time. "A theory explains a natural phenomenon that is validated through observation and experimentation. A hypothesis is an educated guess based on certain data that acts as a foundation for further investigation." Correct. Dark matter is not even a theory its a hypophesis. A measurement which is in conflict with the given model doesn't spawn anything. We observe the conflict and automatically make up hypophesis. The correct sentence is: "There is a conflict between the model and our observation" Thats it. Nothing more can be said. Everything beyond is already interpretation and hypophesis. Of course there are very good arguments for the Dark Matter hypophesis....but again its not even a theory. "Dark matter is a hypothetical form of matter thought to account for approximately 85% of the matter in the universe." - wiki (Edit: There is a discussion bellow about the correct definition of a theory in physics. This doesn't change the fact that Dark Matter is not an observation, as acollierastro said in the video, but an hypothesis. The observation is a model versus reality conflict. I just wanted to add this here)

[@Rc3651]

What if the next spike on this video is from your own video? 🤔

[@billyt8868]

was thinking exactly the same. 100% going to happen.

[@TheBlackKnight22]

I love finding new educational channels with personality. Love the casual vlog style and your vibe, subscribed

[@mr.zafner8295]

I don't hate when you repeat stuff. You are (a) making a stylistic choice which is fun and (b) making things easier to understand. I get it, and please keep doing it

[@lattice737]

100%

[@tuomasronnberg5244]

There's a lot to take in, so the repetition helps. The one take home message I got from this is that the dark matter is just a theory, not an observation.

[@mr.zafner8295]

@@tuomasronnberg5244 absolutely true. It is widely understood. I bet it would be boring if you were a teacher, like she is effectively being; I'm sure my high school algebra teacher was so sick of the quadratic formula she probably had dreams about murdering it with a fork. But we learned it because she kept repeating it over and over

[@georgelionon9050]

I do hate it, because it feels like talking to an idiot..

[@eekee6034]

@@georgelionon9050 I know how you feel, I grew up in a culture which associated repetition with idiocy, but found this culture to be very bad for me because in several ways it arrogantly opposes things which are good for the human brain. I had a lot of challenges to my mental health, and my culture was an obstacle to my recovery. I don't want to get into all the details, but repetition in particular is good for learning. When you hear something again, your brain refreshes the original memory and associates a new one, and may make connections with things you're thinking about at the time of the repetition but perhaps weren't when you first heard it.

[@valentinaaugustina]

A certified collierastro banger

[@careymcmanus]

Love your crusade against the use of plots/graphics that are incomprehensible or given no explanation.

[@JeffCowan]

This video is aging like fine wine!

[@FKProds]

8 questions to ask yourself about dark matter: 1. Do we need it? 2. What is it? 3. Where is it? 4. How much? 5. Do we need it? 6. Do we need it? 7. Do we need it? 8. Do we need it?

[@Designed1]

​@@Fritz_Schlunder 1. the us government is most likely lying about aliens as they have shown absolutely no proof of their existence despite their claims. 2. unless you can explain why all matter in the universe are not moving towards each other at rapid speed due to gravity, then please do not throw the expansion of the universe out the window like that. 3. that's not how quantum fluctuation works. virtual particles aren't technically real and only arise in mathematical calculations of the quantum world. even if they did really exist they would disappear so quickly that they would have absolutely no effect on any real particles. 4. if physical components of gps satellites are being affected by low gravity then scientists would've noticed that way before they had to include time dilation in their equations. also, science is all about building and improving on what we've already known. scientists don't come up with completely new ideas when observations proves their current models wrong because it is a much safer bet to just reconstruct their current models so that it matches up with the observations. unless some truly radical observation is made that their current models cannot explain no matter how much they try to change it, or some new model is created that explains everything the old model can and the new observations as well, then it is unlikely that the current models are going to be just thrown away like nothing.

[@sebastiangomez-wu9gh]

6,7 & 8 make me think you are a hardcore MOND defender. 😂

[@marvin.marciano]

I'm a 16 years old science-lover from Brazil, and KZbin just recommended me this amazing video out of nowhere. I've loved it. Please, continue posting stuff like this!

[@TheDutLinx]

Esse canal é bom pra caramba pra coisa de fisica! Feliz de achar mais um BR aqui

[@archwaystation]

I'm 16 as well! Looking to go into astrophysics and finding gems like this is really helpful when you're trying to surmount the seemingly endless cliff of knowledge to understand what you're actually reading. One of the reasons I love science communication is because it bridges that gap, and I want to be good at it someday as well so that I can help people understand the concept itself instead of reading a headline with the word "breakthrough" and assuming something beneficial is going to come out of that. I think a lot of that is whats lacking right now in the field as a whole.

[@atlasatlastt]

III EU TBM VCS FIZERAM A OBA?

[@DeltaNovum]

Have you tried more of her videos? She's one of the best science communicators to follow for the average layman imo. Very chill communication style. This channel has really been helping me get motivated to do deep dives into physics and cosmology.

[@fransxescoli4834]

This video gives off 90’s or beginning of the 00’s vibes

[@Rkcuddles]

Please keep doing this for fun. We absolutely love this hobby of yours.

[@lovergurl4528]

i had no interest in physics before finding your videos. you’re such a good storyteller, you’ve opened my eyes to the interesting world of physics!!!

[@benegmond6584]

Welcome to the real world of magic and stuff, but real, it's not just in movies.

