All the evidence we have for dark matter | A century's worth of science history

[@jwardcomo]

This lady has an extraordinary gift of clarity. I have about 10 astronomy books and she blew them away with a 30 minute You Tube video!

[@776281]

On reading your comment my first thought was that wasn't anything like thirty minutes. And yet it was only a few seconds short, 30 mins flew by.

[@georgesheffield1580]

The PhD is why

[@chloewebb5526]

Im super big on history, so seeing something like the histories of these discoveries organised into such a comprehensive video is so satisfying! Most people only hit the high notes when describing the history of discoveries. Thank you so much Dr.Becky!💜

[@duckrutt]

You might enjoy The Discoverers by Boorstin.

[@MrToastercide]

Me and my wife have a Joint bank account.. There is always less money than I expect in there. My wife calls it 'Dark spending' and says that it can not be investigated by normal accounting procedures.

[@Scorp7867]

Lmao

[@TrickOrRetreat]

Hahahahaa 🤪😋🤘👍

[@UltimateBargains]

That seems to violate the First Law of Financial Dynamics.

[@Jens.Krabbe]

@@UltimateBargains That's because it's the first law of Marital Dynamics :-)

[@ole555]

I think I know what you mean. Thankfully, I have no wife; Once I was proposed one, but it turned out the proposition entailed the spending of money in exchange for promises of great prosperity and prestigious achievement pitched with reassuring, plausibly sounding modeling which is never actually born out in reality. On a totally unrelated note, modern astrophysics is great, isn't it?

[@timbeaton5045]

"...designed by Henry Ford...!" You can have a hole in any colour, so long as it's black!

[@61O_42]

lol!

[@irrelevant_noob]

TBF, Tim, she never said "Henry..." (14:22) But otherwise your comment fits quite nicely. :) LE: oops, never mind... i hadn't gotten to 28:55 yet. :">

[@Earwaxfire909]

The history of modern astronomy is captivating. You've done a hell of a good job getting all of that together. Thanks Dr. Becky!

[@boudicawasnotreallyallthat1020]

Dr Becky looks, and sounds like, a sex therapist.

[@ffggddss]

@@boudicawasnotreallyallthat1020 The channel you want is "sexplanations," with Dr. Doe, not Dr. Becky's channel. We do serious astrophysics here. Not to knock Lindsey Doe - she's good, too, at what she does. Just very different. Fred

[@MrLaptopus]

History of astrophysics is a bad joke

[@RWin-fp5jn]

Well, don't thank Becky too soon :-). Dark matter is a misnomer. Scientists should have called it 'Dark Gravity' in stead since that's what it is: an not understood gravitational phenomenon. By calling it dark 'matter' it implies scientists would already know what it is: some form of missing matter. Unfortunately it is not. There is nothing mysterious about the extra gravitational component of mass, we just did not understand what gravity is until recent. A recent study was very clear; Gravity is the emergent longitudinal spacetime contraction effect caused by MOVEMENT of mass, both within restmass itself (subatomic particles spiraling around core of atoms) as of the macro object itself moving in spacetime. This longitudinal spacetime contraction is in effect what Einstein (Lorentz) already described as 'length contraction in special relativity'. Also the gravity produced by each atom is longitudinal in nature, yet due to the many unaligned atoms and 'electron' planes, it only appears radial to us. Einstein's GR thus is only the mathematical approximation of this collective radial ST contraction appearance. So the fast moving stars at the outer end or our galaxies have this extra orthogonal ST contraction (gravity) effect, holding on to each other effectively. This is the explanation. There is no dark matter, we just did not get what gravity was....problem solved....anything else Mrs Becky?

[@kapoorh]

Would you say the same thing if the videos were made by some intelligent but ugly dude? 😄

[@toucam]

So much work went into this video it's actually insane. This is worth so much, and available for free, thanks a lot Dr. Becky! (I know I'm three years late on this, but there's no better time to learn than the present)

[@Veptis]

This channel is growing by your passion. You had multiple appearances on TV and now even some awards. Glad you keep the Science up.

[@Anthro006]

Beautifully clear, succinct and relatable history and narrative! Thank you for an amazing job and for sharing!!

[@DrBecky]

Thanks Lloyd 🤗

[@light1531]

Anyone that has done presentation, especially some kind of public presentation, will be in total awe of your approach and clarity. I agree fully with Lloyd.

