Is dark matter made of black holes?

We can’t see black holes. We can’t see dark matter and we don't know what it's made of. So what if the elusive dark matter is actually made of black holes? Primordial black holes to be precise. This is an idea that has been kicking around the astrophysics world for 30 years or so - but how realistic is it? And how we do we even figure this question out?
Macho Collaboration et al. (2000) - arxiv.org/abs/astro-ph/0001272
LIGO collaboration (2016) - dcc.ligo.org/public/0122/P150...
Bird et al. (2016) - arxiv.org/pdf/1603.00464.pdf
Clesse & García-Belledo (2016) - arxiv.org/pdf/1603.05234.pdf
Munoz et al. (2016) - arxiv.org/pdf/1605.00008.pdf
15:51 - Image credit: Julian Muñoz
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👩🏽‍💻 Dr Becky Smethurst is an astrophysicist researching galaxies and supermassive black holes at Christ Church at the University of Oxford. drbecky.uk.com rebeccasmethurst.co.uk

[@SoleaGalilei]

Dr. Becky: This idea has been around for 30 years. Me: Ah, since the 70s. Dr. Becky: Since the early 90s. Me: $%#(&, I'm old!

[@Pow3llMorgan]

That's exactly what I thought. Somehow, the idea that the 90's are only some 10 years ago seem to haunt me.

[@franz-helmuthorhauser9398]

The Idea that our world is round as a ball ist also old, even some centuries older yet. Ideas live forever so to say. And that ist not so bad because even a bad example may be helpful sometimes.

[@unnamedchannel1237]

Yeah I had the same thought....

[@rogeriopenna9014]

The idea Earth is a sphere is actually 24 centuries old. And I mean written ideas and hypothesis and discussion about it, since it was probably somewhat common knowledge for any sea faring civilization, used to see tops of mountains appearing first over the horizon. In fact, 350 years BCE, the Greeks had already calculated with very good precision the size of the planet, and that knowledge survived the fall of the western Roman Empire and by the time Spain and Portugal kickstarted the Age of Discovery, it was pretty common knowledge, among any cultured European, not only the Earth was round but also its size. What was not known wasd the existence of the New World, thus the Atlantic was rightfully considered TOO WIDE for any ship to cross and reach Asia before the crew died of thirst and hunger.

[@RedRocket4000]

@@rogeriopenna9014 Correct it was flat was the common man belief and any uncultured Noble as I have seen reports some were illiterate. Columbus's math error in his claim of a smaller world got the mission funded. The process that the Greeks used to calculate the size is interesting forget the name though and doing that math without a zero is something else. All the while a better spot to try a crossing was along the North Ice were fish could be found and ice melt for water, yes risk of collision but better than open Ocean stab. Some better research they would have found tales of landing on the New World because of being thrown way off course. And the Norse people were sitting on the information there was land there that most of them did not know but it was recorded. At a minimum their west sailing history should have been checked. I don't call the Norse New World info a discovery as discoveries require the information to be published widely. And it is a discovery for Spain and the rest of the old world. Just stating Columbus discovered the New world for the old world should settle the you did not discover us for us arguments. Love to make Columbus day a two day thing first day the day of Acknowledgment were all ethnic groups admit to the wrongs they and their leaders did. Acknowledge because you actually cannot apologize for any action you or your current nation has not taken. And making that clear should help ethnic groups more forthcoming in their leaders and themselves errors and atrocities. And day two day of celebrating each groups heroes and the people themselves ignoring the bad that was covered day one. So those of Aztec background could acknowledge the huge atrocities day one and celebrate the fantastic civilization day two. Columbus would be condemned day one for atrocities that actually got him fired as Governor in the New World and the bad effects of the discovery. Day two those of Europe can celebrate the bold effort of discovery he made even if foolhardy and the massive benefits to the Old world from it. Note very few Western native groups can actually say they would not have done the same as the Europeans if the shoe had been on the other foot. Wars for territory and atrocities was the norm. Only major lie of interactions was the Whites were civilized otherwise all sides with a few exceptions were savages. It helps to understand racism better if you study how the early centuries of European conquest were not racist in nature as in example you can't say the Spanish treated the Dutch better than they did those in New World see Sack of Antwerp and many other cases. There was still white slaves in Southern Europe and Serfs a form of slavery common many places. But as Western civilization developed people started going slavery is Wong , raping burning and killing is wrong when you take a town, spreading small pox deliberately as done many times in Europe vs others in Europe is wrong. So then some made efforts to say those of different skin color were not fully human. One example first wave of slaves to North America were brought as indentured servants to be freed in seven years but then it switched to slavery.

[@michaelhoffmann2891]

Electrical Engineer: it's a software problem Software Developer: it's a hardware problem Particle physicist: it's primordial black holes Astrophysicist: it's an unknown particle Douglas Adams: it's an OPP (other people's problem)

[@JB-ym4up]

I had network issues with a computer ages ago. The software guy told me it was hardware, the hardware guy said it was software. I had them both sent up at the same time unbeknownst to each other. Then I said hardware or software it better be working when I get back from lunch. Weird thing, it worked. Another weird thing, they never ever gave me a line of crap again.

[@RedRocket4000]

@@JB-ym4up Loved that you actually may have given them the tool needed to solve it as well as they bounced ideas off each other. Radical idea of yours put everyone involved in possible problem in same conversation on how to solve it.

[@richardengkraf7040]

Q: How many computer programmers does it take to change a light bulb? A: It can't be done, it's a hardware problem!

[@andrewharing2637]

He called it an SEP - Someone Else's Problem. Get the terminology right at least.

[@michaelhoffmann2891]

@@andrewharing2637 oh no! I shall now kill myself honourably. I read it years ago and in another language. I bet you're fun at parties!

[@KonekoEalain]

I love how you explain complex ideas in a very relatable way, I always learn something new from your videos, thank you!

[@zapfanzapfan]

Leave it to Canadians to build a radio telescope in the shape of a half-pipe :-)

[@busybillyb33]

Skateboarders: It's free real estate!

[@AnimationGoneWrong]

And it's carefully guarded by Canadian Cobra Chickens... so DON'T mess with it! :-)

[@kidmohair8151]

and your problem is....? (that's not agro...just a feeble attempt at humour....and just b/c I can.....sorry)

[@calamusgladiofortior2814]

Well, we already had a telescope in the shape of a hockey rink, so it seemed the next logical choice, eh?

