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0:00
what's going on my friends welcome back hope you're all doing really well and surviving this whatever this is this existence can be brutal so hang in there going through rough times especially if you're studying physics it can be tough and just hope you guys are doing all right today we're gonna watch some more physics more science check out cal vpn if you haven't already i'm gonna briefly tell you about my other thing that i'm doing it's like so if you haven't
0:25
been watching lately i'm creating two startups one of which i've already talked about go watch the other videos kelvin first quantum proof vpn check it out in the bio and i'm also creating something that might appeal appeal to you guys a bit more it is a square space for youtube creators so maybe i won't say too much more right now but if you want to create a youtube channel this is going to be something you want it's going to help people do what they want so i'm looking forward
0:55
to telling you more stay tuned that one will be developed rapidly uh i'll have much more to say within the next week about that and i can show you some stuff anyway let's get on with the video let's go watch something and we are checking out the largest black hole in the universe size comparison so let's do this the largest things in the universe are black holes in contrast that's you know i don't think you can say any such thing with such certainty because as far as we can tell
1:27
but again i don't think it's correct to say objects i mean things maybe if you said objects it would be more correct but i think the largest things the most massive things in our universe as far as we can tell are dark matter halos maybe the cosmic web itself which is the largest scale structure of dark matter so things like planets or stars they have no physical size limit and can literally grow endlessly although in reality specific things need to happen to create
1:55
different kinds of black holes from really tiny ones to the largest single things in the universe like i mentioned in the last video i did on him the kugel blitz is another kind of way to make a black hole uh but if you want to know about that go watch that so how do black holes grow and how large is the largest of them all it's pretty big and i'll let him explain how they grow and then i'll chip in it's a bit of mystery involved this video will not discuss how black holes work or
2:26
how they form since we've looked at that in detail in our black hole and neutron star series you can check them out afterwards for now we're interested in finding the largest thing in the universe let's start with really small primordial the smallest kind of black holes may or may not exist if they do they're probably the oldest objects in the universe older even than atoms they would afford older subjects in the universe absolutely not that is not true there's uh there'll be you
2:58
know a lot of things older but let's not get into that um i did want to say though you might have heard how there could be a planet nine in our solar system you know well beyond pluto yes i know pluto isn't classed as a planet anymore but there could be something well beyond pluto that has you know a large mass and some people think it's potentially a planet but they're confused as to why we haven't you know potentially seen it but some people think
3:26
it could be a pro primordial black hole and it would have about i think it's like nine earth masses seven to nine earth masses and it would be the size of a baseball size of a baseball with nine earth masses crazy formed just after the big bang when the universe was so dense with violent energy that any tiny pocket that was just slightly more dense than its neighbors could produce a black hole exactly the smallest primordial black hole that could still be around
3:55
would be a trillion kilograms or so the mass of a big mountain and yet they would be no bigger than a proton a primordial black hole with the mass of earth would barely be larger than a coin this makes them very hard you missed the golden opportunity right there because yes if you squash the earth down to the size of a peanut a nut you'd get a black hole uh it's schwarzschild radius if you go beyond that that's what creates a black hole
4:22
theoretically and uh so yeah this guy could have you know used the nut that's his name right in a nutshell earthen and up mr golden opportunity not to find so we haven't actually observed any yet if they exist they may even be the mysterious dark matter he's saying if they exist but i think he should be saying they're theoretical you know they yeah but they could be out there for sure and like he's saying could be could be dark matter but all black holes could be
4:52
you know other black holes could be the dark matter as well so that holds galaxies together
4:59
let's move on to the kind of interesting question for you out there do black holes uh do they eat dark matter let me know down under coals that we know for sure are out there stellar black holes
5:16
okay but even stellar black holes you know like are they really out there because black holes might not be what we think they are and you might be like but dylan we've got pictures of them but that doesn't mean you know that these holes in space-time it could just be something dense enough to you know swallow light doesn't mean there's a singularity inside it could be just something extremely dense um and that would be sad because you know hopefully they are
5:43
way more mysterious than that uh and you know if string theory is correct there are these even weirder things again called fuzz balls yes fuzz balls the most violent things in the universe in string theory are potentially called fuzz balls which is like you know this string theory right so you've got these large strings and they're all like mixed up together and i think uh from memory they they uh have a solid surface but i think anyway we'll have to