[@AndrewHillis_2024]

​@@DrBecky Does Dark Matter REALLY Matter Dr.Becky AND If So WHY ? ? ? I Am VERY Curious To Know WHY Dr.Becky ? ? ?🤔

[@stefanhennig]

I thought that whole Dark Matter issue had already been resolved by Douglas Adams who stated in one of the last HHG volumes that dark matter is merely the left over packaging material from when the universe got installed. According to my personal experience, the observed ratio would be about correct.

[@John.0z]

Wouldn't that depend on how thorough Magrathea was about their packaging of new bespoke planets?

[@Jens.Krabbe]

@@John.0z Yeah, but DNA never revealed that ratio.

[@gabrielbelouche3954]

10 times more package than product it must be delivered by amazon

[@jackkomisar458]

Check for dark peanuts.

[@erichodge567]

I love these "How do we know..." videos that give us an historical overview of a specific question in physics. Thanks for making them.

[@matthewrowell8518]

Couldn’t agree more. Some things I just took as fact without giving due appreciation to the efforts of so many to get to what we know today.

[@ledzep331]

Love your vids and this is by far the best. Please do more like this, with the historical trail (and blind alleys) that leads to the point where we are today. It really helps to understand why the currently held best theories are what they are. It also gives a good feel for how likely it is that the theory is in deed correct, great for people (like me) with minimal specialist knowledge.

[@Nyruami]

The problem is, there is no theory on dark matter. Somehow Becky forgot to mention that we do NOT know and all we have are mere hypotheses. We know that there is more gravity than we can account for. By itself, this means absolutely nothing. Either there is some form of spooky invisible matter that somehow manages to be only "out there" which is a bit weird or it´s only our understanding that is flawed, which would be way less weird. Let´s just remember Ptolemy who had a perfect working model of the solar system with earth at its center, with formulae and everything you need to be called a theory. His model was the accepted truth for over a millennium and it was completely wrong. Given that fact and the fact that all we "know" about the universe are at best good guesses, it´s more than just a little bit arrogant to claim that an observation "has to be" something special just by ruling out some other explanations as if we had the full understanding about everything in the universe.

[@myra_gee]

Woah! You explain this very complex topic so well! I have a few assignment questions on dark matter and this not only helped me answer them but it helped grow my interest in dark matter.

[@Yamo314159]

"Do you mind? I am trying to prove Dark Matter." Thank you

[@gammaraygem]

@@RampagingCoder watch david lapoint the primer field series kzbin.info/www/bejne/qpnIh2iYa7dghMk he is at odds with some of EU theory, but still compelling stuff , showing dark matter isnt needed for explaining galactic formation

[@SernasHeptaDimesionalSpace]

A dna photo shows entanglement, it shows we might not need it.

[@bazoo513]

Amazingly well narrated, Dr. Smethurst! You make this piece of scientific history sound like a good crime story, and your enthusiasm is contagious.

[@Skukkix23]

I just love that a scientist straight up quotes a movie about christmas

[@rylian21]

Scientists don't pop into the world fully-formed. In their larval state, they begin as simple nerds.

[@John.0z]

@@rylian21 Or "not so simple" nerds. I think I was deemed a "simple" nerd when I emerged from my larval state, but I am NOTHING like the good Doctor! So my nerdishness was, perhaps, just simplistic?

[@liammcguinness5465]

I don't believe in Santa ,so where do all the gifts come from

[@Skukkix23]

@@liammcguinness5465 china

[@falxonPSN]

It's all good. Inspiration can come from all sources, both real and fantastical.

[@richardgreen7225]

re: "Dark Matter" - Suppose inertia is relative. F = m a = G M m / R^2 ==> a = F / m = G M / R^2 - Suppose it is not M that is relative to R but m (inertia). The Dark Matter conjecture proposes that the anomalous (lack) of centripetal acceleration is due to M being bigger than expected. But it could also be that small-m (the object's relative inertia) is smaller than expected. So instead of modifying Newton's law, perhaps we should be modifying Mach's. This idea could also explain the effect we call "Dark Energy".

[@joen0411]

Dark matter is like raccoons. I don’t see them but I do see the overturned trash cans and garbage all over my yard every morning.

[@jerryjohnson6810]

damn fine analogy

[@davidschmale3359]

Maybe you’re a sleep walker

[@YodaWhat]

Giant, mutant *_SPACE RACCOONS!_* Oh Nooooo!! When does the B Ark come?