[@antonioarroyas7662]

I love the design, it's relatively simple, cost effective and just works. What would be really neat is if another nation built one on the other side of the planet so we could gather twice as much data.

[@freddiefox.]

"That was done waaay back in the nineties." 😂😂😂 Time is relative, Dr. Becky.

[@brucelovejoy9435]

Thanks so much for laying this all out so succinctly. For an amateur, but enthusiastically interested person such as myself, while I am all too aware that my mathematical skills are not sufficient to fully understand all of what you are saying, I like to think that I can at least keep up with the concepts you are dealing with, and I very much appreciate your sharing of these ideas in a manner that I can get a grasp of. I look forward to Wednesdays as "Oo, I got some cosmological learning to do today!" days. Cheers! ( and Thanks again very much for your efforts!)

[@johnm.v709]

If U R Mathematician Here is the true one kzbin.info/www/bejne/pJ_Op6J_fd-nhtk

[@ButzPunk]

I hope I live to see humanity learn what dark matter is made of, and dark energy too, for that matter.

[@patrickkirby7612]

And by then, people will be si much more intelligent, that love and compassion will solve almost all existing ignorance, hate, poverty, crime, etc. I ONLY WISH I COULD BE MY GRANDCHILDRENS GRANDCHILDREN LOL.. Well maybe grandchildren's children.

[@patrickkirby7612]

K Dr Becky, no disrespect to your mate, or children....but I'm in looooove with yooooou. I could listen to your brilliant minds, thoughts, and voice for daze. Ha! Get it? Daze? I keep forgetting what your talking about...sigh

[@patrickkirby7612]

Crazy i thought of these hypothese and wondered if others had..LoL Flattering to hear her tell all my thoughts and fun to learn from her. Teach me wose one. Teach me everythiiiing⭐💚⭐💚⭐💚⭐💚

[@benjystrauss2524]

Dark energy is probably the repulsive effect of gravity on large scales. Not a lot of people like the idea, but it seems to be the most logical. (At least to someone who spends a lot of time fixing software bugs)

[@grafgeo9194]

I hope to see us learning about the dark matter too many human hearts are made of... But yeah, science! I know it sounds evil, but i am curious about for example what climate change or A I will work out.

[@jeremyspayne]

really organized discussion of a super-complicated topic which kept it super-accessible. thanks!!!!

[@michaeldean4712]

When you said "..way back in the 90s..." I suddenly felt quite old. No worries, though. I am old. Keep up the great work.

[@zacktoor1591]

IKR? The 90's feel like yesterday to me.

[@worldofameiso5491]

Michael Dean Age is all relative...

[@dwayne7356]

Half my life was before the 90s. But when the age of the universe is measure in billions of years, 3 decades is nothing. Might as well have been 5 minutes ago.

[@gdwnet]

The 90's where when I finished uni and started work. So long ago..........

[@rjonboy7608]

What dichew say? You young whipperschnapsers always schomplaining...

[@jamessharier7529]

I have no degree doctorate or otherwise but I always enjoy watching your videos, I love the way you explain your topic and your enthusiasm is most refreshing.

[@DrBecky]

Thanks James - glad you enjoy them! They're made for those with enthusiasm 🤗

[@AnimationGoneWrong]

Dr. Becky... presenting subjects such as these would normally make my head spin... but you manage to explain things in a way that not only make sense, but the majority of us can actually understand! Is there not a Nobel Peace Prize for that??? There SHOULD be! You make astrophysics accessible to the masses (that's us regular folk, not black holes or "prime ordeal" black holes). THANK YOU!

[@dwightk.schrute8696]

I was going through prime ordeal today and this video saved my evening :)

[@Aleonore22]

Very clear and educational, I am happy to have found your channel !

[@rosellabill]

She is brilliant. And uses basic language so everyone can understand. Her books are great also.

[@BothHands1]

amazing video as always, ty Dr Becky!!!

[@t.c.bramblett617]

You're so great Becky!! Thanks for this and all you do.

[@middleway5271]

OMG I love these videos. Prefect for Sunday morning coffee!

[@iris7750]

You make my day ❤️ I watch your videos when I feel down, the way you passionately talk about things you love, gives me hope in this dark times. 🤗😊

[@xnnui]

"Way back in the 90s" oof I feel OLD -_-

[@sgillespie1190]

Love your presentations! Thank you for sharing

[@fermin7c1]

Dr. Becky , I just found your channel and let me tell you, I haven't enjoyed someone talking about physics this much since I found Richard Feynman. So yeah...you know what that means.... I subscribed

[@DrBecky]

Welcome 👋

[@xBris]

8:05 - You label Alcor and Mizar as a binary star, which is - as far as I know - wrong. While they are a "naked eye double", they are in fact a 6-star system, which is an even more "fun" fact ;)

[@jamesmcarthur1229]

I bet your level of smugness and self satisfaction looked like the American corona virus infection rate graph that you got to tell DrBecky she'd made a mistake 🤭

[@johnnyrivas2619]

@@jamesmcarthur1229 calm down, she even "liked" his comment. The best scientists can not only tolerate being corrected, but they welcome it. xBris was just stating a fact.

[@MemoAkten]

I'm so glad to have discovered this channel, your videos are awesome! And I've been wondering this exact question, thanks for answering it so clearly!

[@DrBecky]

You’re welcome 😇

[@sanjchiro]

Superb and up to date discussion. I love the shirt too!

[@francoislacombe9071]

I have read somewhere that those larger than expected black holes could form as ordinary sized ones in the dense star clusters orbiting supermassive black holes. In that environment, they have the accretion disk of their mega sibling to feed on, as well as a much greater probability of encountering each other and being captured into the mutual orbits that result into mergers. This would explain how they could be so massive, they merge much more often and have vastly more gas to feed on than your average stellar mass black hole.

[@meskahmusic]

Are you trying to outdo Curious Droid with your shirt game? Nice palm trees by the way :)

[@MorRobots]

Must be an Oxford thing

[@ianalanneilgrant4626]

She has a gargoyle too: kzbin.info/www/bejne/f5jQfKNmgNGoirs

[@jimtuv]

I know it's probably a dumb question but I was wondering; Do gravitational waves experience a Doppler shift and if so could that be used to verify the expansion rate of the universe?

