The King Model - Sixty Symbols

[@adamking9183]

What a wonderful tribute to my father. It is great to see that his legacy endures!

[@Zaddy69wake]

Your father was a legend ! What are you upto?

[@adamking9183]

@@Zaddy69wake who is asking?

[@EasyLifeEntertainment]

He is just showing intrest lol

[@Zaddy69wake]

@@adamking9183 bruh don't get mad. You do you

[@meestyouyouestme3753]

“Glad to see my descendent getting so many likes on his comment” -Adam, the first man

[@balping]

5:31 "If you add up the stars all the way out to infinity, you end up with an infinite mass". It should be noted here that just because of integration limits are infinite, doesn't mean that the value of the integral is infinite: improper integrals can converge. For example the integral of a Gaussian from -∞ to +∞ is famously √π. In the case of an isothermal sphere, this integral is indeed infinite, but only because the density distribution is proportional to 1/r^2, whose integral indeed doesn't converge.

[@alimanski7941]

Since he's discussing the distribution of velocity in the cluster, wouldn't the gaussian be normalized, and thus integrate to 1? You're talking about the specific Gaussian integral, of exp(-x²), whereas the standard normal distribution is normalized by 1/√2π.

[@lukasschmitz9030]

But the integral of 1/r^2 from e.g. 1 to infinity does converge...

[@MK-13337]

@@lukasschmitz9030 Since we are using r^2 then I'd guess we are dealing with a multivariate function and then the integral will not converge.

[@balping]

@@lukasschmitz9030 That is true in 1D, but I too should have been more careful, because what you want to do is evaluate the integral of 1/r^2 over all volume, that is (in spherical coordinates): ∫0→2π ( ∫0→π ( ∫0→∞ (1/r^2 * r^2 * sin(θ) ) dr ) dθ ) dφ = ∫0→2π ( ∫0→π ( ∫0→∞ (sin(θ) ) dr ) dθ ) dφ = ∫0→∞ 4π dr This diverges even if you choose lower limit r=1

[@einsteinwallah2]

@@alimanski7941 he is discussing the distribution of velocity as well as making a statement about distribution of number of stars at distance r from center of cluster ... as balping rightly points out this distribution need not be such that integrating over r all the way to infinity all the mass in all the stars in a cluster adding up to infinite mass ... r runs over from zero to infinity and at each r the density of stars need not be proportional to area of sphere with radius r ... if there is "thinning out" then total mass could be finite

[@exoplanet11]

RIP Ivan King. I took his upper division astronomy class at Berkeley. One of the questions on the final exam involved King models.

[@PopeLando]

I knew Ivan King would be no spring chicken, as his paper is six months younger than I am! This video has been uploaded the week of another venerable astronomer passing, Antony Hewish at 97.

[@Fractus]

Apparently he won the Nobel prize for being a party to discovering Pulsars. They should totally do a video on his contribution.

[@exoyt7575]

always a thumbs up for all of Bradies vids !

[@flamencoprof]

In 2015 I was astounded to learn that gravitational interaction between low and high mass stars in a cluster can actually fling the lower mass star right out of the cluster, and that this process was called "Evaporation". I jokingly Blogged that "a similar process to what leads to that dry brown ring in the bottom of a finished coffee, is happening to stars in a cluster, and even to galaxies in a cluster of galaxies."

[@NoNameAtAll2]

that's the reason for coffee ring?

[@flamencoprof]

@@NoNameAtAll2 Yup! Evaporation. Hotter things move faster, right out of the cup!

[@mrsapplez2007]

When you sneak a look at your phone, stick in an earphone and this is what you listen to at work. Saving my boredom. THANK YOU

[@TheInselaffen]

What job can I have where I don't have to be doing my job at my job, please.

[@Triantalex]

ok?

[@x3ICEx]

Why do you make the background flash!? Keep it simple, black please. It's almost distracting enough to trigger one's epilepsy. In hyper-photosensitive individuals, discomfort levels rise noticeably.