[@djschultz1970]

Excellent analogy. Better than the current one I use to explain it which involves trying to determine the source of a really smelly fart that nobody will admit to. :)

[@Dadecorban]

Yeah but how do you know that the trash cans don't just act differently at the distance from your house to the curb? (Modified Newtonian Trashcan Dynamics)

[@Me-vz1rl]

I appreciate a lot that people like you with a profound understanding of the topic, take the time to share reliable information on science :)

[@a13Banger]

Wow, I can't tell you how happy I am that I found your channel a few weeks ago.. Yours has been my absolute favorite channel to listen to while working and driving.. I love your enthusiasm and clear love for the subject matter and the ever present references to modern culture like Game of Thrones. I will absolutely be picking up your book. Dr. Becky, you complete me. :)

[@astraldreamhead193]

Dr.Becky You rock! I am so excited for your research, and appreciate your videos so much, I am so glad there is a resource that breaks this down in a manner I can really wrap my head around, thank you

[@jamiewallis2797]

I love audio books. I will definitely be getting yours Dr Becky.

[@spideythekd]

I am super glad that I came across your channel. it's overwhelming to see the types of content that you make. Thanks a lot for all that time you spare to educate us with your knowledge and experience. Thanks for this channel once again.

[@DrFrank-xj9bc]

very good summary. I was not aware up to now, that Dark Matter had been in discussion or in assumption to exist that long.

[@martinvllk]

What a nice surprise to mention Einasto and his group. We here are very proud of his accomplishments and he has made astronomy, astrophysics, cosmology a very popular subject in a whole society and has inspired a lot of people to choose this as their main subject. Thank you for a fair overview!

[@amonw1994]

allready bought. you narated it? double the joy . i listen to your videos to get myself to sleep. ( insomnia is shitty) your voice is so calm. but positively energetic.

[@Mortico88]

I use Matt Odowd from space time to put my 7 year old to sleep (bonus points if he retains anything).

[@DrBecky]

I use ASMR to get to sleep. Perhaps one day I'll do an astrophysics ASMR 😂

[@amonw1994]

@@DrBecky wow. thanks for replying. if the time comes , i will be there to get/buy it

[@fityou12]

I love you too Dr. Becky. I’m an electrical engineer who loves astronomy as a side interest. This video sums up all the proof in 30 minutes why science really considers dark matter to be pervasive unknown ‘stuff’ that we can’t sense, instead of just being intergalactic cold ordinary matter, black holes, dim stars and astronomical bodies that can’t be seen. Wish I’d have seen this video 10 years ago; maybe save me some time pulling out hair. I especially liked the explanation of rotating gravitationally bound matter that isn’t distributed like our solar system (with over 99% of its mass at the sun’s center of gravity) doesn’t follow Keplerian motion. I see they don’t give out Phds unless you’re REALLY SMART. You’re a great communicator! Super videos!

[@deeiks12]

Can't wait to listen to the book. It's great that you narrated it yourself!

[@splank3]

Best take on Dark Matter I've ever seen or heard. Thank you for all the background, and your enthusiasm is contagious, thank you Dr Becky!

[@condorboss3339]

Have you attached a blooper section to your audiobook? ;P

[@willinwoods]

Well that would be a USP, right there.

[@DrBecky]

Condor Boss Next week’s video is essentially just that

[@MrAnibl]

Bloopers are like dark matter they are there but edited out.

[@biomechanique6874]

@@DrBecky The error is in the formula used to calculate galactic mass. Galaxies are bound by a gravity matrix of exponentially variable density, meaning that every single particle in the galaxy is bound by the entirety of the rest of the galaxy. The gravitational density (therefore concentration of mass) increases exponentially nearer the centre. Density of galactic matter at its maximum at the core of collapsed atomic particles in what science calls a black hole (that much at least I'm sure you already know). As an aside, what modern science doesn't account for in black holes is that the collapsed atomic material will only compress so far before it will compress no further - in effect sub atomic particles are non-compressible. Much of Hawking's work is based on erroneous assumptions as is that of most of the quantum physics crowd - phenomenal accumulative error! Dark Matter doesn't exist.

[@TheMarrethiel]

@@biomechanique6874 show me your peer reviewed proofs. Personally, I think that DM exists, if I was going to say it wasn't I'd prefer (as the universe cares about what I prefer) that it's proof of a simulation. The coders that made the universe didn't put enough detail in the universe to make the math right. "Say Jim, you know that galaxies make no sense, right"" "Sure thing Sal, but they look cool, right?" "Yeah, they do actually, especially that cool lensing thing you have going." "The rubes'll never figure it out." The other reason we need Matter Obscure, is we need some kind of exotic matter to power our FTL drives!