[@buzhichun]

exactly the same here

[@aegiswim]

love your pfp

[@totallycarbon2106]

​@@dragon67849why did you feel the need to put this exceptionally creepy comment out there? Jeez dude, maybe read your comments before you post them and if that isn't working then my guy you gotta think about developing some kind of filter - it should be obvious why that comment is rank, and if it's not you have some introspection to do.

[@lovergurl4528]

@@dragon67849 weird freak

[@ryanm21212]

binged your channel after getting recommended the string theory video . big fan of this style of content, keep it up 😁 i was casually interested in astronomy and physics when i was younger , but i chose to study electrical engineering instead. the way you present science has reinvigorated my interest in these topics.

[@XxyGoddam]

I binged the channel as well! It's dope, eh? I love this type of content as well. Yet when people tell me to make something similar about art, I say "ahhh who is going to listen to me talk for an hour?" Lol. And yet here I am, watching long videos with pleasure.

[@izzyonyt]

​@@XxyGoddam Same, I came from the String Theory vid and have binged every video. It's like having someone talk to you about physics haha

[@szaszm_]

same. I'm pretty sure the channel is in the process of blowing up and becoming popular.

[@XxyGoddam]

@@izzyonyt yeah, exactly. It's like your buddy, who has amazing stories, who you can listen to nonstop. Which is rare to me because usually I'm that buddy to everyone and rarely I encounter people with such cool storytelling on interesting to me subjects. I'm so happy to find this channel!

[@XxyGoddam]

@@szaszm_ I feel that as well. Like, I believe that very soon she's gonna become insanely popular on KZbin. Because there is everything: good storytelling, relatability, comprehensive explanations and genuine, funny, authentic lady who is just amazing by herself with a strong values system. It's destined to blow up.

[@gstlynx]

Thanks for generously sharing your time and attention. Your presentations illuminate, captivate and amuse me like nobody else's.

[@vooracco]

“New existential dread just dropped” has been in my head for the past five months.

[@Allurian90]

As a mathematician I really wanted to interact, but then I was specifically requested not to. So now instead of a compliment about how that's a perfectly reasonable handwave-y concept of why fourier is the greatest analysis tool of all time, I will be like Dark Matter and not interact with anything. PS I love your work, these are great

[@piffe]

@@DowJonesDave copy pasting your response just shows that you need someone to validate your stupid fucking view

[@dinobotpwnz]

@@DowJonesDave 50%? I think you missed a few orders of magnitude there.

[@drachefly]

@@dinobotpwnz And, well, the entire video... or any other not completely-made-up argument for dark matter.

[@philosoraptor3]

Second that, as an applied mathematician specializing in harmonic analysis.

[@clintholmes2061]

@@philosoraptor3 Nerd!

[@toatrika2443]

an 18 hour video on fourier analysis sounds like a sick one million subscriber special

[@elliotdale6020]

Thank you. I just discovered your channel. You explain so well a lot of topics in pop science from physics that I'd always thought were sus but was never smart enough or diligent enough or not physicist-y enough to say or know for sure. 🤯

[@potato.pancake]

the alignment chart is extremely entertaining thank u for creating it

[@monkweirdo]

After finishing my MSc in theoretical physics I felt a burnout and been working in finance for 1.5 years barely looking at science. Finding your channel like a week ago brought back my enthusiasm and I started once again studying multiple fields by myself and I'm loving it. So thank you and keep up the amazing work

[@lattice737]

I’m glad it’s not just me. After my Bachelor’s, I wasn’t sure I wanted to do a PhD, so I’ve been in telecom. After discovering her content, I’m giving a PhD a serious rethink. She is reminding me why physics is so special

[@monkweirdo]

Yea I've been thinking about giving PhD a chance too.

[@AnderStibSkatexD]

I was about to drop out from physics major because of the burnout, but i found this channel and now i'm thinking deeply about leaving the university. xd

[@lattice737]

@@AnderStibSkatexD you can do it, man

[@JorgeSanchez-je4bt]

There was a lecture done by David Tong several years ago at Ri where he explained that the fluctuations of the CMB was due to the vacuum field fluctuations. You presented an idea that the fluctuations of the CMB are due acoustic barions that vibrate between dark energy and photons. Are these two ideas the same idea?

[@sgutowski58]

This video aged like milk, which is a great thing because that’s how cheese is made and I love cheese.

[@jameshughes6078]

I too watch a bunch of Jeff Dunham, the famed cheese maker.. cheese farmer... cheesier? Perfect pre-physics binge content.

[@luiiz2138]

Yogurt too 🤤

[@crashstarr6531]

It took 27 minutes of this video for me to fully comprehend what was meant by the title, but when it clicked that 'dark matter'is *only* the phenomena amd evidence, without any explanation implied, it was a pretty cool realization. These are the observations, and the theory comes in when we start trying to explain what the dark matter actually *is*, or why it behaves the way it does.

[@crashstarr6531]

@quark-soup that overly literal interpretation of the phrase 'dark matter' is like... the whole thing this video is refuting. We don't know for certain whether or not a form of matter is responsible for those observed inconsistencies, but the collection of inconsistencies exists, and regardless of what hypothesis you propose to explain them, it's still purely descriptive to say they resemble the behavior that would be expected if there was matter in places where we don't see matter. Explaining why galaxies exist like there is some matter near them that we can't otherwise see is the question, not the answer.