[@akizeta]

According to wiki the most cited paper (as of 2014) is a paper from 1951 on assaying proteins by Oliver Lowry, with 305,000 cites. The top ten papers have more than 40,000 cites. But only 14,500 papers have more than 1000 citations. So 3000 really isn't bad.

[@l.ijspeert9040]

Only when he showed the globular clusters did I realize this is the same King model I have used in my master to... model globular clusters.

[@yoloexpectz8637]

Hey, I've seen ppl talking about a new discovery about black holes having pressure. Would love a video explaining it.

[@justin_5631]

He did work that wasn't just classified. It's _still_ classified.

[@mscir]

Do you have any more information about that?

[@InternetStranger476]

You would be suprised by how much benign stuff gets classified

[@kreynolds1123]

As the stars in a cluster exchange energy over time, you might expect that the lighter stars get higher velocities and "evaporate" (for lack of a better word) from the cluster as they get tidally ripped from the edges. If so is this stealing energy from the cluster and should we expect that the cluster will get more and more dence?

[@PetraKann]

What a strange condition to impose on a post-doc researcher. I am not surprised that the jib was turned down. Very unscientific and unprofessional to exclude the discoverer of a new phenomenon or new knowledge from being a co-author in a published paper. Looks like they were looking for a slave rather than a post dic researcher

[@dav1dsm1th]

Jocelyn Bell Burnell enters the chat.

[@formolzinho]

There is a "legend" about the military imposing some rules because the HST had something to do with the KH-11 Kennen satellite project and a lot of secret data involved.

[@iTeerRex]

Beautiful modeling! Great tool to have in the tool box.

[@iTeerRex]

@8Truth Seeking Yes, that “stuff” was invented to fix problems, but now people are treating it as if it’s real, without a shred of evidence.

[@iTeerRex]

@8Truth Seeking By the way “trust the science” takes us to another topic, but I won’t mention it. Lol I trust you know what I’m talking about.

[@majorproblem8796]

@8Truth Seeking ok flat earther

[@majorproblem8796]

@8Truth Seeking Your argument makes no sense you’re just saying that things you don’t understand aren’t real. Believe what you like, don’t push it on others.

[@johnpawlicki1184]

What about using a model incorporating escape velocity as with one star and the remaining cluster is the other body? Stars moving at escape velocity or higher relative to the rest of the cluster would simply leave the cluster.

[@chrisg3030]

Prof Merrifield seems to be saying that stars do leave the cluster, but probably only when they venture too far out and get whipped away by the gravity of the Milky Way, which is why in fact a globular cluster typically has a sharp cut-off, a tidal radius. He doesn't seem to consider that some stars could also be escaping under their own velocity. I don't know why not.

[@sahilshah4141]

Could you do a video on Thanu Padmanabhan? He passed away recently...

[@samcottle]

Can you guys do a video about fusion?

[@thejll]

Ivan also wrote an interesting paper on the shape of point-spread functions.

[@JandCanO]

I'm taking an astrophysics course and now I wonder if we're going to cover this

[@michaelsommers2356]

Assuming it's an introductory course, I would guess not. Such a course would probably not discuss globular clusters in any detail.

[@mcvrs1223]

After 2 years, was this topic a part of the course?

[@c.s.hayden3022]

Beautiful problem solving.

[@dibenp]

6:14 I see what you did there, Brady, and I approve. 😁

[@stevenjones8575]

Why do globular clusters not flatten into a disk, like galaxies (bigger scale) and solar systems (smaller scale)? I get that stars rarely collide, but galaxies also composed of stars still manage to flatten out.

[@cobblebrick]

I think it has to do with the fact that there is a lot of gas present in galactic scales. The gas molecules colliding with each other helps dissipate the translational kinetic energy but not the angular momentum. This can be seen within our solar system too. The region of the solar system which had the highest amount of gas and dust has planets with the most coplanar orbits (the inner planets), and the orbits get more and more inclined as we head outward until we arrive at what is essentially a spherical distribution of bodies. Globular star clusters don't have a way to dissipate the momentum of their constituents in various directions. Galaxies don't have to flatten into disks either. Many galaxies are elliptical, and they usually have a lower gas content.