[@theastronomer6259]

You have done it again Dr. Becky. I am a 13 year-old amateur astronomer from Rwanda, an African country. You are an inspiration.

[@DrBecky]

Thanks for watching - so glad to hear you enjoy my videos 🤗👍

[@TheWTZ1983]

Great video Dr Becky! Now, a little bit aside of the science and the Universe, I would like to say, that I really like "the music" and "the flow" of your language, it sounds and feels really nice for my non native ear :D Have a nice evening... ;)

[@roypatton1707]

I will never understand how anyone can take this much information and organize it in a way that it makes sense to anyone. This is a great video, you are a great teacher, and I appreciate your efforts. Oh, and I will be buying your book.

[@-yeme-]

Despite your efforts I bet there will be people in comments doing the "scientists just totally made up dark matter because they don't understand anything" routine, closely followed by the "despite having no background in any related subject and having made no real effort to understand the material particularly when there's any maths involved, I've decided I know better" shtick.

[@davidschmale3359]

Math is a superset of reality, be careful, you can be brain washed by mathematicians.

[@boggers]

@@davidschmale3359 What a great turn of phrase. Just to fulfil @yeme's prophecy... Personally I think given that GR breaks down at singularities, and the known universe is riddled with singularities, it is far more likely that the "next Einstein" will come along and do to GR what GR did to Newton, long before anyone ever detects a WIMP.

[@Ni999]

I just hope you are satisfied with what _you_ started.

[@murraymadness4674]

Some of the most innovations come from people 'outside the bubble' of conventional wisdom.

[@duncanwallace7760]

it's very mundane, but I don't understand how relatively un-dense gas clouds can stay hot in space, which is very cold.

[@francoislacombe9071]

French being my first language, I can say that "matière obscure" can be translated directly as "dark matter"

[@noxabellus]

Really?? Sounds like it would translate to obscure/d matter

[@Ni999]

Everyone serious about the history of photography probably knows that obscura is Latin for dark. _Introduction to the Camera Obscura - National Science and Media Museum blog_ blog.scienceandmediamuseum.org.uk/introduction-camera-obscura/

[@georgeholloway3981]

But her pronunciation isn't quite right, right?

[@MegaSpartan007]

As a French, she sounded more like trying to speak italian or latin then french. But don't worry, Dr Becky, we forgive you. :D

[@olmostgudinaf8100]

I found her pronunciation of Jansky in another video quite funny too. But that is kind of expected from a native English speaker, so it's OK ;-)

[@moorsum]

Congratulations on the audio book!! Awesome news! Love the channel 💛

[@TomLeg]

Love the pic of Dr Becky pre-kindergarden

[@KarlBunker]

Clearly she was full of enthusiasm about the universe even then.

[@kikufutaba1194]

Just because you haven't seen it doesn't mean it's just one thing and not a combination of things. Much like a constant in an equation, it is what makes the formula work thus it has to be correct even if it isn't. I love your channel. You are a wonderful enthusiastic presenter and my favorite Dr. of Physics by far.

[@larsgottlieb]

This was on astronomer Jan Teuber's office door at the Brorfelde Observatory: Twinkle twinkle quasi-star Greatest puzzle from afar How unlike the other ones Brighter than a billion suns Twinkle twinkle quasi-star How I wonder what you are

[@soup4865]

this is underrated

[@FUnzzies1]

I love that an audio book is actually read by the author. Finally everything is pronounced properly!

[@mikebrown354]

Are we just going to ignore the name "Lord Kelvin" @2:29 I mean .. what a bloody cool name yeah?

[@irrelevant_noob]

*title

[@alainmaury5941]

By far, one of the best video on dark matter, how it was discovered, lots of references, very detailed. Thanks a lot ! Congrats !

[@davidgover5187]

How do we know that we got the mass of the visible stars correct?

[@joyl7842]

The idea that we don't fully understand gravity is definitely one I favor. It just makes sense to me that we don't yet know everything rather than there being 5 times more stuff out there we cannot detect in any way apart from its gravitational effect and know nothing about.

[@Vergarecords]

It should be called Ghost Matter - I vote we start calling it Ghost matter after(or on) October 31st

[@Dragrath1]

There are so many things in astronomy and well science in general that could have way better names. Ghost Matter would be far better but alas....