[@bbbl67]

Yes they do actually experience doppler shifts. The only problem is we don't know what their original frequencies should be. Unlike with light, we know what frequencies various elements would emit light at, we don't have that same reference point for gravitational waves.

[@G360LIVE]

That is far from a dumb question. Here's the way I look at it: If I can picture Neil deGrasse Tyson getting excited over answering your question, then it's not a dumb question, and I think Neil would be super-excited to answer a question like that. :) Excellent answer from bbbl67, by the way. :)

[@Linshark]

@@G360LIVE Indeed, a very good question.

[@DrunkenUFOPilot]

Yes, definitely. Any kind of wave, any pattern of matter/energy moving along without changing shape (or just very little). Over cosmic distances, just as with light, wavelength gets longer with farther objects. We won't know the original frequency in any simple way. But the intensity helps. A strong wave we might assume is "closer" at least cosmically, and therefore the Doppler change is small, and from the frequency and details we might deduce masses for a pair of black holes, at least a first estimate. From simulations we know what the frequency and intensity should be, if we assume GTR to be true. Circular reasoning must be avoided! The point is to match simulation results with observations of frequency, intensity and details of the wave's shape. Doppler can be accounted for in simulations, so we have an expectation of what the wave should look like for any given masses, spin orientations, and distance from us. Sometimes when you have expectations, you find what you're looking for rather than what is. That was an early criticism of LIGO data analysis. We have enough separate observations now for that concern to have faded. Not enough data yet, though, to help pin down Hubble's constant, but I'm expecting that with a few more years of observation, and with new instruments starting up.

[@Linshark]

@@DrunkenUFOPilot I wonder if there are any attempts to find the Hubble constant already. Edwin Hubble inferred his law from incomplete data in 1929.

[@peterstrong772]

Nicely explained, I'm not keen on most of the videos out there that say this is what they are, so there, attitude, but you have explained what we really do and don't know in a way that makes it understandable.

[@petebrandon8160]

Thank you Becky! You are a source of wonder and delight - pretty, charming, fun, jokey, awesomely intelligent, a brilliant explainer, perfectly balancing so much information, so many alternative explanations, so many papers and results, - awesome lady! Keep them coming at us! I never tire of watching your programmes - even when there is much that I don't understand, you are always able to put the science across so that I really really WANT to understand 😊😊

[@robertholmes6348]

Science with a smile! My favourite topic! 😃

[@godsbeautifulflatearth]

Lies, lies and fantasy.

[@bruceyboy7349]

GOD's BEAUTIFUL FLAT EARTH What's the alternative?

[@suvamyadav2943]

A question " imagine there are two entangled particles away from each other and one of them falls inside a blackhole, does it effect the other in anyway?" ps: love your videos!

[@kindlin]

You're confusing what entanglement is with the popsci version. All entangled means is that the knowing of one particles conserved property (say, spin) lets us know the others. You can't transfer information with this, it's just a simple consequence of the universal wave function. The black hole does to the entangled particle what it does to all particles, gobbles them up. Measuring the spin of the non-gobbled particle tells you what the spin would have been for the one the black hole ate up if you had been able to measure it, but that doesn't actually change anything about the situation.

[@kindlin]

@spaghettarius a Is this in response to my post? You didn't seem to reference my post at all but you replied to my post. Maybe you meant to reply to the OP. I think you are answering it in a very similar way to me, that something being entangled doesn't change anything about what happens when it crosses a black hole. In fact, everything is entangled with everything else all the time, look up quantum darwinism for a possible explanation on how superposition, etc. gets perpetuated up to the macroscopic level, where things look classical and nonquantum. Time stopping and infinities happening at the event horizon is more of a problem of coordinates, not an actual feature of a black hole. Most physicists (something which I am not, this is just a hobby of mine) don't really believe in the firewall theory, but some do. No one actually knows. Also, hawking radiation is often misunderstood and is actually something that happens to all objects in spacetime, and is caused by and happens within the curvature of spacetime surrounding a black hole. It would just be more pronounced given the extreme curvature surround the event horizon.

[@kindlin]

@spaghettarius a Interesting reply, and yes I have previously understood basically all of what you are talking about, but I think you are taking some of the math and understanding too much at face value. GR/QM are necessarily incomplete as they do not work together, and some of the fundamental assumptions of one or both of them must be incorrect (I think that's likely GR, but no one knows). First off, it's now believed that information that falls into a BH is not lost, this is a new mathematical discovery in the last few months and the consequences of this are still being debated. Energy is not lost either, but is also conserved in general only because of time translation symmetry, and weird stuff with time does happen in a BH, so energy may not necessarily be conserved in the literal sense at all points in a BH (I don't know of any saying this, but it seems possible). I'm also a little confused about your discussion of time approaching a black hole, because we're always moving forward in time at c, unless we're traveling very fast in space. And the weird thing about a BH is that it's space (or spacetime) itself that is traveling inwards towards the BH at the speed of light, and one should be able to be considered motionless even as it's sucked into the BH, as you're just following what the space you're sitting in is doing. From an outside perspective, you know that you'll know that you don't ever see anything actually reach a black hole, but your a local frame, the black hole event horizon is nothing special. Also, as I understand it, time and space don't literally swap and time definitely isn't going backwards or acting in a freely traversable way. It's just that within the black hole, your only possible destination is the singularity, and not moving toward the singularity is as impossible as traveling backwards in time, so space acts as time and time as space, but it's all still 'normal' in truth. Sean Carroll has been putting together an amazing set of videos called The Biggest Ideas in the Universe which has really opened my eyes to many of the false popsci interpretations of technical physics.