[@stevenjones8575]

@@cobblebrick That makes sense. Thank you.

[@shruggzdastr8-facedclown]

Cross-referencing an episode of Numberphile, does this King paper have an Erdös number, and if so, what is it?

[@Zeuskabob1]

I didn't realize that the HST was so dodgy on initial launch! Was that a result of the faulty gyroscope they had to replace? Nope! It was because of their mirror, which was out of round by a whole 2200 nanometers! Sounds like not much, but that was over 200 times outside their design criteria, and resulted in results at least 10 times worse than they were going for. According to Wikipedia: "the fact that the mirror had been ground so precisely to the wrong shape led to the design of new optical components with exactly the same error but in the opposite sense"; they couldn't replace the mirror so they made optics to precisely solve the problem without changing the mirror geometry. I wonder if this is another example of a metric/imperial issue? It's not like they'd grind it so precisely wrong if not. The HST actually had a lot more problems, and the mission to repair it required 5 extra-long EVA missions! What an incredible risk NASA took to repair Hubble and what incredible astronomical discoveries it's made since!

[@whitcwa]

The error had nothing to do with metric vs US customary units. It was an error in the test setup while grinding. NASA did not have a way of testing finished mirrors of that size, but the USAF did. I heard they offered to test it, but NASA felt it would cost too much and was unnecessary.

[@gusbisbal9803]

There was a particular instrument called the Autocollimator. It is the element that directs the grinding. It was off and because it was assumed to be super accurate it was not checked. Hence why the check is what was considered out. But in fact it was the Autocollimator.

[@whitcwa]

@@gusbisbal9803 It was caused by an incorrectly assembled null corrector, not an autocollimator.

[@TheGodlessGuitarist]

I'm probably way off in my thinking but the idea that stars are "ripped away" from the cluster beyond a certain limit because of the gravitational forces of stuff outside of the cluster doesn't make sense to me as an explanation for the shape of GCs. The gravitational forces in any particular direction away from the GC will vary hugely and so if that was the cause of 'trimming' at the outer reaches of the GC then surely GCs would have very eccentric shapes rather than being globular. Even if you factor in cluster rotation you would still get eccentric cluster shapes rather like clay on the potters wheel. Anyone else having trouble with this?

[@dhavalbhalara7261]

Wondering what would be the night sky look like if you are in the globular cluster? I think it will be too bright that it would have cast a shadow ... Can they ever come to conclude that universe has galaxys in it as sky would be like completely homogeneous...

[@michaelsommers2356]

They would still be able to see the Milky Way, which would demonstrate conclusively that the universe is not homogeneous on the scale of a galaxy. Also, once they figured out how to measure distances, they would see the true picture.

[@dhavalbhalara7261]

@@michaelsommers2356 Here on Earth when we lookup to the sky without any equipment - most of the stars are part of the our Milkyway - and yet Milkyway (where our solar system is placed) is far less denser compared to these clusters - wouldn't they experience too many bright stars in the night? Wouldn't this brightness obscure Milkyway Stars? Would they obscure other Galaxys? I mean when I see this clusters and put my self in center of it - I found myself totally surrounded by densely packed globular stars wiggling everywhere... I might be wrong- just a curious human who had enjoyed countless nights sleeping under these beautiful heavens during childhood with my siblings - making stories and what not. I remembered our imagination were quickly get wild everytime 😆

[@michaelsommers2356]

@@dhavalbhalara7261 Stars in globular clusters are typically about a light year apart, although they can get closer. At such distances, stars would just be points of light. If you were there, you would not see a solid wall of light.

[@dhavalbhalara7261]

@@michaelsommers2356 oh! My mind can't comprehend such vastness of space...I thought it's densely packed by looking theses images. thank you for explanation!