6:12
go look into that i haven't read about those for a while good name for a pet black hole
6:19
so that it collapses into itself after that the more mass we throw at it the larger it becomes in today's universe only the most violent cosmic events can create the necessary conditions such as the merger of neutron stars or when the core of a very massive star collapses in a supernova to have a unit to work with here we'll use the mass of our sun about 2 million trillion trillion kilograms it's a big boy the smallest known black hole has 2.7 times the mass of the sun
6:48
which works out as a sphere around 16 kilometers in diameter large enough to cover paris yes it's not the size of a small town if you crush the sun down to the size of a small town black hole
7:01
another lightweight black hole is the companion to the v723 mon red giant star this star is 24 times larger than our sun 30 million kilometers in diameter and yet it's thrown around by a tiny black hole just 17.2 kilometers wide this tiny thing bullying the star is so much smaller that we can barely even show them in comparison those black holes got that small person syndrome to you know exaggerate a degree but i just wanted to chip in say here i actually named my cat after
7:33
a black hole his name's cygnus uh it's named after the first ever discovered black hole cygnus x1 and there's a funny story behind it stephen hawking and kip thorne had a bet that it either was it wasn't a black hole and the wager was like a year subscription of penthouse magazine or something back then which is like playboy
7:53
classic one of the largest known stellar black holes is m33x7 it currently spends its time eating a separate solar mass blue giant bit by bit as all that stolen matter circles towards the black hole like water going down a drain friction heats it up to temperatures high enough to shine 500 000 times brighter than our sun and yet x7 is only 15.65 solar masses and 92 kilometers wide just big enough to cast a shadow on corsica to grow one of the largest known stellaback
8:30
coals is m33x7 it currently spends its time eating a 70 solar mass blue giant bit by bit as all that stolen matter circles towards the black hole like water going down a drain friction heats it up to temperatures high enough to shine 500 000 times brighter than our sun and yet x7 is only 15.65 solar masses and 92 kilometers wide just big enough to cast a shadow on corsica
9:01
black holes have to either devour a lot of stars or better merge with one another the instruments that make it possible to detect these mergers are very new so we're currently discovering a lot of exciting things like two massive black holes that we detected in a galaxy 17 billion light years away as they spun around each other violently they released more energy in the form of gravitational waves than the combined light from all the stars in the milky way in four
9:29
thousand years the new black hole they formed is about the size of germany and is a hundred and forty i liked how in these little animation it was like warping the actual fabric of space-time as well that's what happens uh it's crazy they drag around the fabric of the universe itself
9:49
new solar masses and here we hit a curious gap in scale there are lots of black holes up to 150 solar masses and then there's nothing for a long time until we suddenly hit black holes that are millions of times more massive which is a bit confusing because we had this idea that the black holes are consistently growing and growing but for the most massive black holes this process is not fast enough to explain their existence today the universe is simply not old enough
10:21
for these curious gap is probably we just haven't found them yet uh we think there's something like 100 million black holes in the milky way alone everywhere i hope that doesn't scare you though um but there was something else that's going to say that yeah these supermassive black holes are curious things because we really don't understand how they got so big and how they got so big so quickly because they got big very quickly we'll come back to this i'm sure he's going to touch
10:47
on it massive black holes to have formed by eating stars and merging with each other something else must have happened to explain how we got the largest black hole we think everything can in the universe grows hierarchically you know from two things and they merge and becomes bigger right everything's gravitationally bound in the universe we might need the largest stars that ever existed quasi stars to get a sense of scale we can compare them to the largest identical things
11:17
today our sun is like a grain of sand next to them we they're not normal stars they're really cool right now this quasi-stars actually existed but they're an interesting concept when it comes to supercharging black hole development the idea is that the matter in the early universe was so dense that quasi stars could grow to thousands of times the mass of our sun the cause of these stars might
11:41
have been crushed by their own weight so much to actually collapse into black holes while the star was still forming in contrast to stars today that would destroy themselves in the process inside quasi-stars a deadly balance could emerge gravity pressed the supermassive star together feeding the black hole and heating the material falling in to such a degree that the radiation pressure
12:02
kept the star stable and so these quickly growing black holes might have been able to consume the quasi-star for millions of years and grow far bigger than any modern stellar black hole black holes several thousand times the mass of the sun and wider than the entire earth these black holes might have become the seeds for supermassive black holes yep and uh you know in that early universe obviously everything was a lot more dense the universe was smaller things were closer together