[@jmerlo4119]

Constructed Identity - Good idea, for if there is, that is what it is. Lol

[@Dragrath1]

@@jmerlo4119 That assumes we can ever conclusively determine what it is. Unfortunately there is a real possibility that potential dark matter particles don't have any reaction with the weak or strong forces(which is what dark matter detection projects rely on the hope of) in that case gravity would be the only way to detect them assuming it is a particle. The particle model is currently the simplest possibility as it requires the least assumptions but yeah we may never know unless nature decides to throw us a bone so to speak. Whatever it is there does seem to be some indirect evidence from the Early universe that it both exists and can exchange heat through some means which if true maybe it isn't a hopeless endeavor after all but as always I'm skeptical.

[@jAfr0Thunder86]

HI Dr. Becky I found your videos via your "don't look up" video. Nice. I'm NOT a scientist, I am an enthusiast. I'm getting caught up on your Dark matter videos. This one, the "new evidence" form Jan 2021, and the "Smooth or clumpy" in June 2021. My unsupported theory is there is no dark matter, just micro black-holes, or quasars that have spectrum shifted (possibly in the UV direction too, no idea why), that cause the mass and lensing that's been observed. I'm excited to see where the videos go, and I wonder if we'll ever figure it out in my lifetime. Cheers!

[@TArnoldFerguson]

You mentioned the "Red Rising Saga" by Pierce Brown at the beginning of this video. Are you familiar with "The Expanse" book series by James S.A. Corey (the pen name of co-authors Ty Frank and Daniel Abraham)? It's a series of nine novels (8 have already been released), and is a TV series now on Amazon Prime Video, It has been described as Game of Thrones meets Battlestar Galactica, though personally I think it's better than either of them. It is know for getting the science right - mostly. They do take a few (very few) liberties for dramatic effect (e.g., sound in space), but no warp droves, shields, artificial gravity, etc., and is set a couple of hundred years in the future when humans have colonized the solar system. The first three seasons are now available for streaming; season 4 comes out Dec. 13. Some folks feels it starts "slow" and takes 4 - 6 episodes to get "hooked." You night find it interesting, and each episodes is on about 45 minutes, since they were originally made for the SyFy channel.

[@poppypuppy5372]

So a thinking self replicating molecule that constructs warp gates isn't taking liberties?

Poppy Puppy nope, neither is "the slow zone" with changes to the laws of physics locally. It's still an awesome books series though 😊

[@TArnoldFerguson]

@@poppypuppy5372 I did say they take a few.

[@malik_alharb]

I love Dr Becky's enthusiasm

[@DrBecky]

Thanks Malik 🤗

[@lenin972]

Would love to hear some bloopers of your recording your book ;)

[@DrBecky]

Welllll then you’ll be very happy next week

[@lenin972]

@@DrBecky I'm always happy when you release a video. This one was great by the way, very comprehensive history of dark matter. One cannot avoid being in awe by the amount of thought and work put into these discoveries.

[@koln2109]

I don't know if you've made it already, but it'd be good to see a video about all the problems with dark matter, from how all experiments to detect it have consistently failed to the various observations that cannot be explained by it.

[@mattmccullough5104]

"Brief" introduction to chapter four?!?! Damn Becks, don't give the whole book away! 🤩

[@DrBecky]

There’s a lot more in the book - it takes a more meandering route 😂

[@BTRAXX]

Thanks for the effort you put in to make Astronomy fascinating. Nuff respect. One Love!

[@m00niee]

NOTIFICATION SQUAD ASSEMBLE!

[@Jehannum2000]

The term "dark matter" is fine. The resistance to its acceptance is because it's adding another assumption, which goes against Ockham's razor. Everybody's hoping scientists will come up something that doesn't need additional assumptions.

[@lnchgj]

Doesn’t dark matter presuppose that we know exactly what gravity is, exactly how it works, and have an accurate model for its behavior. Since we don’t, isn’t the more reasonable (Occam’s razor) answer that we don’t have a theory of gravity that explains what we see? Or have we given up trying to understand gravity because it's too hard?

[@Jason-gt2kx]

I study dark matter and this was the best comprehensive video I have seen. Great job.

[@JaSon-wc4pn]

Any updates ?

[@marcoschincaglia]

like then watch

[@dipi71]

As soon as Linux is supported by any major audiobook platform I will listen to your audiobook! Cheers!

[@Dadecorban]

What if dark matter is actually souls? I'm just kidding. These videos always have this comment.

[@Dadecorban]

@Just Looking lol. It was 1000% a joke because there are always idiots that say that in dark matter and dark energy video comments.

[@TanjaYouAreMyLove]

@Just Looking If something is in watts its per second as second is unit of time in SI system. A light bulb that has 100 watts power rating is using 100 watts per second. U re maybe thinking about price of electricity that is often shown as price per kwh (kilowatt hour) lets say 15 cents for kwh so u think it should be in hours but its in seconds.

