Next step: spectroscopy → cusp or core?

34:08>> Mhm. >> We need to do more spectroscopy. We don't have that data right now. All we have is phototric data. What we'd have to do is figure out the >> the spectra to figure out the red shift and the blue shift and all of the really nittygritty details of what that dark matter clump looks like. Because what we'd expect given that there's no stars is there's no smoothing out. >> And because there's no smoothing out, right? Then the >> we should have a cusp. We should have a higher density of dark matter in the center and we should have low density out in the in in the in the outside. We shouldn't have this flattened profile where in the middle there's just a bunch of dark matter, but there's no real big

34:49over density right at the center, right? there's no like clump of dark matter that's super dense in the center. So that is that would be the case if we accept the current models of lambda dark matter which is lambda CDM which is the idea that dark matter is some kind of particle. It doesn't interact with itself unless >> it's through gravity >> and now we get a cusp. If we see the cusp great >> right >> okay if we don't see the cusp what does that mean? So, so what we're saying is as we go out and get more data like spectroscopy data, >> um it will further clarify is there a core or is there a cusp?

35:29>> Yes. >> And if there is a cusp, >> then we're good. >> Great. This lambda CDM well done. >> Yeah. >> The experimental data is now further validating the theory. Mhm. >> If it continues to be a core, which is kind of what we it appears to be. >> Yeah. It appears that like >> it appears that way. >> Yeah. >> Then we got to go look back at the drawing board a little bit. >> Yes. Then we got to be like, what exactly is dark matter? Is dark matter really just like another particle like a proton or an electron. That fine. The only thing that's different about it is it doesn't have any charge and it doesn't interact with electromagnetic field. It doesn't interact with light.

36:09Right? That's that's the normal thing. And that's like like naively I would expect that it's just another particle but it doesn't interact with light which is why we see its effects across giant time sc giant scales of the universe but not like you know nitty-gritty stuff. >> This one is pretty cool. There's something called fuzzy dark matter. This is very different from lambda CDM. Okay.