[@crashstarr6531]

@@theta-rex that's a lot of ad hominem for a conversation about science, friend. I think you are maybe missing the point here, and that's okay, but it's not my job to explain it better than the doctor of the field who made the video in the first place lol

[@crashstarr6531]

@quark-soup and *my* point is that you've come into the comments section of a video about a topic you clearly don't understand, and decided it was worth your time to insult a random stranger while also being wrong yourself. Maybe stop, it's just kinda sad at this point.

[@justlolatthisworld7917]

@@crashstarr6531 Your theoretical physics religion is one big logical fallacy word salad.

[@crashstarr6531]

@justlolatthisworld7917 the fact that you think any of this has anything to do with 'religion', or belief of any kind just proves that you are thinking about this thing like a dogma yourself, and thereby completely missing the point lol

[@annegajerski-cauley7624]

I'll tell you something about the 60's and 70' as personally experienced by a particle physicist. The mystery of the rotation curves that was being occasionally mentioned at the time - departmental colloquia, reading "Sky and Telescope" (remember that?), etc. - seemed like an oddity that could wait. No one in my group of colleagues talked about it for more than 5 minutes after some interdepartmental colloqium. We - really my smarter colleagues - were busy with the "heroic" period of standard model building and accelerators. As also a lifelong amateur astronomer, I recall it also being NOT a big deal outside a university astronomy department. Only on those occasions, especially recently, when particle physicists become piqued by "bright , shiny" new things in other people's playgrounds, or, being like Oppnheimer are as true renaissance men, did attention turn back to the cosmic aspect of physics. Having faced the humiliation of a bad, oversold prospective theory (strings), theoretical physics has in the past decade basically turned to hints from the sky to make up for running off the end of the Standard Model. A little oversimplified, but clearly to me a big shift in attitude. regards DKB

[@YeaaIJusShiddedOnEm]

This is me, reading along to your comment and pretending I’m following along with all the details: 🧐🧐🧐 yes, yes indeed.

[@onehitpick9758]

Dark matter wasn't a common term until the mid 2010s, although anomalous rotation problems were noticed as far back as Vera Rubin. Now, every kid thinks it's a fact that solves everything, but it's really something that can be placed anywhere, any time, in any amount, to make some equations work. There is a theory, it is not well understood at all except perhaps by a few, and dark matter is a requirement of the theory for it to kind of, but not really fit observations.

[@domenicobarillari2046]

Is this a mock? Because if it is it marks more clearly than any example I can offer what a dumb generation we are now raising.

[@Andrewbert109]

​@@onehitpick9758just curious are you also a physicist or astronomer?

[@L2p2]

Thats what I gather from physics communicators of today. I got back into this field after college and its refreshing now.

[@inxiti]

Who's checking in to see if they commented on this video? :)

[@billyt8868]

i can’t find mine but 100% commented like “she’s talking about observations not trying disprove dark matter”no idea how to find it. ha

[@karlbarlow8040]

I found mine straight away and was surprised how much I still agree with it.

[@doughaffner5087]

Finally someone heard my "I'm in the dark, does it matter?" plea and took the time to help explain it. Thank You, Angela.

[@incaroads001]

I've said it before, and I'll say it again: Dark matter is made out of math, and the tears of physicists.

[@Azure1964]

"The electromagnetic force is having a party and you just have this oopy-goopy plasma" is my new favorite sentence.

[@sammiller6631]

oopy-goopy plasma was my favorite part too.

[@Remiwi-bp6nw]

thanks for making these videos. you've made me think abt astronomy a lot more, which in turn made my Intro to Astronomy elective super easy. you made my semester measurably 25% easier

[@luketaylor1257]

Audio was loud enough, but I think your audio is occasionally peaking, (also called clipping) which gives you static and noise. On any volume monitor this is represented when the bars go into red. There's a lot of filters and techniques to deal with that depending on what software you use to edit.

[@lattice737]

It’s all for the sake of driving home the value of Fourier transforms haha jk

[@reellezahl]

you should have performed windowed Fourier analysis to back up your claims 😅

[@Volvith]

@@lattice737 They're not mistakes, they're learning opportunities. _Educational immersion._ 🥳

[@gianni_schicchi]

Yes, good observation. (as a semi-pro / hobbiest mix engineer) Software can certainly help but it depends where the clipping is happening in the processing chain. If the mic pre-amp is just too hot, the recorded audio is forever clipped. Software can only smooth out the harshness but it will still be a lost of dynamics and fidelity. If the mic is hooked up directly to the recording software via a built-in pre-gain or on a mobile phone with the direct mic, then a software setting shoudl be able to prevent the clipping, as already ironically mentioned, a DSP probably doing some FFTs to predict a peak as soon as it’s about to happen and auto-duck the analog gain into the DAC. Finally, you can also just use more headroom if using an outboard mixer or some software with a fixed gain level if you don’t want to be monitoring while recording, and then later use a software compressorlimiter combination to reboost and normalise the volume. This will also boost the now lowered noise floor though, and her room already sounds pretty echoey so I wouldn’t recommend relying on too much software gain later. -12db tops I would guess. Always leave -3db headroom on the final product. KZbin will re-compress the dynamics a bit anyway as will most operating systems on playback from mobile video / yt. tldr; lower your gain a bit on your mic settings or hardware mixer pre-gain use a software limiter/compressor on the exported audio after editing leave ~ -3b to -1.5db headroom on master stereo output limiter. (sometimes this is a setting while exporting the video in the audio transcoding section) possible get closer to the mic to reduce need for gain which willl amplify the room echos and A/C noise etc.