[@Michael75579]

@@dhavalbhalara7261 Stars are small enough and far enough apart on average that you're unlikely to get any stellar collisions even when two galaxies collide. The Sun has a diameter of 4.6 light seconds and the nearest star is just over 4 light years away. Even if you count passing within the diameter of the solar system as a collision, you've still only got a diameter of around 11 light hours (taking the edge as the average distance of Pluto)

[@awkweird_panda]

Love this guy.

[@AdamHill42]

I wonder what the average shape of orbits is - in the universe, if you align eccentricities so they don't cancel out. With that constraint it must be off circular, but how much?

[@piedruickz1033]

3:10 Does it relate to fluid movement, turbulent in the room vs laminar in space?

[@ratandmonkey2982]

great video !

[@will2see]

11:05 - Are you sure about this? "Almost entirely dominated by the mass of the stars,..."

[@thestruggler3338]

Hmmm I thought the plank length was meant to deal with the similar problem of isothermal (non spherical) black body.

[@1schwererziehbar1]

The fastest observed star (8% light speed) is S4714, which is at the center of the Milky Way. So the story checks out.

[@chaotischekreativitat9391]

🤔 how exactly is this related to the video? Given the supermassive black hole in the center of the Milky Way, the dynamics should drastically differ from the presented model. After all, even for those globular clusters that it tries to describe, it should suffer from ignoring the varying masses of stars (if I understood the argument from 10:01 onwards correctly)

[@thegodofhellfire]

So fascinating!

[@owenspears8662]

From a Layman's perspective it seems a bit convenient that dark matter and Dark Energy play Vital roles in shaping the density distribution of temperature of the Universe on the galactic scale but somehow dark matter and dark energy can just be ignored when it comes to globular clusters. It seems a bit convenient.

[@AplaTaSpaw]

Why isn't anyone commenting about the laugh at 10:55? This is the proper reaction you would expect from a physicist when dark energy is mentioned.

[@craigcollings5568]

I wouldn't have started with a gaussian. I would have asked what velocity distribution does a bunch of ellipses make?

[@alnilam2151]

What goes up must come down per se: to know one must live first; and second will be the time it motions takes or swallows in order too attempt understanding that which is? It's not all fun and games when someone gets hurt: who knows what then & where's the model for it???

[@shantanubharvirkar7759]

Damn, mike did PHD from Harvard

[@nicovandyk3856]

Yeah, I was thinking a DC offset

[@Richardincancale]

It’s nice that globular clusters should be simple(ish) - but why should they get away with not being affected by Dark Matter ?

[@pas.]

because they are very small and very light, yet dense (compared to galaxies). dark matter (as far as we know) only interacts through gravitation, and since the cluster is light it doesn't attract much dark matter, nor is it attracted by dark matter much. and since it's compact and pretty homogeneous (it's a sphere) the effects of gravity on it are basically also homogeneous (so if a dark matter "cloud" is near the cluster, the whole cluster is attracted). so basically DM cannot really disturb the structure. (because it'd need compact DM things that can get into the cluster, but - as far as we know - DM can't really accumulate in a dense compact thing, because it cannot shed its momentum through collisions, so it ends up just orbiting the center of mass and very-very-very-veeeeery slowly dissipating kinetic energy through gravitational effects - but so so so slowly because the system only radiates gravitational energy if it's spherically "lumpy", but dark matter tends to form a big boring spherical blob - smoothed out by gravitational tugs)

[@chrisg3030]

Could our universe be a globular supercluster with a tidal radius set by a superverse?

[@sycodeathman]

No

[@RUBBER_BULLET]

I usually refer to SAGE's Covid predictions as a 'king model.

[@hackbyte]

Yay, added to playlist ;)

[@Baggytrousers27]

It seems like the graph would end up looking like you cut off the the bottom of an egg.

[@alexdemoura9972]

there is an engraving of Rio de Janeiro with Christ the Redeemer on the top shelf by the window

[@benquinneyiii7941]

The normal or bell curve

[@kingstoler]

3:39 ASMR

[@shaunnichols4664]

13:00 Aliens

[@ucngominh3354]

hi

[@lennykoss8777]

💗

[@Ana_crusis]

another 60 symbols vid is always welcome of course but...we haven't heard anything from prof. Moriarty for a while Brady: give him a buzz

[@kwanarchive]

What a strange ad-hoc post-doc rule. Really blows any argument out of the water that science is based on merit and apolitical.