[@kindlin]

@spaghettarius a ​ Well, motion is relative, right? So if you were in deep space and seemingly not moving, you could claim to be traveling through time at c. Actually this is an interesting thought experiment, because only by comparing clocks with someone else would you recognize any potential motion. It seems like you could define the singular stationary reference frame as the frame that has the fastest moving clock relative to all other frames. I wonder how this plays out in our universe? Anyways, even if you don't ignore the inherent motion of our planet and sun and galaxy, we're still just moving at a tiny fraction of c, like 1/1000th or less, so you are, to a decent precision, moving through time at c anyways. Also, you jump around so much in your comments that I don't get half of what you are trying to say, what parts are in comment to what parts of my comments, etc. Where did space expansion come in and what does infinite density have to do with time besides whatever the weirdness is near a singularity (I get infinite density could be thought of as the opposite of a massless particle, but that train of thought is still peculiar)? And what do you have against your capitalization and periods? FYI: Sean Carroll is definitely not a random youtube video creator, he's a practicing physicist and his videos are very grounded and well put together and actually goes through a lot of the math in GR/QM. Also, I've watched many many many videos on SR/GR/QM on youtube and most do a decent job of explaining concepts to their target audience, at least from what I've seen. There are always nutters out there, but I don't watch those ones, and you can typically tell pretty quickly if they have any actual idea what they're talking about.

[@malyuki39]

You explain things so clearly 🌸

[@rejecteddriftwood314]

Love your channel! I've been trying to binge watch your videos, but my brain is starting to hurt! So I'm going to have to space it out! Lol

[@embyrr922]

I wonder if there being so many more intermediate mass black holes than expected could be due to direct collapse being much more common than previously thought, rather than primordial leftovers. At least that was my first thought as a layperson. 🤔

[@bbbl67]

I thought the same thing, but if direct collapse was so common, then all of our galaxies wouldn't have all of these heavy elements forming so quickly after the Big Bang.

[@RobertMolan]

bbbl67 sorry could you expand on that?

[@JM-yd7rq]

Or, the Big Bang produced trillions of planet-mass black holes each the size of a sugar cube.

[@RobertMolan]

@@JM-yd7rq it may well have, but they shouldn't exist now. Or at least that's what our current understanding says.

[@bbbl67]

@@JM-yd7rq Direct collapse BH is not the same thing as primordial BH, though they are produced in similar ways. The main difference between them is that primordial BH was produced by the immediate aftermath of the Big Bang, while direct collapse is just a big star that skipped the supernova stage.

[@RedBatRacing]

We know it's there, we know it's dark, we know it matters

[@alyoshakaramazov8469]

Great explanation. I love the watch!

[@Bazzo61]

Really enjoying this channel after finding it some weeks ago. Now addicted :-)

[@DrBecky]

👋 welcome

[@turbocayman8047]

I like your "Florida" shirt!

[@inerlogic]

This video needs a trigger warning.... my Echo Dot was triggered and started talking about black holes when you talked about the CMB as an "echo" Also, can we have t-shirts with the graphic from 15:39 on the front and the words "Get Bent" on the back? 15:50 great... now the dot is reading me the FRB wiki entry.... i need to change that wake word.....

[@kindlin]

Never heard of an echo dot before. No one can put enough warnings about the various things people quip about without there being a 5 min disclaimer at the start of every video, just something individuals have to adapt to.

[@kindmartin]

amazing videos Dr. Becky, fresh/kind,/spontaneous, massive attractiveness towards astrophysics I ever watched anywhere including university times. It would be fantastic if Dr. Michio Kaku takes you for an interview in the future on kids' education/support. You also inspire me more to support my kids in their studies/careers/job decisions. thanks from Argentina, the lucky at southern hemisphere who see our Milkyway AGN directly in his glory ;-)!

[@b.d.s.socialadvertisingand6055]

Good morning Dr. Becky. Besides being delightful you seem to put fun into Physics. I'm 62 in Ohio, USA. Thank-you for making a very complex conversation interesting.

[@AV8R_Surge]

@2:00 Dark matter is made up of sugar and spice and everything nice. @3:56 Microlensing: like during an eclipse.. just before the moon fully covers the sun? @4:52 "what do you call a blind deer?" - no eye-deer 😉

[@jimmyc6066]

NO!! Snakes and snails and puppy dog tails!.

[@onehitpick9758]

Way to pick up on the microlensing smoke and mirrors. Not many would be able to realize this. We can't even see the nearby white dwarfs (including their microlensing), even though actually emit quite a bit of light relative to a BH, without an extremely sensitive system like GAIA. So the presumption that we should be able to consistently detect accurate microlensing is ridiculous.

[@kindlin]

The sun is curving light around it as do all massive objects (even light objects, just anything with 'mass'). The point of a lensing event (micro or otherwise) is that the light from a much further object is deflected on multiple sides of the intermediate object, smearing it out and simultaneously amplifying it. Same underlying mechanism, sure, but entirely different measurable outcome.

[@kindlin]

@@onehitpick9758 What are you talking about? Do you not believe that gravity bends light? Do you also not believe that glasses bends light? You have seen glasses and telescopes, right? I'm sorry to insult you so, but you sound like a flat-earther, trying to call out 'big science' for perpetuating some 'myth' that you, in your infinite wisdom, have deemed unreasonable. And I have no idea what you're going on about with nearby white dwarfs. Care to explain further such that I can help shed some light on your confusion? Also, microlensing would be detected only when an object, BH, rogue planet, etc., passes in front of another object we are viewing, and we essentially see the object twinkle. I'm not sure what this has to do with nearby white dwarfs.

[@onehitpick9758]

@Just Looking Find all the shiny white dwarfs before even claiming you can count the micro-lenses. Gaia just turned up many in our own neighborhood.

[@ericarrington808]

What if black holes destroy matter and break it down into the simplest form of matter aka dark matter

[@morto360]

I dont know anything about this stuff, but I did hear recently from a video that black holes do "evaporate" over time... so cant it be that what ever they give up from them while shrinking IS dark matter?

[@ericarrington808]

@@morto360 according to Stephen Hawking it's Hawking radiation being expelled from black holes. BUT since dark matter is basically only able to be theorized that's kinda what my thought is as well. In my head it makes sense that the matter that's being taken in by black holes is actually being expelled as dark matter, but just like the majority of theories it's a whataboutism and I don't have the ability/money/intelligence to take it any further than a brainstorm lol

[@nmarbletoe8210]

@@morto360 Yeah... in theory Hawking radiation should include every type of particle. . The wavelength and energy of the particles would be determine by the event horizon radius. The bigger the radius, the longer the wavelength of the hawking radiation, and the lower it's energy. .