[@neon-daddy]

You’re doing a great job at translating subjects that have been out of my reach for many years. Thank you.

[@FFGG22E]

There are plenty of other videos that present the same failed bs.

[@lubumbashi6666]

​@@FFGG22ELower left quadrant

[@stephanieparker1250]

Nearly a year later, I still refer people to this video when discussing dark matter. Thank you, Angela 👍👍

[@andregomesdasilva]

Wow, your videos are super high quality. I'm impressed and I learned a lot today. Thank you!

[@Ttarler]

You are a phenomenal science communicator- I learn so much from your videos. Keep it up!

[@aslanburnley]

Dark matter is a theory, because a theory is an idea validated by evidence. Dark matter is not a hypothesis.

[@pailiaq]

Heads up, the audio is clipping sporadically throughout the video. Dunno if its a microphone issue or because as you said in the description you may have increased the gain too much. I recommend looking into using compressors for increasing average loudness over just boosting gain (assuming thats what you did) Great topic and great video

[@titactaco]

A compressor to normalize your volume is always good, and the resonance from your walls can be toned down a bit with a little eq tweaking, even.

[@krisspkriss]

Came here to say the oldest audio trick in the book is to compress all vocals. I actually recommend doing two compressions one with a short attack and release and another much longer to act as a intermediate length normalizer, and then finally normalize the entire piece. The short compression is to take out the spiky staccato of hard constants and mic pops. The next one is for acting like a normalizer and mitigating things like bad mic usage (varying distance/direction) and overly dynamic speech patterns. Then in the final edit, normalize the entire piece. It sounds like a lot of effects, but it really isn't and is a fairly standard practice that goes back to reel to reel days.

[@ThisSteveGuy]

@@krisspkriss Yeah, I didn't even notice anything was wrong since I run all podcasts and videos of people talking through a compressor (Thimeo's Stereo Tool).

[@adammcconnaughey1716]

it's a little vocal butt wiggle causing an unexpected spike in the auditory y axis

[@PentodeSensations]

Agreed! Apply compression instead of just gain, EQ some body into the vocals, better mic setup, pop filter, maybe a little room padding to avoid echoes.

[@itsmeL6]

Thank you for this!! To distill a lot, I feel... better? Like, i already feel better having watched so far (I haven't finished the runtime yet), so, thank you.

[@Yup712]

I am LOVING this channel! I have a little bit of a background in Engineering, but my degrees are in Political Science. But I find Physics and science fascinating. I’ve actually started taking a math class with a tutor to better understand and maybe one day get to do research. But this channel has helped a LOT!!! Thank you so much!!!

[@abc-lt7kk]

Hey, I just wanted to give a big thanks to you for making these videos. Seeing someone being so passionate about research or also just nerding out about an interesting topic is really encouraging me to take steps towards eventually getting into research myself. I think I really needed that at the moment.

[@carlosaguayo8761]

You and me both, brotha 🙏

[@sakuyarules]

Prefacing this with: I have a bachelor's in astrophysics. Most of my family and friends aren't scientists, so I get asked to explain a lot of science questions. When I try to explain dark matter to people, I usually say something like: "We know how a galaxy (for example) should look/behave based on our current understanding of physics. When we take measurements of a galaxy, we see something different. The galaxy behaves the way it would if there was extra matter (mass); we can do the calculations again with extra matter and show the results match what we measured. We refer to the discrepancy as 'dark matter.' 'Dark' because we don't 'see' the material like we would regular objects; and 'matter', because it has a gravitational affect on the surroundings in a way similar to regular matter. We aren't necessarily saying 'it is a new exotic material', though it very well could be; the name is more of a descriptor there's something that acts like 'matter' but that doesn't give off light (sometimes I explain ElectroMagnetic Radiation), so this matter is 'dark'." Which is basically what you said throughout the video. :D

[@lowersaxon]

This a preposterous way of adjusting reality to ( a completely flawed) theory. This is scandalous and a sign of the sad corruption of the science of physics. But: egos, pride, missing theoretical alternative, ‚back to aquare one‘ - horror, really. Therefore we will soon see the „detection“ of Dark Matter ( the fraudulent excuse) and a little later the „detection“ of „Gravitons“. You know why and I spare the effort here to explain it.

[@GiriGagan]

So dark matter is a place holder till we figure out what the hell is causing the mass discrepancy, yes? Also the assumption that the same physics laws apply in every part of the universe (not including the event horizon stuff) it is just an extrapolation of the geocentric philosophy that plagued us painfully for a long time. Unless we go and actually measure inside say m31 we won’t really be able to confirm our assumptions. I am not trolling. Just a curious nobody.

[@oAv3ng3dB055o]

@@GiriGagan Correct. In fact, the only way scientists can infer the presence of dark matter is via its gravitational influence which literally holds together most galaxies, preventing their constituent stars from flying apart as they spin. No dark matter particles have currently been directly detected, but the physical observations we make are real. It is possible dark matter is something else, like multiple states of unknown matter of forces caused by unknown phenomena. Most believe that because dark matter ask so much like normal matter and not like anything else in the universe, that its even less likely its something else.

[@GiriGagan]

@@oAv3ng3dB055o thank you for sharing your perspective.

