Your father was a legend ! What are you upto?

@@jbzaddy1980 who is asking?

He is just showing intrest lol

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

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

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

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.

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

@@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.

@@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

@@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

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

that's the reason for coffee ring?

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

@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.

@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.

@8Truth Seeking ok flat earther

@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.

Do you have any more information about that?

You would be suprised by how much benign stuff gets classified

Jocelyn Bell Burnell enters the chat.

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.

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.

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.

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.

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

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

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.

@@UseQPixinDune That makes sense. Thank you.

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.

@@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 😆

@@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.

@@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!

@@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)

🤔 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)

No

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)

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.

@@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.

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

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.

Smacks of military interference.

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.

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

@@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.

191th

4,846th

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