[@duderoony]

Another nice little mind bender Becks. Thank you for uploading more for us to digest.

[@Barney1051]

Hi Becky, love your video's and especially this one connecting so many different concepts. I'm wondering if you've seen the paper that came out earlier this year about black matter being made up of data? They are looking to test this with a harddisk weight-test between holding information and not holding information, similar to how a battery is ever so slightly heavier if it's charged than if it's uncharged. Would love to see you opinion on that!

[@bazedjunkiii_tv]

'poofed out'... my phrase of the day.

[@timm4811]

Its a technical term. Made me 😃

[@TheMotlias]

Dr.B: "I know a lot of people don't like waiting" If people don't like waiting then astrophysics isn't for them. Your field reminds me of nature photography or camera men, sitting around for 3 months hoping to have your camera pointed at the natural phenomenon then shouting "quick its doing the thing" *snap snap snap "awww, we missed it"

[@zapfanzapfan]

Astrophysics is like photographing snow leopards in the wild then :-)

[@gordonstewart8258]

Fun with astrophysics. Thank you, Dr. Becky.

[@storage000]

fascinating, thank you Dr. Becky... love that song too "Messages keep getting clearer Radio's on and I'm moving 'round my place"

[@aussiebloke609]

0:18 "Dark matter...doesn't interact with light in any way..." I would think that characteristic would exclude black holes entirely, as they do interact with light - to the extent that they actually trap light and keep it from escaping (which I think would be considered a fairly robust interaction.) From memory, dark matter doesn't directly affect light at all - that is, light passes through it and continues on towards its destination completely unimpeded, or completely the opposite of "doesn't interact with light in any way." PS: That said, dark matter does appear to interact with light - or at least, it's gravitational field does, in the form of gravitational lensing. So maybe it's the original statement that needs to be more modified to "doesn't _directly_ interact with light." Thoughts?

[@karatepop]

It doesn't interact with light in any KNOWN way, specifically.

[@ariochiv]

No, dark matter has to affect light with its gravity -- gravity is the only evidence for dark matter in the first place. Dark matter would lens light passing near it in exactly the same way that black holes or any other matter of equivalent mass would. Lensing observed in the halos of distant galaxies is one of the pieces of evidence used to support dark matter's existence.

[@aussiebloke609]

@@karatepop But gravitational lensing shows it does affect light, at least in that way. This is known, as it's how the problem of dark matter was first found - the lensing effect was found to be too great for the known mass causing the effect. That's why I suggested the defining statement could maybe use a bit of tweaking.

[@bbbl67]

"Interacting" in this sense means absorbing and radiating, i.e. an interaction through the electromagnetic field. An interaction through gravity is not a true EM reaction.

[@aussiebloke609]

@@bbbl67 Gravity is obviously not an EM reaction. However, the definition wasn't restricted to EM reactions - hence my query. You're ascribing meaning that wasn't directly implied or explicitly stated.

[@theCodyReeder]

I’m beginning to suspect that dark matter is a combination of different things; Black holes, hydrogen ice bergs, unobserved particles, etc.

[@jeremyspayne]

absolutely a possibility there is more than one "thing" out there contributing to the mystery ... could be BOTH black holes AND axions.

[@kindlin]

Becky's 20% figure for black holes seemed quite high to me. Get 20% from a couple more sources and we're basically there.

[@jeremyspayne]

That’s not physics ... that’s just story-telling ... fun ... but not science ...

[@TheLethalDomain]

At this point it could be similar to an electron quantum orbital around a nucleus, but in this case the nucleus being a supermassive black hole in the center of the galaxy, and the quantum probability cloud around that "nucleus" is the dark matter, taking different configurations based on the parameters of a galaxy alongside probability. I'm imagining this entirely without proof. But still.... Though perhaps my idea falls apart when realizing there are galaxies where the dark matter has left and the galaxy itself is trying to follow it..... Yet that also seems to be expected if that black hole was entangled to that overall energy state, meaning the center of the galaxy must move in the general direction of the dark matter field it plays a part in agitating. I imagine this would lead to quite confusing calculations and behaviors across the cosmos between different galaxies, as the probability function itself would lead to chaotic patterns of sorts. (and for all we know the vast amount of potential smaller black holes within that galaxy may create further disturbances that throw off calculations) I feel like our measurements of dark matter will become much more "common-sense" to us later when we merge relativity and QM into a single statistical mechanism.

[@TheLethalDomain]

​@@jeremyspayne Hell, we can have fun and say that 2D calculations from anyons are blurring the topological structures upon which we evaluate the geometry of space-time and thus dark matter lies there. The great thing about adding fiction to science is that we can quite frankly go to any depths of the imagination based solely on the allowable unknowns set by our current limits of knowledge within science. I present another idea of what dark matter is below as well. It's likely entirely wrong, just as that "Anyon Interference Conjecture" I literally just now invented is probably entirely nonsense. We sure as hell can have fun wondering though. The problem is when people take their ideas and end up in a realm of unfalsifiable dogma where the person is unwilling to be wrong. You seem like the type of guy that I can throw around crazy ideas with while having us both be self-aware of what we're doing. When the day comes that science presents new testable observations that contradict our ideas, we will update those ideas as such. However, I am also an artist at heart. I see the precious time we have left here on Earth and find enthusiasm in the implications that scientific wonder brings us. If I have children one day, I would want their imaginations to begin at the greatest depths of mystery, as just by happenstance I find this method to provide people a higher potential to derive the natural laws from there. An interest in science is a good reason to pursue actual science. Not only do I want them to investigate these things, but I want then to experience bliss doing so. I am diagnosed with major depressive disorder, and find that this method is powerful even for myself. You'd be amazed to see the journey I went through that drew my attention to quantum field theory. All of it began with mystical childhood wonder about philosophical concepts I had no idea had valid scientific basis. It's worth noting that people like Einstein and Max Planck were more than just great mathematicians. They were visionaries who had wonderous imaginations. They had imaginations that began by challenging the status quo and then derived mathematical proofs for those ideas that also happened to explain just about everything by proxy.

[@honoriosergio5454]

eu moro no Brasil e adoro seus vídeos, são aulas sensacionais de astrofísica!