[@hannesgranlund8838]

I dont really think scientists really believe science is based entirely on merit and is apolitical, but they kinda have to assume that it is because it wouldn't really work otherwise.

[@kwanarchive]

@@hannesgranlund8838 Oh there are plenty, believe me. You can argue with them on Twitter, even. I've argued with a biologist who dismisses any notion that science is not a meritocracy, and views that any effort to actually get there is actually an attack on actual merit. They shouldn't assume, because that's where science goes wrong. There's no reason why the practice of science can't itself be studied scientifically.

[@hannesgranlund8838]

@@kwanarchive yeah science should be studied, and we should try to improve it to become more of a meritocracy

[@exoplanet11]

Yes, rules like that go against the general grain of science: discover and share. That's why you hardly ever find them, and why Prof. Merrifield regarded them as an undesirable anomaly. As a professional astronomer, I have only found such rules in place regarding data from space telescopes. Having said that, all data from space telescopes, which are funded by the public, become public, usually after 1 year. So if the scientist who proposed the experiment does not make use of those data, then other scientists, or members of the public can.

[@tim40gabby25]

Smacks of military interference.

[@klausthorn1209]

Why are these clusters dominated by the stars' masses and not dark matter?

[@scowell]

So the collaborators were like Watson and Crick? Yuck!

[@nomadexplorer6682]

Can the phenomenon be Brownian Motion in super massive cosmic scale where the fluid medium is a combination of Dark Energy and Dark Matter ? In our planetary scale, the Brownian Motion collisions are in micro or nano seconds. In cosmic scale, the star collisions will be super massive time scale of millions of years. Our detection instruments are too rudimentary now in this point in time. After all, the laws of physics around Singularity and Event Horizon are not comprehensible now. There is more to unravel.

[@mitchellsteindler]

Doesn't seem like a useful model to me. We understand the physics of large bodies interacting, so I don't see how modeling the system as random would be beneficial.

[@chrisg3030]

3:05 "Stars don't bump into each other"

[@nomadexplorer6682]

@@chrisg3030 Stars don't bump into each other ? Evidence suggests, galaxies bump into each other ! It means at least 2 billion stars bumping into each other! Only, the time scale is different. By the the time all the billion stars have suffered one collision starting with the first one now, few more 100 billion earth years would have passed. A catastrophic asteroid collision with the earth happens once in 65 million years, like the one which wiped out the dinosaurs.

[@JonnyMack33]

Calling him Ivan🤦🏻‍♂️

[@MelindaGreen]

Don't be embarrassed that a model doesn't perfectly match experiment. They're not supposed to match. They're supposed to be simplifications that capture the essence of an idea. A perfect match wouldn't explain anything.

[@richardbrown7970]

So there is no black hole in the center of a globular cluster. Can they grow into a galaxy given enough time and distance from any other galaxy? Please stop doing the artistic thing with images with the zooming in and out or scrolling around, just show the image.

[@phantomwalker8251]

henry the 8th,,had gout ian.. was his doctor..

[@jooky87]

Useless mathematical exercise. Doesn’t predict anything.

[@pauldirac6243]

I love this channel but in the last year every video has been solely on astrophysics? Maybe time to divide the channel?

[@elmirelmir842]

first

[@simengrootjans]

191th

[@cdmacd]

4,846th

[@elmirelmir842]

@@cdmacd great you are ahead of 90% of the watchers

[@Narutofan825]

fifth

[@LuisJavierOcampoAraoz]

psalm 19:1 KJV

[@tostupidforname]

globular cluster sounds like rick and morty

[@jdc1957]

Looks Brownian.

[@Triantalex]

What a wonderful tribute to my father. It is great to see that his legacy endures!