[@jimmyshrimbe9361]

It's really cool that you narrated you own book. More authors should do that.

[@christinearmington]

William Pullman does an amazingly good job reading His Dark Materials, along with outstanding character actors.

[@peterq1978]

dark matter is the astronomy equivalent of cats, its pushing everything away!!

[@pioneer_1148]

That's dark energy, dark matter attracts stuff gravitationally

[@johntaylor1102]

There are cats in space?

[@Telesto13S]

Are you sure you're not thinking of "Dark Energy"?

[@jerryjohnson6810]

sounds like my ex lol

[@dietmarkrah5319]

Thank you for this thorough walkthrough. You are truly one of the most astonishing accumulations of baryonic matter I have ever seen.

[@tim1883]

We don't know Dark Matter exists! We do know there are gravity wells, or something that acts like gravity, that we cannot account for from what we otherwise see. Something is keeping galaxies from collapsing and produces gravitational lenses. The only thing we know that does that is sufficiently dense matter. That however does not really add up to "Dark Matter".....yet.

[@RedRocket4000]

They cheat the Definition of Dark Matter includes any answer that does not have matter in it. Same with Dark Energy any answer even those without energy are still Dark Energy.

[@substantivalism6787]

@@RedRocket4000 The definition of dark matter is matter that we cannot see or is dark. This includes all of the known standard model of particle physics as well as more exotic entities not known to exist but hypothesized such as micro black holes, weakly interacting particles, and matter that doesn't react with electromagnetic fields.

[@russellbarndt6579]

It should be said , you have a wonderful way of saying "the what" then the explanation for a interested untrained person to have a chance to grasp "the how" . Thank you my good Lady !

[@DrBecky]

Thanks Russell 🤗

[@kathyfausett9301]

Oh--dear--what can the matter be? Try plasma.

[@ExistenceUniversity]

The known 5% of the universe is 99.9% plasma. We know it is not plasma.

[@kathyfausett9301]

@@ExistenceUniversity I suppose that you KNOW that dark matter exists as well?

[@ExistenceUniversity]

@@kathyfausett9301 In the sense that I know I can measure the mass of a galaxy and discober that the plamsa and baryonic matter doesn't account for the whole mass that some "dark" weighted object (i.e., mass i.e., matter) must exist, regardless of in which measure it exists.

[@kathyfausett9301]

@@ExistenceUniversity Is that a YES or a NO?

[@stargazer7644]

@@kathyfausett9301 Dark matter doesn't emit light of any frequency, it doesn't absorb light of any frequency, the only evidence we have that it is even there is gravitational interactions. It can't be plasma, or any other type of baryonic matter. It is something else.

[@Vicorcivius]

It blows my mind just how so much of what scientists say they know exists is actually nothing more than guesses and speculation. There is nothing wrong with guessing and speculation when you are honest about it.

[@ExistenceUniversity]

Its not speculation or guessing. Its interpreting real from data.

[@Vicorcivius]

@@ExistenceUniversity Please try to make some sense.

[@StasiSLG]

maybe it's a stable form of compressed/condensed space, or its from a remnant from a Universe before ours...

[@freeman2399]

That's my theory too. The way I envision it is if you think of space time as a 2D fabric, but the fabric is not Isotropic, IE some parts of the universe have been "worn out" or "wrinkled up" and when this happens seemingly empty space can have gravity, or anti gravity, properties. Basically gravity is not the sole domain of Matter and Energy, but empty space can itself have inherent gravity.

[@StasiSLG]

@@freeman2399 Kinda the same as I envisioned it. And my other imagination based theory was with the example of when you make cake and you have leftover eggshells, the cake is done.. But the eggshells remain yet their are not needed anymore for the cake to continue existing, they were needed in the initial creation process.

[@frederickwoof5785]

May be lol. It's gravity effects from another anti universe. Like in the 'brane' theory, all the gravity/matter in our universe affects the universe on the other side of this brane. And vice versa. Like one universe 'pushing' into another. Just gravity with no matter.

[@StasiSLG]

I wondered If no new energy can be created where does all the new extra space is coming? If space is expanding then does one see it as ballooning or continuing to silently invisibly big banging here and there. Space is weird, so are my neighbours.

[@awesom1awesom13]

Dr Becky you explain things in a way that makes it exciting to learn more about how the universe works....THANK YOU

[@Problembeing]

Start off by finding it first. No matter how good your mathematical recipe, if the cake doesn't rise, it's wrong.