[@rogersledz6793]

Thank you so much for uploading this video. It is helping me get through the pandemic!

[@annexcelestial]

Hello Dr becky I just got your book in the mail and it made my day...I was hoping that your autograph would have been included but you can't win them all lol...thank you for your channel!!!

[@MrBluebeard3]

Great show , what we don't know about the universe is as interesting as what we do know. It moves me in a pri-more-deal way!

[@Grobulok]

This is a great channel.

[@vishnumthss]

The way you introduce a concept is really good. Please continue to make such great videos! One doubt though: aren't AGN masses much more than 30 x solar mass? So before the detection of gravitational waves, did we have a chasm between

[@gravitonthongs1363]

Dwarf galaxies host intermediate size BH’s

[@minamandal2994]

Ma'am your videos are breathtaking and truly amazing and i would love it if you please...please...please provide updates about the Planet X or the predicted grapefruit sized primordial black hole that you once said in one of your videos that you were researching on....please😁😁

[@samuela-aegisdottir]

I have heard the "dark matter is black holes" theory form PBS Space Time, it was exiting (and scary) idea and I did not kno why it is not discussed more, but you explained also the arguments against, which make it rather unprobable. That is good to know. Thanks a lot fot the explanation.

[@WolfiiDog13]

0:50 - when the "sound" of gravitational waves was palyed I got goosebumps xD

[@quahntasy]

*Very interesting video. I loved watching it. Black holes are going to be always an interesting topic. The more you know the more you don't know about them.*

[@DrBecky]

YUP! Welcome to my life 😂

[@silaw7413]

@@DrBecky could temporal mechanics explain the observations which lead to the nescesity for dark matter/energy? ie. in a void more time happens, so many more virtual particals can pop into existance then annihialate against their counterparts etc thus creating the outward pressure and expansion of space. Transversly approaching the center of a galaxy as the density increases less time is experienced which may explain why the structures hold their shape without overwinding etc. ps. sorry if incoherant, tried to make it brief, Im just a plumber

[@timsullivan4566]

The singing at the very end was my favorite bit!

[@brownbalak4641]

I just wanna ask If I can be of any help, except the mathematical part :P . Because I'm just so mesmerized by everything. Your videos contain references for everything and I thank you for that. Stay Awesome.

[@brianhester1996]

Dr Becky, I saw a piece that surmised that "Planet Nine" in our Solar system may be a grapefruit-sized black hole. Love to hear a comment on that hypothesis.

[@gravitonthongs1363]

kzbin.info/www/bejne/d6HPd4Oqfb5jb6c 🙂

[@brianhester1996]

@@gravitonthongs1363, thanks for sharing that!

[@sayanAcharjee]

Loved this episode 😍

[@50PercentBS]

Loved this!!

[@ninsmeowmeow]

love your channel

[@siddharthsaran5173]

I find your videos are very interesting, please try to make a video explaining string theory

[@cicad2007]

Great video! I always look for you on KZbin! :-) Btw, I saw a post today with a Dr. Becky having her video editing software free trial expiring. I wanted to help, but found out there are a LOT of "Dr. Beckys" on KZbin, Who knew? I can't find the post again. so I have to ask... was that you?

[@DrBecky]

It was yeah - if you go to my community page on my profile you'll see it!

[@cicad2007]

@@DrBecky Oh, dear. How can I help? Do you have a Patreon page? I am a friend and Patron of Tibees (only person I have on Patreon) but I can easily help you. Please let me know, ok? :)

[@roberthogue5138]

You are very intertaining

[@materialdialectics]

That shirt is a win. Black holes, dark matter and fast radio bursts are cool too though.

[@PatrickPoet]

This is so fun:) btw, got my copy of the Yank version of your book, thanks:)

[@Strype13]

If I'm not mistaken, we've very recently discovered the first FRB within our Milky Way, and it just so happened to arise exactly where a known magnetar exists...

[@DrBecky]

Yup - did a night sky news video on that back in June 👍

[@phila8226]

Great show Dr. Becky. How do you keep your head from exploding? A lot going on in there.

[@tulmar4548]

Ooh I just finished a 65 page thought experiment about space/time and this was last question I asked myself before I had a break and couldn't get back into the headspace again lol but essentially, dark mater /energy is just space/time . Space with density , time with energy. I'd explain that more here but it's not so simple and takes some writing lol anyways , it's all just fun to think about.

[@surendrapadamata2123]

Hi, It's a great video. Thank you for sharing few references on MACHO and dark matter from LIGO too. Microlensing of FRB, that's an interesting idea! Will have to check it out. At 7:43, 8:29 and some other times, you said that the masses of BH formed after a supernova explosion would be 1-3 solar mass. But I would like to point out that typical mass of BH after a supernova explosion is something above 5 solar mass not 1-3 solar mass (please correct me if I am wrong). As you may have heard, there's a lower mass gap (which I don't think something fundamental and will be removed) between 3-5 solar mass where there are no detections of such masses of compact objects have been made in anyway astronomically. It's also tough to make neutron stars below 1.4 solar mass (at least through supernova simulations). I should say we don't yet understand supernova explosion mechanism to firmly say anything but yeah the typical observed masses of BH is above 5 solar mass in simulations.. As you know Chandrasekhar limit and TOV equation tells that objects with masses above 3 solar mass (not rotating) typically form BH but not something below. Even then also to point out, we don't yet understand the 2.3 to 3 solar mass range properly.. But yeah I completely agree with primordial BH being in the mass range from microns to few times the mass of the Sun.

[@bbbl67]

Yes, I also heard that most most stellar mass black hole remnants are thought to be in the 5-10 solar mass range. Most neutron stars are supposed to be in the approximately 1-3 solar mass range (actually more accurately in the 1.4 to 2.2 solar mass range). And then there is a mass gap between 2.2 to 5 solar masses which we have not seen too many of yet.

[@surendrapadamata2123]

@@bbbl67 Yes exactly! But I also want to point out that we have observed neutron star with mass around 1.14 solar mass! So it should be 1.14 - 2.1 solar mass till date observed.. But yeah the 1.14 Mo Neutron star is hard to explain using supernova explosion mechanism..