[@AbeDillon]

​@@GiriGagan no. "Dark matter" is a term astrophysicists use to refer to a collection of observations that share one thing in common: they all deviate from what we expect to see in a way that looks like there's extra matter that doesn't interact with light. They're not referring to an explanation of those observations. They're not saying the deviations ARE caused by excess matter that doesn't interact with light. It's just a sort-of misleading *short-hand* for the collection of observations themselves. Those observations definitely exist.

[@lazyscholar7932]

An observation is not an explanation, so it is not a theory. Got it.

[@ravenlord4]

I understood the content of the video, and I loved your delivery of the topic.Please add me to the 60% crowd on your graph, and also posting for the algorithm, even if a bit late. Your video has aged like fine wine :)

[@vicenteherrera]

"Not a theory" sticker getting closer😂

[@joed180]

Gonna make a t-shirt. Dark matter: not a theory. String theory: not even wrong.

[@StephenLeaSheppard]

My dad's position on dark matter -- and he was very much an amateur science appreciator, a category of person you've mentioned in other videos -- was always that it seems like a systemic error to have to invent a whole category of matter you can't directly observe in explain a bunch of measurement discrepancies, but that was in the 80s and 90s before a lot of the measurements you've shown off here were made. I think you've firmly moved me from there into "Okay, it's real and it's something, even if we don't know what."

[@cookechris28]

Same, I was unconvinced, then it all added up. There are 2 rooms in a house we can see, but looking at math and measurements, we know there's like 40. No idea what's in them, what kind of "rooms" they are, or what their dimensions are, if they have doors or windows, any furniture, but we can concretely measure that there SHOULD be about 40.

[@algorithmgeneratedanimegir1286]

I agree with your dad.

[@ggwp638BC]

@@cookechris28 It's like the universe is committing a gravitational/mass tax evasion. It reports X, then we look at it's prior history and current spending and we find it should be at least 10X.

[@lattice737]

Yep, I also held your dad’s position and came into this video fully expecting to be validated. Instead, I learned something new and changed my mind

[@Duiker36]

This might help: dark matter is not a category of matter. She kinda zoomed by it, but didn't really explain what it meant: we *don't know* what "dark matter" is. The reason it's called dark matter is because it's the *cosmological definition* of matter. It's not a new particle. It's cosmological weirdness that we've observed. There's a reason it shows up on the pie chart next to "matter" and "dark energy". "Dark matter is a particle" is a hypothesis. It's the one you think you're hearing when scientists say "dark matter", because you think matter must be made of particles. But we have not observed particles. There is no evidence for particles yet. It is entirely possible that it is particles, but I don't swing that way. I'm not sure we even have a prediction yet. "Dark matter is a consequence of our equations being incomplete" is another hypothesis, which is the one I'm partial to. This one is basically that general relativity isn't perfect and it's missing some piece that we haven't found yet. You know, like how Einstein basically said Newton's laws of motion were incomplete. This is googleable as "MOND" which stands for Modified Newtonian dynamics. The problem with this one is that no one's come up with better equations yet. Those aren't the only two hypotheses, but they're the biggest ones, and there are lots of internal variations (since obviously, the simple version of both has yet to be confirmed). Also note that I'm not an expert in this subject; I just watch a bunch of science KZbins.

[@praecorloth]

Books on shelf. Home Improvements 1-2-3. Black Holes and Time Warps. I have no idea what kind of home improvement mods you have planned for your house, but I can't wait to see them. :D

[@robertcanup4473]

The properties of Dark Matter sound like Dineutronium. That is, two neutrons bound together by electron exchange between the two of them. It would be invisible, it would pass through regular matter, it would have a mass of ~ 2 Atomic Units and it wouldn't even react with nuclei like individual neutrons do. Experimentally one could try to find Dineutronium by cooling free neutrons down and trying to detect missing neutrons, while measuring the neutron decays.

[@Toxoplasmosic]

Neutrons are neutral, the electron would just fly away and the neutrons separate

[@hedgehog3180]

So to give an analogy, Dark Matter is sorta like how in the 1400s people around the world were perfectly aware of roughly how big the Earth was because they could observe it's curvature and make calculations based on that, but they didn't know what was on the parts they had yet to see themselves, they just knew something must be there.

[@sunnydlite-t8b]

You can not observe curvature. Where do you guys get your science information from?

[@TheArtiKle]

@@sunnydlite-t8bWatching ships disappear on the horizon is an example of observing curvature no?

[@nicholasevangelos5443]

@@sunnydlite-t8b They call it a horizon.

[@ironfist7789]

@@TheArtiKle thought they were being eaten by sea monsters :P

[@03chrisv]

​@perrystuart8035 Another dumb FE'er that doesn't understand math, science and denies all the evidence and technology that proves a spherical earth.

[@markTheWoodlands]

Dr. Collier, You have managed to address these topics in a manner that is simultaneously (1) precise, and technical and (2) delightful and fun. I really hope you continue to produce content, because you are exceptionally good at it. Also - your extensions to standard English are hilarious and self explanatory. I hope you continue to keep your edit mode set to ‘artistically scientific’.

[@crapsquire]

Sometimes I wish we could at least give 2 thumbs up. 👍 👍

[@literallyjustgrass]

Mr Moessinger, you have managed to write this comment in a manner that is simultaniously (1) showing how incredibly seriously you take your own mediocre writing style (honestly, dont try so hard, its kinda strange and makes you seem unsincere, just like, talk like a human) and (2) i dont really have a 2

[@eugeneplay9416]

This video stands out as timeless knowledge that has no expiry date. I watched this one and also the follow up and enjoyed them both.