[@IamGrimalkin]

Of course, you can say the same thing about MOND variants.

[@Problembeing]

IamGrimalkin well... All laws are man made, and after 300 years perhaps it's time to re-evaluate things that are taken for granted; seeing as physics is at a crisis.

[@IamGrimalkin]

@@Problembeing Yeah, of course. All I'm saying is, MOND has had similar problems to evidence not turning up as the WIMP solution does. One that seemed particularly prominent to me is that almost all relativistic versions of MOND predicted that gravitational waves would not be affected by Sharpio delay coming out of galaxies (unlike em radiation), but the LIGO results have shown that the light signal and GW signal come at the same time, so they most both have undergone Sharpio delay. What would be helpful for more people to take MOND more seriously would be for MOND models to predict something that gets confirmed, rather than predicting something that gets found to be untrue. Also, in general, MOND models now consistent with the evidence from e.g. the bullet cluster mentioned here still require some dark matter to work, just less of it (but the idea is, it lowers the amount of dark matter needed enough that it could be baryonic matter rather than something more exotic). So the baryonic dark matter needed for the theory to work would still need finding, in the same way conventional dark matter theories need to find WIMP dark matter or whatever.

[@Problembeing]

IamGrimalkin thank you for your reply. I'm sorry - I just do not accept this ad hockey of adding whatever amounts of 'dark matter' required to make a model work. It's gone from 98% to 95% to 68% currently. All of these problems ensued when Einstein cut-off aether at the neck. It's been anathema ever since and I think we've been paying the price for it. The irony of creating this exotic matter is that it is acting precisely as a surrogate for aether in the first place and I predict one day it will be anathema as today's current mob treat aether. I do not see how one is considered so utterly incredulous whilst the other (seemingly far more ludicrous) is almost accepted as a given without absolutely ANY physical evidence. It's all pervasive to work but gradually less pervasive than we need it to be... Do you see how unconvincing that sounds? Before going ad hoc looking for new particles; new physics; black this; dark that, surely - it is in our best interests to take another look at Einstein's peers that he and his acolytes dismissed into obscurity. The idea we may have 'missed something' before 'thought experiments' and mathemagics were interpolated over actual physics seems to be of the highest pertinence today than ever. Physics is stagnant. There are no new advancements and everything is at least a 100 years old without 'allowed' revision and the peer system is corrupt and outdated. Like any institution that goes unchallenged for too long, it becomes fat, lazy, arrogant and useless, and I think WIMP is about as desirable as it gets and that's depressing.

[@Problembeing]

IamGrimalkin sorry for ranting.

[@philiphurrell5872]

Newton discovers gravity and writes 'accurate equations' a few hundred years later Einstein re-writes them while Newton can still be used, Einstein is an improvement. Sounds like we still don't fully understand gravity, but rather than re-write it again we 'invent' something that we cannot see, measure, or describe. I'm definitely for exploring different gravity equations to explain what we observe.

[@hibiscus779]

Could just be haphazard coding of the simulation

[@arpeggioblue]

Ah yes, cause we all know how wonky those silly little simulations were back in the 1880s...

[@hibiscus779]

@@arpeggioblue kzbin.info/www/bejne/qp23fIeKqZlqjac

[@arpeggioblue]

Hibiscus oh, that simulation

[@keithalexander6154]

Dr Becky this is a really excellent summary, thank you so much. Your channel is always great but this is one of your best yet.

[@tfsheahan2265]

Despite the unbelievable amounts of grant money spent searching for it (the single largest employment of physicists going), the fact that it still hasn't been found should tell us there is something fundamentally incomplete or wrong about our assumptions. Maybe gravity isn't a fundamental force, for example, but an emergent property of some other thing(s). Maybe those other dimensions of string theory actually exist, but they can't be sensed by ordinary scientific instruments.

[@andyroo777uk]

Thank you, you and Neil Tyson are my favourite people to listen too, both so excited about their work

[@angrybeluga1697]

Excellent piece. I appreciate the lucid explanation of what dark matter isn't. Thank you!