[@bbbl67]

@@surendrapadamata2123 Yes, there have been some neutron stars detected below the Chandrasekhar Limit of 1.4 solar masses. They are hard to explain, usually involves some kind of very high spin rates on the original progenitor star that produced it. But I think below that mass range, a neutron star is unstable, it can't hold its mass together as a neutron degenerate matter because it doesn't have enough gravity.

[@surendrapadamata2123]

@@bbbl67 Theoretically, from the TOV equation of hydrostatic equalibrium, you can get neutron star masses even of 0.11 solar mass or less. But can they form astrophysically, probably not but don't know for sure.. On the other side, Well if there was a high spin initially on the progenitor then I think it would rather form a heavier neutron star then a lighter one as there will be extra support from centrifugal pressure. If it's very very high, I don't know.. I personally didn't see any such studies which involved such very high spins, it may break up mid way before forming..

[@oceanlawnlove8109]

Yesss successful found another great space channel

[@apophis1337]

I just read an article on Planet 9 being hypothesized as a primordial black hole a couple of days ago and such black holes could be responsible for the dark matter. Your video clarifies it well. Thanks!

[@DrBecky]

Yup 👍 did a Night Sky News video on that a few months ago - such an exciting idea that the solar system could have a pet black hole ❤️

[@nonomiconone9124]

You are so fantastic! I think you’re the reason this universe exists.

[@tiago4561]

ngl, I only clicked the video because that title just broke my mind Your video is really good though

[@bsa45acp]

Interesting comment at 3:16 as it almost parallels a 'saying' in medicine which is that 'Lack of evidence is not evidence of lack.' It is logic which applies in many areas.

[@3756hans]

Yet atheists turn that upside down and consider " Absence of evidence as evidence for absence(ie non-existence)"

[@Nilguiri]

​@@3756hans Do you realise how ridiculous that sounds? It means that you believe in something for which there is not a scrap of evidence! You are the ones that believe in magic and atheists are saying is, show us some evidence and we will believe it. The burden of proof is upon you to show evidence for your claims of the existence of gods. you are the ones turning things on its head, not us. Do you believe in literally everything until you are shown evidence of its absence? That is an absolutely illogical, ridiculous and cynical misrepresentation of what atheism is and says more about you and your lack of knowledge about the way logic and the universe works than it says about atheists. If I told you that there is an elephant living in my fridge. Presumably you believe that? If not, why not? If you looked in my fridge and found no evidence of there having been a giant elephant in there, not even footprints in the butter, or piles of elephant shit, that would be a pretty good clue demonstrating that there never was an elephant in there. In other words, absence of evidence, in this case at least, is evidence of absence, isn't it. You haven't thought this through, have you? If I claim that there is an elephant in my fridge, then it is up to me to provide evidence for it, like a photo, or video, or several hundred trustworthy eye-witnesses. Surely if these gods exist, it should bot be that difficult to provide some kind of evidence for them? Not only that, I don't think you will find a single scientifically minded atheists who actually claim that absence of evidence is evidence of absence in the case of gods. That makes no sense. What experiment would show that no gods exist? It is impossible! So your whole point is irrelevant. I repeat, you are the ones who claim that gods exit. All we atheists are saying is show us some evidence and we will change our minds. If you find any, I would be fascinated to see it and I will change my mind. I won't hold my breath. One last thing, the vast majority of atheists, including myself, do not claim that no gods exist, although a small minority do, obviously. Most of us are agnostic atheists. Instead will say that due to the lack of evidence, we are not convinced that gods exist, which is very different from claiming that we know that no gods exist. Your short comment demonstrates that you are extremely confused about the whole subject.

[@CodgerBiker]

What’s the difference between Space-Time (presumably the medium for gravitational waves?) and the old notion of ether as a medium for light waves to travel through. Cheers, I always enjoy your channel 👍

[@MCsCreations]

Pretty interesting!!! 😊

[@timmykk1]

Just curious. If gravity is the curvature of space-time, why must there be a particle or other object of dark matter? What if space itself isn't flat, but were to have curves, depressions, or other terrain features that would look for all the world like gravity from an object but simply be a feature of space itself?

[@tommylakindasorta3068]

This is the same question I have about gravity itself. Why do we need gravitons, yo? Is it because human scientists like particles a lot?

[@queenvrook]

My understanding of why physicists introduce the idea of the graviton is that they can't see how "action at a distance" can occur. That's one object affecting another object in the absence of any sort of contact whatsoever. So the Sun can warm us through the relative vacuum of space because it emits photons, which cross the distance between it and the Earth. But if the Earth exerts a continuous pull on the Moon, how? They aren't touching. A billiard ball that passes near another but doesn't strike it also doesn't make it move. Relativity postulates that the Earth and the Moon affect each other by their masses distorting the fabric of space, such that motion in a "straight line" actually follows a curve. In the case of Earth and Moon, the curves bend round to their own tails and we have orbits. But if spacetime has curves that are not caused by the presence of a massive object, that leaves us with a huge number of problems to answer. 1) Why do those dents seem to match up so nicely with the actual mass and location of visible objects? 2) Why haven't we seen an object that seems to be "denting" spacetime more than its mass suggests, just because it's resting in a "natural valley" in spacetime? 3) Why aren't there any visible objects that exert less gravity than we expect, because they rest on a "natural hilltop" in spacetime? 4) Why hasn't the apparent gravity of the Earth shifted over time, as it moves through spacetime? It should randomly fall into spacetime "valleys" and ascend to spacetime "hills" and thus change its gravitational intensity. And if we postulate that the Earth is actually stationary with respect to spacetime, then why haven't the Sun and the other planets done this? Why are orbits so nearly circular, when they can't all be stationary with respect to spacetime at once and they should be drifting into hills and valleys over time? Why hasn't the galaxy dissolved into chaos? Upshot: There are good reasons to postulate gravitons, much of them due to the philosophical problem of how scientists can understand "action at a distance," or objects affecting one another without any form of contact whatsoever. If you come up with an answer to this other than the exchange of particles, you might bounce it off the esteemed author of these videos and see what she thinks. Cheers!