12:34
uh there was just you know a lot of gas that was closer together and so you could imagine that you know through gravitational you know everything coming together some stuff might have just collapsed in on itself and created these huge black holes because it was so much you know so close together now everything's a lot bigger the universe is expanding it's accelerating in its expansion the black holes have probably consumed a lot of that early stuff
12:59
not a lot but some of it at least you know because it's important to recognize that in galaxies the supermassive black holes make up like a really really small amount of the the mass it's crazy
13:13
i can't remember the exactly it might have been like 0.1 or something but anyway
13:18
so now we arrive at the kings of our universe the largest there is in existence there is a bigger the centers contain a supermassive black hole and they are monstrous in the milky way we have sagittarius a star a supermassive black hole with about four million solar masses that is calm and collected so i think it's a little bit inaccurate to show
13:43
them differently like this like look it looks different to the last one but this big boy would also have an accretion disk and look just like the last one um and we just took an image of it as well you know christians just does its thing we know it sits there because we can see a number of stars being thrown around by a seemingly empty spot and despite its incredible match brilliant woman won a nobel prize in physics for basically you know looking at how all
14:13
stars at the center of our galaxy they're all like moving around in this complex pattern and there must be some huge amount of mass at the middle of it and supermassive black hole in the middle of the milky way i can't think of a name right now but yeah it's a cool little thing its radius is still only 17 times our sun smaller than most giant stars but millions of times more massive because supermassive black holes are so massive and located at the center of galaxies many
14:43
people imagine them as being a bit like the sun in the solar system an anchor that glues everything else together and forces it into an orbit but this is a misconception while the sun makes up 99.86 percent of all the mass in the solar system supermassive black holes usually only have zero point zero zero one percent okay that's what i was saying i was a little bit off it was zero point zero zero one not zero point one lexi crazy the billions of stars in galaxies gravitationally
15:12
bound to them instead it's the gravitational effect of dark matter which holds them together
15:18
okay many supermassive black holes there's a lot of darkness in galaxies that are holding a lot of them together uh because otherwise they would just kind of fly apart
15:31
anyway see when they're feeding on the clouds of mass in their galaxy the one at the center of the bl the 30 galaxy is devouring so much material that it produces jets of plasma accelerated to nearly the speed of light if earth were orbiting this huge body it would seem 115 times larger than our sun in the sky and we'd be burnt to a crisp in seconds by its glowing hot accretion disk at this point black holes become so large that stars seem ridiculously tiny compared to them
16:02
the galaxy cygnus a has a supermassive black hole with 2.5 billion solar masses and 14.7 billion kilometers wide which would mean that if it took the place of our sun it would swallow all the planets and stretch halfway to the edge of our solar system it's devouring so much mass and material that it turns its disc into a kind of magnetic funnel spewing gas out making tremendous radio lobes towering over the galaxy half a million light
16:30
years in diameter that's two and a half milky ways wide another pretty large supermassive black hole sits in the galaxy messier 87. it has 6.5 billion solar masses and was the first black hole we got an actual photo of or rather of the glowing gas around the edge of a menacing shadow this sphere of darkness is so large that it covers our entire solar system and yet there is a scale even above these kinds of objects extra ultramassive black holes
17:09
now we reach the most massive black holes perhaps the largest single bodies that will ever exist these black holes have eaten so much that they've grown to tens of billions of solar masses their gravity the engine for a quasar an accretion disk shining brighter than thousands of galaxies full of stars unbelievable so massive that they deserve a title of their own ultra massive these are the ones that our theoretical models our simulations of the universe of cosmology
17:38
really struggle to we i mean we can't really find them they black holes just won't grow this big and so there's some some stuff we're missing whether it's you know some mechanisms we're missing or you know the baryonic physics the physics of the stuff you know we can see
17:55
where we could have some things wrong you know like i said i think earlier you know our understanding of gravity could be wrong dark matter might not even be real it could be something like uh modified newtonian mechanics who knows we it seems like there's some problems and like the dark matter stuff you know it might not just be made of one kind of thing that could be like an entirely new standard model of different dark matter stuff or even multiple like who knows
18:24
poles the ultra massive black hole at the center of galaxy oj287 is 18 billion solar masses it's so big that it has a supermassive black hole nearly 40 times larger than sagittarius a-star orbiting it like i said uh actually i'm not sure if i said it earlier but these quasars only exist in the early universe they don't we don't see them anymore around us there's lots of dead galaxies around us now where star formation is stopped