[@americanenigma_5108]

Can u make a 2-3 minute video of this while explanation ! I mean as a general viewer i would love to see someone explain everything in simple and shortest possible way , otherwise it’s so long and hard to focus and ünderstand

[@aaronstonebeat]

Dear Dr. Becky, I admire your work. I tune in regularly for updates. One question: I thought I heard you say 'ek cetera' in stead of 'et cetera' at some point (and I have heard this elsewhere). Did I hear this right and if so: why? Forgive my linguistic curiousity and best regards,

[@DrBecky]

I’m going to blame my northern English accent for that one 😂

[@ArveEriksson]

I thought music composers had, uh, awesome names, then enter: Fritz Zwicky. Science, *the competition is on.*

[@bradmoyer9737]

Your presentation of the historical chronological timeline of the discoveries that led to our current level of knowledge of the universe was eye opening and understandable for a non science person. Please add a link to your new audible book. Very well done!

[@z-collector7518]

"How do we know dark matter exists?" There is a big difference between knowing and assuming. The reality is we don't know, we only need it for the mathematics to work. It doesn't mean the concept is reflected into reality. Maybe we are way off - that's what I think. "Frame dragging" is more plausible in my opinion.

[@mrr5835]

A very well explained video. Nice work. I'll keep my eyes open (ears open?) for your audiobook as the US release. As we learn more about the possibilities of interactions with other dimensions (through theories on virtual particles, etc), dark matter could be beyond the 3rd dimension, and thus, really tough to see? 🙈

[@zengalileo]

This is such a great show! So fascinating.

[@gregcoree2]

Small point but I think dark matter is a fairly good translation of matière obscure. Obscure does have the meaning you mention in the video but it also means "something that emits few light" or dark.

[@markcohen7991]

You are truly the best. Carl Sagan and Michio Kaku, I have followed for years. You are now in the conversation. I love your book Space and the Speed of Light. LLAP 🖖

[@michaelc3810]

Dr. Becky, I have a question, if I may. Given the existence of Dark Matter is inferred from its observed gravitational "attraction", why then does it not appear to coalesce to form "dark stars"?

[@rudra62]

Thank you for your simple, concise, explanation of what dark matter is. It seems that it's not this weird mysterious thing - it's just stuff that doesn't glow. Now, of course, just what that huge amount of matter that doesn't glow or reflect or interact with light is, is a much larger and more complex question - and well above my pay grade!

[@swjackson2]

This video really underplayed the importance of Vera Rubin, who did the most accurate surveys of galaxy star rotation speed vs the expected speeds for a large number of galaxies and observed what is said to be the first direct evidence of dark matter. I've seen several dark matter documentaries over the past 20 years that clearly point to her as the main person. Could her role have been overplayed by such documentaries? She must have done something to get an observatory named in her honor that has a 28ft diameter monolithic primary mirror and a 4 gigapixel camera!

[@yashrajmehta3602]

You have explained the timeline quite clearly in a easy to understand manner.. Thank you!

[@georgecarr9561]

I am hoping someone can confirm. My understanding is that while the density of matter in interstellar and intergalactic space is quite low and extremely low, however the volume of space between stars and galaxies respectively is so vast that the mass of the matter in these mediums can become quite large.

[@kjkellogg]

I’m very impressed with your knowledge Can’t wait til your book arrives

[@elbenny68]

Thank you Dr. Becky for this genius compilation on DM! 😊

[@kaptainkrunch593]

your pronunciation of "matière obscure" is so cute i can't handle it :p

[@vrajpanchal4088]

The way you say "TINY", thats really cute and at 27:27, there should be a GIF for that😆😂😂

[@miss_lisa]

Fascinating discussion. Love your vids...two areas i'm surprised you didn't cover in more detail. First, how do we get estimates of mass from the amount of light and is there room for error in this calculation, especially given the changing estimates for the expansion rate of the universe. Second, how much does the discovery of super massive blank holes at the center of galaxy's explain?

[@khalidomar1381]

Definitely one of my favourite episodes to date!! great job

[@robinwinsor4392]

One of your very best Becky. Well done!

[@PFCMackG]

so glad i decided to watch some of your older videos! I snort laughed when you said "It's AMAZING!"

[@willinwoods]

23:22 "'Half-a-Ken?' Well, that's a funny name, inn'it. [takes another look] Oh...ok." Excellent exposé btw, I will be recommending this to all my friends and aquaintances until they explicitly ask (tell) me to shut up about it! And I usually don't get or use audiobooks, but I have to say I'm extremely tempted to get yours by now. Keep it up Dr., you're quite a fabulous educator!

[@suryahitam3588]

This is a fascinating video! Learning about the path scientists took to believing there is such a thing as dark matter is a great way of persuading doubting lay people of the likelihood there is such a thing.

[@thecynicaloptimist1884]

Me, reading the thumbnail: "How dark do we matter know exists?" Joking aside, love your videos, Dr!