[@tommylakindasorta3068]

@@queenvrook Thank you for the detailed and thoughtful reply. Maybe I'm just not smart enough to understand what's going on, but I still don't see the need for a graviton when the curvature of spacetime by mass seems to explain all the behavior we can observe. If an object with mass always curves spacetime "downward," and surrounding objects "fall" toward it naturally, what would the graviton even be needed for? What would it add to the picture? If the idea is that spacetime can't curve without a particle exerting some force upon it, the particles we know of already do that, as in any particle with mass. Why do we need another, as-yet-undetected particle to explain what we observe? Again, I don't know anything about the subject beyond what's available in popular science books and articles, and I certainly don't have the mathematical skills to follow the equations. But it seems to me that the graviton theory has more to do with people wanting to be able to call gravity an apple because they already have a basket of apples and it would be easier for us to understand if we could add one more apple to the basket. But maybe gravity isn't an apple. Maybe it's an orange.

[@crisdmel]

Reasearchers like Le Esmolar and Le Padaroy have obtained very accurate results for relative particles emitted by black holes.

[@mp6756]

Thanks for the toughts

[@MrKydaman]

Love the video. Lol at the end!

[@hrshovon]

Hello Dr. Becky, please do a video on GRB and possibility of GRBs affecting earth. Should align with your limitless love for black holes :D

[@annasahebpatil1775]

Hey I love watching your videos you are doing great work Also I am 15 and I am really interested in being a astrophysicist and hearing from all perfect maths and physics can you also tell what I can do other than this

[@kevinhanley3023]

Now, I just have to wait. Thank you Becky :P

[@TheGreyfoo]

Hello Dr Becky, thanks for another excellent video. I've always contemplated the fates of hypergiants like UY Scuti with 1700 solar masses - is there a possiblity that 'paired' black holes could be formed when these monsters go supernova? Some kind of dividing force at the moment of big bada boom that splits the mass into a pair of orbiting twin singularities?

[@TheGreyfoo]

@spaghettarius a Oooh thanks for the update. Clearly I'm running on old data (fittingly). Appreciate the fix. Do you think my idea might still be possible though?

[@TheGreyfoo]

@spaghettarius a Oh that's on me, I'm no Astrophysicist, I just wondered if there might be a condition where a massive star, in going supernova, might somehow split freakishly during the collapse and blow two pre-singularities away from each other to become binary black holes. If that's not how space time works and can't possibly happen, then I'm fine with that! Appreciate your response though.

[@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".

[@defel1]

Yes, one can afford to be excited during the ten-year wait to accumulate adequate data, if you are young enough to live that long. For some of us, the time is beyond our survival. Oh, to be younger! Excellent video.

[@mavicinpowys1301]

Hi Dr Becky I love your videos ☺️ I’ve got a question / theory regarding dark energy... you will surely think that it’s completely stupid but I would like to know your point of view if you have a bit of time?

[@Stadtpark90]

Thanks. This was actually something I was interested in, and not some randomly interesting stuff.

[@DrBecky]

You just summed up my entire KZbin experience 😂

[@Stadtpark90]

Dr. Becky you mean, that my comment was pretty low level for being intended as a compliment? To completely drive home my point: I actually derive quite some pleasure from you being more than randomly interesting! - No, seriously: I hope you have had as much fun making the video, as I had watching it!

[@The_Viscount]

I remember discussing this with my astronomy prof. We both agreed someone tried way too hard to make those acronyms, and probably had fun laughing along the way.

[@koldfizzion3762]

You're very cool. thank you

[@kenmunozatmmrrailroad6853]

You’re too good Dr. Becky... too good😀

[@RulioOW]

I have this idea for a long time now and the more I think about it, the more everything seems logical about black "not holes", but we have to start from the beginning: This theory takes into account that there are elements outside our bubble we call the universe (i call them primal elements and maybe these primal elements and our universe, along with other universes due to other big bangs, are inside another primal universe). What if the big bang created multiples explosions in every directions, like a flower with 3D petals for representation, and during the sudden fast expension of its petals(full of fresh dark matter) it caused a reaction with primal elements creating in the process every elements we know (like the "dust" of the primal elements but only existing through dark matter). The petals finaly crushed each other forming chaos, whirls and with time the universe as we know it. (In the moment, we live in the ongoing aftermath of the big bang and everything except dark matter is part of the "dust" of the primal elements). Note that if these petals were of different sizes, the universe would result in a non-uniform shape. Now, imagine that one or multiple or every primal element, in its primal state, is not compatible with dark matter (like oil in water to put it simple), and during the fast collisions of the petals, some primal elements were not destroyed and could not escape therefore they were trapped, compressed, and also could have been separated into multiple pieces by the force of the whirls (like mixing oil and water / mixing primal elements in dark matter during the last stage of the big bang =p). So the black spheres (DEFINITELY NOT HOLES) we can observe, in this theory, are trapped primal elements non-compatible with dark matter causing it to stretch therefore we can not see the primal element but we can observe the resulting outer distortion around it. Note that our universe should have limits and they should be completely black and have the effect of an inner distortion. I can go further and say: if everything existing in dark matter comes from the "dust" of primal elements, then maybe a magnetic effect occurs, maybe primal elements in a black sphere state are attracted to each other. And maybe this is the answer to gravity, maybe primal elements in a black sphere state have also an effect on everything composed of the "dust" of primal elements, everything except dark matter, trying to re-absorb them. So before everything went "calm" in the universe maybe some of those black spheres were small enough and surrounded by too much of the "dust", they coudn't absorb it all, forming celestial bodies until the gravitationnal force is not effective anymore, and past that the "dust" would be driven by whirls until being catch by another black sphere or not. To conclude on black spheres, they generate gravity but they are trapped in the ongoing aftermath spinning forces in the universe, and spinning forces have more effect on them if they formed a celestial body around their core. If you're still here thx for reading, share your thoughts, i hope i've blown your brain in a good way and sorry if it's not well put together, i'm not english. Peace ;)

[@RulioOW]

​@spaghettarius a It's a suggestion in this theory, just like I don't know if any primary elements existed before the big bang but i like to think it did not start out of nothing, sounds dumb to think like that.

[@caloss2]

I think with a bit more work you can get Dark Matter and black holes to fit all the lyrics of "dancing in the dark" by Bruce Springsteen. Still loving the out-take endings thank you Dr.Becky :)

[@bristephens9642]

Great 👍 Question 💯