[@NachinBombin2]

this gave me the feeling that dark matter at the end of the day , its not a theory, its just a list of observations

[@sumitaghosh615]

I’m about to get my PhD in wavelike dark matter (axions if you’ve heard of them) and I’ve been looking for good explanations of dark matter to send my undergrads. Thank you so much for making this - it’s exactly what I needed! Especially your explanation of Fourier analysis.

[@pandaman2840]

⁠@@DowJonesDave Arms in spiral galaxies are observed to rotate at the same speed regardless of distance from the center of the galaxy. However luminous mass decreases as you go further from the center of the galaxy. Therefore how is it this happens because of time dilation? Why do the arms rotate at the same speed even when they have less luminous mass? If time dilation is behind dark matter then why can we observe less stars, but they still have the same rotational speed. "Because time dilation makes them release less photons" ok but this still doesn't explain anything. Less photons overall still means we can see less mass further out from the center right? So why do the arms move at the same speed regardless of distance when we can observe them containing less stars. I'm so confused why time dilation matters at all when we can see with certainty mass decreases the further out you go. By your logic the arms aren't affected by time dilation as much as the center so they appear heavier due to the center having photons be emitted over a longer period?

[@pandaman2840]

@@DowJonesDave After googling things to get a better understanding of this I think I can refute this better. 1. We measure a galaxies mass in a variety of ways. Measuring light to get mass isn't the most favorable. Gravitational lensing seems to be the best method. So I must ask, have you looked into there being a dark matter curve for a galaxy we have calculated the mass through gravitational lensing? If so then how would they not have simply gone "uh guys this mass is weird from the observations, the middle is way more than it seems" and thus forming new ideas about your time dilation hypothesis. 2. Time dilation barely matters, as it'll be very small. GM/Rc^2 shows just how massive that galactic center has to be to even get near time dilation you're claiming. I'm talking egregious amounts of mass for that time dilation factor to take place to the point it explains away dark matter. Also why would this even happen? And wouldn't we see the redshifting of light as a result? 3. You don't fully understand time dilation. Time dilation is a result of a change in gravity. You're assuming the center of the galaxy must be so massive (again insanely large) that it's strong enough to cause alterations felt throughout the ENTIRE galaxy and VERY noticeably in the center. Does it exist? Yes. But to such a small extent it's negligible. It's not some linear thing that neatly ends at the tips of the arms and causes the galaxy to rotate uniformly, it is a negligible thing to an observer on Earth.

[@lissythearchitect]

@@DowJonesDave ' if time is dilated by 50% by the galactic mass' then we'd see much stronger gravitational lensing than we actually observe.

[@victorbukhaltsev9010]

I was so happy when understand fourier analysis as analog of linear combination in vector space but for functions before it actually was compared in a textbook long time ago.

[@rewar5870]

PhD in dark matter ? ...Axions (which don't exist ) ?? Dude , I would seriously give that career more thought.

[@tobias76]

Two things: you repeating the same phrases, bits, jokes, whatever, throughout your videos is literally one of my favorite things. Please never stop! Second, your explanation of BAO and dark matter's role in the early universe is the first time I felt like i at least got an understanding that i could hold onto more than 5 minutes after the video was over

[@nobody3622]

Can gravitational waves crash into one another and cause bigger waves like sound waves can?

[@kikakuvr4198]

Oh my. The Fourier explanation...you started simpler than I expected with the swing...and then a miracle happened and then psd...when I have to handwave through an explanation of FT and what they mean I usually use the example of a band or orchestra at a given moment in time with the decomposition allowing one to see what notes each section is playing...I can empathize with not wanting to go into details and getting stuck in the infinite recursion of having to explain an equally complex but dependent concept...keep being awesome, am a differently focused physicist and I enjoy your explanations!

[@gmansplit]

But if dark matter definitely exists, doesn't that make it a theory by definition, since in science a theory is the highest classification level?

[@acollierastro]

Dark matter is a thing we observe. The theories of dark matter attempt an explanation. Is it particles? Dark photons? Modified gravity? 1200 other ideas in papers you can find on the arXiv? Who knows. Any successful theory of dark matter needs to explain the observations in this video.

[@crapsquire]

​​@@acollierastro​ Thank you for that explanation. I am still wondering though if the ideas proposed to explain dark matter are theories before becoming established science or is it the case that theories are by definition established science. In other words if I am Darwin just setting out on the Beagle and I make some observations and then come up a with possible explanation, namely evolution by natural selection, yet there is not enough evidence to correctly claim it as a fact. Is it a theory or just an idea which when proven becomes a theory. So when the "reverend" says to Darwin "no, God did it by waving his wand", is that the God theory? Or at this point (before the evidence) is it that there are yet no ideas worthy of being called a theory. Sorry to belabor this, but I would say neither version of "theory" makes dark matter a theory, nevertheless they are 2 different uses of the word. Which of these definitions is the standard in science. Like you it appears I can't be short. Sorry, (and thank you )

[@ianhiggs]

The word you're looking for is "hypothesis." Hypotheses that withstand rigorous investigation without being disproven are elevated theory status. Evolution started as a hypothesis and through ensuing rigorous investigation/refinement was elevated to theory status. Religion/belief in gods would be essentially hypotheses that are mostly untestable (e.g., rely on psuedo-science or "faith"). The methods to observe dark matter would be what you need to investigate further to ascertain whether they are valid techniques. Then of course, other hypotheses to explain what dark matter is and why it can't be detected via most normal means.