18:54
um they're not really forming any new stars and the quasars or the supermassive black holes aren't igniting their accretion disks like they did in these in the early universe uh and
19:08
i just wanted to add these black holes that he's talking about you know we find them in the very early universe it's like how did they get so big so quickly it just doesn't seem like there's enough time for them to grow to this size hierarchically there must be other mechanisms
19:23
um just like like i was saying like you know the clumping together really quickly and collapse of stuff could potentially explain it but in our models it still doesn't um so it is a mystery so if you're interested in this stuff you should go get involved help figure it out and you know even the galaxies at this early time they got so big so quickly and then they started um quenching which is what we call like a kind of like a dead galaxy essentially um
19:53
we see quiet galaxies in the early universe and we really can't explain it but anyway let's keep going this thing defies imagination and is really hard to compare to anything it can comfortably fit three solar systems side by side inside of it let's end this insane competition and get to the king of kings ton 618 a black hole that we can observe consuming galaxies worth of matter is shining with the brightness of a hundred trillion stars visible from 18 billion light years away
20:25
it has an incredible 66 billion solar masses a black hole so large that it would take light a week to reach the singularity after crossing the event horizon about 11 solar systems could sit inside of it side by side wow it may very well be the largest single body in the universe it has like 40 billion solar masses this one but in reality it's probably even larger since ton 618 is so far away we only see what it looked like 10 billion years ago in any case
20:56
black holes are only like three and a bit you know billion years after the big bang it's crazy scary and mysterious and gigantic they'll be here after everything else dies and growing larger and larger okay now let's do the trip again from the smallest possible black hole all the way up to the largest
21:24
uh yeah like i said they probably should all look fairly similar wow okay there's the earth
21:34
and we're already beyond what we can comprehend secretaries a the center of our milky way
21:42
very big now there's the largest star
21:49
there's the first image
21:52
really big now nice
21:57
beautiful try something new today we can call it behind the lies a short behind-the-scenes bit about the necessary inaccuracies in this video because it's not really actually possible to rank black holes like trading cards how so well while we've catalogued millions of stars we really only have good data on a couple of dozen black holes that's because black hole gazing wasn't i'm glad he's going into this this is really great
22:23
until 50 years ago and technically still isn't because we can't see black holes we can only derive their properties from studying their gravitational effects on the matter around them like the orbit of stars that come close to them this effect depends on the mass of the black hole which we can approach now we have the images as well so some direct evidence but yeah he's exactly correct these things are still they're radicals the way they work
22:49
we still don't understand level with kepler's laws but this comes with huge uncertainties and error bars then we have to convert mass to size next which brings new uncertainties for example we calculated the radius from the mass using the schwarzschild equation which for the sake of simplicity assumes black holes are perfectly round and don't spin a kind of black hole that doesn't really exist the reality is that physics on these scales is a bit fuzzy so some of the black holes
23:18
we talked about here may be way smaller or way bigger we just don't know for sure we shimmered around this problem by comparing different sources with different kinds of values and using different mass calculations to arrive at a standardized list that allowed us to be as accurate as humanly possible you can look at all of this in our source dock as a result this script was written with the tears of experts we drove crazy with our obsession for the best values they could live with
23:46
in this process tons of stuff got cut and didn't make it into the final video but luckily we found a way to not waste all of it we've created a lot of black hole merch spanning the whole range from somewhat bonkers to more serious this way we get to explore a topic from different angles and you get to continue having fun with black holes after that okay so i don't think they were
24:10
going too in depth with the research but i'm sure they looked through different academic papers i just say that because a lot of people doing the actual work in the in the field on this stuff they want to spread the actual communication of it so they um you know write media articles so yeah i'm sure these guys just were able to found find information collate it uh i just also want to say
24:33
i feel like this guy should win some huge award in science communication or this team because these videos are truly amazing maybe even like there should be a thing like the nobel prize in science communication i think that would be actually awesome and i think it might be a thing in the future because science communication is just as important as the science itself came up with this thing the other day science communication is the science what human senses are to the universe so
24:59
it's very important anyway that'll do go check out this guy's videos i'll catch you next time
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