Cusp–core problem + why a no-star halo is a clean test

16:57problem. >> Here's the idea. Dark matter does not interact electromagnetically, right? There's no like, you know, electrons, they want to they want to move away from each other >> and protons want to move away from each other. Even when we have atoms, these atoms, you can't just compact them. >> But if you have a particle like dark matter that is only interacting with gravity, >> that means that the closer you get to the center of the gravitational potential, the density should just get higher and higher and higher because gravity is just clumping everything together. There's nothing that's pushing out like when we think about like like hydrostatic equilibrium and things like that but there's nothing pushing out. So the closer you get to the center the density of dark matter should be higher

17:38and higher. That is not what we see. We see instead of a cusp which would mean in the center we get like a little pointy. >> Yeah. >> We get a core type where it's like at the center the dark matter density sort of flattens out. >> Interesting. >> That's weird. >> That is weird. If dark matter is purely gravitational, why would it just >> flatten out? >> It it could should be continuing. >> It should continue to get bigger and bigger as it gets closer and closer to the center. The density should be higher and higher. That's not what we're seeing now. Okay. The defense that the um lambda CDM people make, like the guys who make the cosmology model and they're drinking the Kool-Aid, right? They're like, "No, well, there's something called berionic feedback. This is the

18:18idea that towards the center of the of the galaxy, there's a bunch of supernova explosions. >> Okay. >> Okay. And that supernova explosion is going to send shock waves in spaceime. And those shock waves are sort of going to diffuse the center of that galaxy. So even though the normal dark matter would create a cusp. Yes. Right. Because there's so many explosions happening in the center of the galaxy that's going to sort of flatten out. Right. Kind of makes sense. >> Right. That could work. >> Okay. But this is why this particular galaxy is significant. This galaxy has no stars. Basically no stars. >> So there's no supernova expos. >> Right. Right. >> Right. Which means that this should definitely have a cusp. >> I see. >> That is why it is worth studying.

18:59>> So So the CDG2 >> Mhm. >> it's interesting because >> Yeah. And by the way CDG2 CDG means candidate dark galaxy for for those Oh >> no. My Siri is >> I'm trying to figure out what someone is, one of the intelligence agencies is apparently trying to hack our phones at the moment. >> Um, but this is interesting. So, there's currently a cosmological model >> of normal matter, dark matter, and dark energy. Like what is the composition of the universe? >> Yeah, >> that model has two problems that we just talked about. The missing satellite problem and the cusp core problem. the the folks who are in defense of this

19:42lambda >> CDM >> CDM believe that supernova explosions is the reason that we don't see a cusp. >> Yeah. >> Sort of like like you know blurring stuff. >> It moves around. It moves around rather than aggregating it. Let's let's say for example, right? Um the problem is observationally we've now seen something which is the CDG2 that has a very few amount of stars which means very few amount of no supernova explosions. >> Yeah. No one's dying cuz no one's alive. >> So how do you so so no? >> Yeah. So so so this this galaxy can now offer a test to your lambda CDM. >> So and this is actually an interesting

20:22point about understanding the intersection between theoretical >> sciences and experimental sciences. And the experimentalists are constantly in the real world looking for >> ways to test ways to test. >> You need some sort of stability blah blah blah like something that can be consistently >> measured. >> And we have something now. >> Yes, we finally found something. And we haven't done spectroscopic analysis because this we we just found it. >> That's why it's in that's that's why it's interesting because now we can we can get time on the James Web. Subaru Mellraight. >> And I just want to know because getting

21:03time on these instruments is >> is everyone there's very few of them. Everyone thinks their thing that they're studying is the most important thing in the world. >> But this seems to be because of the importance of dark matter generally as a concept >> a good candidate to be able to quote skip the line. >> Yes. >> Okay. Exactly. And so I want to make a case for why this is important, right? And that's what these people did in this particular um paper, right? The