[@crapsquire]

​@@ianhiggs I mostly agree with you. I didn't want to use hypothesis because I was concerned it would add further confusion. I'm curious though what Dr. Collier thinks.

[@megaing1322]

Would it be correct to say "dark matter is a question/problem"? Similar to the ultraviolet catastrophe: We know that our current methods don't explain the observations, so we need a new theory.

[@unfairleyc]

I really enjoy the conversational way you teach. It feels like I'm sitting with someone who learned something really cool, researched it, internalized it, and is sharing that passion and it makes me personally excited about it. I also really enjoy physics and science more broadly.

[@Blankphotograph5799]

Just diacovered your videos. I absolutely love them! Good work!

[@johnathanhenley2251]

I appreciate your videos so much. Please keep being awesome and producing videos.

[@DanielFoley75]

I love your channel. You make it look easy to make these videos but I know it must take many many hours. I am one of the people out in the public that reads a lot about science. I have an undergrad degree in Engineering Physics and your channel really takes me back. Oh and I also own a vintage oscilloscope. Mine is a BK Precision probably from the 80s. It still works. I repair vintage stereos and other audio gear as a hobby so I do use it occasionally to troubleshoot.

[@oscarfriberg7661]

This is the best video of dark matter I’ve ever watched. Or, I’m still completely clueless, but now I’ve gained more respect about the subject.

[@joed180]

But I will now walk around confidently telling people that dark matter is not a theory but a set of observations, but not to ask me about dark energy because I don't want to get into it.

[@RockyTremblay]

Angela’s explanation of why we know that dark matter is real, is crystal clear. Thank you Angela.

[@richsmith295]

Is the home Depot book useful?

[@xmlthegreat]

Depending on what you used to edit videos, there will be tools within the software to make audio sound acceptable. Right now, the audio is clipping. You don't want to increase overall gain, because that means the peaks cross the threhold of Max output for a device (0dB) and distorts into a noise. Instead you want to 'compress' the sound signal into a narrow-er range of amplitudes. E.g. in Adobe Premier, there is an effect called Multi-band Compressor in the audio effects section. There are a number of presets once you open up the options of this effect, you can try them out to see which sounds best. But it does send you down a black hole of audio engineering stuff, so be forewarned.

[@XxyGoddam]

It's great that people help out beginning KZbinrs to figure the technical parts

[@Bamdd5]

Using a compressor could cause distortion in the audio (depending how how much gain reduction you put in it). I think a better method for clearer audio is record the audio at a lower level so that there is no clipping on the input and you still have some headroom to raise the level while keeping the clarity.

[@XxyGoddam]

@@Bamdd5 true. And what do you say about those ai audio enhancing tools?

[@xmlthegreat]

@@Bamdd5 the recording level is usually automatic on devices, e.g. iphone. So setting a lower level is either not possible or not a good idea. The automatic gain control is fine while recording. She specifically mentions that she increased the volume in post, so a compressor is the best approach. It gets you most of the way there, just chaining it in series after a noise gate and/or noise removal and limiting the compressor output to peak at -6dB is what will deliver the best output.

[@xmlthegreat]

@@XxyGoddam it depends on which one you mean. Nvidia broadcast does a good job at removing noise but it makes audio sound like a zoom call. Adobe Podcast does the best job at taking a recording and making it sound like studio output, but it does the same stuff I just described above. I think it's basically running Adobe audition on the back end and the AI part is what tunes the effects instead of working directly on the audio, based on the output I got putting an audio file through both. I don't know of any other notable AI audio clean up tools.

[@gusgarrison9211]

"The argument degenerates; it's soon a bar room brawl." Thank for for introducing us to this glorious rap. I love the snark present throughout

[@dlrager]

This was one of the best presentations I've ever seen! I'm an amateur astronomer/astrophotographer and greatly appreciated your recognition at the end. I've been a science nut all my life. Today, as an IT geek, I still love to think about these topics and stay up on the latest developments. The way you explain things is genuinely amazing. This video helped me understand the "theory of dark matter" as an observation and terminology. I think the terminology is what confuses people. I've long had questions around this topic that I've never been able to truly find good answers. For instance, I've read a lot about MOND and that seems to be a better alternative to address the observations. Do you consider this as a potential solution? My biggest issue with the DE/DM theories is that we are unable to observe anything at the micro level to explain the observations at the macro level. But again, maybe the terminology doesn't properly translate. Now for my "crackpot" theory, lol. I've thought a lot about this and have read articles on things like "Warp Drive", etc. which talk about bending space on either side of a starship. This made me think that we really don't understand how to interact with space. We understand that spacetime is a thing, and can see how the presence of matter can "bend" it to explain gravitational attraction. At least, that's the assumption of how it works. I've also read about quantum theories on particles like gravitons that do this interaction, yet, no evidence has been found to support this. I've read about string theory, etc., which tries to explain some of this. However, what if we simply don't fully understand the nature of space itself? Is it possible that it's just a property of space that it has to expand much like a balloon in a vaccum where the fact that there's no barrier at the edge of our universe to stop it and it simply must grow to fill the void? Is there a difference between space and a void where spacetime doesn't exist? What if we treated space as a separate physical construct that doesn't require particles to explain? I've noticed that they are always searching for a physical particle to explain such theories but never seem to contemplate the notion that spacetime has more properties that are yet to be defined? Can the equations that use the values for DE/DM be used in such a way to explain these properties? The thing that makes this make sense to me is the variance in red shift for more distant objects and explains the observation that the universe seems to be expanding in all directions away from us while accelerating. Perhaps this rate of expansion can be quantified and used in these equations. So when you're calculating the spin of a galaxy, are you also allowing for this expansion of space within the galaxies? Have we measured the rate of expansion between objects within the Milky Way? It has to happen everywhere if it's true. We wouldn't see it within very close proximity of a gravity field such as us walking on the earth or even between here and the moon. It would be only very slight between objects closer to the center, but more noticeable on the outer rim where things are much farther apart. We should see stars in the outer parts of our galaxy sort of pushing each other away very slightly because of the distance of space between them expanding if this were true. Ok, I've probably outdone myself on the crackpot scale, but would appreciate any further discussion to better understand these ideas. If I'm totally off base, I'd appreciate that feedback as well. These are just questions I have that keep me up at night. Thank you!

[@williamloyd8606]

I'm one of the 60%. Commenting to bring up the average for the next time you pull stats and do analysis

[@jessisamess4062]

as an undergrad studying physics/astronomy i love how these videos combine great educational content with a fun conversational style that feels like a friend telling you all about something they're excited about. i'd also never heard a good explanation of the WMAP plot before, so thank you for that! also, thank you for introducing me to my new favourite song, the dark matter rap. P.S. the sound on this video sounded very good to me, definitely louder than before.

[@syddlinden8966]

I love the way you explain things. Tv talks about dark matter like it's this mysterious, invisible stuff, and you do swiftly demistified it. I love this. And the actual science is so much more mind blowing and cool than mystifying it.

[@norsanh3010]

Have you checked out the Janus model ? I find it interesting but I can't understand the maths behind it but it's giving good predictions

[@winterhtech]

As a lifelong lover of science, thank you for making vids and extra thank you for part 2

[@matthieuhenocque7824]

I wish KZbin had more "amateur" content creators like you. Dang your video are pleasant to watch. Thank you very much Dr Collier.

[@5ben2]

Thank you Physics Mommy

[@ninadgadre3934]

Damn I feel old now

[@stevesherman1743]

The WMAP background radiation plot has different coefficients for each of the 12 sections of the sky. Can you explain the need for that and why those coefficients vary so wildly from sector to sector ?

[@timmo971]

Was this recorded on a rainy day? Or do you have a cosmic background soundtrack maybe?

[@phoemma]

As a second year chemist in uni, your videos are always fascinating. Thank you for illuminating other areas of science to the world!

[@tractordude234]

In science, theories are the most advanced and reliable explanations, but they can still be subject to revision based on new evidence or insights.

[@trvrshoe4518]

lol, that's what confused me about this title and opening lines of the video

[@michaels4340]

Yeah, dark matter is a theory in the same way that gravity is a theory!

[@tractordude234]

@@michaels4340 I think the point of her video is that dark matter is a thing like matter so it's not a theory.

[@michaels4340]

@@tractordude234 yeah it's a difference in terms between how scientists and the public use "theory"

[@conchobar]

Except the theory of gravity consists of empirical evidence, while dark matter isn't much more than a mathematical construct.

[@erin-rt6vn]

at 26:20 you said the cmb is from when the universe went from radiation to matter dominated - isn't it from recombination which was much before matter-radiation equality?

[@billyt8868]

10:40

[@chrisworthington9296]

What a smart, fascinating, appealing person! One of the best physics explainers I've encountered on the net, too. BTW Angela, your apologetic summary of fourier transform was actually very good for the scant time it needed. You deserve to be very happy.

[@Sheggies]

I love your crackpot compass and your genuine appreciation of the amateur science quadrant! A rare occurrence of YT's algorithm suggesting an actual informative video, produced by a knowledgeable, competent, and kind individual 😊

[@alexanderkonczal3908]

String theory researchers: "what if there's a mean fairy that decides what each fart sounds like, and it changes each person's sphincter as they pass gas accordingly?" Dark matter researchers: "someone farted. I don't know who, but I heard it, and I can smell it. I'm not going to rest until I find out who to blame."

[@nonyadamnbusiness9887]

It's an observation of nature not acting in accordance with our current understanding of gravity. Got it.

[@dotprodukt]

Second time watching this video. Just wanted to say as a big fan of Fourier analysis, I think there is much people could benefit from developing intuitions on seeing the world in the frequency domain. It is certainly not an easy perspective to translate to the general public and I think any attempt at all is worthwhile even without the math.

[@michaelblacktree]

I'm usually not a fan of repetition. But you did the "repetition for effect" thing expertly. Two thumbs up. 👍👍

[@Trollificusv2]

I thought the repetition was necessary and effective. As a nearly innumerate ex-English major, I had early on formed the idea that "dark matter" was something that existed in, or was predicted by, some kind of cosmological theory and that wee couldn't find it in our mundane observable universe. Instead it's what she said. Repeatedly.

[@FuzzyPanda53]

I need an 18 hour Fourier Analysis video. But more seriously you're so good at science communication. Please keep it up.